Engine Cooling problem
1997 Pontiac Transport 6 cyl Two Wheel Drive Automatic 197000 miles
!997 pontiac transport with 3.4 litre, 197000kms, I suspected a stuck thermostat, however the engine coolant slowly diasppears, not much, and I see no leaks at all, nothing in the oil, no smoke in the tail pipes and no odd smells. The engine will heat up almost to the red mark on the temp guage before I get any heat from the heater. I figure there is a leak somewhere but I thought the heating up is a result of a bad thermostat. Was to a garage today and they thought likely the intake manifold and not a thermostat. If it is a intake gasket issue would a leak sealant be a temp fix until I have the 900-1000 to fix it? And would a thermostat replacment help this at all? Once the temperature goes back down the car operates normally with normal temperature though sometimes the low coolant light comes on and off. It has never overheated, never any steam or smoke.
Ok, I spent yesterday thinking about the problem and checking things over under the hood. I noted that there were no signs of leaks obvious, no sign of oil/coolant contact, and no puddles or wet areas under the car. I checked the level of coolant in the rad, slightly low and the resevoir was full, I suspected a bad rad cap, pressure checked it, its ok, presure checked the system, found a pin hole leak on the upper rad hose under the clamp on the thermostat housing. I changed the hose, refilled the coolant, and bled out the air. No leaks, and things seem to be operating normally. I spoke to my local mechaninc who was going to have a look today, and he agrees that I might have solved this and now I will drive it for a few days and see if anything changes and if it stays normal then I got it. Thanks for all the other posts here which gave me the ideas of what and how to check.