My 92 Honda Accord is overheating. Thermostat checked out OK. Fans seem to be working fine. However, car seems to only overheat after driving a while. But the temp gauge at first flucuate, then it moved all the way up beyond the "H"

My 92 Honda Accord is overheating. Thermostat checked out ok. Fans seem to be working fine. However, car seems to only overheat after driving a while. But the temp gauge at first flucuate, then it moved all the way up beyond the "H"

Is coolant (water & antifreeze) visiable in recovery container?--- Is radiator filled with coolant? ---Have you added coolant recently?---Could be blown head gasket but lets not go there yet------Need more information. How did you test thermostat? When airconditioner is operating does both cooling fans on radiator run at the same time?---They should.

Try flushing your cooling system with vinegar but don't leave it in long idle for 15 minutes. Ensure you flush it really really well with lots of water but put the cap on so your thermostate opens and goes through the engine and also ensure your switch for interior heat is on so it has this valve open when flushing. Do this three times with water and drain thoroughly. Then put new glycol/water mixture in. Also flush out the overflow tank. This should get rid of all the scale buildup which will make your cooling system more efficient.

p.s. you just need a couple of litres of vinegar with the water (not glycol)

After the flush, if you refill with a 50/50 mixture of antifreeze and distilled water, you won't have problems with phosphate scale again. Alternatively, refill with slightly more expensive prediluted coolant.

That's a great point and if you really want good water use reverse osmosis distilled water as it has no minerals what so ever.