w124 e300 Diesel experiences

mjrose

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Apr 11, 2008
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27
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Newcastle
Car
1996 w124 E300 Diesel Saloon
I thought I would share my experiences with my car, as I have received a fair bit of help from these forums and want to pass something back!

I bought a 1995(N) multivavle diesel saloon six months ago knowing it had been standing for a while and that there was no history. However the 125k mileage was warranted, the engine was strong, and the gearbox felt OK considering it hadn’t been used recently. The bodywork seemed fine (with one or two rust spots in the usual places), the interior was very tidy, and all the electrics worked as they should.

Unfortunately I’ve lots of problems! Although, with one expensive exception most were a relatively simple fix, once identified.

Gearbox – This went badly wrong two weeks after purchasing the car. The box would not shift into 3rd, but given enough speed and high enough rev’s it would shift straight from 2nd into 4th! This did not last and a week later the box self destructed (non repairable). My local independent (Staiths Garage, Dunston, Tyne and Wear) sourced and fitted a reconditioned box. However at £700 this was not a cheap fix! I found that when I got the car back I still had to do a fair bit of tuning to get the shifts right for me. Has anyone else found the throttle position is very critical for good smooth shifts!? I do have one outstanding problem though; the gearbox shifts up too late at high throttle openings. I.e. when I pin the throttle for an overtake, the engine will rev to 5,000 if I don’t ease off. (the previous box changed up around 4,500). I have booked it into my local independent who promises to sort this problem.

EGR – A fault here caused some on/off power cycling at a 55mph/60mph cruise (manifested as jerking, as if you were on off the accelerator). This was traced to an open/close cycling of the EGR valve. The EGR was subsequently disconnected by removing the vacuum line to the valve. The car drove noticeably better after disconnection.

Fuel Leaks – Everywhere! In the plastic lines, on the shut off valve and now (I think – not fixed yet) from the injector return lines. These have been a bit of a pain but easy to fix. The shut of valve was replaced by a plane bolt from an earlier car (freebie from indy).

Inlet Manifold – This was very dirty! A combination of the soot from the EGR, and the crank case ventilation fumes which enter the inlet tract just before the com chamber. The fumes from the CCV had turned the soot to gunk, almost blocking the centre inlets. Cleaning this out produced a MUCH smoother engine, more torque, and more power! I think re-routing the CCV away from the inlet tract would also help keeping the tract clean in the long term.

Underbody rust – There was quite a bit this, although it seems very much surface only. Waxoil Treatment seems to have stabilised any progression. However I will be keeping an eye on it.

Fuel Sender Unit – Fuel gauge was behaving erratically. Removal of the sender unit in the tank produced an obvious cause; it was caked with black gunk! Cleaned and refitted; its now behaving perfectly.

Fuel starvation – This one a little more serious and happens only when the tank is less than ¼ full. The engine gradually drops power, runs rough and knocks out lots of white smoke. This occurs intermittently and will usually self fix after a couple of moments (at the side of the road). As it seems to be only at low tank volumes some one on the forums here suggested it’s a block in tank strainer (probably with the same gunk that was on the sender unit). Its on my job list to fix, but until then I don’t let the car get below ¼ full of fuel.

Bodywork – I think my car is one of the water based paint ones and as such there is a fair bit of body rust (which I missed (was well hidden) when buying): Aerial hole, wings, drivers door, passenger a-pillar and a couple of small spots at the top of the windscreen. All of which has now been treated with rust inhibitor (and will continue to do so), however I’m not sure whether it’s worth trying to sort it all out properly (bodyshop) or just try to keep on top if it. Does anyone have experience of rust treatment on these later 124’s?

Mildew/mould – The car had been sitting and getting damp for some time, and therefore the interior needed a thorough cleaning with mildew/mould killer. Finding a good, clean, black MB-tex interior also helped (for £50!).

At the moment the car is running beautifully on 80%veg.
 

Ade B

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Joined
Nov 26, 2006
Messages
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Location
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2006 Accord Tourer iCDTI EX
I thought I would share my experiences with my car, as I have received a fair bit of help from these forums and want to pass something back!

I bought a 1995(N) multivavle diesel saloon six months ago knowing it had been standing for a while and that there was no history. However the 125k mileage was warranted, the engine was strong, and the gearbox felt OK considering it hadn’t been used recently. The bodywork seemed fine (with one or two rust spots in the usual places), the interior was very tidy, and all the electrics worked as they should.

Unfortunately I’ve lots of problems! Although, with one expensive exception most were a relatively simple fix, once identified.

Gearbox – This went badly wrong two weeks after purchasing the car. The box would not shift into 3rd, but given enough speed and high enough rev’s it would shift straight from 2nd into 4th! This did not last and a week later the box self destructed (non repairable). My local independent (Staiths Garage, Dunston, Tyne and Wear) sourced and fitted a reconditioned box. However at £700 this was not a cheap fix! I found that when I got the car back I still had to do a fair bit of tuning to get the shifts right for me. Has anyone else found the throttle position is very critical for good smooth shifts!? I do have one outstanding problem though; the gearbox shifts up too late at high throttle openings. I.e. when I pin the throttle for an overtake, the engine will rev to 5,000 if I don’t ease off. (the previous box changed up around 4,500). I have booked it into my local independent who promises to sort this problem.

