1998 V70 T5M Misfiring, No Compression Cylinder 2

[Ozark Lee]

Once you have it off look at the rest of them. I re-lap all of the valves, including the new one, any time I have a head off and it is fairly easy to see if they are starting to burn. Since you have 20 of them it can get pretty expensive to replace them all. The turbo exhaust valves, which is where you are going to find your problem on #2, are particularly expensive.

Once you look at them just replace any that look iffy.

...Lee

[erikv11]

A used head, like one you pull from a junkyard car, is a great source of valves. Just inspect them as Lee suggested, or tell the machine shop to keep 20 good ones if they are doing that part (I don't lap the valves myself, just not (yet?) something in my bag of tricks). Any 94-98 turbo will have the same valves.

Lifters just keep them immersed in oil. New valve stem seals are a must and as bad as it hurts $-wise, buy them from Volvo. You can get a kit to make it a more manageable expense, see https://www.matthewsvolvosite.com/forums ... hp?t=71962.

[nikolajs]

Slow response here… sorry.

Thanks to everyone for the input, and especially Robert for your videos.

So I did the work late last winter/spring in my driveway. Sure enough, it was one burnt exhaust valve on the no-compression cylinder (pretty good chunk missing out of it). Got the head machined (mating surface, valve seats, valves); lapped valves; re-used all valves except the bad one; cleaned everything up; installed with new seals all around. After I got everything back together, checked it over once more, cranked it, first shot it fired right up. The lifters made lots of noise in the beginning but settled down nicely in 20 min or so.

Drove it no problems for a bit, then started to notice a slight oil drip on the driveway. At first I thought it was from my other car so didn’t think much of it…

The drip has gotten progressively worse, at first not much volumetric loss (1 quart every several weeks) but making quite a mess everywhere I park.

Last night was cold (one of the first hard frosts)- when I went outside there was a solid stream of oil underneath it and a large puddle. Maybe a eight to a quarter cup (plus/minus). But way way more than I was used to seeing.

I’ve driven almost exactly 5,000 miles since the head rebuild. Car has 175,000 on it.

I did the seal/gasket on the turbo return line a couple weeks ago hoping that was the culprit. When I was down there it looked like the fresh oil drops were coming from the engine/trans junction, making me think it’s a rear main seal. But hard to tell because it was so dirty.

I’ve looked around on the RMS posts, but have two new questions related to the head rebuild job:

1) Is it common for a rear main seal to fail after new seals (cam seals, valve stem seals, head gasket, etc) are done with a head rebuild?
2) Has anyone ever heard of a seal (RMS or other) failing overnight or due to cold (~30F) weather (while just sitting in a driveway)? Seems kind of extreme, but nothing else changed. The car wasn’t driven for several days before or after the major leak started.
3) PCV system was done at 150,000. Coolant in expansion tank is clean, and level stays constant. Car doesn’t seem to burn any oil and runs well.

thanks!

AND... please post responses here (new thread): https://www.matthewsvolvosite.com/forums ... =1&t=78358

[Ozark Lee]

1) Is it common for a rear main seal to fail after new seals (cam seals, valve stem seals, head gasket, etc) are done with a head rebuild?
2) Has anyone ever heard of a seal (RMS or other) failing overnight or due to cold (~30F) weather (while just sitting in a driveway)? Seems kind of extreme, but nothing else changed. The car wasn’t driven for several days before or after the major leak started.
3) PCV system was done at 150,000. Coolant in expansion tank is clean, and level stays constant. Car doesn’t seem to burn any oil and runs well.

Where does the leak appear to be on the ground - at which side of the engine?

I have never heard of a top end refurb causing a RMS leak. A very common problem with the turbos is leaky oil cooler lines to and from the radiator and that would typically have the leak showing up toward the right hand side of the car. A RMS leak would show up left-center. There are tons of places for oil leaks and if you can try to wash the engine and see if you can pin down the source. I have seen many rear cam seal leaks misdiagnosed as a RMS leak since the oil gravity flows down the back of the engine to the same place.

What did you use for camshaft seals when the head got reworked? Many of the seals that come with the kits are pretty pathetic but the good news is that at least the rear seals are easy to replace.

...Lee

[nikolajs]

Hi Lee,

Just FYI i started a new thread about this here: https://www.matthewsvolvosite.com/forums ... =1&t=78358

The major overnight leak looks to be coming from the very front right (sort of near where the window fluid reservoir is).

The other leak looks like a different spot, more left-center.

I need to go back under there and check again, but its actually parked in the street tilting slightly towards the curb (passenger side).

I don't think its the cam seals because I checked out the head/top of engine and around the cams a while ago (after the drip started, but after head rebuild) and don't think its coming from there because it was clean (but will check that again too).

I used the cam seals (front and back on the intake and exhaust cams) that were in the IPD head gasket kit. I think they are Victor Reinz or Elring. Not branded Volvo OEM but don't think they are garbage either...

thanks

[Ozark Lee]

The major leak is exactly where it would be with a bad oil cooler line.

...Lee

[nikolajs]

OK- good to know! I will look into that.

Also on the topic of cooler lines- does this car (with manual transmission) have a transmission fluid cooling system or is the fluid fully contained in the trans?

[abscate]

No cooling needed on a manual transmission. They are already cooler than any automatic, in so many ways...