What are the known issues with each of the diesel engines (1981-present) - PeachParts Mercedes-Benz Forum

graydonblair · #1 06-16-2010, 07:08 PM

If there's a thread for this, just point my way, I couldn't find it.

Just wondering what issues each of the different diesel engines tend to have (ie. ones to avoid) over the years.

Looking from about 1981 forward.
ie. 617.951 - xxxx

I'm aware of head gasket issues with engines with the #14 head, but what other issues are out there that are major enough to watch for?

Here's some info I've found:
Engine information: (Very cool page!)
http://www.mbwholesaleparts.com/wholesaleparts/ModelChart/usmodels.htm
(has gas engines too, but is very specific on which engines were in which cars during which years)

More Mercedes Engine information:
http://en.wikipedia.org/wiki/List_of_Mercedes-Benz_engines

OM617 - 5 cylinder 3.0 liter
http://en.wikipedia.org/wiki/Mercedes-Benz_OM617_engine

OM602 - 5 cylinder 2.5 liter
http://en.wikipedia.org/wiki/Mercedes-Benz_OM602_engine

OM603 - "Rod Benders"
http://en.wikipedia.org/wiki/Mercedes-Benz_OM603
- Issues: Weak piston rods

Thanks,
Graydon

pawoSD · #2 06-16-2010, 07:33 PM

616/617 - Its only issue is that it is so awesome/reliable that the engine will probably outlive you.

I've put 100k on mine and it still runs as good or better than when I got it.

601/602/603 have more tendency to headgasket issues but are still excellent engines

early 603 the head can crack if temps get too high

603 3.5 liter = rod bender engine, but the heads are good

the later engines also seem to suffer from more fuel leak issues than the earlier engines.

Actros617 · #3 06-17-2010, 01:17 AM

OM617 got an issue that is the oil line tends to burst, bringing the mighty 5 to its knees.

DieselPaul · #4 06-17-2010, 01:53 AM

Quote:

Originally Posted by Actros617

OM617 got an issue that is the oil line tends to burst, bringing the mighty 5 to its knees.

Looked at one like that last month. It was $250 but a 350k mile motor that had been run without oil turned me off. No room for more parts cars, I wanted a $500 runner I could fill with veggie oil and kill.

turbobenz · #5 06-17-2010, 03:52 AM

Quote:

Originally Posted by DieselPaul

Looked at one like that last month. It was $250 but a 350k mile motor that had been run without oil turned me off. No room for more parts cars, I wanted a $500 runner I could fill with veggie oil and kill.

Same here. I want a 300 dollar 240d stick to pour used motor oil and veggie oil into

LUVMBDiesels · #6 06-17-2010, 05:58 AM

The one weakness I found in my 617 was that the oil pumps can fail. Mine did that at 75 mph on the NYS thruway.

!!
The oil pressure went from 3+ to 0 in an instant! By the time I pulled off the road - like 30 seconds - she was toast and had thrown the proverbial rod. Oh, and the engine only had 149,000 on it!

JohnHef has a piston that a 617 threw right out of the engine hanging in his garage!

I do agree on the sound of the 5 cylinder. It reminded me of a WWII radial when it was running at 3000 RPM. I guess the odd number of cylinders does that.

My OM603 now has 347000 on the #14 head!

buffa98 · #7 06-17-2010, 07:17 PM

Quote:

Originally Posted by LUVMBDiesels

The one weakness I found in my 617 was that the oil pumps can fail. Mine did that at 75 mph on the NYS thruway.

!!
The oil pressure went from 3+ to 0 in an instant! By the time I pulled off the road - like 30 seconds - she was toast and had thrown the proverbial rod. Oh, and the engine only had 149,000 on it!

JohnHef has a piston that a 617 threw right out of the engine hanging in his garage!

I do agree on the sound of the 5 cylinder. It reminded me of a WWII radial when it was running at 3000 RPM. I guess the odd number of cylinders does that.

My OM603 now has 347000 on the #14 head!

The #14 head issue seems to border on paranoia at times. I have 240K on mine and no issues (with the head at least).

Moral of the story-find one with maint records sift thru them and come here to get opinions

JEBalles · #8 06-18-2010, 10:55 AM

Quote:

Originally Posted by LUVMBDiesels

The one weakness I found in my 617 was that the oil pumps can fail. Mine did that at 75 mph on the NYS thruway.

