M104 Head Gasket and 722.6 questions - PeachParts Mercedes-Benz Forum

KyAl1013 · #1 06-11-2002, 07:47 PM

I know this topic has been beaten to death and I have searched the archives, but I have a few questions that I have not been able to find an answer to. I have recently purchased a 1997 E320 with 32,000 miles.

Did MB have a better head gasket design by 1997 on the M104 and, if so or not, what would be an average mileage for replacement (not min or max, but average) on this year? Does time (age) affect the gasket or is it mostly mileage (usage)?

Is it confirmed that there is a better replacement now?

When people say where this gasket leaks, they say at the right rear of the engine and at the front by the timing chain cover? Which side is the right rear (driver or passenger side for US vehicle)?

When these gaskets go, do they just usually leak oil externally or is it common for antifreeze to get into the oil also? What I am trying to find out here is if the infamous M104 head gasket leak also has potential for ruining the engine bearings?

What is the best procedure for checking for leaks? Should I have a service shop do it or can I see these areas fairly easily?

I have read that there are several updates to the 1997 722.6 transmission because of some design problems. Does this create a shorter life expectancy for my 722.6 if these have not been done? I don't know how I would go about doing these updates since the trans shifts just fine and the car is out of warranty (4 year or 50,000 miles), but I really don't want to have to pay for a 722.6.

Thanks for your time. I hope you all aren't too bored by my rehashing these topics.

jsmith · #2 06-11-2002, 08:41 PM

there was a post about the head gasket problem being fixed in the 97 model year. you can do a search and maybe wait for someone to reply to this thread to verify it. as far as MB is concerned they did not have a head gasket problem in the M104 engine. they just developed a better head gasket (see Steve Brotherton's [aka stevebfl] dissertation on the problem and the new design - a most excellent piece). re: 722.6 tranny - the concensus seems to be not to follow MB's guideline as regards ATF fluid service intervals - change it early!

royaiii · #3 06-11-2002, 09:10 PM

I too have bought a 1997 E320 recently and our mileage is close together. I have an oil leak on the front oil seal that the previous owner thought was normal. I havent attempted goodwill yet but I will keep you guys posted. As far as the tranny goes, I think it is too early to diagnose any problems on cars w/ 30k miles. I think there was some problems with it but it is not a definite occurence. Most likely a handful of owners experienced this problem (most likely people like me whose car's production date is late 96 although I have had no problems w/ it.)

loubapache · #4 06-11-2002, 09:14 PM

I have a 97 E320 with 60kmi on it.

I wish you are right about the fact that the head gasket was fixed in the 97 models.

However, the timing cover seals were replaced on my car at 48kmi and it is a bit wet again in the passenger side/front of the engine area.

About the tranny, I believe there were early problems with the electronic control module. Mine was replaced at around 15kmi.

blackmercedes · #5 06-11-2002, 10:46 PM

1997 AND 1998 model year 722.6 trannies have some problems, but despite so many out there, as a percentage it's surprisingly low.

The 97's have an updated valve body for some applications (I understand the SLK is the prime culprit here) and others have the control module changed.

I talked to a very knowledgable tech this week that talked about seeing a few 1998 722.6's with a failing temp sensor that would throw the car into limp home mode. The "other" shop would dissconnect the wiring/sensors, and rebuild the tranny. Problem NOT solved.

As to the 1997 M104 engines, I know one 1997 C280 with low miles and a leaking gasket, and one 1997 E320 with ridiculous miles and not one single leak. Luck of the draw?

KyAl1013 · #6 06-12-2002, 08:59 PM

Thank you everyone for taking the time to give me your replies. I appreciate it!!

I believe that these questions from my first post are still unanswered so I am going to try again:

Did MB have a better head gasket design by 1997 on the M104 and, if so or not, what would be an average mileage for replacement (not min or max, but average) on this year? Does time (age) affect the gasket or is it mostly mileage (usage)?

