Technical E Class W210

Technical E Class W210

Mercedes Diesel Injector Advice – Sprinter and others

 

Having rectified many ‘chuffing’ injectors and dealt with the famed ‘black-death’ on many sprinter engines and its close derivatives used across the complete range of Mercedes Diesel vehicles, I can honestly say that the hold down mechanism used to secure the injector in the head is definitely the engines number one Achilles heel.  I am afraid that a single 6mm cap head pin used on one edge of a single steel injector clamp, tapped into an aluminium head is just engineering madness from a commercial maintenance point of view.  Now that’s  out of the way – rant over – how do we best deal with this problem and get that vehicle back on the road.

You will be reading this if you have begun to hear the release of combustion gas from around the engine bay of your vehicle (chuffing) or you may have discovered a black shiny coal like deposit building around one or several injectors (black-death) in addition to lacklustre performance and increased fuel usage. Before we carry on, it is of great importance to bring to your attention that we are dealing with a direct injection fuel system with operating pressures around 23,000 psi or 1600 bar!  This fact is to be remembered when working on a running system, when either fault finding or during rectification – Serious injury may result if you do not respect the obvious dangers involved.  If you cannot identify the dangers of working with very highly pressurised fuel systems you would probably be better to entrust the work to a specialist.

If the ‘chuffing’ has been noticed early on, none or very few ‘black death’ carbon deposits will be seen, just wetness from ejected diesel resulting from the failing combustion process forced up around the leaking injector out to atmosphere on the cylinder head.  If carbon deposits are present then they will have to be completely cleared and chipped away with a blunt screwdriver/scraper and vacuumed away as you go.

Injector Black Death Mercedes Sprinter

Injector Black Death Mercedes Sprinter

Because of the close proximity of other injectors it may be difficult to identify exactly which one is the culprit.  If the leaking injector is not obvious, then clean down the area with Gunk or other degreaser and dry off the area (engine off of course) completely.  Using 2 inch strips of old brown paper cut from the envelopes of your unpaid bills (joke) make hollow tubes and wrap them around the injectors, fastening the ends together with a paper clip. Do this for all suspect injectors.  Start the engine and watch for the darkening/spotting of the brown paper with diesel spray, this will indicate quite clearly where the problem lies.

Once identified the work can begin – Run the engine until nice and warm then turn it off and remove the keys.  Remove the turbo supply hose to the inlet manifold and split the composite intake manifold by removing the pins that secure it to the lower section.  Remove the two pins that are also fastened to engine brackets at the rear and front of the head by the fuel filter.  Lift off the manifold and stuff the remaining open ports with paper/cloth to prevent bits dropping inside.  Check the gasket at the back plate/cover of the upper section of the inlet manifold as this is prone to squeezing out causing turbo boost leak and is this a good time to take a look/plan to rectify.

Remove completely the steel fuel supply pipe from between the leaking injector and the fuel rail along with its injector electrical connector; tie this cable out of the way of the work area.  Remove the long single 6mm torx bolt that secures the injector clamp and place it safely to one side with the clamp itself.  Inspect the threaded portion of the 6mm bolt if it is damaged or showing heavy signs of alloy material deposited on the threads then further action may be needed later on to rectify the threads in this failing all important tapped hole.

The next part of the procedure is ‘make or break’ for the DIY repair and is the point of no return so please take heed.  Try to rotate the unclamped injector, if it moves freely by hand then great, if it won’t budge try a little more force – but not too much.  If it’s seized then at this point re-assemble the engine and take it to a diesel specialist as damage to the injector or head can be very expensive indeed and botched repairs will easily exceed the cost of it being done by a professional in the first place – you have been advised.  If the injector rotates, begin to pull it upwards whilst twisting the body, if it jams, twist it the other way and work it using some penetrant or WD40 in the area around where it enters the head.  In some cases the injector lifts out instantly, in others it can take hours of wiggling and fiddling, don’t be tempted to use hammers or heavy tools to do this job as commonly expensive damage results.  The image below shows damage to a rocker/cam cover caused by levering against it to extract a stubborn injector.

