W124 Big End Bearing Replacment

[Steven Stoole]

Hi all, i have a W124 E280 1994 model, and it sounds like my big ends are on their way out. Has anyone changed them with the motor still in place? I really dont want to hall the engine out.

 

[grober]

To be honest if the big ends are away [ mercedes bottom ends are usually pretty near indestructable given oil ] I would look for a replacement engine or a full rebuild.

 

[allias]

To be honest if the big ends are away [ mercedes bottom ends are usually pretty near indestructable given oil ] I would look for a replacement engine or a full rebuild.

Check his location.... either way its going to be a small nightmare job. Good luck with it.

 

[grober]

Check his location.... either way its going to be a small nightmare job. Good luck with it.

Quite lot of w124 in South Africa I believe [ may have even been assembled there from kits at one point? not sure]so breaker sourced engine might be a possibility.

 

[Steven Stoole]

Thanks for that. I only seem to hear that distinct bearing noise at around 3000rpm or when i accelerate and back off. I can play with the noise at around 3000rpm doing around 120km/h. if i press my foot on the accelerator slightly and go over 120km/h then it goes away, when i back off then the noise is there but only at around 3000 rpm?

 

[grober]

Doesn't sound like big ends to me [said without hearing it of course] I would suspect the hydraulic variable valve timing unit on the front of inlet camshaft is faulty. You will be pleased to know that if its that-- repairing it does not require the removal of the engine. To test remove the electrical connection to it and see if the noise characteristic changes?

 

[Steven Stoole]

Great, well let me try that tonight and i will let you know the results. I really hope it is that. Thanks for the advice Graeme.

 

[kth286]

Mercedes has a car factory in S Africa.

 

[NISFAN]

^^^ Yes and most UK W203 RHD cars were built there.

 

[Ted]

Not a huge expert, but if the big ends are shot, I would expect to hear them knocking for a few seconds on cold start up.

 

[spock500]

What's your oil pressure like hot/cold?

Also mileage/service history.

I changed the shells on mine which is a OM605, not sure how similar but jacked up engine after undoing mounting bolts for access.

This was my rebuild as such, OM605/6 piston advice - PeachParts Mercedes ShopForum

Best of luck,

 

[Steven Stoole]

The Mileage is 240000km, the oil presure is good all the time, when i start the motor it is on max presure and when it warms up it drops slightly. cant tell you about service history, i managed to get it from the agents up to 100000km. They are very good like that here with top end cars. I did try and Varable cam unit and that didnt make a difference. Ill keep you posted, Thanks

 

[Steven Stoole]

Not a huge expert, but if the big ends are shot, I would expect to hear them knocking for a few seconds on cold start up.

The only noise that i get are the tapets for a second or two, thats it. Maybe the next step is this guy who specialises in Mercs.

 

[Vlad]

I would be surprised if its big ends...bottom ends on the 104 engine are virtually bomb proof....if you can play with the noise could it not be a diff/propshaft grumble or even wheel bearing?

As has already been stated a worn bottom end would make a pretty noticeable knock on start up and I suspect that your oil pressure would be poor as well.

 

[spock500]

You could try one of these, not sure how good they are though.

320MM MECHANICS STETHOSCOPE ENGINE DIAGNOSTIC PROBE on eBay (end time 07-Sep-10 17:55:49 BST)

 

[Steven Stoole]

Thanks David, just bought it so will take a few days to get to SA. once here will give it a good go. chow for now

 

[Steven Stoole]

Well, it has been some time. I have taken it to quite a few guys here in SA and it looks like it could be a small end on one of the pistons. The big ends are fine. I thought it could be the shock absorber for the fan belt so changed it but the noise is still there and starting to get worse very slowly. I hardly drive the car now but will be pulling the motor out shortly. Thanks for all the help. i will post some photos and document it when i start the job.

 

[ventech]

I am in S Africa 3 months a year & I have an 89 W124 200 which has done 400K kms
My oil pressure is about 2.5bar idling cold and drops to 1.2 when very hot. There plenty of W124 still in regular use here &should not be difficult to find an engine, but shipping back to UK would cost about £300.
Also second hand cars are 2 -3 times the price of UK and spares prices are higher. However I think engine rebuilders may be cheaper. I am just getting quotes for mine, which I can copy to you. You can reach me on 01889 878 288 which is a UK based VOIP phone, so it will be a local call from the UK. It may be an option to get a second hand engine here & have it rebuilt before sending it back to the UK

I know the C series cars were built at the East London (S Africa) factory, don't know about the W124.

 

[Steven Stoole]

I know the C series cars were built at the East London (S Africa) factory, don't know about the W124.[/QUOTE]


Thanks for the info, i have just ended up rebuilding the motor. It is on another thread on this forum (taking motor out) which i will complete and finish off this week some time. It has been running now for just over a week and it is like music to my ears. I am based in South Africa so you are correct in saying the C class is built here as was the w124.
With regard to your motor if you are wanting to take one back with you i would look for one there in the UK. much cheaper and you can source more spares for it there. I battled to find piston rings for my motor and was on the verge of buying new pistons for it but got one of the last sets in SA. so was very luky there. Anyway if you need any help contact me and i will see where i can assist should you need help. I am pretty well connected here with the motoring boys and love my Merc's.

 

[bolide]

Does the car have air injection? The air injection pump runs for a minute or so on startup and can be very noisy

It's on the serpentine belt and isn't an a/c compressor or alternator!

Nick Froome
the independent Mercedes Estate specialists