Why Is My Car Still Overheating After All This!?

[PAV34]

Ok from the start....

Ive got a Greddy Informeter which tells me the water temp, 02 sensor voltage etc in the car and over the last month or so ive noticed the water temp goin up, i think its even hit 100 degrees!

Anyway, i babied it to the mechanic and basically flushed out the coolant and replaced the thermostat.

Got it back and still running a bit hot. Mind you the standard gauge was sitting on normal.

Decided to take it back and do a 100K service which included the water pump, belts, spark lugs etc...Still running hot when i got it back, i think i even saw it go past 100 and the standard gauge went up about 10mm! Obviously the Oil temp went up also, it hits about 100-110.

There are no coolant leaks, no discloured or bubbley coolant so i dont think its a headgasket, ive have replaced the Coolant Temp Sensor on top of the block, bled the system again and again.

I notice when i put the foot down the temp will rise, but steady driving it will sit on about 96 - 100.

I put the heater on flat out to cool the engie down and that seems to work.

PLEASE HELP DIAGNOSE! searching hasnt helped much.

Could it be that the fan belt is a bit loose and not working to its full potential cos i have a hunch its loose??

I friggin pamper this car and never miss a service.

[blind_elk]

Of course check the fan belt. (Although you would also have battery troubles.)

Are you still running the factory VC fan? And the shroud? Cams are not out of alignment? Timing is correct?

[PAV34]

Yeah factory fan and shroud, Racepace did all the work and they even dynoed it and said everythings was fine.

How do i know how much to tighten the belt?

[ssshonky]

are you sure you have a reliable baseline to compare to?

you state that your standard temp guage looks ok .. so I guess what I am trying to say is are you sure all the other 34's dont operate at this range?

maybe just because you can now see a numerical readout of the temperature vs a guage readout your just a tad paranoid? I was under the impression ( and someome PLEASE correct me if I am wrong ) that standard radiator systems can get close to and above 100 oC ( boiling ) and not boil over because they are a sealed system

I am by no means an overheating guru but thats just my thoughts on the matter.

[PAV34]

Workshop guide states that it should run between 82 - 95 degrees.

Thats what it used run before the temps started to rise.

I thought the standard gauges only start to rise when the system is getting very hot.

[n15m0]

I'm with ssshonky...if the standard gauges read normal then you should be fine? IF you didn't have the Greedy infometer you wouldn't have a clue and think tht everything is ok? Unless you had the infometer prior and it was reading lower? If you get what I mean?

[PAV34]

I know what you mean, but when the Greddy digital gauge shows past 100 degrees, the standard gauge starts moving up, and thats with normal driving.

Is there another sensor that could be playing up by any chance?

[n15m0]

I know what you mean, but when the Greddy digital gauge shows past 100 degrees, the standard gauge starts moving up, and thats with normal driving.

Is there another sensor that could be playing up by any chance?

Ah ok, if the standard water temp gauge starts moving up then u may have an issue. Mines never gone past the normal spot just below middle.

[infamous_t]

Did you actually flush the radiator? or just drop the fluid? theres a difference.

In my old car I did the latter which actually caused a blockage which caused to overheat constantly until sorted.

I'd recommend taking getting it looked at by a radiator service place (like NATRAD) and get it flushed properly.

But try tightening belts first...

[blind_elk]

A/C on or off?

[PAV34]

A/C off

[West]

Ok from the start....

Ive got a Greddy Informeter which tells me the water temp, 02 sensor voltage etc in the car and over the last month or so ive noticed the water temp goin up, i think its even hit 100 degrees!

Anyway, i babied it to the mechanic and basically flushed out the coolant and replaced the thermostat.

Got it back and still running a bit hot. Mind you the standard gauge was sitting on normal.

Decided to take it back and do a 100K service which included the water pump, belts, spark lugs etc...Still running hot when i got it back, i think i even saw it go past 100 and the standard gauge went up about 10mm! Obviously the Oil temp went up also, it hits about 100-110.

There are no coolant leaks, no discloured or bubbley coolant so i dont think its a headgasket, ive have replaced the Coolant Temp Sensor on top of the block, bled the system again and again.

I notice when i put the foot down the temp will rise, but steady driving it will sit on about 96 - 100.

I put the heater on flat out to cool the engie down and that seems to work.

PLEASE HELP DIAGNOSE! searching hasnt helped much.

Could it be that the fan belt is a bit loose and not working to its full potential cos i have a hunch its loose??

I friggin pamper this car and never miss a service.

Hi mate,

Firstly i used to have the same issue in my old gtr,

Turned out to be the radiator's top tank was clog up, i removed it, took it to a radiator shop, had the top tank removed, clean + new seal, $85 and the heating issue was gone.

Also after you've flush the radiator, while toping up the coolant again, did you jack the car up a bit, had the heater at full blast and bleed it through that little screw on the side of the block?

[ssshonky]

yeh the use of the bleed screw is good information indeed! perhaps a pocket of air is causing problems

so the Greddy guage has its own sensor.. so if the 2 ( the Greddy and the factory guage ) both increase at the same time you can basically remove the possibility of one of the sensors being dodgy.

now.. I am not sure on the skyline motors but on the sr20det's I know there are 2 temp senders

one that sends info to the guage and another that feeds the ECU the engine temp .

so maybe clean and re-seat your temp sender?

[Roy]

Is there a menu in the Greddy thingie somewhere for calibrating it to your sensors? Next tiem you start teh car from cold see what it is reading. If its reading 20deg higher then ambient or somethintg weird then can it and just go on the std gauge

[33_skyline]

I have the same problem at present, I have taken the theromstat out which didn't open at all, fixed that problem

and temps still read 95 degrees.

I have now got a GTR N1 water pump comming, and am taking the radiator out to get it flushed tomorrow.

hopefully this solves the issue.

[PAV34]

Ben,

Let me know how you go with flushing the radiator please.

[R34GTFOUR]

My bros r33 gtst has an apexi water temp gauge and it sits on 78 degress all day long, no matter if you boot it or not.

100degrees is too hot for a rb and it is not normal. In saying that its not in the temp range to do damage, but its definately not at the proper operating range. You said that if you put your foot down that it starts to climb. This shows that there is a restriction in your cooling system, and as you start giving your car a flogging, it creates more heat and if the cooling system can't disperse this heat obviously your temp will rise.

So, luckily cooling systems are relatively simple and you have covered the main areas already:

- new water pump

- new themostat (is this genuine? i will never still aftermarket thermostats in any of my cars, i have had too many straight out the box not working right and actually causing overheating)

-new coolant

-radiator cap (cooling systems rely on pressure to work correctly, if you have a dodgy radiator cap that releases pressure too low, this can also cause overheating)

-headgasket (generally this is a last resort, but if your oil is milky or you coolant smells like exhaust this could be the problem, but unlikely)

-hoses (its not leaking so i assume they are ok)

-radiator

My guess would to take the radiator out and get it cleaned like it has been said above. It is the most likely cause for overheating, especially if the coolant hasnt been changed in a long time.

Edited September 12, 2007 by R34GTFOUR

[PAV34]

Thanks Stephen, ill get it flushed.

Cheers.

[ssshonky]

what condition is your cat converter in ? if its blocked could cause restriction and thus make your motor work harder - specially when you boot it

[PAV34]

its about 20,000kms old, Its a Catco hi-flow big body

I just got quoted $190.00 to pull out and clean the radiator