rooobaru

hello all..my g/f's pathfinder is having a couple issues...first off the temp gauge would hover around normal for a while ,then soar to max hot on the guage.then a couple minutes would pass and it would very quickly go back down to normal...the blower would have heat at both points.

i went out and put in a new thermostat and coolant and took it for a ride.everything was normal and i thought it was an easy fix...two weeks go by and now the problem is back.the only thing that is different is she says that when it's overheating,there is no heat coming from the vents.then while driving,the heat will start coming down on the temp gauge and the heater works again.also the notorius belt squeaking has been going on throughout this whole ordeal...

so what should i do???get a new thermostat and try again???
thanks for any help guys!!!

dokbrown

You say that the belt is squeaking; are you sure it is the belt? This sounds like a water pump to me. Here is a simple test:

1. With the engine cool (perhaps let it sit overnight), remove the radiator cap. (DO NOT REMOVE THE RADIATOR CAP IF THE ENGINE IS HOT!!!!!) You probably already know that, but I just want to be sure.

2. Start the engine and let it run. Watch the temp gauge. When it starts to move to the normal range, go to the radiator and look at the coolant. When the thermostat opens, you should see noticable movement in the cooland in the radiator.

3. If you do not see movement in the coolant as the temp rises, it is probably your water pump. Could it be the thermostat, maybe, but I really do not think a new one would go out after just a couple of weeks.

4. If the water moves, but you still have heat issues, check your oil. Is it milky white or frothy? If it is, you could have a cracked head or a blown head gasket.

5. If the oil is OK, and the water moves, you may have a problem with a blockage in the radiator or heater core or somewhere else in the cooling system.

That should be at least a starting point. My money is on the water pump though. Hope this helps!

rooobaru

thanks doc...i've narrowed it down to the water pump...can't wait to start this job.