Head Gasket or Engine Totaled - M104?
 

My wife drove our 1994 E320 about 5 miles with a badly leaking head gasket. The car then would not start and was found to have a#1 cylinder full of glycol. Should I have dealer remove the head thinking it is the headgasket or head, or should I just change the engine?

You have a good chance that a head gasket will fix it. You could have a bent rod or whatever, but if it was sucking coolant while running, it may very well have been throwing it as fast as it was coming in.

If it were me, I would pull the head and check for a bent rod with focus on that cylinder. If there is no bent rod, I would do a valve job while the head is off and put it back together.

You are probably going to get it back in good shape with the the head work.

Best of luck,

When you tried to start it, would the engine crank but not start, or would it not turn over?

If it wouldn't turn over, then it was hydrolocked (antifreeze in the #1 cylinder), and you do have that potential for a bent rod...

G-Benz is right, but it sounds like maybe she drove it, then it sat and filled up the cylinder with coolant. If it was not started AFTER that point, it may very well be okay.

Hope this helps,

Wow! Great Replies! >
 

When we tried to start it it would not turn over - much as a dead battery. Even when I tried to jump start it it would not turn over although it made some peculiar rasping noises. So it never restarted once it sat for awhile. Also it never overheated throughout the whole episode. I take it you do not think the starter motor can bend a rod? You guys give me the confidence to tell the mechanic to pull the head, rather than the engine. What's more, the dealer has said he may be willing to replace the head gasket under goodwill - engine only has 87000 miles on it. Thanks again - VERY MUCH.

The starter motor sometimes can indeed bend a rod. This is like any other engine situation, you just can't know what you're up against until it comes apart.

The head must come off regardless, so it's time to do exploratory surgery.

Good luck,

Please answer this question...1995 E320 M104 with a (probably) head gasket leak. Bought at 39k miles...now has 52k on it. Before winter just changed the (green) coolant back over to pink MB. No sign of oil, no smell, no pressure, etc. The coolant does not appear to have dropped from the time of change. The engine DOES leak a fair amount of oil into the catch pan. You will see a little puddle here, a larger puddle there, etc. So the engine leaks oil--I assume this is the headgasket...car runs superb. BUT...Am I risking the engine by continuing to drive it like this until the head gasket is done this summer? Oil is changed about every 3k Vavoline 10W30. No sign of coolant on the stick.

As long as the symptoms are ONLY the oil leak and you keep oil in it, it really won't hurt anything. That said, you should be very dilligent in watching your coolant and dipstick to see that there is no oil in coolant and vice versa.

Best of luck with it,

m104 engines are notorious for leaking oil from the timing case cover or sometimes the valve cover, a leaky head gasket would also lead to loss of coolant.... you need to make sure exactly where the leak is first... did you try some commersial products to stop the leak?

ChipJ

You may want to look at installing a new O2 sensor. Coolant is one of the items that will " poison " an O2 sensor almost instantly. ;)

Yes, that's true, the 103 AND 104 engines are bad about leaking at the timing covers. When you said it was leaking at the head I took that to mean that you had already examined and found that this is indeed where it is coming from.

If you have not made this determination, wash the engine thoroughly and start looking for a leak.

Have a great day,

TROVERMAN...check the oil pan gasket as well.

My timing cover leak manifested itself as oil loss at the dipstick until repaired, but my now-leaking oil pan gasket leaves telltale signs on the garage floor.

On the M104, the impending head gasket leak usually shows up at the rear of the head...not to be confused with a valve cover leak (which also occurs on some models in the same manner just above the exhaust manifold)...

...bottom line, is, there are a host of leaks that can occur, and some are more imperative to correct than others...like Larry said, clean the engine first, to isolate the source of the leak(s)...

...and 52K sound a bit early in the mileage for a head gasket failure...usually it will occur between 100 and 150K. I'm at 138K on mine and still holding (knock on zebrano)...;)

This is all very odd...I was told that the leak occurs where the t-cover meets the headgasket, and to solve the prob the head gasket must be replaced and the t-cover resealed. Nothing is leaking from the rear of the engine...it appears to come from the front of the engine down the side (pass). There is a very small amount of oil which has appeared under the 1st or 2nd exhaust port on the manifold--probably blow back from the front cover leak. The eng. pan is always coated with oil...pan gasket? I always assumed the leak was where I said earlier, and it just leaked down. Now I am confused. There is always oil like on the plastic part of the alternator and that acessory braket.

Now we're getting somewhere.

The head gasket does not need to be replaced. This the standard upper timing cover reseal situation. The oil between the 1 and 2 runner is oozing back from the timing cover leak.

There is a special sealant from MB that is best to use at the bottom rear corners of the timing cover. Use oil on the lower U seal to allow the cover to slide back in place without moving the U seal. Replace the shaft seal while you have the cover off. Use your fingernail to see that the seal lip goes over the camshaft sealing surface to keep the seal from "folding" while you slide the cover rearward.

Good luck,

Update on M104 Head Gasket
 

I have had the car towed from Foreign Motors West in Natick, MA to Hatch & Sons in Wayland, MA. Ken Hatch seemed to have the same approach advocated by Larry and Benzmac. He felt that he could tell pretty well if there was internal engine damage by removing the coolant and turning over/running the engine for just a short time to listen for any weird noises. No noise = probably just needs a head gasket. It is also possible to borescope the #1 cylinder to see if it is scored. Mercedes dealer was not interested in doing this much diagnostic work so I fired them. Thanks again to all who posted.