Hi all,

I just replaced the head gasket on my 1995 E320 and it ran very well but was leaking water and oil. I found out that the o-ring that goes on the metal piece at the heater hose connect to the head at the drivers side rear of the head was bad. I have a brand new o-ring and so I am pretty confident that was the source of my coolant leak. Now I need to track down the oil leak which is the reason I replaced the head gasket in the first place. I am as sure as I can be that the oil is not leaking from the valve cover. I saw one place on the drivers side of the head gasket, not far from the above mentioned heater hose connection where is looked like oil might have been leaking but I am not sure.

I have the valve cover off and that gasket looks fine as I expected. The only place on the valve cover that I am unsure about is at the very back where those half moon gaskets are that go below the regular gasket. I think that the passenger side one might have been leaking. If it was it would sort of make sense as to where I was seeing the oil dripping from under the car. It was definitely the rear of the engine. Is there any trick that I should know about to these strange half moon insert gaskets? As far as I could tell, without having dealt with them before they seemed to be right in place when I took the valve cover off. It is a brand new head gasket and I had the head shaved. I did the head bolts in the three stage manner going from inside to the outside. Used a torque wrench and then two 90 degree turns. I even used tape before I did each round to make sure I kept everything straight. It is hard for me to imagine how a shaved head with a brand new gasket could leak at that gasket if it was tightened down correctly. Any guesses?

My big question is, is there anything I should be doing now other than loosening the head bolts and doing the tightening sequence over? I really do not want to remove the head again and buy another gasket set if I do not have to. I have inspected all of the head bolt holes thinking that one or more of the washers could be missing. None were missing. The bolts are brand new and looked very clean. When I did the tightening sequence I had no problems that I was aware of. My plan is to clean everything as much as I possibly can and then button it up again. I am getting very good at getting the intake manifold on and off but I hate to be giving it the wear and tear. New wire so that is not a problem.

The main problem is that I can see just about nothing when the intake manifold is on. Is there some bare minimum amount of work I can do to get it just to run so I can see where a leak is coming from?

Any thoughts or ideas very much appreciated. It is running better than ever (at 200k miles) and I really am anxious to get it back on the road.

Thanks very much,
Jim Lee
1995 E320 Wagon

One of the things the service manual mentions is that the head gasket expands and the engine will not be tight untill it reaches operating temp. Therefor they warn about pressure testing the cooling system until you get the engine up to operating temp.

Have a look at this thread:

A New M104 Oil Leak: "Thrust Pieces?"

Hope it helps.

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles