Just got bad news... - PeachParts Mercedes-Benz Forum

dtf · #1 06-29-2004, 03:09 PM

Brought the '94 wagon in for brakes and rotors all the way around and to find a slow coolant leak and the dealer said that the coolant was seeping out the passenger side of the head gasket near the rear of the engine. This is not the original head gasket as I had that replaced at 67,000 miles. Looking at about $1,200 for that job. I'll do a 'search' looking for other things to do when they have the head off. I don't know the design of the headgasket but I thought oil usually leaks out at that spot.

mbdoc · #2 06-29-2004, 05:44 PM

There is an o-ring on the engine lifting "eye" on that side that can make you think a head gasket is leaking.
MB number 012-997-51-48. Takes about an hour to replace.

J.HIDALGO · #3 06-29-2004, 10:21 PM

I have an older model and I though I had a head gasket leak. Well, it was that "o" ring. Do a search ! I posted this before. I hope it is an "O" ring and not the head gasket$$$$.

Gilly · #4 06-29-2004, 10:58 PM

I agree with MBDOC, it's that o-ring. It's a pain to change, but not like having to do a headgasket! The typical scenario with a headgasket is an OIL leak in this area, not coolant. It doesn't make sense that it's this o-ring over on the drivers side, but what it does is drips down on the left side, then across the top of the engine block itself behind the cylinder head, then down to the ground on the right side, this is because the engine leans a little to the right on these 104's. I wonder if that makes the engines "conservative" (right leaning, hee hee)

Gilly

Greg in Oz · #5 06-30-2004, 02:22 AM

I remember after replacing the head gasket on our '90 300TE a few years ago, the horrible feeling after completing the job only to see coolant leaking at the rear right side of the head where oil had previously been leaking. Closer investigation revealed it was leaking from the O-ring at the heater hose connection (at the lifting eye) on the opposite side of the head and running around to the right side before running down the engine block. I was much happier to replace the O-ring than to have to remove the head again (especially unecessarilly). I realise that mine is an M103 and yours is an M104, but I assume they have a similar arrangement (I haven't studied the M104 in this area). I'm with the techs on this. It's sure to be that O-ring.

Gilly · #6 06-30-2004, 04:57 AM

WOW I didn't know the M103's would leak like that too, my experience has been that the M103's if they leak at that o-ring would just generally make a mess on the left side, more towards the rear, not the right rear corner like a 104. Maybe your 103 thinks it's a 104! If a 104 leaks at the o-ring, seems like it ALWAYS heads for the right rear corner.

Gilly

dtf · #7 06-30-2004, 09:10 AM

Thanks guys! Gilly - I understand what you are saying. Not only is the engine 'conservative' but I've noticed it also is not 'true North - South' orientation in the engine compartment. The aft part of the engine is a couple of degrees toward the passenger side. I'll relay that info to the dealer.

I love this site.

J.HIDALGO · #8 06-30-2004, 05:20 PM

Do you think the dealer is going to admit they made a mistake? NOT! but, they may be right. What do you think they will tell you: replace an "O" ring or replace the head gasket? $$$$

My advice, for what is worth, find a good and honest independant MB mechanic and stick with him.
P.S. My car has also a 103 engine.

dtf · #9 07-01-2004, 10:25 AM

Thanks J.H. I am looking for a good indy in S.E. CT but no luck yet. My dealer has very good customer service and do very well with maintenance things but their trouble shooting skills are sometimes not so good.

yosshimura · #10 07-01-2004, 11:21 AM

Take the car out of there and take it somewhere else. The dealer is smarter than you and me and probably knows what's really wrong with the car... Come on how many cars have they seen with this problem???

scenario: Pocket $1K and do expensive job or pockt a couple hundred on a less expensive job... You know they have to make those payments and with scr.ewing over you and scr.ewing over guys claiming they need computer modules or computers while just changing ovp's... they make a killing....

Just go to an independant or it sounds doable, do it yourself. Definitley don't give the business to the dealer who was going to nail you

Hatterasguy · #11 07-01-2004, 09:03 PM

dtf I don't know if Milford is to far but right off exit 34 or 35 on I-95 is a MB mechanic that seems to be pretty good. I have never gotten any work done by him but their are always tons of nice W126, W124, W201, W210, and R107's outside. Someday I might take my car to him.

dtf · #12 07-01-2004, 10:10 PM

Thanks, I'll have to look him up. Unfortunantely Milford is on the other side of New Haven from me. Right now I'm running the car with the cap only partially on - is that a cause for concern? I figure the reduced pressure on the system might buy me a day or two on the o ring.

Greg in Oz · #13 07-01-2004, 10:44 PM

Quote:

Originally posted by dtf
Right now I'm running the car with the cap only partially on - is that a cause for concern?

Operating cooling systems at pressure is done primarily for two reasons. Firstly, it raises the boiling point of the coolant. This reduces formation of bubbles which would otherwise reduce conduction of heat into the coolant. Secondly, it helps reduce cavitation at the coolant pump. Cavitation reduces the pump's efficiency.

Remember too, that these cooling systems were designed to operate at pressure with the thermostat regulating temperature to relatively high values, close to and even above the the boiling point of water without any additives. So long as your are aware of these issues while driving with the pressure cap released, and drive the car accordingly you should be OK. I would suggest avoiding high ambient temperatures, high engine loads, high engine speeds and use of the air-conditioner. Use of the heater can also help reduce the coolant temperature.

I remember many years ago, "nursing" my 350SLC back home over several hundred kilometres with a badly leaking coolant pump. I too, removed the pressure cap to reduce the coolant loss. The problem was that on any uphill climb or with any attempt to cruise at speed on the freeway, the coolant wanted to boil, all aggravated by summer temperatures at the time.

Chevota · #14 07-01-2004, 10:55 PM

Smart man, I was going to suggest breaking the seal on the cap. It will be fine as long as you don't blow too much water out, and that probably won't happen. I hope that the O-ring is the problem. If not, I would try some Alumaseal. It's powered aluminum sold at any parts store and it works great. But brace yourself, it'll set you back about $2. I've tried and have seen others try different brands of sealers without much luck, or only to have it leak again months or weeks later. Alumaseal will stay in the system and patch future leaks as well.

Good luck!!

dtf · #15 07-02-2004, 02:42 PM

So I call the dealer and say 'I've been doing some reading and I want to try an experiment. I want to replace the engine lifting 'eye' o ring because the way the engine sits and the lack of other clues like no oil in the coolant and no coolant in the oil suggests this part and not the head gasket'.
He says 'The WHAT??????????????????? Had to laugh to myself but made the appointment anyway. I'll update later.....

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