Damaged Sprinter Rocker Cover

Damaged Sprinter Rocker Cover

Once the injector is out, clean it off and place it safely out of the way then recover the single copper washer from the hole in the head that forms a gas tight seal for the injector against the aluminium cylinder head.  Use a torch to inspect the injector seat in the cylinder head, it will likely be blackened and carbonised, this needs to be cleaned off and in severe cases re-cut to present a perfect sealing surface.  I have in the past had great success using a wooden dowel, rather like the ones used on a valve grinding hand tool.  Using contact adhesive stick a square of medium abrasive paper to the end of a flush cut dowel, allow the glue to dry then trim round with scissors.  Pop this tool down the hole and clean the seat as if you were grinding in a valve.  Inspect it regularly and if there are slightly deeper grooves remaining keep going with new paper until clean and flat.  Now the top tip, it will be necessary to purchase a new copper sealing washer.  The best thing to do here is purchase a Honda part in preference to the genuine Mercedes Benz item.  This washer is the standard CDI injector seal used on all modern Honda 2.2 litre diesel engines (More info on the Honda seal – here).  I personally have had great success using the Honda part as they seem to be made from a superior material and appear more compressible thus making a better seal against any slight face imperfections.

Sprinter Injector Seal

Sprinter Injector Seal

If your 6mm torx clamp bolt came away cleanly and without damage, discard the old one and purchase a new item from Mercedes.  This part is a stretch type bolt and once used must be replaced.  The bolt hole has to be spotless and clean and have no debris or metal swarf at its base.  Any solids in the hole will be compressed at the base of the drilling when the bolt is tightened and can cause cracking or worse – bursting through into the water jacket of the cylinder head (really easily done) so clean that hole with an air-line or blow gun until you are sure it’s clear.

Sprinter Diesel Injector

Sprinter Diesel Injector

Replace the injector with its new copper sealing washer, using a slight smearing of high temperature ceramic grease on the body sides and position it correctly with regard the electrical connector, replace the clamp and clamp bolt, fit the new clamp bolt and torque it down to 7Nm then 90 degrees turn to finish – NO MORE.

While the actual MB recommended spec for tightening the hold down clamp bolt is 7Nm plus 90 degrees, plus 90 degrees – 7Nm plus 90 degrees will provide a safer torque to yield on a new bolt in an old head.
The Honda washers are ‘softer’ (unmeasured science, but you can tell) and I have always consciously never bothered with the extra and last 90 degrees crank. Never had any trouble.

Each 90 degree rotation past 7 Nm with a new clamp bolt and clean hole results in a further 0.3mm stretch bolt yield, so my view has always been – softer composition, less crush and a little less beads of sweat on the final swing of the wrench! (Those threads are a weakness) Correct spec by the book with thinner less malleable copper MB washers is 7Nm +90 +90.

The full factual reference write up is here, I always have agreed with the final conclusion that offers this advice and hence never added the increased stress of the final 90 degrees. Obviously the final choice of wether to use the factory torque spec or the modified spec is entirely your choice, but the tests carried out below are well worth a read before you make that decision.

Technical Reference Article:-

Tightening the fresh hold down bolt and seal ring will produce the same clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used.

The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure. Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in ‘as new’ condition.

“Here at the Global Sprinter Research Center I am always eager to investigate Sprinter related technical issues.

Group members have noticed that Mercedes Benz has a published torque spec for the injector hold down bolts that seemingly differs significantly from the long standing DC published specs as shown in DC workshop manuals as well as on the instruction sheets that DC at one time included with replacement injectors. The extended threaded shank length, 85.83mm long, 6.0mm dia., 8.8 grade, factory hold down bolt, hold down pawl and injector seal ring are identical part numbers for both the 5 cyl. and 6 cyl. engines.

Using my ‘test’ 647 Sprinter cylinder head, which is permanently mounted to one of my work benches, I have recently performed tests related to hold down bolt torque. This dedicated ‘test’ cyl head has been quite useful in my repair tooling fabrication.

As many of you know I have developed in-house tools and fixtures for removal of broken hold down bolts, repair to stronger than new stripped hold down threads, and various custom black death repair tools for my in-house use. This test head features my custom carbon steel hold down threads making it ideal for these hold down bolt torque experiments because data is not compromised by any aluminum thread deformation or failure.

