C200 oily water

[Tiff]

I'm looking for advice before I take the head off my 94 C200.The radiator has that horrible white gunge in it,but it runs 100%,and uses no oil or water. and no water in the oil..please someone tell me there is a simple cure,or is it just wishful thinking...? Had the same symptoms in a Golf GTi,and it was just a leaky oil cooler...
Just to add,it passed its MOT yesterday with only new tyres needed,emissions were spot on,and its done 170000 miles...

Tiff
Scotland

 

[turbominor]

White mayonnaise in the cooling system normaly means oil has got in to the water.. It is more common to see it the rockerboard/breathers on cars that do short journeys and don't get hot..

But i you are not using any oil or water i would be tempted to get some decent trade radiator flush and have several goes at cleaning the cooling system out. Then see if it comes back

appart from head/gasket/block problems some cars have a factory oil to water cooler that can fail. My mk2 golf gti did this and i only worked it out after changing the head gasket!

 

[Robby]

On my old 190E the radiator cooled the water and the ATF, so I assume it was possible for the barrier between the two to break. Not sure if this would make the water get mayonnaise on it, but its something to check.

 

[Steve_Perry]

On my old 190E the radiator cooled the water and the ATF, so I assume it was possible for the barrier between the two to break. Not sure if this would make the water get mayonnaise on it, but its something to check.

I believe that the radiator cores for the water and auto gear box oil are totally separate although they are housed in the same unit/frame, so I think it's unlikely that you could could get auto box oil in the water system or vice-versa, if you get a failure in the radiator core, you'll either see water or auto box oil in the engine bay.

S.

 

[grober]

Cylinder head gasket probably

Get your garage to run a compression test on all the cylinders which might pick up a head gasket which is on the way out. What you are looking for is a cylinder giving a markedly lower compression reading from the others. they should all be roughly the same but at the age of your engine will be lower than manufacturers spec. Sometimes water in the oil is hard to spot, its like very thin streak of white emulsion in the oil at first, hardly noticeable. The 200 and 220 engines had a known cylinder head bolt stretch problem so if its the head gasket use a new set of cylinder head bolts when you rebuild.

 

[Tiff]

Thanks for the advice guys!,I just did a 530 mile trip yesterday,and it never missed a beat,even at slightly illiegal speeds...Used no water,or oil,and coolant temp stayed perfectly at about 85-90.Only thing I did notice occasionally,was when I gave it full beans to overtake,it hesitated slightly,like the rev limiter cut in,but much more gently.I'm a mecahnic,and have done a compression test,and a rad pressure test,and have found nothing,the car is manual,so It can't be the rad.I just hoped there was a simple explanation before I pull the head.The car is running so well!

 

[grober]

MB antifreeze??

After what you said it might be worth trying the radiator/cooling system flush recommended by turbominor. I suppose the white scum could be a cooling system internal corrosion problem Do you have the pukka MB ANTIFREEEZE or equivalent with suitable corrosion inhibitors at 50/50% in the cooling system??

 

[Tiff]

The car came from Perth auction,no service history with it,although only 2 owners.It does,and has always run faultlessly,including towing a caravan up from Norfolk.I would have expected the fault to develop,and I have been waiting for this before I start stripping it down.I have flushed the rad out,and refilled with 40% quality anti freeze.The water that came out the drain on the rad was clear,until the end,obviously because the oil floats on the top.I've done maybe 4000 miles like this,and its never missed a beat.Is it worth nipping down the head bolts I they are known to stretch?<P>

Here you can see the car after I did nearly a full respray...rust everywhere when I got it!

 

[PJH]

Could the car have had the gasket replaced before you acquired it ?
I have a small amount of white gunge in my water header tank.
As the engine was replaced a couple of weeks ago, I'm putting it down to some oil remaining in the coolant system, despite being flushed several times.
Falling Oil Pressure

 

[grober]

monitor oil and coolant.

PJH might be right.what you might be seeing is evidence of an old blown gasket which has been replaced and the cooling system not flushed properly. Not knowing the history of the head bolts(maybe been retorqued/stretched a couple of times already ) I dont know if I would risk it. Maybe best to monitor the oil and coolant for now and see if things get any worse Nice paint job by the way.

