Coolant disappearing

benefield · Post by **benefield** » 19 Jun 2010, 12:58

My 99 S80 runs hot within in just a few miles of driving. The coolant bottle will be completely empty and take maybe a 1/2 gallon to refill. I have not found any visible leaking, no white smoke, and the oil does not appear to be milky. Any suggestions?

Post by **boosted5cyl** » 19 Jun 2010, 13:12

I had a pinhole leak on the radiator hose that goes over the transmission towards the passenger cabin. It clamps onto a metal pipe as you follow it back. Wiggle it around when the motor is warm/thermostat is open and see if is oozes at all.

Post by **JDS60R** » 19 Jun 2010, 13:17

Does the car studder? = headgasket

Did you check the trans fluid? = possible trans cooler leak in radiator

if not one of above
Do a pressure test on cooling system to find leak.

benefield · Post by **benefield** » 09 Jul 2010, 19:57

Problem appears to be solved. Can't explain it, but I simply replaced to evap tank cap and coolant level remains steady. Go figure.

Post by **polskamafia mjl** » 09 Jul 2010, 21:55

If the cap seal is flaky the coolant will evaporate; it is about 50% water after all.

trtvolvo · Post by **trtvolvo** » 19 Aug 2010, 18:04

benefield - is your problem still "solved"?

I am having similar problem with my 2003 S80. After even short, slow drives, engine is extremely hot (as measured by hear radiating off the engine after turned off; still too hot to the touch after 5-6 hours off). Thermostat never pops above the mid-level.

Also, slowly losing coolant (about max-to-min line in reservoir over 1,000-2,000 miles). Originally, I noticed a cracked reservoir cap and thought that was the problem (I suspect the used car dealer added that cracked cap to throw me off from the real problem for a while longer). But, since replacing the cap, I still have the slow coolant leak.

Also related to the running hot issue, it sounds like there is a fan in the ECU box (passenger side front of engine), not the radiator fan, that continues to run for about 20 mins after the car is turned off.

Any ideas? Possibly multiple issues?

1. Pin hole leak or blown head gasket causing the slow coolant leak (no visual signs of coolant in oil, exhaust, or transmission fluid).

2. Running hot? Something like broken water pump? But, I would think that any failure that caused it to run that hot would show as excessive temperature on thermostat? The thermostat "appears" to be in working order, with engine cold, it starts at the low end, as the engine is started and runs a bit, it slowly rises to the mid-point and stays there for the duration of the drive (and hours later). Is it possible to tamper with thermostats to ensure they get pegged at the mid-point despite the actual engine temperature?

trtvolvo · Post by **trtvolvo** » 08 Sep 2010, 00:28

Update - seemingly good news. Regarding slow coolant leak - it became a faster leak, dumping small puddles on the garage floor - was tracked down to cracked coolant reservoir, fixed, problem resolved (for good I hope). Regarding running hot, seemingly typical (T6 twin turbo hotterthan my other 5c turbos) - I'll relax a bit on that "issue".