Are the M104 head gasket and wiring harness issues a one time fix?
 

If there is evidence of replacement on an e320, should that be essentially permant fix? (excluding expecting either to last 500,000 miles of course...)

Also, how much money should I "discount" a car that has not had this done or evidence of it being done?

How much do I need to budget for each at an independent (not dealer) if not done? I know there will be a range on the price...

Thank you!
-Andrew

The harness should be a one time deal however the HG seems to be every 100k from what i've read.

I would budget about $1500 for the harness and another $2200+ for the head gasket service unless you want to do them yourself... These aren't the only major problems that can occur--don't forget a/c evap and throttle actuator problems that are prevalent.

Just be careful--you should be able to find a car with a good service history if you are patient. The wiring harness's are being made better, although I have heard of cars needing 3 before they are dead, and the head gasket situation kind of just depends on the car. Some guys don't have it happen until 150K+ miles and some need it at 75K...

You can see how these cars can be a "total loss" really quickly. Buy the service history just as much as the car itself...

Good Luck...

-GH

There are two brands of headgasket, Reinz and Elring. One has reinforcing tabs in the common failure area, one does not. If the reinforced gasket has been installed, I believe this is a one time fix. It might be hard to know for sure though--there just are not enough E320's with 200K plus miles. Not really enough "sampling" to draw a conclusion.....

The wire harness is a one time fix. You can verify an updated harness by the part number.

J. M. van Swaay

You hear people argue that the head gasket is a one time fix given the improved gaskets but in the real world it isn't. How long it lasts depends on which gasket and how well it was done. It's just a design flaw of the engine, i.e. cast iron block and alloy head in such a long engine. Lots of cars have had to have two or more head gaskets even with the updated gaskets. Dealer mechanic once admitted to me that the MB head gasket part was inferior to those available through jobbers. It's not really a DIY job which to me is the principal argument for a 119 motor.

All of these replies have been quite helpful!

-Andrew

M104 Head Gasket and Wiring Harness
 

The head gasket issue is completely random. I have seen some cars in the shop with 180,000 on the clock and the original head gasket is in there, and then I have known people who had them replaced under warranty with 34,000 miles. It completely depends. As for the wiring harness, many people still have the original. The reason why the original harness is still in place is due to it has never been disturbed. My 1992 300SE hairline cracks in the harness for years, and I did not replace it until I had to replace the trans, in which removing some plugs disturbed the harness and that was the end of that-

The replacement wiring harness looks similar but is heavier and has been bound with heat-resistant fabric. I am quite impressed. The quality is getting better and better guys! Hang in there-

The 2007/ 2008 models are just stellar out of the box!!! The 2007 E-Class is going to be the best value on the market as soon as the next-gen E-Class comes over shortly!!!!!:)

[quote=J.

The wire harness is a one time fix. You can verify an updated harness by the part number.

J. M. van Swaay[/quote]

Can anyone tell me where the part number is on a wiring harness? Also, which number(s) I should be looking for to determin if it's the updated part?

Thanks-
Andrew

There should be a white tag with part number very close to the ECU plug end of the harness. Sometimes you have to remove the battery to find it. Any MB parts dealer should be able to tell you if it is an updated harness.

J. M. van Swaay

I'll put in my $0.02.

When I had my 1993 300E (3.2) "E320", the mechanic who replaced the head gasket on my motor told me the "latest, greatest" Elring head gasket with the metal tabs / inserts have never failed on him.