After careful measuring of bolt length (before and after torquing) and injector seat seal thickness to 0.01mm tolerance, and using a calibrated Snap-on electronic 1/4 inch drive torque wrench set to display in/lbs and accurate to 0.1 in/lbs, I have the following observations to report:

TRIAL 1– A fresh, factory hold down bolt torqued to 62 in/lbs (approx 7 Nm) and then an additional 90 degrees, results in 0.08mm crush of a fresh factory seal ring.

The Sprinter’s copper seat seal ring features a double convex cross section and the clamping force induced ‘crush’ creates narrow sealing flats on each side of the ring.

Monitoring the bolt torque during the 90 degree rotation reveals a peak of 180-190 in/lbs before full 90 degrees is achieved and remains at this level all the way to 90 degrees. This peak/plateau signals bolt yield has occurred.

TRIAL 2– A new seal ring and a fresh, factory hold down bolt torqued to 62 in/lbs. (approx. 7Nm) and then an additional 90 degrees X2 (FULL 180 degrees), results in the same 0.08mm crush of the seal ring as well as a steady 180-190 in/lbs torque reading during angle tightening.

Being a stretch to yield, non-reuse, bolt it was not surprising to see permanent elongation. Elongation was approx. 0.30mm for each increment of 90 degrees of tightening rotation (after the 62 in/lb initial torque).

TRIAL 3-A fresh hold down bolt tightened to failure. The bolt tolerated several additional 90 degree sequences PAST the initial 62 in/lbs and 2×90 degrees.

It has previously been reported that fresh hold down bolts have failed when several group members had torqued to 62 in/lbs and then 180 degrees (mistaking 1/2 turn for 90 degrees). I now suspect this occurred because of bolt bottoming in the base of the blind bore. Bottoming can occur because of debris at bottom of the blind hole.

CONCLUSION:

Tightening the fresh hold down bolt and seal ring will produce the same clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used. The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure.

Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in ‘as new’ condition.

Be sure you test your cyl head’s bolt hole threads by using a wire brushed used hold down bolt with an indexing paint mark, turning in by hand while counting turns, to assure threads are clean and bore is unobstructed to full depth.  This is especially critical when performing black death surgery.” 

Information source provided with thanks by Andy Bittenbinder 

If you had a problem with the thread you can use this type of kit or as a more desperate measure carefully tap out the hole to 8mm using a long series drill and tap, if you do this you will also have to drill out the clamp bracket to accept the new diameter bolt.  When drilling/tapping take care to not descend deeper in the head than you need to and break into the water jacket.  Sometimes you may find that the previous repairer has broken into the water jacket – add a small amount of silicon gasket compound to the last section of threads of the pin and tighten down in the normal way.  This is not the best way to get out of trouble, but will at least enable you to complete the job.  If you don’t do this and a bolt hole is broken through – you will leak water!!

Now your injector is back together, in the cylinder head and clamped down, reconnect the steel fuel supply hose and electrical connector and build up the inlet manifold and turbo pipework.  Start and test the engine.  The engine should fire after a couple of cranks as no fuel bleeding is necessary.  All should now be well with the repair and you have carried out a major maintenance repair saving you hopefully quite a lump of cash.

More info dealing with the actual removal/installation of the injector and its seal – here

Good luck.

Mercedes front wheel bearing noise – or is it? – Tyre Choice

Here is a little gem of information that as Mercedes Benz owners you may or may not be aware of regarding a common occurrence that has presented itself many times in my personal experience maintaining and servicing MB vehicles.

C200 tyre noise

Correct tyre tread pattern choice will often improve your vehicle rolling noise and in some cases – A switch to the correct type will often ‘cure’ mechanical worn out bearing sounds!

If you are like me and are ‘in tune’ with the noises your car produces in the normal course of driving, you may be aware that tyre choice is fundamental to the quiet running of a vehicle.  None more so than in the Mercedes Benz range.

