Hey guys, I recently bought a e320 94' with blown head gasket (i know its not a diesel) and was wondering do I need to mill the head also or can I just replace the gasket and call it a day?

Thanks!

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1987 Mercedes Benz 300D Turbo Black/Black

With the head off you may as well check for level, and machine it if necessary.

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Cheers!
Scott McPhee

1987 300D

How man miles on the engine? Burning oil before? Mercedes gas engines should have at least new valve seals installed.

Get the real deals from a dealer as some aftermarket seals are inferior. Flip the head upside down and put some thin lubricant in the valve pockets that are closed. Liquid level stays up for hours on all valves under test?

Move the cam if still on the head and check them all. Or you could do a leakdown test before removing the head. to see what the general condition is like.

Once somethingis apart usually it is much harder to establish faults in my experience. Others may find otherwise. A precautionary valve job used to be cheap but not so cheap anymore. Also when the valve springs are removed to install new seals checking for valve guide wear is always wise.

So there are things that should be done with a head once removed in my opinion. Unless the car has very, very low milage.

Agreed. Valve stem seals and possibly valve guides as a minimum. A machine shop that specializes in heads can advise you, clean up your head and tell you what condition it's in. It may be a bargain or it may need more work than you're willing to spend. Better to find out now before you invest a lot of time installing it.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I would be worried that the Engine had previously been overheated as the cause of the Head Gasket Failure.

If the above was the case there is a really good chance that the head is warped. (The top of the Engine Block should also be checked to be sure it is not warped.)

And, the Head should be pressure tested for Cracks or use one of the other crack detection methods.

If it turns out the Head is warped take a good look at the Camshaft Bearings area for abnormal wear.

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84 300D, 82 Volvo 244Gl Diesel

The head is still on the car, im just trying to take few things apart in front of the engine (like that retarded clutch fan which is held by 3 hex screws... ugh!). I was thinking of maybe doing a compression test + leakage.

But the guy that i bought the car from(brother's friend), he took mostly everything apart because he wanted to remove the engine and replace it with a used one... but never got to it since the people at the house that he used to store the car told him to either move the car or they will call towing

He said that the engine has around 250k miles. I will for sure be changing valve stems when I be doing head gasket. I will need to ask the guy more questions (thx barry!)

I dont want to sound stupid, but the guy drain the oil and coolant, do you guys think I should put some in it? I am certain that i will need to put oil in the engine, not sure about coolant when I be doing compression/leakage...

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1987 Mercedes Benz 300D Turbo Black/Black

On the 617s the Compression test is supposed to be done with the Engine Hot. If a person was going to do it the right way the cooling system needs to be filled.

If you are going to do the tests cold (not running the Engine at all) no need for the Coolant but as you said you do need Oil because you will be cranking the Engine.

However, with no Coolant during the leak back test you would not be able to see any Air Bubbles in your Coolant Overflow Tank that would indicate a Head Gasket Leak into the Cooling System.
But, you might not care about that since the Gasket is going to be replaced.

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84 300D, 82 Volvo 244Gl Diesel

Ok guys, I did compression testing and here are the results:

1. 175psi
2. 180psi
3. 160-65psi
4. 180 psi
5. 140 psi
6. 25-30psi

NOTE: The engine was cold (60-70 degrees Fahrenheit outside)

I already taken the head off and you can clearly see it was cyl. 6. I'll post picture of the gasket (the head is already in the shop). The head had a small chunk missing but they said that they are able to fix it. Since I wanted to do it right the 1st time, I've also got the valve stems and gave them to the shop so they can replace them, they also informed me that exhaust valves had bad valve guides. So they quoted me almost 600 bucks for everything, so im guessing thats not bad. Now i got few questions:

1. Whats the symptom of bad valve guides?
2. Does exhaust system from any 6 cylinder mercedes is the same? (the guy took it off, and some1 in his family scrap it because they "thought" it was junk... it was right before i went to pick it up -_-)

I'll keep you guys updated Thanks!

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1987 Mercedes Benz 300D Turbo Black/Black

On a gasser, bad guides -> burns oil, blue smoke

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Cheers!
Scott McPhee

1987 300D

oh ok. I got the head back from the shop, looks like it just came out of the factory. The fixed the chunk missing and everything. They also told me that there were few cracks but they welded them, i was surprised since i dint see any.

now, when i be putting the cylinder head back on the engine, do i "lube" the head gasket or just put in there without lube?

what about the engine bolts, do i use thread locker on them or no?

thanks guys

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1987 Mercedes Benz 300D Turbo Black/Black

Am I the only one concerned?

Head gasket goes on dry. Head dry, block dry.

Head bolts go on with a light coat of oil. Chase the threads in the block then make sure the holes are clean and dry. No thread lock!

Cracks welded? We'll be hearing from you soon. [edit] Oh, you meant M104. Maybe the welds will hold.

Sixto
87 300D

Because of the cost factor try to find a complete exhaust system in a pick and pull. All six cylinder gas are not the same in my opinion. You can check this out but try for a simular car is easiest in my opinion as a donar.


You will need the torque values and recommended proceedure to torque them down on that head . Thats if you do not have them already.

Sixto: You know how to make a person happy

I was thinking about the same thing, but its hard to find e320 these days, thats why i was asking if maybe different engines use the same exhaust system (like the exhaust routing on the chassis). I have the exhaust manifolds, but the rest i dont have. Im guessing patience is my only option for now...

As for torque specs, I have the paper work on how to remove the cylinder head and all of the torque specs that I need are listed in it. So Im good for now.

Thanks guys!

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1987 Mercedes Benz 300D Turbo Black/Black

BTw, I cant remember what I used on my 606 diesel, but ordinarily ARP thread sealant is used on head bolts. Again, donnow if the MBz has bolts into water jackets or not.

Ok guys the head is on the block and the head bolts are tightened to specifications. I've put the timing chain on and did the timing. but im facing another problem, for some reason, when i tightened the timing chain tensioner, the timing chain felt over tightened... did i did something wrong?

the timing chain fell in the oil pan before i did the timing but idk if i've routed the timing chain back up correctly? do you guys have a picture of the timing chain routing for 104 engine?

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1987 Mercedes Benz 300D Turbo Black/Black