Very bad news...

[farley556]

Been doing a head gasket job for about 2 weeks now (the valve job took about a week at the shop) Got everything together on sat. and was leaking oil and figured out i needed a new chain tensioner, so i got one today and we put it in and started it up and it sputtered and poured out mass amounts of oil around or under the tensioner. The oil looks like chocolate milk. My friend who is working on it does not really no whats wrong with it right now. I am so angry right now i could punch something or just cry. my friend said he thinks that the oil is not mixing and is just oil, but it looks like choclate milk. All i know is that this is no good. Im sorry dont have anymore details at this time, but hopefully one of you guys can help me out. i will post more once we know something. I just want my car back

[farley556]

we found out that the leak is coming from the brand new chain tensioner??? What could be going wrong? Can we have put this on wrong? Please help...

[strictlyspeakin]

punch something-yes. give up hope-no.

keep the faith man.

[farley556]

He thinks its the lower timing cover thats causing this. Is this a possibility?
the oil looked odd when it came out but the oil in the valves looks brand new and normal...I just like to get some advice on this so we dont make another mistake. I need my car back!

[Proven Guilty]

if it looks like chocolate milk, there is water (antifreeze) mixing with the oil. when you're doing the head, did you have it all machined flat? usually after a severe overheat when the gasket lets go, its common to warp the head. it can be out as much as 0.04 and wont allow it to seal properly.

that's the first thing i would start with if you didn't have that done, and remove and reinstall the tensioner.

[OzC36]

farley,

I agree with "Proven Guilty" that chocolate milk oil means that it is contaminated with coolant. This normally is one of the reasons why the head gasket is changed (oil leaks being the other major one).

Question: Did you refill the engine with fresh oil and a fresh oil filter when you finished the head gasket change?

With regards to the chain tensioner assembly order see below:

http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=202028&M=104%2E941&GA=722%2E328722%2E424722%2E604722%2E605722%2E629&GM=717%2E441&CT=M&cat=520&SID=05&SGR=015&SGN=01

[OzC36]

This might help (also detail on installation of chain tensioner):

http://www.mercedesshop.com/Wikka/M104HeadGasket

[farley556]

yes fresh oil+filter all new gaskets including head. Machined head, valve job, everything is clean and new. There should not be any reason the oil looked like that. Like I said, after the oil came out looking like that, we checked the in the oil in the valves, etc and it looked clean, freash, normal color, perfect. Could the oil that leaked aerated or something?or maybe it mixed with something on the garage floor. This was the first the first time we started the engine with everthing freash. Any ideas???

Also, i just talked to my friend (hes doing pretty much all the work) and he got back into the engine last night and said the leak is coming from the lower timing cover, because some of the groves where the tensioner goes in are stripped and is basically not sealed ...he knows this is the reason for the leak, but is still not sure about the oil. He is going to get another lower timing cover. i would just like to figure out whats going on from someone that knows this car. I think he thinks he knows whats wrong but is not REALLY sure.

Oh yeah but the oil that leaked out does NOT match the oil in the engine, So how could this be. Wouldn't ALL the oil look like milk, especially in the valves,etc??
Another thing is, when i started the car up for the first time, it was sputtering and at low idle, then it finally just shut of itself, this is just another factor.

[JRE320]

Time for a real mechanic to look at it.

[farley556]

Yeah I think we figured it out hopefully. Got a new lower timing case where the oil leak was. So we will be putting that on. As for the oil color, i have not got the car up to running temp for the gaskets to fully seal. And a little water can be getting in. So I will change my oil in about 50 miles or so. If everything works out. Sound about right?

[farley556]

Is this true? gaskets have to get to normal operating temp. before the gasket seals 100%??? So this is why my oil mixed with something? anybody heard of anything or dealt with anything like this before??? HELP please...
He is putting everything back together right now..

[OzC36]

Doesn't sound right. Have you seen chocolate milk oil in brand new cars (which have brand new gaskets)? I would change the oil and filter again right now. I wouldn't run the engine at all with contaminated oil.

After the change and test run, if the oil turns milky again, stop, find and fix the source of contamination.

The oil leak from the timing case cover of the M104 engine is very common. It requires special skill, materials and technique to achieve a leak-free result. You will find that information in the link I posted above.

[Proven Guilty]

generally if the oil looks like chocolate milk, AND you blew the head gasket from an overheat.. the block is also likely cracked / cylinder wall damage allowing water jackets to leak into the oil.

i've never heard of a bedding time or temp for gaskets. they seal as they are, which is why it's generally OK to start a car after changing the water pump without having to worry about it sealing.

[xvvvz]

>>Is this true? gaskets have to get to normal operating temp. before the gasket seals 100%??? <<

Did you read the documentation I sent to you? Here is a quote from it:

"The cylinder head gasket is not watertight until the
engine has reached operating temperature, in other
words, until a swelling operation has taken place.
For this reason, the cooling system must not be
pressure-tested until after the engine has reached
operating temperature."

With that said, I, like PG said, am worried there is something else going on if you are still experiencing what sounds like a large and continuing amount of contamination.

[Pagz]

The engine will run rough for some time after initial start up...its likley the self adjusting lifters lost some oil when they were removed for the head to be serviced.

Can i ask did the friend reset the tensioner properly before installation...im curious because of this statment

"because some of the groves where the tensioner goes in are stripped and is basically not sealed "

My engine builders almost damaged mine because of this.

Hope you find the source of the chocolate milk....it does sound like a thickshake of antifreeze/oil! =)

Cheers,
Paul

[farley556]

thank you all very much. We got it all put back together and started it for a min to see if leak stopped. It did stop. No funny smells. Ran a little rough. But not bad, that will correct itself like said above. We drainned the dirty oil and are changing the oil and filter twice tommorow to make sure the other oil is washed out. Hopefully everything works out. I will let u all know. Thanks again.