# New Thermostats and still overheating.... Water Pump?



## breezeman23 (Sep 5, 2016)

Hey all, just started work on a 2001 Nissan maxima 3.0 and am having some issues after installing both of the thermostats.

The car was overheating within the first 5 minutes of starting the engine. First thought was thermostat. So i went down to AA and bought both of the thermostats. I figured while i was in there i would replace both of them to rule out an issue with one or the other. After replacing i ran the car, filling the radiator with coolant (50/50) until it was full, leaving the rad cap off to get rid of any air. 

The car is still overheating within the same amount of time it did previously. Now ive read alot about blow head gaskets and i realize this is a possibility. In the past ive seen BHG's and the coolant is usually, in my experience, a murky oily color. The smell seems to be different too. When i initially took out the old thermo's the coolant flowed out, and i couldn't notice a change in the coolant, so a BHG was ruled out in my mind. Upon further reading, after the overheating issue persisted, i realize i might be wrong. 

The water pump would have been my next step but being that it is gear driven and not belt driven, im thinking theres less of a chance of it malfunctioning. But could this still be the culprit?


Basically ive boiled it down to this:

-thermos replaced
-haven't flushed the radiator yet
-Should I replace the water pump?
-Could it be a BHG?


Please help me out, I need to have a resolve for this vehicle tomorrow and my options are running slim. Thanks so much in advance, hope to be back here for help in the future.

Cheers!


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## smj999smj (Jan 1, 2006)

Make sure you purge all of the air out of the system. Blown head gaskets occasionally occur on VQ engines, but it's not what I would consider a common problem. I would use a Lisle Spill-free funnel connected to the radiator neck to make sure all of the air is out of the system; if there is a blown head gasket, you'll see a never ending trail of air bubbles coming up through the coolant into the funnel. Turn the heater to full max when purging and, if you can, jack up the front end of the vehicle to help push the air forward and up out of the coolant system. You should be able to notice by looking at the coolant in the funnel when the thermostat is opening and the coolant is cycling. Make sure the radiator fans are not only working, but turning at fast enough speeds (I had a 2007 Maxima with overheating issues caused by a fan motor that was turning too slow and needed replacement). A restricted radiator is a possibility and can be checked for hot and cold spots by using an infrared thermometer. It's rare that a water pump fails on a VQ engine that doesn't result in coolant leaking or a loud noise.


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## Car guy (Mar 31, 2016)

New radiator and new radiator cap (for correct pressure, and in turn, thermal control).

How many pints new 50/50 did you add?

Use distilled water (not tap)? (Or pre-mix?)

Ever replace the heater core? Rusty-clogged?


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