How many higher mileage M104s with original head gasket
 

Hi all,

Have a 95 E320 and have been reading a lot on the forum here about the head gasket problem. The question: is this an absolute guaranteed failure after some period of time or are there a lot of cars that never have the gaskets replaced?

Also, on another car I had, after noticing some oil seepage between the head and block, I did a hot torque of the head bolts which helped a lot and was able to run the car for many more miles before getting rid of it and never replaced the head gasket. Has anyone tried this on the M104?

TIA.

philmartin

I believe there are 94-95 M104s that will never need the headgasket change. Mine failed at 66,000 and was replaced and now has 179,00 on it (>100,000 on the new gasket). The headgasket failure was not inevitable but common.

My M104 has 94k miles on the original headgasket with no signs of leaks so far (now watch it start leaking tommorrow).

Increase your odds..
 

by keeping your cooling system running correctly and efficiently. Typical head gasket failure results from overheating (warping) or near overheating, so keep your cooling system in good shape and you should have no problem!

Good luck :)

I believe the early head gaskets 93-95/96??? will all leak.

It is a problem of a bad design.

It has been said by many of the techs and moderators on this forum that the head gaskets were redesigned several times, and that finally the newest gaskets do not leak due to metal inserts in the gasket.

I did a search and found this one. According to these mechanics, it is unheard of to go past 100,000 miles w/o a leak. My head gasket started leaking at 130,000 miles with a small drip, but by 137,000 miles, it was leaking tremendously bad and I have had the gasket changed:

http://www.peachparts.com/shopforum/tech-help/34494-m104-motor-seals-guides.html?highlight=gasket

how long till u gotta replace it?
 

Can I ask...

If or when (hopefully never) my head gasket fails, is the car undriveable? Do I have to get it replaced there and then? Or is it possible for me to replace the head gasket at home?

Thanks

Christian

1989 300TE
1994 E280

Mine was leaking badly at 54k miles. No other signs, but I replaced it anway. I felt that I was going to have to do it eventually. I would like to ask the same question for the wiring harness on these models. How long have you gone before having a problem with them? Or is this not a sure a thing as the head gasket going out?

The head gasket leak on these engines is usually just an external leak, not a mixing of oil and coolant. When it needs to be replaced is really when you cannot tolerate the dripping anymore as long as you keep the oil topped off to its proper level.

Could not hurt any to follow the TSB on reduction of oil capacity on 104s [ down i/2 qt from man specs ] and to go with the dip stick "In Between mark" when
at operating temp.
Seems to have helped a few other leaks...
Though prob not the HG, which has been modified......

From my experience with my head gasket, and talking to my local mechanics, and the posts on this site, I believe you can let your gasket just leak only until it gets so bad that you can't stand it anymore.

I took my car to Mr. MB Motors that Ashman recommended in the Good Shops forum. Enrique has been a MB dealer technician for about 30 years, and said that my leak was among the worst he has ever seen.

My leak was so bad that oil was pooling on the floor of my garage. The leak was so bad that the oil residue on the engine block was smoking when I would drive the car. When I parked the car in the garage at night, the garage would smell of burning oil.

When I took the car in, finally, to Enrique, he put it up on the lift, and the whole undercarriage of the car was covered in oil. The tail pipe, catalytic converter, exhaust manifold, etc. were caked in wet oil. It was a helluva mess.

It seems that some gaskets leak very slowly and will stay that way for a while. My went from a tiny drip to a waterfall within 1,000 miles.

Regarding the wiring harness, from '93-'95 on M104 engines - they are all bad. It's not a question of if, but when.

If you do a search, you'll seen numerous posts of owners whose wiring harness went out and ruined some very expensive parts with it, turning an $800 wiring harness replacement cost into a several thousand dollar repairs, taking out throttle actuators ($1,100 part), EHA's, idle control valves, computers, etc.

I don't understand why anyone would let this go, considering their high failure rate and the possibility that it will take out much more expensive parts with it.

Check out these posts:

http://www.peachparts.com/shopforum/tech-help/38054-95-c280-wire-harness-badwill.html?highlight=engine+wiring+harness

http://www.peachparts.com/shopforum/tech-help/40246-picture-bad-wiring-harness-400e.html?highlight=engine+wiring+harness

http://www.peachparts.com/shopforum/tech-help/40795-94-c280-wiring-harness-gone-bad.html?highlight=engine+wiring+harness

http://www.peachparts.com/shopforum/tech-help/40246-picture-bad-wiring-harness-400e.html?highlight=engine+wiring+harness

http://www.peachparts.com/shopforum/tech-help/18441-94-c280-wiring-harness-leaking-head-gasket.html?highlight=engine+wiring+harness

http://www.peachparts.com/shopforum/tech-help/6064-engine-wiring-harness-hfm-control-unit.html?highlight=engine+wiring+harness

Even the newest m104 engines can still leak. My dad drives a 1997 w140 with the m104, and had the head gasket replaced. This happened a few years ago. The car had very low milage at the time - heck, I think it only has 25k miles now. In defense of Mercedes, the leak had to be exceptionally small, but dad has a very good - perhaps overzealous - little dealership which insists on his car being absolutely perfect.

head gasket
 

94 e320 with 151k miles 241k kilometers
minimal leak at front not a problem, noticebale on trans cooler lines at rad bottom, not considering a head gasket yet

I believe the "oil in the coolant" problem is symptomatic of M103 head gasket failures (which is not as common a problem as on the M104). For the M104, the external leak near the rear of the cylinder head just gets worse.

In it's severest form, the engine simply overheats rapidly, and that would put it in "undriveable" mode. Otherwise, when you choose to do the replacement is based on how much oil leakage you can tolerate.

I'm at 121K miles on my 93 W124, and during my latest trip to the dealer, the service advisor noted that the head gasket was leaking and should be replaced.

I think I saw the leak beginning about 20K miles ago, so it's a slow leak. Replacement is inevitable, and I'm saving up for the eventual task as we speak.

Consider that while the head is off, it's a good time to look at doing some other top-end reconditioning if the budget allows...

Good advice.

since replacing the head gasket is 95% labor and 5% parts cost, it would be foolish to not spend the extra $300 and get a complete valve job done with guides and seals.

When discussing headgasket leaks on a 104 or 103 motor they leak oil externally , couple 103 I have seen coolant leak in the ol but not very common. When doing head gaskets we reseal the lower timing cover as well, it will leak . As for wiring harness' well most produced from 92-95 have the blues of the harness. E-320's have the engine, throttle valve and starter alternator harness problems. C-220 have the engine,trans ,throttle valve and some you have to remove airpump and remake the harness for it. Any with the 119 motor in it have the engine,throttle valve, starter alternator (on some) harness bad. v-12 (120) motor have the engine,starter/alternator and on some the harness that go to the HFM air flow meter bad. Like most things they cost money and will have to be fixed some time. Remember on the head gaskets to replace the head bolts and use permatex (right stuff) on the timing cover. Have done alot of these reseals and have learned from them. Just paaing on some advice:D