19 replies to this topic

[850-Turbo]

I lost compression in cylinders 1, 2 and 3 on my '95 850 turbo, over night! The car drove well the day before. The engine wasn't misfiring prior to the problem, like a burnt valve.

Here's the story. One morning, my wife started the car and moved it 5 feet down the driveway, turned it off and gave the car a wash. Afterwards, she move it back 5 feet. Later that day, she got in the car to go shopping, but the engine wouldn't start.

When I got home, I thought she "flooded" the engine (I know it's injected, but...), so I opened up the throttle and cranked it. It barely started and died after "chugging" for about 10 seconds.

I checked the cam timing, thinking that the T-belt skipped. It was fine. When I checked the compression on 1, it was near zero. about 25psi on #2. I didn't check the rest(silly me).

I injected compressed air through the plug holes and the air was leaking into the intake on all three cyls. I rechecked it with the cams removed. Same thing. I thought of broken valve springs (3 cyl's? Unlikely), or some junk got in the valve seats(plauable). I did notice oil in the air tube from the turbo (is that normal?). I wonder if there is any connection?

Has anyone heard of, or have experienced a sudden loss of compression on three, or more cyl's without any warning and without stressing the engine (like sustained high rpm/load)? The engine had been running strong until now.

If it is some junk on the valve seat, is there a good way to unjam the junk without removing the head? I tried tapping the valve stems a bunch of times. Didn't help.

Any thoughts?

[ericutexas]

Just to eliminate a few things from the get-go ...

How did you test compression? Screw-in gauges are ideal as they will allow for minimal leakage of compression, giving a more accurate reading. Removed the ECU/fuel pump fuses, cranked the engine for 4 or 5 revolutions with throttle at full open and obtained maximum compression reading? Compression will be on the low side if the engine is not at operating temperature, but not zero or even close to it.

Remember that for the leakdown test, the cylinder being tested needs to be at TDC so that all 4 valves are closed.

If you've verified that the timing is definitely correct, then you can only be losing compression from the following places:
a. Intake valves - air from leakdown can be heard by intake manifold/throttle body
b. Exhaust valves - air from exhaust pipe
c. Piston Rings (highly unlikely) - can hear/feel air from the oil fill opening
d. Head gasket - this might also be possible since you say that you have no compression on three adjacent cylinders. Coolant in oil? Oil in coolant? Open coolant reservoir tank - bubbles show up in coolant when you add compressed air into faulty cylinder with leakdown test?

Those are the most obvious things I can think of at the moment. Buildup on valve seats can happen, but I wouldn't think that your car would go from running fine to not at all within a day's time, and it would also seem unlikely to cause a zero compression condition. When you can narrow down where the air is leaking from using the leakdown test, if it's valves, then you can further diagnose those particular valve seats/valve guides, etc.

Good luck and let us know what you find!

[GT2]

This is a way out there long shot.... Did you notice anything that looked like tiny water droplets on the spark plugs when you removed them? Or water on top the plug?

[James100]

I lost compression in cylinders 1, 2 and 3 on my '95 850 turbo, over night! The car drove well the day before. The engine wasn't misfiring prior to the problem, like a burnt valve.

Here's the story. One morning, my wife started the car and moved it 5 feet down the driveway, turned it off and gave the car a wash. Afterwards, she move it back 5 feet. Later that day, she got in the car to go shopping, but the engine wouldn't start.

When I got home, I thought she "flooded" the engine (I know it's injected, but...), so I opened up the throttle and cranked it. It barely started and died after "chugging" for about 10 seconds.

I checked the cam timing, thinking that the T-belt skipped. It was fine. When I checked the compression on 1, it was near zero. about 25psi on #2. I didn't check the rest(silly me).

I injected compressed air through the plug holes and the air was leaking into the intake on all three cyls. I rechecked it with the cams removed. Same thing. I thought of broken valve springs (3 cyl's? Unlikely), or some junk got in the valve seats(plauable). I did notice oil in the air tube from the turbo (is that normal?). I wonder if there is any connection?