I recently test drove a 75ooo mile young, C200 2004 model, in excellent condition and I would have been convinced that the noise from the front off side was a worn wheel bearing in the latter stages of its life.  As usual it turned out to be a poor choice of tyre on that corner of the car.  So many times have new owners of used Mercedes vehicles described an annoying ‘drone’ and are convinced it is a worn out rotational component such as a wheel bearing, when actually it turns out to be nothing more than a poor choice of tyre fitted to the car by someone who does not know any better (or the used car dealer fitted any ‘odd pattern’ of tyre to the vehicle to make its tread depth attractive to the would be purchaser).

The truth is that MB make quiet running vehicles and resonances are often heard that would normally be drowned out by road and engine noise in lesser vehicles – that’s why new owners regularly pick up on the odd noises that play above the serene quiet inside their passenger compartment.

The outline details below are from my own findings and experiences, I am neither promoting or slating any manufacturer of tyre, nor am I suggesting that every tyre of certain types and tread pattern all produce the same noise issues, they may not – however, quietly ask a well informed reputable tyre dealer and the chances are that he will impart to you the exact same recommendations.

The worst offending tyre to generate ‘wheel bearing type noise’ on the front of a Mercedes is the aggressive ‘V’ tread pattern that is often seen on modern tyres.  As a rule the cheaper the tyre – the worse the noise!  Their tread pattern looks very similar to this:

V Tread Pattern

V Tread Pattern

 

The next high ‘noise’ offender is the Winter or All Weather tyre, with its much smaller tread features moulded into larger segmented tread blocks placed again in a ‘V’ pattern, rather like the one shown below:

Winter  All Season Tyre

Winter All Season Tyre – Block Pattern

Both of the tread patterns above will more often than not give increased rolling road noise and in some cases a very pronounced ‘humming’ noise on all road surfaces, this often gets progressively lower in frequency as you brake to a halt or roll to a stop line.  A far quieter, better choice of tyre would be ones with a more ‘radial grooved’ tread pattern that rings the complete circumference of the tyre as opposed to the noisy ‘V’ or ‘Block’ sections above. See below for good choice tread patterns.

20130624_172305

Maxxis Economy Tyre

20130624_172320

Pirelli Premium Tyre

 

 

 

 

 

 

 

 

 

 

 

The tyres above represent tread patterns that are far more favorable to the quiet smooth running of your Mercedes Benz vehicle, it does not have to cost a lot to get the best from your tyres, just an informed choice of what style of tread pattern you should be selecting at purchase. Past experience with both the ‘E Class’ ( W210, and  W211 Chassis ) and ‘C’ Class model ranges has proven this time and time again. Often if I suspect that there is a tyre problem or the possibility of a worn wheel bearing I will quickly switch the tyres front to back if they are a different more forgiving tread pattern, to see if the noise changes or disappears.  It often does, and by changing the rubber set up on the car will frequently cure the suggestion of any other mechanical defect.

Try it out for yourself if you are in any doubt, whats to lose? – it could save you some money in unnecessary garage bills !

Mercedes Benz Registration Plate Frame – Installation

Unsure of the outcome of the pending insurance claim on the Mercedes E320 CDI I decided to transfer the registration plates to the Vito to cover me in the event the insurance company declared my car a ‘total loss’ and switching plates became more complex overnight.

Mercedes Vito W639 Registration Plate Frame

Having removed the original plates from the Mercedes Vito I decided to clean up the area and use some new mounting frames for the fresh plates. A quick scan on the online auction sites drew my attention to these.  They seemed cheap enough and of reasonable quality, I thought I would give them a go.  I was skeptical as to whether they would be any use as out of all the reviews of previous purchasers there was one who complained and stated they were ‘rubbish and binned them’ – being objective and not expecting the world for what I was about to pay for a pair, I took the plunge and glad I did!

Mercedes Registration Plate Frame

From placing the order to delivery through the letter box was two days, I was pleased with the packing and the frames looked well when I inspected them.

Mercedes Registration Plate Fixing

To fit the rear plate, open the frame by springing the clips and open it up (hinged). Use a little double sided sticky tape on the back edges and other broad plastic sections to give a nice firm mount when fixed with the two original screw in Mercedes door fixings.  I used plastic screw caps to provide a larger surface area for the screws to tighten down onto the frame.  These did not affect the fitting of the reg plate as they fell below the back plate supports.

