Smokey diesel

[Mashty]

Hi all.
I've recently bought a 1995 940 diesel estate, and it cold smokes pretty well, especially with throttle. The smoke doesn't completely clear when warm, but mostly. It doesn't breath excessively, and the boost pipes are oily inside, so I'm thinking the turbo seals are gone/on their way to going.

Can anyone point me in the right direction to a decent turbo core?

Or any other thoughts/advice?

[ngoma]

Let's get some more information.

What color smoke?

How long does it last?

Condition of the air filter? Fuel filter?

Condition of the engine in general? Miles? Maintenance history?

How much oil does it use?

Did anyone mess with the smoke screw?

Please answer all the questions. It will help us arrive at a better solution.

[Mashty]

Okay.

Blue/grey smoke
It improves through driving, but doesn't completely go.
Air filter is clean, not looked at fuel but it was serviced late last year so should be fine.
Engine sounds fine, starts fine, goes well e.t.c. 190k miles, don't have any maintenance history for the past few years, but it's a clean car all round really so I'd say it's been looked after.
Not really had it long enough to notice any oil consumption.
Fuel pump is standard.

Thanks!

[v8volvo]

Good starting is a nice sign of general engine health, so that is good to hear.

For the maintenance history that you do have, is there any sign of a timing belt replacement in the past? If so, can it be confirmed that the work was done with the correct process for setting injection timing and cam timing?

Smoke when cold that improves as the engine warms up can be a sign of timing not being set to spec. But it can also be other things, including condition of injectors, compression, cold start advance system being broken/disabled, etc.

Welcome to the group, sounds like a nice car to have picked up if it is clean! Here in the US we never got the later model diesel Volvos (nothing after 1986) so are always envious of you folks on the side of the pond where they were available into the much improved 940 series in the 1990s.

[Mashty]

It's had some engine work about ten years ago, several new valves, new cam, head gasket e.t.c. and the belt still looks good. It may have been done again since then but no proof.
I've managed to sourced a turbo core so will get that swapped and see if it improves.

It's a nice car, by far the nicest thing I've had!

[ngoma]

Originally Posted by Mashty

I've managed to sourced a turbo core so will get that swapped and see if it improves.

Not where I would start, but since you seem determined, just make sure you are prepared with gaskets, nuts, and studs, just in case.

TB might "still look good" but if you can't verify it has been changed in the last 70,000 miles you are risking an interference engine catastrophic event. The belts also have a chronological shelf life.

Wonder what the valve replacements were for.

Does the cold start system work?

D24 is realistically 1970s technology so they do smoke more than modern diesels. They are better than most of their competition but still...