Mechanics

OVERHEATING PRIMERA P11

2011 Nissan 240SX

I have a Nissan Primera P 11, manufactured in 1999. It has done 138,000 km and is equipped with a SR20DE engine (2000 CC). The problem is that when I stop for traffic lights or when driving slowly in traffic, the engine heats up (temperature indicator goes up). Once the car starts moving fast the Temperature indicator returns back to the normal position. I have already replaced the radiator, thermostat valve and all the hoses. What could be the fault?
Avatar
Ravindra
June 12, 2007.



Is the cooling fan coming on? Check it at idle and keep an eye on your gauge to see when it comes on. If it doesn't, kill the engine before it goes into the red zone.

I checked the fan at idle with and without A/C. With A/C it operates continously and without A/C it stops and after a biref period starts again automatically. I checked the temperature that the fan starts automatically and it is 95 degrees C. The thermostat valve opens at 76.5 degrees C.

Tiny
Ravindra
Jun 13, 2007.
Although I don't have any info on that car (non-US),

Based on the readings you gave, the thermostat and cooling fan sounds like their working right.

I assume you replace the radiator cap at the same time as the radiator?

Looking at the oil cap after removing it, is there any sign of moisture in the form of a yellow slime?

Yes, I did replace the radiator cap at the time of replacing the radiator. Also, I checked the oil cap and there seems to be no moisture as you've said. This is really annoying, because rather than watching the road while driving, I watch the temperature indicator. Any ideas as to what in heaven's name is wrong?

Tiny
Ravindra
Jun 17, 2007.
I don't know what is wrong, but we have eliminated the cooling fan operation, the radiator for restriction, the Thermostat as you have also replaced that ( not to say the new one may not be sticking), the radiator cap, and what I thought may have been a possible internal coolant leak. We have an overheating condition. It cools down when you drive because extra air is getting forced into the radiator cooling it.
I can only ask you questions as I don't have the car here to look at potential symptoms.

Are you adding any coolant, have you lost any? You have checked both the radiator and overflow bottle levels when its cold, right? (This is for a possible coolant leak)

IF you turn the heat on and blower motor at full how long does heat come out- run it for 5 minutes or so. IF it isn't blaring hot the whole time there is a restriction in the heater core.

Thanks for all the help. I'll check and reply.

Tiny
Ravindra
Jun 20, 2007.
The answer for your first question is; I checked both the overflow bottle and the radiator levels when the engine was cold. I monitored this over a period of time and there seems to be no coolant leak. I turned on the heat and the blower at full. The heated air did not start coming in until I adjusted the regulator to 32 degrees C. As soon as I reduced it to 31 degrees C, cool air starts coming in. Will that be the reason or couldn't it be the water pump malfunctioning, which causes the car to heat up? Or is it some other thing such as a faulty temp indicator?

Tiny
Ravindra
Jun 29, 2007.
Ravindra wrote: Will that be the reason or couldn't it be the water pump malfunctioning, which causes the car to heat up? Or is it some other thing such as a faulty temp indicator?

It might be the water pump if there is poor circulation and no restriction. However if there a restriction or partial restriction it will also cause the symptom. The impellers can wear casuing the poor circulation. I haven't seen this very often however.

The coolant temp sensor sends a signal to the computer for air/fuel mix adjustments and also when to kick the cooling fan on. Which we know works.

The coolant is a 50/50 mix correct. IF the coolant mix is weak (too much water) it will also cause it to run hot.

The test with runing the blower motor and making sure heat is coming out basically tests for restrictions in the heater core.

The answer for your first question is; I checked both the overflow bottle and the radiator levels when the engine was cold. I monitored this over a period of time and there seems to be no coolant leak. I turned on the heat and the blower at full. The heated air did not start coming in until I adjusted the regulator to 32 degrees C. As soon as I reduced it to 31 degrees C, cool air starts coming in.

Tiny
Ravindra
Jul 9, 2007.
Ravindra,

I wish I had info on this model. But not being American makes it a little tough as I have no info on it. If this has a plastic water pump impeller, I would try replacing that. The Passats have that kind of trouble. We eliminated a bunch of possiblities, but I'm running out of probable cause.

Page 1 of 2