2001 Nissan Maxima Car starts overheating at 60 mph

DAVERSNYDER

MEMBER
2001 NISSAN MAXIMA
6 CYL
2WD
AUTOMATIC
160,000 MILES

My maxima starts to overheat when my car is between 60-70 mph and the AC is on. The AC continues to blow cold air. If I turn the AC off and drop the mph under 50 then the car starts to cool down.

I've had both thermostats, fans, and radiator replaced and it's still happening. I've taken it to two different mechanics and neither one can find the problem.

As long I stay under 50 mph the car rides fine, but on the freeway is tough.

Let me know if you have ideas. Thanks in advance.

3 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

Make sure there isnt a bunch of road debris clogging up the a/c condenser in front of the radiator. You can wash it out with a hose and low water pressure or compressed air if you have access. Has it overheated before this started? Has it been chemical tested for a blown head gasket?

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Thursday, July 3rd, 2008 AT 10:13 PM

DAVERSNYDER

MEMBER
2 POSTS

It did over heat at the beginning of the year and that is when they replaced the fans and radiator. They've also replaced both thermostats and the radiator cap.

Someone had mentioned the water pump, but I don't know.

Two mechanics are stumped, so I don't know what to do.

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Friday, July 4th, 2008 AT 12:13 PM

KHLOW2008

MECHANIC
41,815 POSTS

Hi daversnyder,

Overheating only at high speed means the cooling is not efficient enough and the probable causes are

1. Clogged radiator.
2. Partially opened thermostat.
3. Clogged water passages.
4. Weak water pump.

I would suggest checking the water pump and water passages since radiator and thermostat had been replaced.

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Sunday, July 6th, 2008 AT 1:45 AM