Mysterious Coolant dissapearance and Overheating!

[Shotgun3131]

OK, This is happening with a 93 Legend L Sedan.

The Temperature guage goes up frequently and will stay there for about 10- 15 secs and then it will return to normal. This happens with greater frequency when the Heater is turned to the on position, but will happen with it completely off.

When this happens the coolant level usually drops rapidly but no one can figure where the coolant is going. No puddles, no steam or anything.

Almost everything has been replaced including the Head Gaskets, Timing belt, Water Pump and Radiotor/ Thermostat/ Temp Guage.

This is a car with 96000 miles on it and no one can figure it out.

[ric]

heater core

[drift]

you didnt top off your coolant the last time it was drained/refilled.

an air bubble passes by the thermometer and gives a high temp since the air is superheated compared to the coolant. when you turn on the heater, the coolant has more area to cover with the same amount of fluid, so it exacerbates the problem.


cool the car down completely overnight with the heater set full red, then open the radiator cap and check your fluid level. you should be low. refill to top off the radiator and fill the reservoir 1/3 full. open the bleed valve at the rear of the motor, usually near the thermostat and let any air bubbles drain. yo know it's done when you get a steady stream of coolant running out. close the bleed valve and top off again as necessary. start the car with radiator cap off and let it idle til full temp with heater full blast and you see the fluid begin to circulate in the filler neck. if the level drops, add more fluid til full.

this should remove the air bubble in your cooling system.

you may need to replace your thermostat as the air bubble could have caused the wax pellet to die.

[Shotgun3131]

It just keeps losing coolant even after its topped off.

Not at a usual rate either, but at a large rate, averaging a bottle a week.
No puddles under car or anything. Its been to various shops and different mechanics and no one can figure out where its going.

Thanks for the feedback

[crxlvr]

it might be leaking into your oil, if you have a blown head gasket it could be seeping into your pistons and oil galleries. check your oil for a sludgy substance, if its there, then you got some serious problems.

[tikerz]

I had almost the exact same thing happen to my 1991 Accord. The radiator blew and overheated my engine so I replaced it. After a couple months of driving I notice the temp go up when I was stopped at a light and go back down when moving again. I went to couple of places and they said the fans must not be coming on so they replaced that and it still does it. I finally bit it and took it to the dealer and they said I must have a crack somewhere in the engine and coolant is leaking into it and is getting burned up through the exhaust. The recommended a new engine or a new car. I did, however, have leaking coolant below my car. Though never when standing still just when I had driven it for a while. I ghetto rigged it to driveable condition by jumping the fans so they're on all the time now. It's helped the temp problem for now... In the meantime, I'm looking for a new car.

[Barwick]

are there water seals (o-rings) that could have blown when it last overheated one time? I know that o-rings and coolant seals are a problem with RX-7's, I haven't messed with pistons enough to know if they've got a similar issue or not.

[jdblack1]

Cooling passage in the head cracked, leaking coolant to exhaust manifold.

I've seen it before