Login Register

Volvo v70 2.5t low compression in One cylinder

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

Post Reply
Eliotlm
Posts: 40
Joined: 7 December 2020
Year and Model: 1999 Volvo v70 2.5t
Location: Sweden
Been thanked: 1 time

Volvo v70 2.5t low compression in One cylinder

Post by Eliotlm »

This is now my third thread on this topic but i think it deserves a new thread as it now concerns another issue. Before, 2 cylinders didnt fire, i have now fixed One of Them by replacing plugs and a coil. Then i did a compression test and concluded that cylinder 3 had really low compression, the other ones had 125psi whilst number 3 had 25psi. I heard that a burnt Valve is Common, is that a really Hard fix and even worth fixing? Do i have to pull the engine? What should i do? How do i (hopefully) Rule out Piston springs?

I should add that i only did the compression test with the engine Cold and without any oil added.

User avatar
FLXC90
Posts: 1132
Joined: 18 August 2014
Year and Model: 98 V70 T5
Location: Florida Panhandle
Has thanked: 16 times
Been thanked: 45 times

Post by FLXC90 »

Next step is a "wet" compression test of the affected cylinder. Pour a spoon of oil into the cylinder, so that it can potentially seal worn rings, and re-test. If the compression comes up, rings are bad, if not, suspect valve. To repair burnt Valve, it is just a head gasket job, r&R of the bad valve, and suggested all new valve seals, lap and reinstall. Then you will be good for another hundred thousand, right?!
Current Volvos:
1998 V70 T5, 112k sat 5 years, still in mechanical coma (finally at the top of the pile )
2004 XC90 T6 AWD: 186k, 60 on transaxle ( traded in )
1998 POS70 N/A: DD/training aid, 236k but really about 240k, I think...ABS module( passed on to son who sold it)

Post Reply
  • Similar Topics
    Replies
    Views
    Last post