Overheating problem again!

[GR40]

Well I thought I had it shorted out last time, but it came back! The car seems to get 100oC while driving at speeds even like 120km/h! It slowly builds up and when decreasing speed it drops down to 80oC! The thermostat is new, the pump has less than 8000 km, there is no leak as far as I can tell by pressurising the system and there is no trace of water in the cylinders! What should I do next?

[poloeatonm45]

well i think i would be changin the rad but make sure you get a proper g40 one. i had this prob with mine and it turned out that my rad was a non g40 one. once i changed the rad i aint had a single prob since

steven

[GR40]

Mine is the original rad! It didn't had a problem before! if I have to change the rad I'll probably go for a custom aluminium!

[GR40]

I took the rad out for cleaning and checked the thermostat! it was really clean on the inside (probably from the coolant I used that had some short of cleaning ability, or so I was told), I counter pressure washed it anyway and putted a new thermostat in! The one I got out had a mark on it saying 80oC and seemed to be the same as the new 88oC but the springs in it where a bit shorter and this made me think that it might didn't allow that much coolant to go through when open and this could be why it kept rising temperature up to 100oC under pressure while it was cooling down back to 80oC as soon as I slowed down! Anyone had used a 80oC thermostat before? Also, is this the G40 original rad?

[breadman]

Yeah that's an OE G40 radiator.

[GR40]

thanks mate!

[GR40]

I hate it when I put so much effort in things and they just don't work! It still does the 100oC but now it drops faster to 90oC and when I stop it after a fast spin it takes forever to cool down! I thing I'll change the fan next and go for a thin one this time!

[wierdo]

Thin fan does not make your car run cooler, just adds more space under the hood.

I have exactly the same problem. My G is full rebuild, new everything, 65mm pulley, chip, oil cooler kit and non G40 rad.
So everything works as supposed to but when running on boost or above 100 km/h the G is at 100+

In my city the summer is a little bit hotter than the rest of regions in my country so, I think this is the cause to my problem.
So now I am trying to solve this problem, by installing bigger rad. G60 fits i think with a little cutting...

What is your setup pal ?

[DKnight]

i forget what was said in the first post but have you checked the gauges to see if they reading right? or got a thermostat gun to check the actual coolant temp against what the gauge is telling?

also is your timing correct? ive had issues with temperature on g40's before and the timing was the problem.

My current G40 runs really nice temperatures, maybe luck i run a standard engine, but with a ported head, purely for smoother cooler running, and it seems to work.

[Justin14100]

Replace the back temperature sensor if you think the readings might be dodgy!

[GR40]

I thought of changing the fan in case mine doesn't run correctly, plus I could use some space under the bonnet! The gauge seems to work right because it reads the exact temperature when the thermostat opens with both the 80oC and the 88oC! I am running an Eaton m45 on my G with a custom exhaust from cat! Nothing else! And I am running that setup for up to 5 years now! It didn't used to overheat!

[GAF2]

after fitting a FMIC my temps went up, so i just fitted a nissens aluminuim radiator and its taken my temps down by over 10degrees C.

[GR40]

Then that is even worse since I haven't yet fitted my FMIC! it does make sence since you do actually block the rad with the intercooler! I was thinking big holes on the bumper to solve that!

[liam]

mate change your fan, it sounds like its dodgy to me from your last thresd

[scotsjohn]

The fan's not going to be relevant  in this; it shouldn't be on at all at 120kph. Airflow through the rad should be enough. Either it's a blocked rad. jammed thermostat(run it with no thermostat) or your timing's a bit retarded.