Has anyone heard of, or have experienced a sudden loss of compression on three, or more cyl's without any warning and without stressing the engine (like sustained high rpm/load)? The engine had been running strong until now.

If it is some junk on the valve seat, is there a good way to unjam the junk without removing the head? I tried tapping the valve stems a bunch of times. Didn't help.

Any thoughts?

If she sprayed water all over your engine from the wash the problems started from that.....certain areas of the engine you dont get wet or you get problems......Cause and effect...

#1 area not to get wet is spraying water on the spark plug cover.

Read This Washing Your Car

[850-Turbo]

Thanks everyone for responding. Let me see if I can clarify some loose ends.

The compression was checked with my trusy "Blue Point" rubber tipped, push-on guage by Snap-On. I've used it since the 80's and never failed me.

Leakdown test was done at TDC, but to make sure, the camshafts were removed, hence all valves are closed at all time.

When compressed air was injected, I heard with a stethascope, felt in my face and smelled gas/oil smell from the INTAKE TUBE coming back from the intercooler(if that's what I have).

Unfortunately, it's alot more difficult to do the exhaust side, but no matter, there's problem in the intake side anyway.

Though my first thought was water on the plug wires/distributor, I would rule out water in the engine compartment, now (no compression), since that would only cause ignition problems. But it was bone dry and I have spark at the plugs.

When the plugs were pulled, they were drenched with gasoline.

Is there anything from the turbo to the intake valves that can break off and jam in the valves? Such as injector needles(if it has one) or pieces of tubo vanes maybe?

I am at a total loss, here. I may just end up removing the head, just to find either valves or head gasket problems.

Ugh, this is not fun at all! I dread it, but still better than paying someone else to do the job. I don't have time, but I have money, less.

[Kashif]

Busted cylinder rings? You might have to pull the head to check this out.

[James100]

You said you thought at first that it was flooded......ask your wife when she was cleaning the car if for any reason she had turned the key on and off several times? If she had been doing this it got flooded......I was doing that to clean and lube my antenna once and the car got flooded.....

[James A Sousa]

This is called "lawn mower syndrome"

You move your brick to get the mower out of the garage, then it won't start!

The valves are stuck.

The conventional cure is to hold the pedal on the floor and crank and crank the engine until it starts. This procedure may not be too hard on the starter due to the lack of compression. The car may actually turn over faster than normal.

NEVER start a white engine without letting it get up to temperature!

If you have it towed to a dealer, they will start it and then change the oil, filter, and spark plugs. I carry an extra filter and a set of plugs in each of our 850s, although no one in my household would dare start one of our bricks without letting it get to temperature.

There are various theories on what takes place.

I think that the only parts that get warm immediatly are the exhaust valves, they expand and stick in their guides.

If you start your white engine brick and turn it off cold often, It WILL happen to you!

Edited by James A Sousa, 05 March 2006 - 11:22 PM.

[anarchyx34]

I've seen several cars lose compression if started cold then shut off a few seconds later, particularly if it's a little cold out. What happens is the excess unburnt fuel (lots of fuel is injected into a cold engine) "washes" down the cyl. walls causing the rings to lose their seal. You can rebuild the compression by injecting a small amount of oil into the cyl's though the spark plug hole and cranking the engine. It should start after that (too much oil will oil-foul the plugs). Just a theory, but that may be your problem.

[James A Sousa]

Thanks, James A Souza. Your response made the most sense. I've never heard of "lawn mower syndrome," your explanation made so much sense. I just wish you wrote sooner. I've already removed the intake manifold and unbolted the exhause manifold and the exhaust gaskets came crumbling down.

One thing that bothers me about this theory is that when I tap on the valve stem, forcing the valve to open slightly, I hear a solid "clank" when it springs back closed. It's the same sound you hear when you have the head off and slide the valves into the guides. When the valves hit the seats, it makes that solid "clank" sound. You know that sound if you've ever worked on heads at this level.

