My car overheats. The water pump,rad,therm,rad cap all replaced. Car been into Simpsons(New Malden 4 times and they can't sort it. They now say its the Head Gasket even though it passes the pressure test. I can tarvel a few miles and it boils up or two weeks and no probs. Today I stopped for petrol and water was coming out from the left hand side. Any ideas...

 

I have had a run of overheating in the past couple of years. My 300 (uk spec) has an auxilliary electric fan that cuts in. That was replaced because it stopped working. After the electric fan was replaced the car was still overheating and even though I kept topping up and had no leaks I was still losing water. Silvia cured it by running the car on a ramp and gradually topping up the water while the engine was running. It would appear that there was some air trapped somewhere in the system.Then I had a leaky heater matrix requiring regular top ups of water. This has burst twice and is currently in for repair. See my reply under the other leak question on the forum. Good luck.

 

Grant

 

Had problems with mine. According to Silvia the Z runs hot as a matter of course, and once it overheats all the hoses go one by one. Happened to me. Silvia capped off all the little hoses going to the plenum and the ones to the turbos! Replaced the others. I upgraded the engine oil cooler too. Also disconnected the ATF fluid from the radiator and now goes thru a dedicated oil cooler.

Car is a stage III, no bonnet scoops (man they're ugly!) Car runs fine. Have you flushed the engine? Can be a good idea but can cause more problems by loosening up lots of crap which have been sealing your system and flushes it through your heater matrix. Oh yeh, had my matrix replaced.

 

Mmm! Z's run hot as a matter of course??

 

My optimum temperature reading, via my digital display, is 85C and this may raise to 90C on a hot day and that pushing min 1bar boost pressure.

 

I haven't experienced any signs of hot running, even after a thrash around the Zandvoort track in very hot weather.

 

I think that you could have the following problems.

 

1. A build up of deposits in the system

cooling system

 

2. A large air pocket in the cooling system

 

3. ECU error code

 

4. Faulty engine fan clutch

 

I would get Nissan to test drive with consult II and determine exactly at which point the temperature rises rapidly.

 

Generally, on a normal day, engine coolant temperature should reach about 80C within 10-15mins with general driving.

 

The engine cooling fan will activate at 105C and then double speed at 110C.

 

Steve

 

 

I'd agree with Steve - I've not had any sign of any overheating. I always run at precisely the same point on the stock temperature needle - that's ranging from sub zero temperatures outside to sustained 140 mph in 34 degrees C (private track of course). I had Steve's digital display linked up to mine as well and, from memory, the difference between idling and boosting at 14.5 psi was 1 degree.

 

Suggest that any signs of overheating are investigated immediately - shouldn't get any overheating.

 

D