I just checked and I'm pretty sure my '92 300TE 4Matic wagon, (131,000 miles) has blown another head gasket. The first one was replaced before I bought the car at approximately 90K miles. I think the gasket has blown again because there is oil in the coolant resevoir.
This condition was suspected last summer by my mechanic, so he did a complete flush of the system. It was clear afterwards, but now, about 2,000+ miles later, the oil is back.
My question, which was not answered when I did a search here, is what damage/danger is there in continuing to drive the car in a combo of short city trips and/or 2-3 hour long highway drives? Am I running the risk of ruining the engine, or will it just cost me some new radiator hoses and a few extra quarts of oil by next summer? Is there a breakdown possibility? The engine is not running hot, there is no white smoke out of the tailpipe, nor is it burning an excessive amount of oil. There are no visible leaks on my garage floor in the morning, nor is the engine valve cover particluarly oily, (though I haven't inspected it closely).
The reason I want to wait until next summer before reparing it if possible, is that I need the car this time of year, (4Matic for the snow), and my "Fintail" is in winter storage so I don't have a spare car. Plus, I'm planning on replacing the leaking 4Matic transfer case next summer so I'd rather just wait, (tranfer case is on back-order), and have it done all at the same time. But, if it must be repaired now, I'll bite the bullet and rent a car rather than hurt my beloved 124. Thanks for any advice. - Bob


1962 MB 220SEb Fintail Sedan
1963 Vespa VNB 4T 125 Motor Scooter
1992 MB 300TE 4Matic Wagon
1995 Subaru Legacy 4wd Wagon (wife's car)

I dont think I could ever recommend someone driving a car with oil in the coolant due to what it will do to the coolant system , besides hoses. Also there is a possibility of engine damage if it completely fails. If you dont wanna fix it till next summer I would recommend not driving it until it is fixed. Just my 2 cents.

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euro 287
Mercedes Technician 7 Years (retired to Hyundai)
2000 Dodge Durango
98 Mazda truck

If water gets in the combustion chamber, you could hydro-lock the engine. The pistons were designed to compress a somewhat gaseous fuel mixture. Coolant is a liquid; not a gaseous mixture. This puts undue pressure further down and can bend the connecting rods.

I know $$$ do not grow on trees, but the $$$ you'll need to fix the car will be much >>> if you keep driving it.

My 2 cents..

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

For our '91 190E, I replaced all the hoses when oil contamination had caused them to 'weep'. Less than a month later, the new upper radiator hose split while my wife was driving in a remote area. A good samaritan was able to cut and re-attach for her, but when she got home - I saw the hose was beginning to leak as the old one had.

Steve

A second head gasket in 40k? Did your tech torque the head down properly? Did he/she verify that the top of the engine block and bottom of the cylinder head were not warped? Have you had any overheating episodes since the last gasket replacement? Did your tech buy the gasket from a non-MB source?

If oil is found in the coolant, there is a good chance that coolant is in the engine oil as well. As coolant is a poor lubricant, damage to the crankshaft bearings is possible. $$$$.

As I'm posting from NE PA, I can understand your reluctance to be without AWD, particularly this week. However, I strongly suggest that you get to the bottom of this problem immediately. The cure will almost certainly be less expensive than an engine failure.

Worth a quick check is to ensure that it is not transmission oil in your coolant. This can occur if you have a defective heat exchanger in your radiator. Check the trans fluid on the dipstick - if it is clear then it is probably head gasket. If it is at all cloudy (emulsified oil) then you have a defective radiator which requires urgent attention to save the transmission.
Good luck
Adrian

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90 300TE 24v (M104 eng) 207K miles
87 300TE (M103 eng) 269K miles (and never had the head off!)
86 300TE (M103 eng) 230K+ miles (donor car)
95 Toyota Lucida diesel 4wd
86 200T 165K miles (sold)

The radiator and first head gasket were all replaced before I bought the car. I didn't take ownership until 20K miles after the first head gasket was replaced at 90K. Even still, only 40K between head gaskets does seem like way too soon. The car has never overheated while I've owned it and the previous owner didn't mention anything about it having an overheating "problem", or even if it had ever overheated, even once.
I checked the transmission fluid, and it is clear, so I am sure it is oil that's in the coolant. I appreciate all of your comments and I will, albiet reluctantly, heed all of your advice. I will call my mechanic Monday morning and make arrangements to have it done asap.
Just a few more questions: is this a fairly straight-forward DIY job for a person of moderate ability or should it be done professionally? What is the typical turn-around time for this job for a professional? What should I expect to pay a professional, and what else if anything should I have checked/replaced while the head is off? Thanks again for all of your sound advice.

Thats a common problem with the 300 and its not common for the water to end up in the oil.. Most always oil in the cooling water... When you have the work done by who ever be sure to get the gasket from Mercedes.. They know they have a problem and have made some changes to the gasket.. Some aftermarket ones are made like the first ones and will not hold up..

Its not an easy job.. in general.. you need to unhook the timing chain.. and all the stuff from the intake and exhaust.. They lift with the head.. So you need some type of lifting device.. its heavy with the intake and exhaust on the head.. Not an easy job.. but not a real hard one ...

I have no idea as to cost.. I have done one but did not even try to keep track of the time.. and spent lots of time checking every thing.. If I had been doing it for wages I would have lost my job... :-)


Ken

On the back part of the head and block the oil going to the cam and rockers is right beside the water passage.. They are a little to close to each other.. because there is more oil pressure than water pressure the oil leaks to the water.. The head gasket seems to have a problem there... The newer gasket has a cure for this.. It does not however leak to the piston area.. just between the oil and water..

Ken

Hay that was intresting... I read your post and posted an answer and my answer was posted before your question..

Ken

I for one would really appreciate it if someone could explain how a bad head gasket could allow oil to get into the water, especially in an engine that seems to be running well. Wouldn't some emulsifcation take place rather than just collecting in the resevoir?

TIA

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Emulsion occurs when water gets into the oil. The M103 and M104 engines are known for their head gasket failures. At the rear of the gasket the water and oil passages are very close. When it fails oil gets into the water. It usually does not dump water in the cylinder nor does compression pressure get into the water jacket which will blow the coolant out.

The danger in driving like this is that the oil will soften the coolant hoses making them prone to bursting.

Sometimes the oil will leak to the outside line between the head and the block and since the engine is leaning 15 degrees the oil will not puddle under the car. The oil will drip into the slip stream and get blown along the underbody.

I was able to get a transfer case for my 300E 4matic in a week-this was this past summer-my guy got it from a source in Canada-email me and I will give you the name of the servicer I used-I am sure he will tell you the name of the supplier he used...The dealership here in CT told me 3-6 months for the part...and the cost on replacing a head gasket in my area ranges from $800-$1000-been there done that....

Fintail Fan:

"Just a few more questions: is this a fairly straight-forward DIY job for a person of moderate ability or should it be done professionally?"

I tend to do these $1000 jobs myself and if I'm strapped for time will let the shop do the $65 brake fluid change though I did do my last brake fluid change myself. Two months ago I replaced a head gasket and I spent all day Thursday and a Friday night after work till midnight finishing it up. I do these so infrequently that it takes me longer that it would someone familar with the process.

If you haven't done it before consider getting together with your local MBCA section and make a driveway-mechanic session out of the task. About a year ago we did exactly this with a Virginia Section member's 300E or E320.

In either event make sure the timing chain is properly bleed and tensioned when you finish.

Robbie - can you explain the procedure for bleeding/tensioning the timing chain.
thanks

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Jim