If the valves are stuck open, even slightly, then I would not expect to hear any metal-to-metal contact sound. To me, metal-to-metal contact means good seal between valve and seat, unless the valve is bent.

I could either put it all back together and hope that your theory is correct, or go ahead with a valve job, which would be a sure thing. Hmm...

I think I can afford to put the pieces back together and crank and crank and hope it will start.

I'm not looking forward to reinstalling the valve cover and cams, though.




As a munchkin would say, the valves are not really very stuck, just merely barely stuck - your work on the engine probably let them release. Do a search and you will probably find many posts on the issue. Ask a Volvo tech

Edited by James A Sousa, 10 March 2006 - 06:55 AM.

[95850]

A LITTLE OIL DOWN THE SPARK PLUG HOLE........BINGO THE DEAD BRICK IS ALIVE.....ITS ALIVE. THANKS FOR THE TIP. WHAT A GREAT WEB SITE!!!!!!!!!!!!!!

[ziddey]

This is good indeed. How much is a little? I'd imagine like a quick slight pour? And also, this is for all 5 cylinders? What exactly does it does? As in, does it permanently stay and restore the compression? My question is really: is it a good maintanence thing to do ever or is it only if there's a problem?

[95850]

I would say a little is about a tea spoon full. This is a fix not a maintenance procedure. Be ready for all the oil to burn off as soon as you start it up. It started my car after 3 weeks of tinkering with everything. If you have high miles what type of oil are you running and what is your compression?

[TorqueSteer]

I thought the oil in the hole was just to check if the piston rings are a culprit for low compression? For what its worth, I had low compression, 120 psi, in one cylinder, and put some oil in there, and it shot up to 180 psi. Anyways the car runs amazing now and youd think the motor was in perfect condition.

[connorb850]

I thought the oil in the hole was just to check if the piston rings are a culprit for low compression? For what its worth, I had low compression, 120 psi, in one cylinder, and put some oil in there, and it shot up to 180 psi. Anyways the car runs amazing now and youd think the motor was in perfect condition.

The oil down the spark plugs holes is just a way to help an engine that is gas flooded build enough compression to start. After it starts, the oil will burn off and it will smoke out the exhaust for a few seconds.

[ziddey]

The oil down the spark plugs holes is just a way to help an engine that is gas flooded build enough compression to start. After it starts, the oil will burn off and it will smoke out the exhaust for a few seconds.

So it's not a permanent fix for anything? Like low compression or whatnot (Is that even a word? Let me check the dictionary. No it's a not a word, I'm dumb!)? I'm just thinking because although I've never gotten my compression checked on my car, if putting oil in will rejuvanate the piston rings for longer life or bring up compression a bit permanently, then it might be a good "maintanence" thing to do

[850-Turbo]

So it's not a permanent fix for anything? Like low compression or whatnot (Is that even a word? Let me check the dictionary. No it's a not a word, I'm dumb!) (Is that even a word? Let me check the dictionary. No it's a not a word, I'm dumb!)? I'm just thinking because although I've never gotten my compression checked on my car, if putting oil in will rejuvanate the piston rings for longer life or bring up compression a bit permanently, then it might be a good "maintanence" thing to do

I'm affraid it's not a permanent fix. What the oil does is it fills up gaps between the pistons and the cylinders caused by wear, tear and damages. When you fill tiny gaps with viscous fluid like oil, the gas mixture in the cylinders would have harder time escaping, thus creating extra compression.

The oil will eventually escape through the gaps and some will be burned off as well.

[James A Sousa]

If you do not start the car and shut it off right away again, you probably won't have the same problem again, no matter what you did to get it started.

If your compression is OK right now, it'll probably remain OK for quite some time to come.

I had "lawn mower syndrome" with our '95 855 base about 5 years and 55,000 miles ago. No worries since then.