EGR – A fault here caused some on/off power cycling at a 55mph/60mph cruise (manifested as jerking, as if you were on off the accelerator). This was traced to an open/close cycling of the EGR valve. The EGR was subsequently disconnected by removing the vacuum line to the valve. The car drove noticeably better after disconnection.

Fuel Leaks – Everywhere! In the plastic lines, on the shut off valve and now (I think – not fixed yet) from the injector return lines. These have been a bit of a pain but easy to fix. The shut of valve was replaced by a plane bolt from an earlier car (freebie from indy).

Inlet Manifold – This was very dirty! A combination of the soot from the EGR, and the crank case ventilation fumes which enter the inlet tract just before the com chamber. The fumes from the CCV had turned the soot to gunk, almost blocking the centre inlets. Cleaning this out produced a MUCH smoother engine, more torque, and more power! I think re-routing the CCV away from the inlet tract would also help keeping the tract clean in the long term.

Underbody rust – There was quite a bit this, although it seems very much surface only. Waxoil Treatment seems to have stabilised any progression. However I will be keeping an eye on it.

Fuel Sender Unit – Fuel gauge was behaving erratically. Removal of the sender unit in the tank produced an obvious cause; it was caked with black gunk! Cleaned and refitted; its now behaving perfectly.

Fuel starvation – This one a little more serious and happens only when the tank is less than ¼ full. The engine gradually drops power, runs rough and knocks out lots of white smoke. This occurs intermittently and will usually self fix after a couple of moments (at the side of the road). As it seems to be only at low tank volumes some one on the forums here suggested it’s a block in tank strainer (probably with the same gunk that was on the sender unit). Its on my job list to fix, but until then I don’t let the car get below ¼ full of fuel.

Bodywork – I think my car is one of the water based paint ones and as such there is a fair bit of body rust (which I missed (was well hidden) when buying): Aerial hole, wings, drivers door, passenger a-pillar and a couple of small spots at the top of the windscreen. All of which has now been treated with rust inhibitor (and will continue to do so), however I’m not sure whether it’s worth trying to sort it all out properly (bodyshop) or just try to keep on top if it. Does anyone have experience of rust treatment on these later 124’s?

Mildew/mould – The car had been sitting and getting damp for some time, and therefore the interior needed a thorough cleaning with mildew/mould killer. Finding a good, clean, black MB-tex interior also helped (for £50!).

At the moment the car is running beautifully on 80%veg.

Quite a lot of niggles but it sounds like you are still happy.:)

Re the damp, have you cleaned out all the drains, pretty much every 124 I looked at had blocked drains and damp in some form or other and my C124 gets water in the drivers footwell under the carpets if I leave it for any time without cleaning the scuttle drains. (Being parked nose into a hedge doesn't help).

Ade
 
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mjrose

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Joined
Apr 11, 2008
Messages
27
Location
Newcastle
Car
1996 w124 E300 Diesel Saloon
Still Happy yes, its such a nice car to drive when everying is working as it should!

Where are the scuttle drains??
 

Number_Cruncher

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Jan 14, 2008
Messages
987
Location
Midlands
Car
1995 E300D
>> I think re-routing the CCV away from the inlet tract would also help keeping the tract clean in the long term.

Despite the temptation, don't do it! You've already got rid of the really dirty part of the inlet, the villain of the piece, the EGR.

The crankcase ventilation offers just about the only way for the inlet valve seats to get any lubrication at all. In fact, I would go further and suggest that you make sure that the plastic bungs into all, but, especially, the rearmost ports are free.

The inlet valves and seats on this engine are subject to wear and errosion. Even when badly worn, because of the engine's smoothness and very long inlet tract, you won't hear the compression/combustion leakage.

Without EGR, the crankcase fumes are just oil, it's the mixture of EGR and crankcase fumes which can lead to serious blockages in the manifold.

I wouldn't be too bothered about reducing the 5000 rpm upshifts - if it's with the kickdown switch pressed, that sounds about right to me.
 

Timster

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Scottish Borders
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Currently Merc' Less.
I have a very similar sounding problem with my engine when the tank is less than 1/4 full. If you are able to shed any light on this then please let me know!

I'm running a w124 250td, but on 100% veg oil. I presumed it was something to do with the veg oil - always works fine once I've topped the tank up.

Regarding your leaks in fuel pipes, it may be that your car has previously been run on veg oil, that tends to corrode pipes quicker and seals need replacing not longer after starting to use the stuff. Did you notice a BBQ smell at first when you were using the car?

Cheers.

Tim
 
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mjrose

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1996 w124 E300 Diesel Saloon
Number_Cruncher - With regards the inlet valve seats, your point is well made and i will leave things as are, new rubber t pieces were used throughout when i cleaned the inlet tract so, the CCV should be functioning and lubricating as designed. Thanks.

