Diesel engine prognosis

Gmachine

Well-Known Member
Joined
Apr 26, 2005
My MK2 VW diesel has some wear & tear on it. The OD stopped working @ 216k, so who knows how many miles are on it. I really hate this car, but for what it's saving me in fuel costs, I'd like to keep it running.

For the most part it runs fine. Starts easily, doesn't overheat. I replaced the head gasket last year, but never serviced the head. It smokes after the oil has some mileage on it (not an excessive amount, but around 3k) it smells of burning oil inside the car if a window is down & you climb a gradual hill. The oil pressure running @ 50 MPH is around 40 psi.I don't know much about diesels. I know the guy I bought it from said he had replaced the piston rings, but based on the other work he did, I doubt his ability or parts choices. I've already replaced quite a few suspension components & other wear items to keep it drivable & safe.

My concern is the blue smoke. I know you can compression test it, but my tester doesn't go that high. I thought of having the head rebuil with new valve seals, but I would think if it was seals it would only smoke on start up.

Any ideas?
 
Run a thicker oil. Wifes ZJ smokes a ton on 5w30, runs great and smokeless on 10w40 valvoline...

I hear gear oil is pretty thick :)
 
if he did replace just rings, chances are the cylinders may have just been honed at the most and were never measured for cylinder wear, resulting in an egg-shaped cylinder wall(lots of compression loss and blow-by). it probably needs both top and bottom end rebuild to be "right"(valve job & seals, bore, new pistons & rings, possible crank grind or polish...etc...). depending on how much the whole car is worth to you, this may be priced higher than what you want to spend. IMO, you have 3 options- 1) complete rebuild(expensive) 2) find a good used replacement longblock(can be hard to find for this age VW diesel, no guarantee that the next engine is much better) or 3) let 'er smoke and hope for the best!
 
flatblackzj said:
if he did replace just rings, chances are the cylinders may have just been honed at the most and were never measured for cylinder wear, resulting in an egg-shaped cylinder wall(lots of compression loss and blow-by). it probably needs both top and bottom end rebuild to be "right"(valve job & seals, bore, new pistons & rings, possible crank grind or polish...etc...). depending on how much the whole car is worth to you, this may be priced higher than what you want to spend. IMO, you have 3 options- 1) complete rebuild(expensive) 2) find a good used replacement longblock(can be hard to find for this age VW diesel, no guarantee that the next engine is much better) or 3) let 'er smoke and hope for the best!
Click to expand...
Pistons are pretty expensive for these, so instead of rebuilding the whole thing, I'll probably choose the third & run her till she quits, I guess.
 
I have two diesel compression testers. Pretty sure one set has the VW adapter.
 
I know the valve cover is leaking oil, so I'm first going to try & fix the leak again. I think some of my oil smell is residual oil getting onto the exhaust. I've read that if compression is down on a diesel it has a hard time starting. Mine fires right up every time. I just hate to put much work into it as its not worth much.
 
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