I have 2003 S80 T6 with about 95K miles. For the last two weeks the car is loosing coolant. If driven about 50 miles the coolant goes from MAX to MIN in the tank. Here is what has already been checked:

1. There is no visible leak. Engine bay and all hoses do not have any traces of coolant (checked with UV light and dye).

2. There is no smoke from the tailpipe (usual giveaway for blown head gasket).

3. No traces of oil in coolant.

4. Dry carpet and windows do not fog (you know, heater core problem).

5. As a precaution, I have replaced the coolant tank cap.

6. System was pressure tested and shows no apparent signs of loosing pressure.

Considering the amount of coolant I have to add almost every day (about a quart), it is kinda strange that there are no visible signs of where the coolant is leaking/burning. There is a small amount of coolant visible near the head gasket in the back of the engine by the exhaust manifold. The only problem is that it is not dripping. So a quart a day should either be visible as a drip or if it burns due to the temperature, it should be visible as smoke. None of that happens.

I have the car checked by two mechanics. One is a Volvo specialist and both couldn't find the cause. So I am reaching to fellow Volvo owners. Any ideas?

Thanks.

 

I would say that your water pump is leaking meaning it's going out. the timing belt cover is probably hiding it.

 

I did replace the water pump last year when I did the timing belt. It is possible that the new one is defective. But wouldn't a quart of coolant every 2 days go somewhere instead of just hiding behind the timing belt cover?

 

1. remove lower plastic shroud (one you remove to change oil, it might be collecting the coolant)
2. pull spark plugs to check to see if any have a clean tip (coolant leaking into cylinder will clean carbon off tips, also look for coolant on top of pistons)
3. remove timing covers to look for signs of leaking (timing belt might have slung it around)
4. check oil for a change in level or a milky look (head gasket could be leaking coolant into oil)
5. check xmsn fluid for a change in level or milky look (internal crack in radiator could leak coolant into the xmsn cooler) not likely since pressure check was good but could if it was a small leak
6. check coolant line next to no. 1 cylinder exhaust manifold (gasket might have gone out, heat from exhaust could cause it to evaporate)

a quart everyday is quite a bit. Hope I offer a little help for ideas. how long are you letting it idle for in the driveway without any leaks?

 

Heater core. Was for me anyways. My s80 was dumping all of her coolant outside the vehicle when pressure started building up. Bypass the heater core. Fixed mine. Good luck.