IPD sale Volvo Parts
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy your stuff using this and it helps MVS!

Oil Cooling Thermostat Removal

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

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

woodycaldercloggs
Posts: 15
Joined: Tue May 26, 2015 4:44 am
Year and Model: v70 1998
Location: France
Has thanked: 21 times
Been thanked: 0
woodycaldercloggs

Oil Cooling Thermostat Removal

Post by woodycaldercloggs » Sun Jul 01, 2018 10:26 am

I have a 1998 V70 with leaking oil cooler lines.
I have ordered new oil cooling lines to do the replacement but forgot to order an oil cooler thermostat gasket.
(where I live it takes a week to get replacement parts)

Can anyone tell me if it is necessary to remove the thermostat to replace the lines or can I do it by keeping it in place because I don't have a new gasket ? :?



VolvoAffair
Posts: 11
Joined: Sat Mar 31, 2018 7:03 pm
Year and Model: 1998 S70
Location: Salt Lake City
Has thanked: 0
Been thanked: 3 times
United States of America
VolvoAffair

Re: Oil Cooling Thermostat Removal

Post by VolvoAffair » Sun Jul 01, 2018 8:00 pm

Yes, you will need to remove the lines...
Attachments
Volvo 855 Oil Cooler Line Replacment rev0.pdf
(5.95 MiB) Downloaded 47 times
These users thanked the author VolvoAffair for the post:
woodycaldercloggs



scot850
Posts: 5483
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Has thanked: 6 times
Been thanked: 134 times
Canada
scot850

Re: Oil Cooling Thermostat Removal

Post by scot850 » Mon Jul 02, 2018 9:42 am

You don't need to remove the thermostat to do the lines, but it does make the job a little more challenging as you have to undo a partially hidden Torx bolt that holds a small end plate at the end of the 2 engine cooling pipes.

Another reason I would consider removing the thermostat is if the pipes have sings of oil leaking at the joint with the thermostat. There are 'O'-ring seals on the end of the pipes and if the oil has been weeping, due to the temperature it forms a hard crust in the seat area of the 'O'-rings. The local Volvo dealer replaced these twice before declaring the problem was the pipes themselves were faulty. I bought new cooling lines only to find it was nearly impossible to fit the 'O'-rings in. So in the end I removed the thermostat housing and found the hardened oil sludge had been tearing the 'O'-rings when pushed home. As the thermostat is no longer available new, I very carefully scraped the crap out and then a gentle rub with fine wet/dry paper all was good.

Bottom line was pipes were fine, but mechanic was lazy and wrong diagnostic. I ended up fitting new lines for no reason but as they are a swine to fit I left the new ones on.

Another thing to watch for is the plate that holds the bottom of the pipes into the thermostat. Over time it bows outwards on the ends allowing the pipes to pull out slightly which is what caused the leak in the first place. Either flatten the plate or reverse it when re-fitting so it pulls the pipes fully home.

I thought I had pictures but can't find them now.

Neil.
These users thanked the author scot850 for the post:
woodycaldercloggs


2000 V70 R - still being an endless PITA
2006 XC70
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - New project and test bed - Sold

scot850
Posts: 5483
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Has thanked: 6 times
Been thanked: 134 times
Canada
scot850

Re: Oil Cooling Thermostat Removal

Post by scot850 » Mon Jul 02, 2018 2:13 pm

Knew if I looked hard enough I would find the pictures:
1998 Volvo Oil Cooler Thermostat housing 001.JPG
Damage to oil cooler lower o-rings
1998 Volvo Oil Cooler Thermostat housing 002.JPG
Thermostat removed for inspection
1998 Volvo Oil Cooler Thermostat housing 003.JPG
Burnt on oil residue
If you look carefully at the lower inner part of the oil line opening you can see (sorry for picture clarity) a black rough patch where the old oil had burned and baked. This had a rough surface so shoving new seals over this resulted in the condition of the 'O' rings in the first picture. This was after the 2nd set had been fitted at the dealer with the same result.
1998 Volvo Oil Cooler Thermostat housing 004.JPG
Burnt on oil residue (2)
This was all caused originally by the lower pipes being able to move outward due to the locating plate having warped outward on the ends and allowing oil to get passed the old hardened seals.

Neil.
These users thanked the author scot850 for the post:
woodycaldercloggs


2000 V70 R - still being an endless PITA
2006 XC70
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - New project and test bed - Sold

Post Reply