300TE Oil In Radiator Fluid
 

Well, I have always been told, if there is water in your oil, then you have a head gasket problem ...............

Well, I have some oil, not a lot in my radiator fluid? The car runs well, does not overheat, does not loose oil, and does not leak coolant.

So what gives here?

A friend of mine, who is a mechanic, told me to bring it by his shop, so that he could make sure the head was correctly torqued?

Whatever you can offer, is appreaciated!

Thanks - William Torres

Are you sure that it's not ATF rather than motor oil?
 

I'm not sure about your model, but a lot of Mercedes, like most auto-trans cars, have the transmission cooler integral with the radiator, so cross leaks are common in their old age. The bad part is not the ATF in the coolant, but the coolant in the auto trans -- that leads to expensive consequences very quickly.

Oil in the coolant is generally a good indication that you have the M103 head gasket problem.

Check the rear corner of the head on the curb side for external leaks. Check the coolant in the reservoir for oil. Even if you don't see oil, try rubbing the coolant between your fingers to see if it's oily.

Head gasket problems can show up any number of ways:
- coolant in oil
- oil in coolant
- coolant burned and going out the exhaust
- exhaust gases forced into the coolant
- external leaks
According to Bud, he pegs your problem as following a classic M103 head gasket problem, oil in coolant. Finum offers the possibility of a problem with the atf heat exchanger.

I recommend you flush out the coolant using a cleaner that'll emusify any oil. MB sells such a flushant. Scour the overflow tank. Then check for any more accumulation of oil in coolant.

Check the atf for coolant. This would worry me most since any water in atf would destroy the clutch packs ($$). I suggest the best way may be to drain a quart from the pan and inspect the fluid in a clear jar.

I would ask if your vehicle has had routine coolant renewals since you have owned it. I have discovered that some head gaskets that I have changed have suffered complete deterioration due to infrequent coolant changes. On a second note: I have also noticed with some of the high mileage engines I’ve dismantled there has been erosion of the coolant jackets in the cylinder head(s). The pattern often points to a lack of coolant changes as well as the brand of coolant being utilized. Engines that have used MB coolant from day one then get renewed on schedule seem to be less affected by some of the above mentioned problems, IMHO.

On a third note there has been a number of material changes with the head gaskets that fit the mid 80's to early 90's 4 & 6 cylinder engines. Early failures may have been a result of the material being utilized at that time, I do not believe this to be the case as of late.

I have a 1991 300E that I bought new on 7/1992. Sometime around the 50K mark I noticed an oil leak from the rear corner of the engine and that there was ENGINE oil in the coolant.

This car had the coolant changed ANNUALLY using a 50/50 mix of M-B coolant and distilled water. It also had Redline Water Wetter added.

This is a well known problem with the M103 and M104 engines (along with oil leaks from the timing chain cover).

It failed not because of a lack of maintenance. It failed not because I used Water Wetter. It failed because of a engineering problem with the head gasket on the M103 and M104 engines.

I had the head gasket replaced by a large M-B dealership in Scottsdale, AZ. That was 1.5 years ago. At that time they told me they averaged at least one head gasket a week on these engines.

It's pretty easy to tell if what's in the coolant is ATF fluid or engine oil. Besides, if there is engine oil leak from the rear corner of the engine, it'll confirm what the problem is.

It you have any doubts, take the car to a qualified Mercedes shop.

Yes, with the early gaskets I agree about the material problems, as I mentioned. I also mentioned that in my experiences with a lot of failures over time most were the result of insufficient maintenance. There is no question that "oil leaks" have been problematic for some time.

My comment was directed toward head gaskets that are removed from a vehicle that have little, if any material left in the cooling jacket areas. Do you know if your head gasket suffered from major deterioration?

Yes, oil leaking externally and intenally no argument. Major gasket deterioration, completely different scenario.

The only problem with the head gasket was at the point at the rear of the engine where the oil and water channels pass very close to each other. The other weak point is an oil leak to the outside parting line between the head and the block. I had this leak and also the very common timing chain cover leak.

I believe that the replacement head gasket has been reinforced at the weak points.

Yes, the head gaskets were modified in the areas that were causing problems. Metal reinforcements were added in the areas that were prone to leaking oil, either to the outside or to the coolant passage.

I trust my comments regarding coolant renewals will assist the DIY'ers with understanding the importance of performing them as scheduled, as well the use of MB coolant whenever possible. I've seen a lot of cylinder head damage from other brands, just passing on my exposure/experiences.

Head gasket goes dry 300E? Other hints....
 

Hi, well I have the same oil in the water failure again (first at 75K) and now at 226K the second....seems a failure at the rear nest to the exhaust.....ready to drop the rebuilt head in....question since I do not remember from the last time but : does the head gasket goes in just "dry", meaning no other sealant than the red streak around the gasket (Reinz) in between two clean and dry surfaces: block and resurfaced head?....BTW mechanic said that exhaust guides intact....226K!...replaced intake only due to exhaust sodium cooled and the oil seals.........?, cris-cross pattern in cylinder intact....and after replacing all cooling system items..all hoses, radiator (milky stuff all around)..how do you get the rest of the milky(oil) stuff in ie..heater core, etc..??.....well, I am torquing tomorrow....70NM first stage....90 deg...other 90 deg....well Thanks
Later

91 300E 226K

Bilge cleaner works.

Mercedes dealers sell a cleaning compound to flush out the cooling system. Since the dealer did mine, I don't know the details but I believe that you add some percentage of the compound, run the engine for 1/2 hour with full heat/defroster on, flush with clean water, repeat until the oil is gone. Then you replace with 50/50 mix distilled water and MB coolant.

Checked w/dealer and says he knows nothing of it...hmmm?...........Thanks for your help I'll keep looking

Some people use home recipes. Bilge cleaner sounds like a good flushant. Others report using dishwashing liquid. I vote for Dawn -- it cuts grease and is highly regarded in laboratories I've worked at.

TKS....I'll check the Dawn....BTW is there an easy way to get the water pump replaced while the intake manifold is relatively out of the way?.....while the intake is removed????....other ingeneous ideas or personal findings please!
tks....