!!
The oil pressure went from 3+ to 0 in an instant! By the time I pulled off the road - like 30 seconds - she was toast and had thrown the proverbial rod. Oh, and the engine only had 149,000 on it!

JohnHef has a piston that a 617 threw right out of the engine hanging in his garage!

I do agree on the sound of the 5 cylinder. It reminded me of a WWII radial when it was running at 3000 RPM. I guess the odd number of cylinders does that.

My OM603 now has 347000 on the #14 head!

Are you sure the oil pump failed? As another forum member once said "the oil pump is the happiest part of the engine--it is constantly submerged in oil" Poor lubrication maintenance (i.e. bad oil, changes far and few between, etc.) can cause the chain and/or sprocket to fail prematurely (which I suspect happened to you). It is good practice to replace your leaky oil pan gasket and inspect the chain and sprocket whilst the pan is removed.

The largest fault I've heard of with this engine (not really the engine) is the combination of aluminum and plastic in the cooling system that can fail do the the heavy diesel vibrations. And because these engines are older, they require more maintenance and are less powerful and fuel efficient. There you go--the only problems with the 61x engines.

clintard · #9 06-17-2010, 05:41 PM

Quote:

Originally Posted by DieselPaul

Looked at one like that last month. It was $250 but a 350k mile motor that had been run without oil turned me off. No room for more parts cars, I wanted a $500 runner I could fill with veggie oil and kill.

I cant find any more info on this. How common?

pawoSD · #10 06-17-2010, 06:43 PM

Quote:

Originally Posted by Actros617

OM617 got an issue that is the oil line tends to burst, bringing the mighty 5 to its knees.

The oil hoses really have nothing to do with the engine, that is a hose issue, and proper maintenance would mean it will never happen. I replaced mine about 5 years ago and they are still perfect.

charmalu · #11 06-17-2010, 08:56 PM

Quote:

Originally Posted by Actros617

OM617 got an issue that is the oil line tends to burst, bringing the mighty 5 to its knees.

I agree with the other posters, that failed motor mounts are the issue here.

we tend to see a lot of these hoses going, but some of these cars may have the original hoses. they don`t last for ever and should be part of the parts replaced like other rubber parts.

when I changed mine the first time, there was a date of 1984 on them. so were original, and they were 20yrs old, and hard as a piece of plastic.

The 617/616 have to have their valves adjusted every 15k miles. the 60x series do not need this. there is a little more maintenance in this area.

Charlie

showme · #12 06-17-2010, 09:03 PM

You guys talked me into it. I've had two new front motor mounts in my 'extra parts box' for 2 years. i've got the 300D up on the stands changing out the oil pan gasket. I'm changing those mounts! Thanks.

Alastair · #13 06-18-2010, 12:45 PM

Hmm, Thats interesting about the Oil Cooler hoses....

Guess it does stand to reason that the hose itself wouldnt just Burst, without first Looking REALLY 'delicate' and 'rotten' first!

Ive run 617's for years, and TBH, never had any problems with any of 'em....

I have a 'spare' engine thats done 350 odd K, has a fair amount of blow-by, but still ran just fine and started well...

Nearly all my 617's have had what sounds like a 'knock'--Just a Very Quiet knock, and only at idle but I'm thinking this is just good ole Piston-Slap on my old high-milers!
--Im beginning to think, Its just the '617' noise!

Only issue really is a Non issue--You gotta keep the valve-adjustments done regularly, it really makes a big difference....

vstech · #14 06-17-2010, 07:17 PM

the biggest issue with the hose is that the motor mount fails, bringing the powersteering belt into contact with it. the belt then cuts the cooler hose, and promptly dumps the crankcase of oil all over the street. if you are paying attention to the car while driving, you will notice oil seeping out above the headlight and pull over and get the car towed before you loose all your oil. the big reason for the motor mounts failure is sometime in the past a gearhead changed the mount and did not replace the diesel shield on it. then normal fluid loss, leaking fuel return hoses, spilled diesel fuel/motor oil gets on them, and the rubber melts and you get serious motor sag. poof there goes your oil cooler hose.
keep an eye on your motor mounts, and inspect your cooler hoses and you'll never have that issue.
I've not heard the oil pump to be a common failure item.
odds are good that something else failed and destroyed the oil pump... vacuum pump comes to mind. also the OCI has some bearing on the life of the pump and the engine in general.

showme · #15 06-17-2010, 07:56 PM

Another big issue with me is that I can't find those damned spark plugs!

(And all those other things I don't have to worry about, or change)