IPD sale Volvo Parts

Thermostat replacement?

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
Post Reply
User avatar
MVS Moderator
Posts: 210
Joined: Tue Dec 31, 2013 11:55 am
Year and Model: 854T 1995
Location: Frederick MD
Been thanked: 8 times
United States of America

Thermostat replacement?

Post by Roger_850T » Sat Jan 26, 2019 4:05 pm

I'm curious. Would you consider a thermostat to be a "wear item" to be replaced at regular intervals just because it's got some miles on it?

I've already got my Volvo apart. (2005 XC90 V8, 140k miles.)

It's not like the aux belt pulleys or tensioner, which have bearings that wear. And I'm replacing the water pump too, because it has bearings and seals that can fail.

I am trying to decide if I should also replace the thermostat. No bearings, no seals. Generally I've only had thermostat failures after replacing them "just because", so there is an argument for leaving it alone and avoiding infant mortality issues.

What do you think? Is there a good reason why I should replace it prophylactically? Or should I leave the old one in there? Discussion please. Thanks.

'05 XC90 V8 140k
'95 854T 310k
'02 V70 159k
'03 S80 111k (crashed)
'93 945T 217k (gone to be parted out)
'87 245 300k+ sold, still going
'84 264 Diesel, RIP at 160k
'78 242 manual everything.
'73 P1800ES, fun until the rust set in...

Posts: 6177
Joined: Wed Mar 31, 2010 9:54 am
Year and Model: 2004 V70 2.5T
Location: Omaha NE
Been thanked: 47 times
United States of America

Re: Thermostat replacement?

Post by cn90 » Sat Jan 26, 2019 4:39 pm


Most thermostat soft fail (open too early) at around 80K-100K.
I routinely replace my thermostat every 80K-100K.
2004 V70 2.5T 100K+
2005 XC90 2.5T 110K+

Posts: 54
Joined: Sun Nov 18, 2012 5:41 am
Year and Model: 2008 XC90
Location: Massachusetts

Re: Thermostat replacement?

Post by Masscomguru » Sat Jan 26, 2019 5:55 pm

The spring which allows it to open at temp fails from the heat cycles.

Post Reply

Who is online

Users browsing this forum: No registered users and 13 guests