My 1987 FX16 has a problem in that the cooling system is pressurized when it is COLD. The cooling system carries a little pressure (something less than the 13 lbs that the cap would release) and if you slowly loosen the rad cap, you see the pressure escaping into the coolant recovery tank. This pressurization causes the coolant to remain in the recovery tank and it is not drawn back into the radiator when the cooling system cools (like down to 30 degrees). The coolant level in the radiator is always low when the car is cold and never is full. If you fill it up, it ie expelled into the recovery tank when the engine warms up and is never drawn back into the radiator when it cools.
New rad caps, thorough check of cooling system, periodic maintenance, 235K miles, no heating problems. No evidence of coolant in oil or coolant being brought into combustion cylinder. No excess pressure when the engine is running.
What's going? What needs to be fixed? I must be missing something, but what? Anyone had experience with this?
um, my first mr2 did the same thing...... and after driving for a while it would slightly start to overheat..... when the revs were up it would lose coolant from the recovery tank, but wouldn't do it on idle. my recovery tank cap was hooked up backwards (i got the mr2 nearly free because after putting a new motor in the car, the previous owner couldn't find the problem and thought it was a HG)
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1) 2004 IS300 Manual/LSD/Sportdesign 2) 2010 Corolla S 5 speed 3) 1986 MR2 "MK1.22" 5sfe/s54 swap 3) 1995 Ford Explorer 4x4, TT/AAL/custom shackle lift, 31"s
FLASHMN - If the headgasket were blown, there should be signs of coolant in the oil or in the exhaust, or the system would be loosing coolant, but that isn't the case here. There is no loss of coolant anywhere. If the car runs correctly, when the engine is hot, the coolant expands and goes to the coolant recovery tank. When the engine cools,the coolant is drawn back into the radiator, but this doesn't happen with this car because there is something causing the cooling system to be PRESSURIZED - for days if you let it sit that long. If it were the gasket, there certainly could be pressure added to the coolant WHILE IT IS RUNNING; but when it it turned off, there is no running engine to add that pressure to the cooling system.
um, my first mr2 did the same thing...... and after driving for a while it would slightly start to overheat..... when the revs were up it would lose coolant from the recovery tank, but wouldn't do it on idle. my recovery tank cap was hooked up backwards (i got the mr2 nearly free because after putting a new motor in the car, the previous owner couldn't find the problem and thought it was a HG)
I thought you were just trying to be funny when I first read your post, but I can see that you really had a problem and you correctly described the casue. I have checked this and indeed my coolant tank tank is correctly plumbed and not blocked in any way.
FLASHMN - If the headgasket were blown, there should be signs of coolant in the oil or in the exhaust, or the system would be loosing coolant, but that isn't the case here
Not 100% necessarily, mine didnt, it just pressurized the cooling system.
Theres no pressure in the coolant system after you turn off the engine, the reason why it doesnt suck the water back in, is because its sucking in air through the head gasket portion that failed, so theres no vacuum to suck back the water in the reservoir. Get it, good, now fix it.
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