Mechanics

OVERHEATING PROBLEM

2001 Nissan Xterra • 150,000 miles

This car overheats while climbing a hill on freeway, while driving around town no problem.I did the head gaskets last nov. While this problem just started. Its a v6 with ac, autotrans. The rad is approx 2yrs old. Since the heating problem i've put a new stat, a new fan clutch, new rad cap.I did a block check plus took it to a rad shop and they did a blockcheck and found nothing in fact they are scratching there heads?I work in the auto industry (for chevy)and have asked everyone.I hope you can give me some ideas as this is my daughters vehicle and a want my wheels back. This seems to be a stumper! Thanks for your time.
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Rusty64
June 27, 2012.




I have come across these cars with radiator problems, being residue casting sand blocking the cores, you still appear to have reasonable flow, but the blockage is enough to cause problems, I would still get the radiator removed and flow tested, start here.

Mhpautos
Jun 27, 2012.
This is a problem with inefficient cooling and the most likely cause is a partially clogged radiator. 2 years is a long time for sludged build-up, especially if no coolant had been used or they had been mixed with different brands.

KHLow2008
Jun 27, 2012.
Thanks for your info.I installed a new radiator as you suggested went on a roadtrip same hill same heating problem, boil all the water out. No problem around town as I stated. Anyother ideas. Thanks for you time

Tiny
Rusty64
Jul 11, 2012.
You have done almost everything except the water pump. Have it checked to see if the impellers are worn.
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KHLow2008
Jul 11, 2012.
I replaced the waterpump along with the headgaskets in november.

Tiny
Rusty64
Jul 16, 2012.
When did this overheating started? Was any repairs done prior to this ocurring?

Have you checked the radiator cooling fins for external clogging?

KHLow2008
Jul 16, 2012.
Have you re checked for an ongoing head problem? Don't discount this just because the heads have been done earlier.

Mhpautos
Jul 16, 2012.
As I stated I did the head gaskets in nov 2011 had no problem until june 2012 when car overheated on a grade. Since then i've done a thermostat, fan clutch, and radiator. The water pump was replaced with the head gaskets in nov.I drove this same grade a few days ago and this vehicle overheated again, at that time I stopped and did a block check with the correct equip and it didn't show a head gasket problem. As I said no problem around town town with only on grade.

Tiny
Rusty64
Jul 19, 2012.
What was the average engine rpm when climbing the grade and what was the driving time?

KHLow2008
Jul 19, 2012.
Not sure about the grade but it last for about a mile, someone suggested the trans converter was heating the fluid while on a grade. Since the fluild runs through radiator I added a ext cooler an deleted the one in the radiator. Well the vehicle still overheated on the hill. The rpm was probably in the 4000rpm range.

Tiny
Rusty64
Jul 25, 2012.

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