Summer Holiday Blues

[PierreC]

... Yes, summer holiday! This is the southern hemisphere ...

Had a "Coolant low. Stop safely" or something similar message one day out of the blue on a scorching hot summer day and a long drive after some cable gliding over a river gorge running into the ocean ...

Managed to limp "home" (holiday home) to discover one of the heater pipes (between engine and firewall, to heat exchange unit inside car) had burst. Managed to shorten the pipe and "fix" it temporarily until I could get replacement hoses fitted by a dealer some 60 miles away. Excellent (albeit expensive) service by the dealer, replacing both heater pipes and top and bottom radiator hoses two days after Christmas.

That solved the problem ... but now there is a new problem: up to this incident, the car reached normal operating temperature very quickly - in about 5 or 6 miles at most. Now, it takes up to 15 or more miles to reach normal (indicated) operating temperature on the gauge, and on my early morning high-speed driving return trip home, the gauge indicated below normal operating temperature for more than 100 miles (160 km).

I suspect that maybe the thermostat got damaged and needs replacement? Any thoughts?

PS Car is almost 11 years old, with 205.000 km (just under 130.000 miles) on the clock. I have owned it since new and it is (in the words of my "normal" dealer workshop manager) the cleanest, tightest and best maintained and performing XC70 of its model year and beyond that he has ever driver and/or worked on.

[BillAileo]

I concur that the thermostat is the likely source of the problem. I wouldn't be surprized if you need to replace the thermostat on that car as a unit including the housing.

[JRL]

Hopefully, you did not bust a headgasket by running it while out of coolant

[PierreC]

Hopefully, you did not bust a headgasket by running it while out of coolant

That was my fear as well and for two weeks now I have checked the oil every day to see if it turns milky - so far, so good. Also, no change in performance nor (now that the pipes are fixed) any increase or decrease in the coolant level in the overflow bottle (hot and cold)!

So hold thumbs!