Excessive Oil Consumption on 616 and 617 Diesel Engines - Page 4 - PeachParts Mercedes-Benz Forum

layback40 · #46 04-29-2010, 07:59 AM

Oil consumption is always a interesting topic. There are motors that use a pint every 1k miles from new and go forever. Yet there are motors that dont use any and fail prematurely. yet still some that dont use any and go for ever.
If the motor is not showing excessive blowby & doesnt have unusual noises, its best left to run even if it does use a pint every 1k or so.
I have seen them that use nothing around town but on the highway at speed they use some.

hobberslobbers · #47 04-29-2010, 04:25 PM

more info... diesel fuel only, car purrs like a kitten and is very smooth at idle and at 80mph. cylinder compression is 320+ psi across all cylinders. i put new nozzles in and pressure balanced them 1900-1950 psi.

interesting note on the turbo, i do get a drip or two of oil on the front part of my turbo on the housing of the boost pressure control valve. i have checked for play on the turbo and there is a small amount (maybe .005") when cold and no play when hot. turbo spools up and works fine and the car has lots of power and is very responsive. i pulled the u-tube the other day and there is a small puddle of oil at the inlet of the turbo in front of the fins. is this normal? i don't think there should be anything other than an oil film in this area. is this correct? i'm wondering if oil is getting through the turbo and getting forced into the intake??? could it be this simple...rebuild turbo????

Biotour · #48 04-30-2010, 06:00 PM

I've got the same issue with mine, I replaced the rubber seal between the u-tube and the turbo inlet which seemed to help with oil leaking. I still have an oil leak in that area though which I believe is from where the inlet turbo housing meets the cartridge. I had a ton of play in my old turbo and just opted to replace the "cartridge" in the middle of the turbo, and reuse my exhaust and inlet housing. The oil is most likely coming from excessive blowby that doesn't get separated. I put rtv around the oil separator "lid" because i had oil-soaked air filters and that cured the problem but now alot of that oil is just getting sucked into the turbo. Anyone try putting a brillo pad or some steel wool inside the oil separator? I'd like to try this but would hate for the material to fall apart and end up in the oil pan.. Even with the oil separator sealed the engine seems to be inhaling enough oil to cause leaks near the turbo.

hobberslobbers · #49 04-30-2010, 08:57 PM

Quote:

Originally Posted by Biotour

I've got the same issue with mine, I replaced the rubber seal between the u-tube and the turbo inlet which seemed to help with oil leaking. I still have an oil leak in that area though which I believe is from where the inlet turbo housing meets the cartridge. I had a ton of play in my old turbo and just opted to replace the "cartridge" in the middle of the turbo, and reuse my exhaust and inlet housing. The oil is most likely coming from excessive blowby that doesn't get separated. I put rtv around the oil separator "lid" because i had oil-soaked air filters and that cured the problem but now alot of that oil is just getting sucked into the turbo. Anyone try putting a brillo pad or some steel wool inside the oil separator? I'd like to try this but would hate for the material to fall apart and end up in the oil pan.. Even with the oil separator sealed the engine seems to be inhaling enough oil to cause leaks near the turbo.

i thought about the brillo pad too, but firmly decided against it because IF it did get through to the filter housing, it WILL go right on through to the turbo. some have made a separator with a "collection cup" made out of PVC which you could plumb right back to the oil pan. i guess the point is to correct the cause for the excess oil. i have an inkling that the oil supply to the top of the turbo is getting past the seals in the turbo and actually getting forced into the intake. any other thoughts on this?

Cr from Texas · #50 05-01-2010, 01:14 AM

Quote:

Originally Posted by Cr from Texas

Check for a blocked or partially blocked check valve on the oil seperator return line. Remove the aircleaner and pour new motor oil down the tube. If it fills to the top, it's at least partially blocked causing oil to go into the combustion air stream. I was able to clear mine by filling with oil and applying a few psi of pressure to the top of the tube. I now pour a couple of oz this way when I do an oil change. No proof, but I think it helps keep it from getting blocked by soot.

Bumping my post #45 as no one responded.
Seems to me that soot accumulated in the return check valve causing it to drain to slow would lead to filling the oil seperator and forcing oil out the tube into the air flow to the turbo would explain the oil in the turbo inlet.

Over the years, as blowby increased, I've found that I need to fill to a cold oil level just above the lower mark on the dipstick. A higher level (up to the full mark) leads to more drips on the right side of the engine.

Clearing the check valve and filling to the lower mark have eliminated almost all of my right side oil leaks.

Cervan · #51 05-01-2010, 05:24 AM

i had a 616 that had massive oil usage i mean 1 quart per 10 miles it was bad. burned more oil than diesel.

Replaced head gasket, checked head head turned out good. Lapped valves and no signs of valve guide wear. Only thing it could have been was worn bores, or bad oil control rings.

Re-ring on a 616 would probibally be around 5-600 dollars. Not a bad deal.