98 S70 Low Compression after Timing Belt

[arnermd]

Fortunately I like Guinness.... will take me a while to drink 12.....

Put an oz of seafoam in each cylinder and cranked it through without plugs, gonna let it soak a few days.... (I can see your eyes rolling)
I am not optimistic, just stalling...

Buys me some time to go stock up on Guinness...

[scot850]

Neil.

[Sveedy]

You guys are preaching to the choir....

IMG_20230930_105433284.jpg (307.63 KiB) Viewed 413 times

I'm obviously laid out on the floor when I took this

[arnermd]

Soooo..... I left the seafoam in the cylinders overnight and repeated the compression test, looking better....
Original, dry: 30 / 203 / 135 / 70 / 90
Latest, wet: 125 / 210 / 175 / 205 / 135

My first thought was rings but I know for sure I had exhaust valve leaks in 4 of the 5 cylinders, and no detectable leakage out the oil fill..... Maybe the lifters/seals are freeing up? Not really sure.

Loaded each cylinder with another ounce of seafoam, cranked it over a few times and let it sit again, hopefully it continues to improve....

Maybe at some point it will be good enough to put plugs in and try to start..... Not sure when that is though. I'll keep messing with it and keep the Guinness on ice.

[abscate]

Another round of sea foam and you will be good

My guess is you had sticky valve guides and they are freeing up

[foggydogg]

Since there was a marked increase in compression after the first round of magic juice, it could be stuck rings. Seafoam will help a bit - it is widely reported on other forums that the secret ingredient in that stuff is odorless kerosene - my suggestion would be to follow that with a dose of oil; the rings not only need to move freely in the piston grooves, there also has to be an oil film captured in the cylinder wall cross-hatch. Same technique, a shot of something, motor oil, ATF, Mr. Marvel's Elixir, &c., plugs out, hand rotate, beverage break.
Patience, tincture of time, you're almost there.

[arnermd]

Yep.... agree with all your statements, but I know for a fact exhaust valves were leaking. Could have been rings and valves....

Fed each cylinder an ounce of 10W-30 last night, cranked it through with plugs out, let it sit for a day. Will recheck compression tonight. Maybe attempt a start.....

Chilled Guinness on standby....

[arnermd]

Compression after oil in cylinders: 245 - 250 all cylinders. Clearly the oil is helping..... Leak tested cylinder #1 and it was tight.

Put it back together and ran it. Started fine, first pop was kind of hard but fine after that..... Idled up to temp and took it for a short drive. Loaded some sea foam in the crank case.

Is that a noisey lifter? Or just the normal Volvo tick....
Have not heard that tick since I sold my 1989 240 back in 2005. I loved that car.... 300k miles on it when I sold it.

Also there is a low frequency howl in the background.... sounds like air flow noise?

Will check compression again after I burn all the oil out....

[scot850]

If the car has been sitting for a while, then it may develop a tick. Once it has had a decent long run it may well settle down. It sounds like the 850 I worked on recently with over 300,000 miles on it. It had been sitting for a couple of months or so and sounded like a bag of nails on first start up. Once we drove it about a mile it suddenly quietened down. Hopefully yours will be the same.

Neil.

[abscate]

It can take 20-30 minutes for the lifters to fill with oil after a dry start. Volvo says to keep revs under 3000 rpm until the clicking stops, source: owners manual.