Timster - i spoke to another member on this forum (silver something i think) who believed his very similar problem was caused by gunking of the tank strainer. My very gunked fuel sender unit reinforced this likelihood!

I will post here if removal and cleaning of the tank strainer elimates the problem.

Cheers
 

Ade B

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Location
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Still Happy yes, its such a nice car to drive when everying is working as it should!

Where are the scuttle drains??
At the bottom of the windscreen, two in the middle under the wiper arm and one at either corner. They are easy to get at with the bonnet open. If you search the forum, the links to the russian site come up with diagrams.

Ade
 

Number_Cruncher

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Messages
987
Location
Midlands
Car
1995 E300D
>>The shut of valve was replaced by a plane bolt from an earlier car (freebie from indy).

I missed this on the first read through.

As the only other way to shut these off is via the vacuum actuator on the injector pump, I wouldn't be too keen on the removal of the shut off valve on the top of the fuel filter.

The odd thing about this engine is that unlike most engines which require the presence of an electrical signal to run, these engine don't. In fact, they require a working vacuum system to shut off! (I really don't think you could get away with this type of design today!)

There are at least 2 obvious scenarios where the vacuum device can fail 1) a failure of the diaphragm in the shut off valve, and 2) a more general failure of the vacuum system.

If you still have the old shut off tap, I would take it apart, and fit new O rings, and use to to replace the bolt. If not, I would be obtaining a good shut off valve.

In all likeliehood, the absence of the shut off valve won't cause you any trouble, but, it's a bit like a fire extinguisher in that regard - you won't use it for years, but, when you do need it, you'll be glad of it!
 
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mjrose

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1996 w124 E300 Diesel Saloon
OK i see your point about shutting down the engine. I still have the original valve so ill put a rebuild onto my to do list.

Thanks
 

bolide

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I know it's not adding much to the debate, but all the faults you list are what I'd expect of a car that's been sitting. They are all typical problems

The upside is that, once fixed, the problems won't reoccur quickly and if you keep the rust at bay you'll have a very good car for the forseeable future

Nick Froome
www.w124.co.uk
 
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mjrose

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1996 w124 E300 Diesel Saloon
>>The upside is that, once fixed, the problems won't reoccur quickly and if you keep the rust at bay you'll have a very good car for the forseeable future

Thats what i'm hoping for!

Thanks
 

Number_Cruncher

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1995 E300D
>>Thats what i'm hoping for!

I'm in a similar position - we've had our E300D since last February, and I've been through and sorted quite a list of problems. How and why do people let the condition of these cars slide? Perhaps people are prone to abuse the general long-lived nature of the cars?

Instead of the gearbox, the expensive work on ours was removing the head to repair the worn intake valves and seats.

It's getting due for some brakes, and I'll probably put some new front ball joints on while I'm there, but, it's all normal servicing work now I'm on top of the usual problems.
 

bolide

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>>How and why do people let the condition of these cars slide? Perhaps people are prone to abuse the general long-lived nature of the cars?
They will soak up the abuse for years - but then you find lots of things need doing at the same time. The secret is to find a proper W124 specialist to maintain your car

I find E300 Diesels kill engine mounts quite quickly above 100k so reckon on replacing those at some point. Similarly, front balljoints, leading rear subframe mounts, front prop doughnuts and diff bushes will all be on your list at some point

Nick Froome
www.w124.co.uk
 

SilverSaloon

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Roger Jones

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On the rust problems, I believe that the water-based paints arrived in August 1995. The Russian VIN site will give you the delivery date of your car:

http://old.mbclub.ru/mb/vin/?lng=eng

I've had a problem around the antenna aperture on my 1996 Coupé. Got it fixed at a trusted bodyshop and it has reappeared in under four years. In fairness to the bodyshop, their line was and is that rust almost always comes back. I'll get it done again and expect a similar problem in another four years, as I can't envisage selling the car; I guess the additional option is new metal when it surfaces again.

Of course, all such repairs are done with water-based paint. For what it's worth, that same bodyshop reckons that it is not the cause of the corrosion problem on MBs since the mid-1990s.

"How and why do people let the condition of these cars slide?"
They assume they're too tough to need mollycoddling with regular servicing, etc. They buy them cheap but don't have the funds for proper maintenance. They turn to a main dealer and are so shell-shocked by the first bill that they don't go back there and think that all servicing costs make your wallet weak.
 

philiggy

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Hi
I've had a few of these (still got 2) and every one at some time has broke a front spring, so have a good look as they tend to go at the very top or very bottom, also check the steering damper if its old change it, you will be surprised at the difference.
I,ve been using POR 15 on rust for a few years and it works very well.

When its done you'll be pleased you went to all the trouble.

Phil
 

Smiley

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Roger
If you are going to keep the car then it is worth going to a proper restorer rather than a repair bodyshop - they will cut the rusty metal out and weld a new section in - should be permanent repair with the right rust proofing. I think the problem around the antenna mast is that some of these antenna holes were drilled after painting and no protection was applied - just put the aerial in quick - shame really 1 minute with some rust proofer would have saved all the aggro now!
 

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