Overheating when AC is on

JWEBB

MEMBER
NISSAN

I just bought a 95 Q45 from a good friend of mine. It's really a nice looking car. It was running fine until I had the car do the coolant and transmission fluid flushes. It started to leak a bit of coolant. The mechanic claimed the coolant flush might have flushed out the deposit which temporarily prevented the leak. So I had a new radiator and thermostatic installed. At the same time, I replaced 3 belts since they are about to wear out. Now, no leaking but when I turn on AC, car starts to overheat. I would like to learn more before I talk to the mechanic. Please help.

2 Replies

GARFIELD

MECHANIC
197 POSTS

Does you car have two electric cooling fans? If so make sure that both are running. The condensor fan should come on whenever you turn the ac on. The radiator cooling will not come on until the temp switch closes and turns on the radiator cooling.

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Friday, February 16th, 2007 AT 7:17 PM

KIN CHAN

MEMBER
453 POSTS

What speed does the over heating occur. If it is over heating all the time even at highway speed when a/c is on. Then u definitely have a cooling system problem. Either blockage or aeration from the water pump. Also does ur last service of coolant flush performed by a coolant exchange machine or just drain and added additive?. There is a good chance of air pockets left in the system if ur flush was done by the latter process. Have ur mechanic performe a coolant pressure test -->make sure there are no internal or external leak, then use a thermometer to pin point hot spot. If both chk out. Then the only remote possiblity is air fuel, timing
ctrl.

Kin chan

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Saturday, February 17th, 2007 AT 4:52 AM