C70 Coolant Leak, cannot find its source?

, DUSTY M

MEMBER
2005 VOLVO C70
2.0L
5 CYL
TURBO
2WD
AUTOMATIC
84,000 MILES

Owned the vehicle listed above for 11 years. 84K. Well, looked after and serviced properly. Got a small coolant leak somewhere. Loses about half the expansion tank every 60-140 miles. Pressure test revealed nothing. Car inspected on ramps and the mechanic could find no evidence of any leaks (dried traces of coolant), also with engine running. Removed and inspected expansion tank and all looked sound. Hoses all good and tightened. No evidence of water in the oil. Two experienced mechanics who are familiar with the car are stumped. Any ideas what's going on or what parts we should systematically replace, faulty or not?

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,949 POSTS

Coolant is either burnt or leaked, have you checked in the passengers footwell to see if the heater core is leaking? Also, I would do a chemical check to see if exhaust gases are inside the cooling system. You could have a blown head gasket even though there is no coolant in the oil.

https://www.2carpros.com/articles/head-gasket-blown-test

Please go over this guide and get back to us.