Mercedes Benz Registration Plate Mounting Frame

Once fixed, tuck the reg plate under the lips provided in the top of the inner frame.  Pull down the four sprung bottom retainers that have a further lip that secures the plate snugly to the back plate.  Making sure the reg plate is central in the frame, close the door downward and snap the fixings closed.  Job done !  Same routine for the front plate, other than to add extra fixing screws in the extreme four corners to allow a more rigid mounting of the frame – this is really important, as the frame would otherwise get easily caught when washing the vehicle etc.

Registration Plate Fixing Clips

A nice simple task that took less than 20 minutes to complete and I think looks a very tidy job.

Mercedes Vito W639 Number Plate Frame

Mercedes E Class W210 Front Spring Perch Failure – Repair

Take a look at this photograph do you see anything wrong?

Front Suspension E Class Mercedes

On the face of it all looks well, but it isn’t !…..

I had heard a slight groaning noise rather like a worn ball joint for the duration of the return journey from work, it was only apparent at very low speed so I dismissed it as an inspection job for the weekend.  Curiosity got the better of me the following morning and I decided to take a quick glance under the wheel arch before leaving for work, glad that I did when I noticed ‘all was not well’.  I took the van to work and when I arrived home I took off the wheel of the E Class to investigate further.

Mercedes W210 Front Spring Turret Problem

As you can see the front spring perch had pulled away from its mounting due to corrosion.  The groaning noise was in fact the road spring scraping on the inside face of the shock absorber/damper!   I had previously checked these out and all looked good at the last service as spring perches are known failure points with the Mercedes E Class W210 model series.  I had previously strengthened the passenger side perch by plating the area that looked slightly suspect.  Failure of this side was a complete surprise as the perch looked fine under my close inspection last season and I had every faith that it was sound.  Just goes to show…

Mercedes E class Front Spring Perch Failure

What happens is that over time water gets behind the perch seams that are only spot welded onto the inner wing, this corrodes the material from the back.  It is feebly protected from leaving the factory with rubberised grey mastic, applied to all the seams before  the paint process, but moisture gets behind it and gets to work.  The original factory perches are spot welded on their lower ears and then one big spot weld inside the upper cup.  Very poor design. Its not just Mercedes, Ford actually attached their suspension tops to the bodywork on the Sierra model with adhesive !  On warranty claim ‘failed’ cars, Mercedes Benz riveted new perches into place with ‘special’ rivets once they had ground off the original failed part, but in my opinion rivets are no better than poor spot weld.  Next time your car fails its MOT on corroded structural bodywork, see if you can get away with ‘riveting’ a patch over it – I don’t think so.  It is however quite easy to weld strong repair patches to this area using 1 mm steel and it does a great job in securing the perch, as you can choose where to reinforce the design and tie it to much strong inner wing metal in a several places.

W210 Spring Perch Failure

I am not going to dwell on the dire situation that would face a driver if this component completely failed at speed, but thankfully all the reports I have ever read have always been at slow speed and always driver has just heard a large bang, on rare occasion I have also read that the vehicle drops to the ground – ‘wheel inside wheel arch’.  …. Moving swiftly on with the repair…… You will need two jacks !

Stage one, open the bonnet / hood and remove the two 17mm nuts, plate washer and rubber pad that secure the shock absorber damper to the inner wing.  Support the car and remove the road wheel.  Remove the lower damper bolt and extract the damper assembly from the car.  Place a trolley jack under the lower wishbone and support the cars weight so the spring is compressed as much as possible. Remove the 17mm nut from the upper wishbone ball joint and use a lever type ball joint splitter as shown below to split the joint (It’s usually very tight !).

Ball Joint Splitter Tool - Lever Type

Once the upper joint is free, undo the lower ball joint and split it using the lever tool.  Finally undo the steering track rod end ball joint nut from the hub assembly and split the joint using the tool.  Place the whole hub assembly toward the rear of the arch in which you are working, supported on a block of wood, taking care not to stretch or damage the brake hose or cables to the ABS wheel sensor and pad warning sensor that are fitted to the brake caliper/hub.  Undo the single torx bolt from the roll bar link attached to the lower wishbone and move it out of the way.

