volvogeek Posted August 25, 2010 Report Share Posted August 25, 2010 1997 855 GLT, replaced plugs/wires cap/rotor, did compression test and cyl 1 had ZERO compression. It runs a little rough at idle, but power is great. CEL flashes occasionally while accelerating, codes are always ONLY cyl 1 misfire. If it ran badly off-idle I'd be more concerned, but it honestly runs fabulously and is getting fairly good gas mileage to boot. I'm hoping it's just carbon keeping a valve open slightly, but at this point it could also be a burned valve. I don't think it's piston blowby else the PCV system would be pressurized. Considering doing a seafoam/chinese water torture treatment to see if that does the trick, but other than pulling the head, anyone have any other suggestions? Link to comment Share on other sites More sharing options...
RZT5 Posted August 25, 2010 Report Share Posted August 25, 2010 absolutely no compression? what are the other cylinders reading? sounds like if you want to fix it you'll have to pull at least some of the engine apart. If your around my area in the next few days I'll look at it, I dont think I'll be able to diagnose it but I'll certainly be able to tell you if it feels right for a whiteblock off-idle. Link to comment Share on other sites More sharing options...
Jippi 855 GLT Posted August 25, 2010 Report Share Posted August 25, 2010 i had this happen you have a burnt valve. Link to comment Share on other sites More sharing options...
aggarcia Posted August 25, 2010 Report Share Posted August 25, 2010 Put oil down cylinder and run compression test again. If it has some compression then broken piston or rings. If no change in readings then top end - most likely a burned valve. A leak down test will allow you to better pin point the trouble area without a tear down. Good Luck. AG Link to comment Share on other sites More sharing options...
Ihatespeedbumps Posted August 25, 2010 Report Share Posted August 25, 2010 i had this happen you have a burnt valve. most likely scenario Link to comment Share on other sites More sharing options...
Keaton85 Posted August 25, 2010 Report Share Posted August 25, 2010 Just had the same thing. Burnt valve, but get it scoped first before taking the head off to double check. Weird that this has been happening more and more lately on these cars! Link to comment Share on other sites More sharing options...
Ozark Lee Posted August 26, 2010 Report Share Posted August 26, 2010 Weird that this has been happening more and more lately on these cars! Not at all weird, gas is getting expensive again and folks are "saving money" by filling up with regular instead of premium. ...Lee Link to comment Share on other sites More sharing options...
Gilhuly Posted August 26, 2010 Report Share Posted August 26, 2010 I do believe that this is a cause of burnt valves on turbos, but you think GLTs need to run premium? What's the compression in a 2.4 GLT? Not at all weird, gas is getting expensive again and folks are "saving money" by filling up with regular instead of premium. ...Lee Link to comment Share on other sites More sharing options...
Jippi 855 GLT Posted August 26, 2010 Report Share Posted August 26, 2010 I do believe that this is a cause of burnt valves on turbos, but you think GLTs need to run premium? What's the compression in a 2.4 GLT? i run 93 octane in my NA Link to comment Share on other sites More sharing options...
Bah Posted August 26, 2010 Report Share Posted August 26, 2010 N/A's don't have sodium filled valves so its an invalid comparison. And GLTs are 9.0:1 i think? maybe a bit higher. It doesn't matter, your components are old, the car and engine are aged. The chances for mishap are that much more likely. Run premium in these engines, avoid the problems. Its moot since people don't listen but w/e. Car manufacturer said to run premium in all of these cars. I'm not one to to listen to what i'm told, but in this instance, i'll listen wholeheartedly. Burnt valve is more then likely in this instance though. Link to comment Share on other sites More sharing options...
Kevin. Posted August 26, 2010 Report Share Posted August 26, 2010 Compression on a N/A engine is right around 10.5 to 1 I only run Premo Gas 93 Octane in my N/A because I love it and I dont want it to die....again :lol: Link to comment Share on other sites More sharing options...
Gilhuly Posted August 26, 2010 Report Share Posted August 26, 2010 If its 10.5/1 (I just checked - that is a correct figure)then i would agree on running premium as well. I never knew those motors were so high compression. I just assumed they would be around 9.5/1. Regular gas will definitely contribute to cooked valves. Learn something new every day, if your lucky. Link to comment Share on other sites More sharing options...
krn Posted August 26, 2010 Report Share Posted August 26, 2010 97 GLTs are turbo charged so I think it is 9.5 for the low pressure turbo. Link to comment Share on other sites More sharing options...
Ihatespeedbumps Posted August 26, 2010 Report Share Posted August 26, 2010 These burned exhuast valves have nothing to do with poor quality fuel. They are dropping valves because the valve stem seals have been leaking for an eternity and have not been repaired. Now that all of these engines have lots of miles and age on them the problem only gets worse, that's why the frequency of burned valves is higher. Link to comment Share on other sites More sharing options...
Keaton85 Posted August 26, 2010 Report Share Posted August 26, 2010 The question is HOW does low octane fuel cause burnt valves? I'm failing to see this? Link to comment Share on other sites More sharing options...
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