 

[Tiff]

yeah,I guess I'll plod on until something goes pop! I've always got the X1/9 to use when its off the road.Thanks for the comment about the paint job! I didn't paint the bonnet,roof,or the drives wing,and you can see the mismatch,red is a horrible colour to work with! basecoat and clear too,with coloured undercoat,on a solid red! times have changed..... at least its not gold!!!

Anyone any ideas on the (slight)missfire? I have heard the coil(s) on C200's can give problems.It only happens occasionly,and only high in the rev range at full throttle.

 

[grober]

coil faulty

Coils have been known to fail on these models but normally means complete loss of 2 cylinders from failed coil so dont think you have a problem. If one coil fails its recommended you replace both as the other may also fail in a short time. there are 2 setups the early one with the coils mounted below the inlet manifold and the second where they are located below a cover on top of the camshaft cover. The other horror scenario is that if the car continues to be driven with a faulty coil then the ECU or wiring can be damaged see http://www.bba-reman.com/content.aspx?content=mercedes_vdo_ecu but I dont think this applies to your car at present.

 

[Tiff]

Thanks Graeme,mine is the early type,so I should be OK.I'll try some redex or similar,as I think the car's always been gently driven,it seems to be getting freer the more I boot it! Am I alone,or is the manual difficult to drive smoothly? I've checked the prop couplings etc,but I find it difficult to pull away without a jerk,and That park brake is STOOPID in a manual.Even wors when towing a caravan...

 

[montur]

Hi

Mine had the white wax type substance in the radiator it completely blocked on of the lines!!!. i had to pick it out then back flush the radiator this cleared most of it as lumps came out. then heavy duty rad flush in the system for about a day and the rest of it drained out. My conclusion is there is not contamination from any of the oil ways as there would have been an oil film in the expansion tank otherwise. this stuff does not float so its water particles (tap water) not mixing with the original merc antifreeze. since flushed and refilled no further signs of contamination.

 

[fnkhan68]

from my past experience there is a possibility that one of the cylinder heads has developed a hairline crack. mercedes engines are prone to this if the coolant is not changed at regular intervals and while at the moment the car is performing fine over the long term this crack will begin to expand causing overheating and oil in the exhaust system and the more you drive at high speeds the quicker this will happen. best way to eliminate this possibility is to drain the system and see what happens. my previous car had the white mayonaise type substance in the radiator as it had a hairline crack in the cylinder head and it drove absolutely perfect and i drove it like this for 18 months even to manchester and glasgow before the oil and overheating problem started and this was in the summer. winter time it was fine and on motorways but eventually the car started to smoke too much so i got fed up and drove it into the back of a pug 406. it was obviously a mishap on my behalf as i was not concentrating on the road!

 

[silverarrow]

have a look for signs of a new head gasket
do the bolts look clean ???

 

[Tiff]

Sounds 100% about the cracked cyl head,I flushed the rad again,and within a day the gunge was back,so I stuck it back through the auctions,and lost a fortune...then bought a Volvo 850T5,which turned out to need quite a bit of work too..

I have the chance of a 190 2.5D on an E plate,which I'm tempted by.I really miss driving the C.Anyone got any info on what to look for on these,I haven't seen it in daylight yet,and don't know much about it at all..I know they are slow,but I can live with that,I'm not gonna have my licence long with the T5....

 

[grober]

190 2.5D big 5 cylinder lump squeezed into the front end so I would check the front suspension/steering and brakes. Being a 5 cylinder engine mountings will also take a pounding. These diesel 190,s had very comprehensive sound deadening panels round the engine compartment to keep things quiet. Its probably expensive/difficult to renew these if they are missing. Otherwise the usual 190 checks service history etc. Lots of these were used as taxis so maybe mega miles. At that age body corrosion may be an issue also. This tends to show first round the sill jacking points. MB made a turbo version of this car but in LHD only.

 

[bolide]

190 2.5d

The 190 2.5D has one of Mercedes best engines in one of their best saloons. I tip them for future collectible status if they've not achieved that already

A good one will outlast you so long as you keep the tinworm at bay and maintain it obsessively. Change the gearbox oil immediately and the engine oil every 5k and you'll be OK

The 190 shares lots of bits with the W124 so parts are easy


Nick Froome
www.w124.co.uk

 

[Dieselman]

The 190 shares lots of bits with the W124 so parts are easy

And even a fair number with the 202 and 210.