Spring removal:  The next procedure can be hazardous so take care and go steady.

I have read many E Class Mercedes Benz W210 owners writing that they have ‘easily’ removed and refitted front road springs without even the slightest hint of using spring compressors. –  I have yet to discover how they do this as the spring is very long uncompressed indeed and not easily compressed without huge force – is just too long in its relaxed state to remove on the Elegance model anyway.

So here is how I do it…  While the spring is compressed under the weight of the vehicle (Jack under lower wish bone) attach a pair of simple spring compressors and take up the tension equally on both sides. If you are worried about the compressors jaws slipping round the spring as they choose to do rather dangerously!  Use a handful of fuel line jubilee clips either side of the jaws of the compressing tool, fixed around the spring – this works great and adds a higher degree of safety to the operation.

Once you have tension on the spring compressors, lower the jack beneath the lower wishbone or raise the body (a combination of the two works well) eventually the wishbone will descend enough allowing you to lever it down further and spring out the coil from its lower retainer. Be careful as even with the widest gap between the spring perch and lower wishbone there still may exist some tension in the coil spring. WATCH OUT!   Do remember also to remove the rubber pad from inside the perch that locates the spring – before you start grinding or welding!

Once removed the spring can be wire brushed and painted along with the damper if necessary.

Spring and shock absorber painted W210

Now clean the spring perch area with a grinder and wire brush and remove all traces of rubberised mastic, paint, under seal and rust.  Inspect the area and ascertain what will need to be done to restore the mounting.  In my case I bent the perch back into its original position and tack welded it in place.

Mercedes E Class W210 Spring Turret Repair

I then welded 1mm steel patches to either side of the perch, anchoring both sides of the perch to solid metal on the inner wing.  To add further support and strength I also welded the rear perch lip to the inner wing using a short strip of plate steel.

Welding of Spring Turret Mercedes W210 E Class copy

Once the welding is complete and you are happy with it, use a Waxoyl type spray to coat all the areas you have welded, make sure that all seams are flooded as best you can with a couple of coats of the sealer as this will hopefully prevent further corrosion of the area.  Assemble the spring using the spring compressor method as outlined above (don’t forget the jubilee clips for safety).  You will have to fit the rubber mounting top to the spring before you insert it into the perch cup on reassembly as otherwise it will be a problem to locate correctly.

Welded Mercedes E Class W210 Front Spring Perch

Once the suspension is all back together, paint on further under body protection or add more coats of Waxoyl, you may even spray the spring itself with the sealer as it aids in protecting it from the elements.  Refit the wheel and lower the car to the ground.  Job done ! (Note the slightly larger gap between the top of the tyre and wheel arch compared to the first ‘collapsed perch’ photograph)

Spring Perch Repair Completed Mercedes E Class W210

My Mercedes W210 E320 CDI has taken a bash !

My prized example of luxury motoring has recently taken a bash from a motorist who in my opinion was not paying attention to what was in front of him.  I was only travelling at a slow speed when an approaching car positioned over on my side of the road, took no action to avoid hitting me.  Thankfully I managed to mount the curb a little and at least thwart a head on collision whilst the other vehicle continued without deviation to strike me from the mid drivers door to the rear arch without even braking, eventually stopping some 20- 25m past me!

Amazingly after some research I managed to get hold of some CCTV footage of the incident, briefly showing the impact in question from a nearby camera.

 

Its my guessing that the insurance company will sadly write my car off, although in great condition all round, it is quite old and has a low book value, we will have to wait and see.  I hope not but who knows !

Mercedes W211 E320 CDI Impact Damage

Mercedes W211 E320 CDI Side Impact Damage 1

Mercedes W211 E320 CDI Side Impact Damage 2

Mercedes W211 E320 CDI Side Impact Damage 2

 

 

 

 

 

 

 

 

 

 

I will keep you informed as to what happens…..  I am however expecting progress to be SLOW.