1999 V70 XC Misfiring Problem

[precopster]

Once you take the cam cover off all valves will be in a closed position so performing the (leak down) test will be less complex.

[DavidsVolvo]

Sorry, but what do you mean by all the valves will be closed when the cam cover comes off? Is there some mechanism that causes the valves to close when taking off the cover?

[erikv11]

In short, yes.

In longer, the cam cover holds the cams in place. With the cams in place, the cam lobes that happen to be pointing down cause those corresponding valves to be held open. Once you let the cover up, the valve springs will all expand, pushing all the valves shut, and lifting the cams off of the head.

You may want to leaf through the relevant section of a good head gasket tutorial so you know what is in store with releasing the cam cover. It's straightforward and you don't need to use special tools but you can mess up if you don't get the cams to come straight up.

This one is the best I know of: Volvo 5-cylinder: How to Replace the Head Gasket

[abscate]

There's a chance I might be in Boston with my bore scope next week. Pm me if interested.

[erikv11]

See this link for a really nice pdf improvement of the tracey's guide

https://www.matthewsvolvosite.com/forums ... =1&t=66484

[DavidsVolvo]

OK, the verdict is in. BTW - Thanks for the offer of the borescope. I forgot I have a very good Olympus borescope in the basement. I used it in cylinder #2 and saw a pie shape piece missing from one of the exhaust valves. At this point, I do not know if it is worth fixing. This '99 XC has a bad rear end and I needed to remove the drive shaft some months ago. All in all, the car needs a radiator, the head pulled, maybe a valve job, the rear end re-built and a few small things. I think I am going to part the car out and get another one for $1000 with easy things to fix.

Thanks to all who helped me diagnose this. I learned a lot.