V70-XC no compression on Cyl. 5

maxi650 · Post by **maxi650** » 20 Feb 2011, 19:36

Bad news from my 1999 V70-XC 2.5L turbo 166K: Friday as I was driving uphill on the highway, it started to run rough, CEL flashed few times and stayed on. Code says misfire Cyl. 5. Back at home I checked the spark plug, coil (already replaced one on cyl 1), injector - all good. Then I checked compression and GRRRR! it is 0, no compression! Checked cyl 4 - just to be sure - and I get > 180.
I have done my homework and have to beleive I have a stuck or burned valve (exhaust valve I guess). Today I drove the car in L at 4000 rpm for few minutes (one post says it can help release a sticky valve). It is a little bit better now. Runs fine above 3000 rpm, really rough below. Then I poured 1 can of seafoam in the gas tank and 1 can in the oil. Drove around the block for 5-10 minutes and it seems to be a little better again. Tomorrow I will drive to work and back (2x30 miles) and I will drain the oil tomorrow night. If it has not improved I will have to consider a head replacement .... I checked the Clearwater website and it looks like they have the head. Has anybody done it before ? (I did a head gasket and valve job on my previous 740 T few years ago and it went well). Welcome any advice ....

Post by **JDS60R** » 20 Feb 2011, 21:46

You can try adding marvel mystery oil and seafoam to the fuel in the tank. A stuck valve rarely goes undamaged. If you happen to be lucky enough to have it undamaged then cleaning and lubricating the valve shaft will help.

Most often this is not the case and the head should be removed and inspected for cleanliness and specification.

Post by **precopster** » 21 Feb 2011, 01:08

If this is the original head, junk it to Clearwater. If a rebuilt head with low miles, disassemble and inspect, unless you are mad keen on keeping the original head.

maxi650 · Post by **maxi650** » 21 Feb 2011, 19:20

We got snow today so I didn't take the Volvo - I figured that AAA would be busy enough and didn't need to have to tow me

... I have Seafoam in the gas and oil, we'll see tomorrow, if there is no improvement I will have to pull the head ...

Post by **Ozark Lee** » 22 Feb 2011, 17:14

It is kinda like opening a Christmas present when you pop the head off - you never know what you will find.

You can try the dollar bill trick before you go that far.

Pull the coil wire and have someone crank the car while laying a dollar bill over the tailpipe. Properly working the bill should always push outwards as the car cranks. If it tries to suck in - in a rhythmic manner - that says a bad exhaust valve.

...Lee

maxi650 · Post by **maxi650** » 23 Feb 2011, 21:09

Of course the Seafoam didn't fix it...
I borrowed a borescope (pretty cool toy) and I can clearly see a damaged exhaust valve. I know it now ... The head will have to come off. This is going to be a long project so I am bidding on an other v70xc on eBay ... We'll see.

bobsnow100 · Post by **bobsnow100** » 04 Mar 2011, 14:26

You say it got better when you drove in low at 400rpm and also when you added seafoam. If the valve was bad, I can't see how either one of these helped. It still would of had zero compression and wouldn't of run better. Are you sure that the coil pack wasn't bad so you weren't getting spark in that cylinder. If it had no spark you would of had raw gas getting into the cylinder and that could cause no compression. Switch the coil pack with another one and see if it corrects it.
You can also try to add a tablespoon of oil into the cylinder via the spark plug hole and see if you get any compression

maxi650 · Post by **maxi650** » 04 Mar 2011, 21:35

Driving in low gear or at higher rpm make the vibration less noticeable, I guess.
I am starting disassembling tomorrow. I found a shop in town that will replace the valve, replace all the seals, check the guides and springs, clean and machine the head for less than $300. My goal is to disassemble over the next few days, place the order for the parts (FCP?) next Friday and put everything back together the week end of March 19. Wish me luck.

maxi650 · Post by **maxi650** » 05 Mar 2011, 20:16

I am working at removing the intake manifold. Here are my questions:
1. Can I leave the charge air pipe attached? how do you release the hose clamp of the charge air pipe on the throttle body side? There is no access.
2. I understand that I need to remove the starter bracket (at the back of the starter motor) in order to remove the wire harness going to the throttle body with the throttle body. But again, how do you remove the bracket when the intake manifold is blocking access ???
Is there any tutorial somewhere for 99 V70-XC T ? All the one I found the throttle is on the side which make it easier, mine is below the intake manifold.

Post by **Pauloil** » 06 Mar 2011, 10:22

the charge air pipe is hard to get off, but it can be done and you don't need to take bracket off starter to unplug TB.
try looking at some of the info on the TBs , as the site for Xemodex under the etm section has a lot of help about getting the TB off. a lot has been written about the charge pipe under PCV cleaning....