1996 850 Turbo, Rough idle, new PCV didn't fix it...

Post by **MoVolvos** » 05 Oct 2013, 11:35

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EDITED for clarification:

In reading the earlier post again you began the PCV work to eliminate fouling issues? Was the car running smooth, a little rough or real bad BEFORE the PCV work? If it was rough before the work did it get better or worse after the PCV? Trying to figure out if the PCV was the culprit as you did find a few loose ends when you went back to inspect the PCV work.

Blessings,

BKM

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Post by **erikv11** » 05 Oct 2013, 13:43

Compression test is free (get the tool from Autozone or Advance Auto etc) and not too hard. There is little value in speculating about what to do next if compression might be "kinda low" or "very low" or even fine, until you have the results of that test.

Test all 5 cylinders, do it with a fully warmed engine. I like to both unplug the coil wire and pull the fuel pump fuse during the test. You want to hold the throttle wide open while you crank it 5 to 7 times. Careful, the spark plugs will be hot to the touch.

futureboycolin · Post by **futureboycolin** » 05 Oct 2013, 14:16

And the moment we've all been waiting for:
Warmed up/teaspoon of oil
#1 - 43/43
#2 - 130/135
#3 - 135/135
#4 - 135/135
#5 - 125/125

Post by **erikv11** » 05 Oct 2013, 14:31

Ouch. Don't worry about them being low, the fact the 2-5 are so close together says they are fine.

The hopeful thing is that #1 is not zero. A burnt valve will be zero, needle doesn't move at all. So it could be a stuck valve, your idea about running it hard etc, to free up loose carbon, is sounding pretty good. It's about the only easy remedy I can think of without pulling the head.

At the shop, I think the next thing they would do is get a boroscope in there (mini camera), to look at the valves. But it is sure looking like the head is in trouble.

futureboycolin · Post by **futureboycolin** » 05 Oct 2013, 14:34

@BKM, the car was running rough before the PCV job. I towed a trailer from New York to Chicago when I moved, which in hindsight I shouldn't have done. On the way it started misfiring and shuddering violently as I was limping into Chicago. Fortunately alot of people here on on the board, including Ozark Lee, RSPI, Tech and Justin Blackburn really helped me out.

I was hoping that the pressure overload from the turbo and old, clogged up PCV caused the oil spewing, and shot motor mounts were the cause of the vibration, however it turns out it must've been a burnt valve all along. Exactly what I suspected, and exactly what I didn't want to face up to. But with those compression results, it looks like I'll have to.

Post by **MoVolvos** » 05 Oct 2013, 16:53

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Several years ago my mechanic inherited from a customer a Ford Bronco because he did not want to spend money on a stuck lifter. My mechanic is pretty good at what he does and try every trick up his sleeve but could not do anything short of taking the upper end apart. I recommend this and after running it for a little bit the lifter became unstuck.

He has used the other products but felt at the time it was not worth the extra cost but now keeps the oil and other stuff on hand. He is not a car enthusiast but an excellent mechanic. The 502 product along with the engine oil has reseated my rings after 6 months of use. No more white puff of smoke for half a block in the mornings. Since you already changed the oil add a bottle of 502 to the oil than 503 to the gas. Have this work from both directions.

502
http://www.pelicanparts.com/catalog/sho ... co_pg6.htm

503 on half a tank of gas
http://www.pelicanparts.com/catalog/sho ... co_pg9.htm

Blessings,

BKM

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futureboycolin · Post by **futureboycolin** » 06 Oct 2013, 10:34

I'm changing the oil on Monday, so I will look for those at Pep Boys for sure.

Is it dangerous to run oil additives long term in the 850? I know Volvo doesn't recommend using additives in their engines, but is that because they don't want to endorse one particular kind over another or spend the time researching them? Or is it because it's genuinely not good for these I5's?

So...now we think it's a stuck lifter? I wish JBlackburn or Ozark Lee would chime in. Anybody seen Tech around here lately?

Post by **rspi** » 06 Oct 2013, 11:33

Man, sorry to see your low number on #1. I don't think your tow job had anything to do with it. If a valve is not seating tightly, it will burn sooner or later. I recently towed a trailer from Little Rock to Cincy, 630 miles at 63 mph. I barely knew the thing was back there, through the mountains of TN. No problems.

I would NOT change the oil. Don't drop another dime in the car until you fix the head. Use that oil for after the rebuild. When I did the head on our S70 GLT I ran the car for about 100 miles then change the oil again. So I change the oil when I did the head (the cheapest stuff I could find 10w-30, then put in what I use after 100 miles, the good stuff, 10w-30 full synthetic Castrol Edge).

Every 3 months or 2,500 miles, I run a bottle of Lucas through my tank. It is suppose to clean the valves along with the injectors. I assume SeaFoam will do the same thing, just more aggressive.

All of your numbers are low, not sure if it's a bad gauge or the motor simply has that kind of wear due to some PO not changing the oil regularly. I'd check it again with another gauge or test someone else motor to see if their motor gives higher numbers. I recently did a test in a 850 R that had low numbers, they did jump wet, to proper allowances once I added a 1/2 ounce of oil so I think it's your gauge. Since my numbers jumped when I wet the test, I replaced the motor. I think you'll be fine rebuilding the head.

Just to let everyone know, I have had a few clogged PCV systems on cars that I purchased and none of them ran hard due to the PCV needing servicing. One blew a RMS, another blew CAM seals, and one was even blowing the oil dip stick out. A clogged PCV will not cause a misfire but will cause oil leaks. There is also a chance that the clogged PCV was helping oil get by the Valve stem seals when would contribute to a valve burning.

Here are my instructions for replacing the head:
http://atthetipwebs.com/technologyinstr ... gasket.htm

Post by **rspi** » 06 Oct 2013, 11:36

futureboycolin wrote:@rspi What was your approach to remedy the problem once you found low compression?

On a 2001 Saturn... Cut bait. I would not suggest anyone putting $900+ (likely $1,500) into a 13 year old Saturn.

On a turbo Volvo 850, I'd pull the head and get it fixed. You may also find a good head in a salvage yard. Do a hand crank compression test on the motor there before you pull the head (you should get at least 70 psi on all pistons even with no oil in the motor. I got 90+ psi but my gauge reads higher than yours does). You can buy a head there for $125, get a gasket kit for $125 and be done with it with less than $300.

Post by **rspi** » 06 Oct 2013, 11:41

The lady with the Saturn is driving the car until she finds a replacement. I pulled the injector wire for that cylinder. It misses as it was, but it's not dumping fuel in there and through the exhaust. You can do the same for a little while, not sure how long it will last. Keep it off the freeway or under 55 mph.

How long have you been driving it with the motor missing? How long ago was the trip?