617 running poorly - PeachParts Mercedes-Benz Forum

martureo · #1 08-19-2014, 10:20 PM

No history on engine. Did not run when purchased.

I've had MMO sit in the cylinders.
Replaced IP (no fuel on 3 pistons) with good working one.
Timing stretch 6°.
268k miles.
Starts up quickly.
Cold compression test 380/360/380/120/360
Smokes like a monster.
High crankcase pressure/lots of blowby gas
Dripping oil out of exhaust (replaced turbo but used replacement may also be the source)
Replaced valve stem seals.
When run for extended periods appears to have coolant leak at rear of head gasket, hissing/smell of coolant.

I dead a leak down test (hot) and got 80% leakage on all cylinders. (yes I was at TDC of each cyl on compression stroke). Could only detect hissing from oil pan. Using 40 psi air. No change on cyl 4.

I was trying to do the leakdown test to figure if I need a head or a new engine. But I don't seem to be anywhere different than I was after the compression test.

So is it worth it to pull the head or am I wasting my time? (btw, its a wagon)

leathermang · #2 08-19-2014, 10:38 PM

Try pulling the fuel line off that number four and see if most of the smoking stops.....take it off at the injector...

eatont9999 · #3 08-20-2014, 08:52 AM

Looks like a problem with cylinder #4. The compression results definitely show a problem. I would pull the injector and look for signs of coolant in that cylinder. If not, it could have lost or broken a piston ring.

To check for a head gasket issue, pressurize the coolant system for a while and crank the engine with #4 injector removed. Check for signs of coolant. If coolant is found, it is a head gasket issue/cracked head. If not, you are looking at a lower end problem based on all the testing you have done.

DeliveryValve · #4 08-20-2014, 09:33 AM

Number 4 is definitely causing the problems.

After checking the head gasket for coolant leaks as mentioned above, I recommend pulling the injector. Get number 4 piston to the top by way of hearing/feeling the pressurized air. Then spray Kroil into the prechamber until it fills up. It will most likely leak down, but repeat the fill up if you like. Let it sit and then turn the engine over by hand while spraying Kroil into the prechamber at various points of the rotation.
Keep repeating this process for a few days. Then with all the glow plugs remove from the rest of the cylinders to provide better speed, turn the engine over with starter to blow out any left over fluid that may cause hydro locking.

My buddy had a similar issue with his engine with one cylinder had about 150 psi compression. I did the Kroil soak and Marval Mystery oil final soak for a whole week. We got the compression back up to an amazing 300 psi. Definitely a stuck ring causing it and his engine ran much smoother after that. So hopefully that could be the case with your engine and be sure to change oil not too long after the Kroil soak.

leathermang · #5 08-20-2014, 10:24 AM

Everyone should have some Kroil in there toolbox....

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