1995 Volvo 850 - No compression in cylinder 5

JackZero · Post by **JackZero** » 30 Mar 2009, 19:42

Hello,

As the subject says, I've got a 1995 Volvo 850 with about 195K miles and no compression in cylinder 5. The cylinder failed suddenly when I was accelerating up a hill. The check engine light came on and it started running rough. I turned around immediately and drove home, but that was 5-6 miles. Without compression in the cylinder I was pumping fuel into the catalytic converter. Was my short drive home enough to destroy the CC?

My mechanic tells me it will be $1200 just to find out why there's no compression. I used to be pretty handy with a wrench, rebuilt an engine 20 years ago, but I don't have access to a garage or anywhere to work on it besides the street. So, is there any way I can find out exactly what the problem is without removing the engine header? If it's a valve spring, or gasket I can probably fix it myself, once the weather gets a little better.

In the mean time, it's parked on the street and I'd like to be able to move it without damaging the catalytic converter. Is it possible to disable the fuel injector to cylinder 5? Is the CC already shot? I have the Chilton's manual, but the section on fuel injectors is tiny and not very helpful.

Thanks for your advice!

Jack

Post by **Ozark Lee** » 30 Mar 2009, 20:06

Don't worry about the cat. Chances are you burned a valve which you may or may not be able to just lap in a new $25.00 valve along with a $125.00 head gasket kit. If the head is real bad I would go with a rebuilt from Clearwater Heads in Florida. I think they run a couple-three hundred dollars and you will still need a head gasket kit.

...Lee

icelandic · Post by **icelandic** » 31 Mar 2009, 08:25

Just had the same problem in my 95 NA 850 at exactly 195k miles. Was on the highway at 65 mph then suddently engine started misfiring and cell went on. I kept driving for five miles, and in the process, the converter got damaged. Took it to my mechanic. No compression on cyl 3. Took head out, one exhaust valve is broken. A 3 x 6 mm piece of the valve rim broke of. I had been planning to heave the head done as I was sure the valve seals were bad, which turned out to be true. What we found out when the head was removed was:

1- Cylinder walls are perfect. They still show the polishing markings.
2-Head gasket was perfect. Some parts of the oil passage ways were almost blocked by a hard carbon like material (only on corners). There was no sludge, and overall head condition was excelent. Water passage ways were clear and clean. Only next to the head gasket, there were some deposits.
3- Valve cams look like new. No signs of wear. Valve lifters are in perfect condition.
4- About 1 mm carbon build up on top of pistons. In odd numbered cylinders, carbon is more concentrated at center. Actually I suspect that the valve broke due to a piece of carbon that may have come loose and got stuck at the valve/head contact point. Otherwise, pistons appear to be ok.
5-Internal head surface also has carbon, although thinner than on piston and more evenly distributed.
6-I haven´t seen the head completely tore down, and expect to confirm leaking seals, and perhaps worn guides.

Icelandic

daveybeee · Post by **daveybeee** » 31 Mar 2009, 14:48

I would seriously consider replacing the lifters while the head is off.

rprestonatmitre · Post by **rprestonatmitre** » 01 Apr 2009, 21:47

Thanks for the info. I just started looking over the engine schematics and am thinking trying to do this myself, on the street, in a day or two, is unrealistic. That limits my choices to either a large repair bill or sell it as scrap. Sigh. (Is there another option?)

Icelandic, could you let me know if you end up having to replace the converter? My engine codes reported converter damage (5-5-5), though I'm not sure how it could know. It seems like something you can't find out until the engine is repaired and an emissions test is done. My converter and exhaust system are only a few years old and I'll probably cut my losses if it needs replacing.

Thanks,

Jack

Post by **Ozark Lee** » 02 Apr 2009, 06:17

The codes that indicate TWC damage indicate that there could potentially be damage, not that actual damage has been done.

...Lee

icelandic · Post by **icelandic** » 02 Apr 2009, 15:46

Ozark Lee is correct. Your converter is potentially damaged, not damaged for sure. You will only know when you repair the engine and it runs again. In my case, the converter was internally damaged as the ceramic honeycomb overheated and became loose inside it. I could clearly hear the rattling and upon inspection I found the innards were really loose.