1997 850R Compression test results

mattman · Post by **mattman** » 17 Sep 2013, 14:41

Hello all, I have a 97 850R wagon and am trying to diagnose blue white smoke clouds from exhaust.
Car was run low on oil (where it went? My daughter doesn't know), no puddles in driveway, slight loss of coolant (reservoir down to min. from max.)
Did compression test, psi results as follows,
Dry, 155-162-165-167-162
Wet, 181-185-181-190-185
Really hoping valve stem seals were the culprit as I was planning on replacing the head gasket anyhow, but these (substantial?) increases in compression concern me. Would prefer to leave the lower end alone...
That being said, what's the next step in diagnosing if it's an upper/lower problem?
Thanks in advance

Post by **JDS60R** » 17 Sep 2013, 14:59

Perform a leakdown test
Compare blue smoke output at idle vs 2500 rpm. report back the info. Video is great but pics are fine too.

mattman · Post by **mattman** » 17 Sep 2013, 15:28

Thanks for the quick response JD, smoke output is like comparing a cigarette burning in an ashtray to a mosquito fogger...
Will try to capture some vid.
Just reading up on how to do a leakdown test.
Do I need to do each cylinder?
How do I get each to TDC?
Thanks again.

Post by **JDS60R** » 17 Sep 2013, 15:46

I look forward to the pics/video

I think you are saying it gets worse as rpm increases.

A leak down test should be performed on each cylinder. You do not have to be at perfect TDC just close. You must hold the crank so the air pressure does not move the piston/engine .

TDC can be roughly determined by pulling the plugs and using a long pencil or other device to monitor the piston height. It will be at TDC every other time it reaches the top as this is a 4 stroke engine.

Post by **rspi** » 17 Sep 2013, 19:30

Were the dry numbers on a warm motor? I would not worry about the compression, the numbers are fine. 1 PSI off of normal is not something to start digging on.

As for smoking, what condition is the PCV system in? I had 1 broken elbow causing mine to smoke. I did the PCV system and didn't know to use Volvo parts only and 18 months later I had bad elbows and stuff. Had to replace the weak links.

Another note, what weight oil are you using? Running light weight oil can also contribute to leaking valve stem seals. I'm sure 10w-40 is fine in your area because it doesn't get below "0" there.

And what in the world you you want to pull a head on a car for? If it doesn't have gross head gasket issues I would NOT go there. Broken head bolts, stuck exhaust manifold studs, stripped bolts, timing issues, mush I go on??? Don't go there unless you have a REAL issue.

mattman · Post by **mattman** » 17 Sep 2013, 22:01

Thanks for the responses guys.

JD,
I picked up a cylinder leakage tester this eve, will start leak-down tomorrow.
Couldn't post vids, but will post picks in the AM.

RSPI,
1. The tests were done on a warm engine.
2. New PCV (from IPD) was installed last Feb.
3. Switched to Mobil1 10w-30 about the same time. (was thinking along this same line)
4. Don't "want" to pull the head, but car will not smog, burning oil and coolant, tiny bubbles in reservoir. Pretty sure valve stem seals are the cause of the smoking and I heard doing an in-car valve job was as big a pain as pulling the head...

Best to you both,

Post by **JDS60R** » 17 Sep 2013, 22:17

I will wait for the vid but if it gets worse as rpm rises then turbo will be an issue.

Post by **MoVolvos** » 17 Sep 2013, 23:19

**

How many miles are on the vehicle? Here is an exceptional article by FCPEuro about motor oils. Hope it links properly. I've had problems with Mobile 1 over the years with at least 4 cars and this article points to the issue about Synthetics in older cars.

CRUDE SCIENCE: Choosing The Right Oil For Your Car
http://www.fcpeuro.com/page/what-is-the ... for-my-car

Blessings,

BKM

**

Post by **erikv11** » 18 Sep 2013, 00:04

I agree, do a leakdown test if you want to be sure about rings vs valve stems. However keep in mind that it is very common for the valve stem seals to go, and extremely rare to have piston ring wear, although you didn't state the mileage on the engine.

PCV is a crucial point but if you cleaned out the PTC and the port to the block, and used Volvo-branded parts, then it should still be good.

For the potential head gasket leak, if there are tiny bubbles in the coolant then do the color-change test for exhaust gases in the coolant. That test will definitely be positive if those bubbles are in any way related to a head gasket problem.

In-car valve stem seals job is indeed as much pain as pulling the head, but pulling the head includes WAY more chances for things to go wrong. The head never goes back on the way it did at the factory, period. So choose carefully if it comes down to that choice.

mattman · Post by **mattman** » 18 Sep 2013, 09:35

At idle