When people say where this gasket leaks, they say at the right rear of the engine and at the front by the timing chain cover? Which side is the right rear (driver or passenger side for US vehicle)?

When these gaskets go, do they just usually leak oil externally or is it common for antifreeze to get into the oil also? What I am trying to find out here is if the infamous M104 head gasket leak also has potential for ruining the engine bearings?

What is the best procedure for checking for leaks? Should I have a service shop do it or can I see these areas fairly easily?

Thank you in advance for your replies!

P.S. Any other info on the 722.6 and whether or not a non-updated one will likely suffer a shortened life would be appreciated also...

KyAl1013 · #7 06-13-2002, 09:52 PM

BTT

KyAl1013 · #8 06-15-2002, 11:28 AM

BTT

Ali Al-Chalabi · #9 06-15-2002, 12:03 PM

When the head gasket leaks, it is usually only an external oil leak, this problem has not been known to mix coolant and oil. To the best of my knowledge, the problem has not been fixed for the 97 engines, but someone correct my if I am wrong.

As far as the tranny goes, if it behaves like it is supposed to, then do not bother with the computer or valve body. My C280 has not had either changed and it is just fine.

On my mom's E320, they changed the computer. There was a vibration from the driveline in the 35-45 mph range. Although the dealer never said why, I attribute it to the torque converter clutch fully engaging with near zero rpm slip at lower speeds instead of following its program of computer controlled slip at that speed range and thus transmitting vibrations through the drivetrain. It was no major problem with her car, but it was not behaving like it was supposed to, was covered under warranty and would not have made a major difference if it was not changed.

Gilly · #10 06-15-2002, 11:19 PM

I am not aware of any production change to the 97 vs pre-97 re. the head gasket.
First, the RIGHT side of the engine is the passengers side. The 2 common areas for a 104 head gasket leak is the right rear corner and right front HOWEVER if the front cylinder head cover "lip" seal leaks, it is difficult to distinguish from the right front corner of the head gasket itself leaking. The tech has to be very careful to clean, drive, and reexamine the area if the leak is right front. The front cover is much cheaper to reseal than doing the whole head gasket. 1/2 the time, with a front engine oil leak, the front cover just needs resealing.
With the 104, a failed head gasket will usually just oil externally, no mixing of oil and coolant. The decision to do the job is up to you, how much leakage can you stand?
It seems like if you are going to have a leaking head gasket or front cover, it'll do it around 75,000-125,000 mile range.
The 722.6 did have several modifications done to it in production. It seems like if they were going to fail, they would do it rather soon. If yours has alot of miles on it, I wouldn't sweat it too much. To update some of these parts is horrendously expensive for both parts and labor.
One thing that is fairly common in the 722.6 is called the conductor plate, it contains the temp sensor and more importantly 2 speed sensors. if one of these fail it will lead to the tranny going into limp-home mode. It mounts to the top of the valve body. I don't believe there was a significant change made to the valve bodies since the 722.6 came out, but there were some other changes made.
Gilly

KyAl1013 · #11 06-17-2002, 10:26 PM

Thank you for the answers to my questions. I appreciate your time.

Kyle

SPIKES · #12 05-30-2003, 11:15 AM

Quote:

Originally posted by Ali Al-Chalabi

On my mom's E320, they changed the computer. There was a vibration from the driveline in the 35-45 mph range. Although the dealer never said why, I attribute it to the torque converter clutch fully engaging with near zero rpm slip at lower speeds instead of following its program of computer controlled slip at that speed range and thus transmitting vibrations through the drivetrain.

i found this thread from the search. this is exactly what my car is doing.
Where is the computor on my car 1997 e320 and how can i test to see if this is my problem?
are the computors expensive?

your help is appreciated.

SPIKES · #13 05-31-2003, 08:03 AM

any suggestions?

SPIKES · #14 05-31-2003, 02:42 PM

bump

SPIKES · #15 06-02-2003, 09:53 AM

has anybody else had this problem?

ANY help would be appreciated.

thanks