Lost compression on 4th cylinder

Post by **misha** » 15 Apr 2026, 00:51

erikv11 wrote: 14 Apr 2026, 20:03 Hmmm, yeah, what's the compression in the four cylinders with good valves?

Don't know yet.

Post by **abscate** » 15 Apr 2026, 03:54

You can get the stem seal kit ftom Skandix ( Volvo only) as well as new valves. Reworked head under $1000 with your labour

Another 300k KM!

Cees Klumper · Post by **Cees Klumper** » 15 Apr 2026, 11:51

I would also encourage you to try and remedy the original engine with new valve stem seals and valves. Likely just need to remove the head, not the whole engine.
I recently addressed oil burning in my 1990 Ford with the V6 Cologne engine by fitting new valve stem seals for $20. 4 of the old ones had just popped loose so were not doing anything.

Post by **misha** » 16 Apr 2026, 04:50

I'm still thinking what to do.
I never opened any engine in my life.

Don't know exactly what to check and what to look for.

I can open the engine and remove the head but that would be all.

Stem seals could be the culprit,but the engine have moderate blowby from oil dipstick tube when running...piston rings,cyl walls,bearings also would need a check...since the engine would be opened anyway.

Piston rings can be easily replaced by dropping the oil pan and pulling the pistons from the top.

We'll see.

Post by **Sveedy** » 16 Apr 2026, 08:13

I agree with erikv11 - check the compression in the other cylinders.
I also had never taken apart an engine till I did the head on my V70. I found it to be surprisingly easy and enjoyable. But I had no time frame in which to get the job completed, so no pressure. Lapping the valves, cleaning everything up, installing new seals using a homemade spring compressor - all of it was very easy and rewarding. But again I was in no rush.
If you do need cylinder work, then obviously that's another ball game. When my 850 needed cylinder work, I just pulled the engine and took it into a shop, and had them do the pistons and rings after machining.

Post by **abscate** » 16 Apr 2026, 08:26

Your shop labour rates will be 1/4 of ours in Serbia - and the shop will have expertise, too.

I just did my first head job and loved it so much I did it twice!

Post by **BlackBart** » 16 Apr 2026, 13:34

100 to 125 mph on an engine with 450,000km on it? There's some stress test right there.

Maybe it's all in the head as abscate suggested. That's likely the cheapest option.

Post by **misha** » 17 Apr 2026, 07:03

Engine never had a hiccup before this happened...well maintained also...but age and high mileage did the inevitable.

Purred like a kitten and no strange sounds from the engine of any kind.
Pulled and ran just like from the 1st day i bought it back in 2000.

Just burned 1l of oil/per 1000km and not a single leak from the engine.
Oil burning was like that for last 15 years.

Post by **volvolugnut** » 17 Apr 2026, 08:18

Boroscope inspection of the cylinders might be good idea before teardown. There are good boroscopes available that connect to your smart phone. If the cross hatch on the cylinders are bad, then maybe no teardown.
volvolugnut

Post by **misha** » 18 Apr 2026, 16:03

abscate wrote: 16 Apr 2026, 08:26 ...I just did my first head job and loved it so much I did it twice!