The head gasket has a leak. My mechanic told me that that the fluid on my garage floor was caused by overfilling the transmission fluid. The dealer says the engine is leaking from the cylinder head gasket. The cylinder showed 165 to 175 on compressor test, with cylinder #1 at 30% leakage, cylinder #3 at 20% leakage, and the rest at 8-12% leakage. The dealer wants to charge $2600 to fix. I had the head gasket replaced approximately 20,000 miles ago, and when I told my mechanic what the dealer said, he told me he would fix it for $1800. I took the car to another mechanic who said he wouldn’t do anything because it’s not that bad. He said to have the gasket replaced when the leak gets worse or if something happens. I just want to know if this is something serious enough that I need to fix now, or can I save some money by waiting.
Just curious, when the head gasket was replaced, did they inspect the head to verify that it was not cracked or warped? How many miles are on the engine, has it ever been overheated? What are they planning to do for $1800 (that sounds a little high if they are just going to do the gasket, and it sounds a little low if they are also going to rebuild the head)?
I don?t know whether the head was inspected for cracking or warping. There are now 133k miles, and it has never overheated. I don?t know what the mechanic will do for $1800, but for $2600 the dealer is going to replace cylinder head gasket, replace rear heater hose, complete engine diagnostic test, and do both a cylinder compression and leakage test. There is also a slight surging when the car is almost coming to a stop but I speed up a little, and the dealer said they would replace 2 vacuum lines for that.
Any more comments on whether I should proceed with having the work done and by whom?
The head gasket problem in the M104 engines is “Officially Recognized” by Mercedes. The problems usually first present themselves as leaking oil at the front and the extreme rear of the head. This is probably where your oil leak is coming from.
If allowed to continue the gasket will disintegrate further, causing fluid migration i.e. oil in the coolant and coolant in the oil. Neither is a good thing.
There is an updated special gasket made by Mercedes that will solve the problem. If you fail to use this gasket,it will start leaking again in short order.
But you already know that.
As stated, Mercedes will acknowledge that a problem “May” of occurred with this engine. Even though the car is now out of factory warranty Mercedes has been known to split the repair bill 50/50, replacing with the right updated gasket. This repair should fix the problem completely. Go through a Mercedes dealer and get the Zone Rep involved. He’ll no doubt know what you’re talking about.
So, best case is getting the repair done with the correct parts at the dealer and only having to come up with 50% of the tab.
Hello Benzman, Thanks for the great information. Had I known this two years ago I would have contacted the dealer at that time. I will follow your recommendation.
The head gasket problem in the M104 engines is “Officially Recognized” by Mercedes.
Good info, but I was wondering if the 104 engines also had head issues like the 603s, or if it’s just the gaskets on those (I don’t know much about their gas engines). What concerns me is the OP’s statement that he had the head gasket replaced 20K miles ago, it there something else going on here?
My guess would be the proper updated gasket was not used for the replacement, hence a premature failure.
The M104 heads themselves are not the problem, it was the gasket material used.
The factory said it had something to do with not using the proper Mercedes coolant.
The 603 heads were, in my opinion, a design flaw from the get go. Some 603 engines went a very long time (300k mi.) before exhibiting problems, but most failed in the first 100k.
The addition of the infamous “Trap Oxidizer” on '86 and '87 engines is what most people attribute the flawed heads failure to.
Ironically the heads off of the next generation 603.971 3.5 liter engine didn’t have the flaw, and would repair the earlier engines with a swap.
I say ironic because the next generation had the flawed connecting rods problem. Fix the top end, and now it’s the bottom end…
It was enough to get Mercedes out of the diesel business for several years.
[/quote]My guess would be the proper updated gasket was not used for the replacement, hence a premature failure. The M104 heads themselves are not the problem, it was the gasket material used. [quote]
Thanks, I had always heard the 104 was a pretty good engine. I didn’t know about the head gasket problems. $1800/$2600 sounds a little steep for just the gasket, how many hours does it take to R&R the head on one of those?
I agree on the aluminum head diesels; between the infamous #14 heads on the 603s, the 3.5 “rod benders,” and the trap oxidizers they had some significant problems. There’s a reason I still drive 616/617s.