1998 V70 T5 - oil leak/smoke on acceleration/deceleration

Seaway · Post by **Seaway** » 10 Feb 2015, 08:51

erikv11 wrote:Yeah, it seems to be the typical cost.

Does the diagnosis sound correct? Seems like the smoke is turbo-related, right? Valve seals would smoke at start and after idling and I don't seem to have positive crankcase pressure. I may run a hose off the dipstick tube to under the engine as a vent and see if anything changes. If not, at least I will have ruled the PCV out as a the problem.

Post by **erikv11** » 10 Feb 2015, 09:23

I agree it seems the PCV is not at fault, so trying the vent hose is a good idea to confirm that.

A comment about these TD04 turbos though: historically they are super hardy, so that 100k is barely getting started. But maybe now that the seals are aging, we will start to see turbo-related smoke, earlier on. So I hesitate to pinpoint the turbo mostly because failure there is rare.

One way to look at this is, can you be happy with the expense of a rebuild whether it cures the oil issue or not? If you can then I say no question, go for it. If not then keep poking around. It sounds like you will keep the car for a while and presently have it in good shape, if that is the case then for me I would probably do the rebuild.

Seaway · Post by **Seaway** » 10 Feb 2015, 09:31

erikv11 wrote:I agree it seems the PCV is not at fault, so trying the vent hose is a good idea to confirm that.

A comment about these TD04 turbos though: historically they are super hardy, so that 100k is barely getting started. But maybe now that the seals are aging, we will start to see turbo-related smoke, earlier on. So I hesitate to pinpoint the turbo mostly because failure there is rare.

One way to look at this is, can you be happy with the expense of a rebuild whether it cures the oil issue or not? If you can then I say no question, go for it. If not then keep poking around. It sounds like you will keep the car for a while and presently have it in good shape, if that is the case then for me I would probably do the rebuild.

That's a good way to look at it. My plan at this point is too hold on to it for 3 years at the minimum. It is the car I have wanted for a long time and I don't mind spending a little money to keep it running well. I am also not 100% sure of the mileage on the turbo as I don't have any documentation for it. It may well have 186,000 like the rest of the car. And your point about actual age (regardless of mileage) is a good one.

If it's not the turbo and not the PCV, is my only other direction to look the valve seals? Is there something else that could be causing the smoke?

Post by **erikv11** » 10 Feb 2015, 09:54

Yes, my bet would be valve stem seals. If you are keeping the car then you should also brace yourself for having to deal with that, and with replacing the o-rings on the pickup in the oil pan. Nether one of those is any fun to fix; the o-rings is especially common. With good oil change habits and more than in-town driving you may be able to hold off the valve seals issue.

It seems it could somehow be the bottom end but that is even more uncommon than turbo failure. Do you have compression numbers, just for info about the rings? If not then you may want to get them.

Seaway · Post by **Seaway** » 10 Feb 2015, 10:41

How do I check for valve stem seal leaks? Leak down test? Seems to me if it was valve stems it would leak after sitting all night, but I get zero smoke on a cold start.

What are the o-rings at the oil pickup? What are the symptoms there? I really don't mind doing the work. I don't think any of it is particularly fun. The fun for me is in the result.

Post by **erikv11** » 10 Feb 2015, 10:51

I agree with your earlier post, from your description, it sounds like the valve stem seals are not leaking. You've got it right, overnight is the most common first symptom. Then it will be at every stop light, then almost all the time. Some of these "white block" engines never develop this problem, in some it shows at 150k.

Leak down test doesn't report about valve stem seals, the valves are all closed when you do that, and the stems are up above the closed chamber.

When the oil pickup tube o-rings start to go, the oil pressure light may flicker now and then, and for sure the top end will get real clickety-clackety due to poor oil supply up there. You'll know it. First it is prolonged clicking at startup, then it gets worse. The fix involves dropping the oil pan, this writeup is a little more complicated than for a FWD car but it is the gold standard, all the relevant info is there: https://www.matthewsvolvosite.com/forums ... hp?t=31236.

Seaway · Post by **Seaway** » 10 Feb 2015, 11:02

Just got through reading that, sounds like a pain in the ass, but certainly doable. Maybe that is where my oil is coming from all over the pan... Looks like a fun night of degreaser and a flashlight for me tonight.

I just spoke with the guy I bought the car from and he says this is the second turbo the car has had. Makes me wonder. His guess was valve seals. Anyone want to come take a drive and give me an opinion? Valve seals may be above my actual dexterity level...

1998v70xcbill · Post by **1998v70xcbill** » 17 Feb 2015, 05:07

remove intercooler hose at bottom of intercooler, and see how much oil is inside.
My turbo has 202k miles, a little play at shaft, no white smoke ever. My intercooler hoses have more than an oil film on the inside.

Seaway · Post by **Seaway** » 17 Feb 2015, 06:04

I have a small amount of oil at the intercooler hose, less than a dime sized pool,if that.

My PCV is leaking at the the short drain hose that goes to the block. Turns out the PO used URO parts when he did it 7000 miles ago and they have obviously failed. I have ordered the parts to redo the whole thing and I am going to do it this Sunday, I hope.

Once it is working properly, I will see what happens with the smoke. Hopefully the two issues are related and it clears up. If not, I will pull the turbo and have it rebuilt.

Seaway · Post by **Seaway** » 02 Mar 2015, 06:37

UPDATE:

I replaced the PCV system which was leaking from the hoses attached to the block. The passages were completely clear, but the hoses were old and leaking. Look as as thought the PO replaced only the two long hoses when he "re-did" the PCV. At any rate, I got the leaks sorted and I have vacuum at the dipstick and the oil fill and now I only have a slight drip from the turbo return line gasket.

Speaking of the turbo, mine is shot. There is almost a 1/4" of in and out play on the shaft and some play side to side. I was shocked how much it moves in and out. I guess this solves the smoke at boost question I had. I have another low mileage 16T turbo which I am going to install next weekend to see if I can get this problem all sorted once and for all.

When I do the install, do people recommend new oil lines? I am obviously going to replace the gaskets and o-ring and crush washers at the coolant lines, but should I get an new oil feed line and a new oil return line, or simply clean the ones I have and be done with it?