mercedes w210 e300 oil in cooling system

[wardtribe]

I wanted to know if anyone has experienced one way flow of oil into the cooling system at a high rate which is about 1 quart per 100 miles.

History:
1. About 6 months after I purchased the car, I noticed traces of oil in the coolent when I flushed the system. I put 30,000 miles since i have owned the car and it was not building up. I thought a repair was done prior to me purchasing the car.

2. A few months ago oil starting to leak into the cooling system at a rapid rate causing the system to overheat while my daughter was driving the car. I had the head gasket replaced. The head was pressure tested and resurfaced. Also, some valve seals were replaced.

3. The oil leak is still leaking at about 1 quart per 100 miles.

In my understanding there are only 4 things that could be the cause.
1. Bad head gasket
2. Cracked block
3. Cracked head
4. Damaged oil cooler which is attached to the oil filer housing.

My questions to the form are if anyone has heard of a cracked block on a 1996-1999 mercedes E300 and could a cracked block have only oil leaking into the cooling system. It seemls like it should be both ways. With this rate of oil leaking into the cooling system it seems like the leak is occurring at a spot where the oil presure is high.

Thanks in advance for any help.

[thatguy]

If you ran cold water through the hot engine while flushing the coolant, a cracked head and/or block would be possible, but I believe such cases are extremely rare on the OM606. I have a 606 car (w124) and did tons of research, this engine doesn't seem to be prone to cracking heads or even blowing head gaskets like the older w124 diesels were. Your oil cooler theory may have merit, although I know little about the oil cooling system on this motor if I'm honest, but it may be worth inspecting. I believe Hatterasguy (sorry if that spelling or name is incorrect) is knowledgable about the 606 engine, there are a few other guys here as well who know these motors much better than I. In any case, I wish you well and hope it's not a disastrous problem causing you your grief.

[Zulfiqar]

does your car have an oil cooler bulb sitting in the sump like the w124?that can be a source of leakage.

[kwmccauley]

Wardtribe,
I may have missed it but what year is your W210 E300? Turbo ('98-'99) or non-turbo ('96-'97) ?
Mine is a 1999 and the oil cooler is air cooled so no chance for antifreeze coolant to mix w/ oil there.
Thanks,
Ken

[wardtribe]

Update:

This is a 1996 e300. The oil cooler for this model is on the side of the oil filter housing. I just had is pressure tested at a radiator shop and they did not find a leak. So, that is off the table. I believe there is only three posibilies

1. Cracked block
2. Cracked head
3. Bad head gasket. The head gasket was replaced but it is possible something was missed.

Is there any seal that could cause oil to lead into the cooling system. Something by the timing chain or water pump. I really do not want to part the car out.

[wardtribe]

I am out of ideas and hoping to get some thoughts on what could cause this issue. As stated the head gasket has been replace and the head was supposidly pressure tested. Also, the oil cooler has been tested.

[engatwork]

I'm thinking you are probably going to have to pull the head and see what is going on.

[Aquaticedge]

take it back to the place who did the head job. something has to be amiss with the gasket if the external oil system checks out.

[kwmccauley]

Based on these original comments:

The head was pressure tested and resurfaced.

The oil leak is still leaking at about 1 quart per 100 miles.

The head gasket replacement obviously did not fix the original problem. This could mean that the original head gasket was not a cause of the problem (in which case we are still hunting for the cause) OR perhaps the new head gasket was not properly installed. When the head was resurfaced, did the machine shop tell you how much material was removed? When I did the cylinder head removal/replacement on my 1999 OM606 engine, the shop removed the minimum possible material during the resurfacing. I asked about using the thicker engine rebuild head gasket and they told me the original head gasket thickness was the correct choice. The original head gasket thickness is 1.65mm. There is also a 1.85mm "repair" head gasket available.
There are dowel pins in the block (present in the 1999 OM606) which positively locate the head gasket on the block before the cylinder head is positioned in place. It would be difficult to misalign the head gasket but if the thickness of the gasket is incorrect it may cause some issues.
All of that said, best path may be to have the shop that did the work evaluate the situtation as suggested by other folks here on the forum.

One thing I am curious about......when you run the engine (which is basically an air pump) with the radiator cap removed, do you see air bubbles in the coolant?
Please keep us posted on progress and process of elimination.
Thanks,
Ken

[Jeremy5848]

AFAIK the OM606NA engine uses an oil-to-coolant oil cooler. There are coolant lines leading down to the oil pan on the exhaust side. The coolant lines connect to a heat exchanger that is part of the oil pan. Oil from the oil pan is sent by the oil pump through the heat exchanger and then up to the oil filter and on to the engine.





Although Mercedes must have given serious thought to the risks involved in such a cooling system, they must also have built the thing so that leakage would be extremely unlikely. Nevertheless, I would advise disassembling and inspecting this cooler. Among other things, it may be easier than pulling the head again.

You might investigate whether it is possible to block the flow of coolant into the heat exchanger temporarily; if the engine is not run hard in hot weather an oil cooler should not be necessary. That will allow you to determine whether oil is still getting into the coolant. With the coolant lines disconnected, oil might leak out of the connections, another good indication that the cooler has a leak.

Jeremy

[Jeremy5848]

Originally Posted by wardtribe

Update:

This is a 1996 e300. The oil cooler for this model is on the side of the oil filter housing. I just had is pressure tested at a radiator shop and they did not find a leak.

Unless your engine is somehow different (is this a RHD car?) I do not believe the oil cooler is on the oil filter housing.

Jeremy

[kwmccauley]

Wardtribe,
Did this oil going into the coolant challenge ever get sorted out to your satisfaction?
Thanks,
Ken

[echobravo]

Would anyone happen to have a photo of the drivers side engine showing the coolant lines that run to the oil pan that are shown in the diagram item 6 shown above? My 96 e300d north american had a huge water line blow-out on the driver side under the injection pump, and I wanted to see what I should be looking for before I crawled under the car.

Thanks,

Ed

[Zulfiqar]

The lines you see in the diagram are behind the alternator. But this is an OM606.910 engine diagram which is found in the older W124 model (1995 only had this engine in the US). The 912 engines (in w210 models - 96 is w210) had it on the oil filter I believe.

[echobravo]

Ah, thank you for the info. I've got the 912 engine, '96 W210, non-turbo. The other day the wife called and said all the coolant ran out of the engine. When I got there, I poured two gallons into the radiator and right back out onto the asphalt. I couldn't pour and look under the car at the same time, (wife is no help) but the water was pouring out the driver side of the engine block, somewhere under and obstructed by the injection pump. The front of the car was completely dry. Radiator, water pump, upper hose, lower hose, overflow hose are all new, and dry.

If I can get my hands on the correct diagrams, I could order parts and replace the broken line, but for some reason, there is scant information or drawings on coolant lines into the oil filter, or sump.

Thanks again for the clue.

Ed