Overheating Issues

[naughtika]

Hey guys, yesterday I experience a little bit of overheating from my car.. car didnt stop or anything but i noticed the temp go up more than usual

below is the scenario
- a bit of stop and go traffic
- was in the afternoon (4:30pm)
- a bit of spirited drive prior to the stop and go

setup of the car
- using Billion 65*C low temp thermostat (for more than 1 year now)
- recently changed fans to 1x 10" (push) and 1x 14" (pull type) - tested and pushes more air than the old one
- using a 40mm thick Aluminum Radiator
- coolant is new and has been air bleed properly
- cooling system pressure tested prior to replacing the coolant (rad cap good) but there is a tiny bit of fluid leak from the waterpump (nothing to be overly concerned of, as long as I watch the fluid occassionally and yes its getting replaced soon)
- overflow tank is active - coolant is dumped in there when hot and is sucked back into the radiator when cold

now Im thinking of dumping the 65*C thermostat and replacing it with the usual 85*C ones

what do you guys think is causing my little dilemma?

 

[Blue legnum]

Hey Christian

The spirited driving prior to the stop n go & the stop n go itself wouldn't of helped it cool down to normal temp!
Was the a/c on as well?

In normal circumstance you could continued driving & it would cool but the start n stop wouldn't allow enough air flow to cool it back down & or especially if a/c was on.. theres more of load on it.

Also ditch the 65degC thermostat for the 85..
The coolant is not staying long enough in the radiator to cool down & it wouldn't of helped with the above!

 

[tails]

Hey Christian

The spirited driving prior to the stop n go & the stop n go itself wouldn't of helped it cool down to normal temp!
Was the a/c on as well?

I think it would have to be very spirited driving to increase your engine temps to a point where it's noticeable on gauge.

 

[NuffNuff]

did your overflow bottle overflow and spill out onto the motor when it overheated? mine did that when my radiator cap disintegrated, replacement stock cap fixed the problem.

 

[VOLK]

Posssibly water pump. Don't think it's thermostat related. Possibly fans too. If it's capable of keeping temp under control on the move but not when stationary then your cooling system is capable of shedding the heat but airflow isn't sufficient when stationary/slow.

 

[The Borg]

Have you remembered to plug every thing in this time?:tongue_smilie:

 

[VOLK]

Also, fire up evoscan and check the actual water temps.

 

[naughtika]

Hey Christian

The spirited driving prior to the stop n go & the stop n go itself wouldn't of helped it cool down to normal temp!
Was the a/c on as well?

stop and go, shouldn't matter as we have the thermo fans to assist with cooling the system down

In normal circumstance you could continued driving & it would cool but the start n stop wouldn't allow enough air flow to cool it back down & or especially if a/c was on.. theres more of load on it.

a/c was definitely on but the overheat was a bit strange where the temp had risen and stopped at a certain point.. then just stayed there..

Also ditch the 65degC thermostat for the 85..
The coolant is not staying long enough in the radiator to cool down & it wouldn't of helped with the above!

I've had the 65*C thermostat for more than a year and have had no issues until yesterday.. and i went for a 'spirited' driving (harder than usual) on a broad day light and low speed.. mostly doing corners and round abouts..

did your overflow bottle overflow and spill out onto the motor when it overheated? mine did that when my radiator cap disintegrated, replacement stock cap fixed the problem.

that's what I thought at first, but then when i got home and had let the engine cool down for about 2-3 hours, the coolant in the radiator was full and the amount of coolant in the reservoir was the same as the day/night before..

Posssibly water pump. Don't think it's thermostat related. Possibly fans too. If it's capable of keeping temp under control on the move but not when stationary then your cooling system is capable of shedding the heat but airflow isn't sufficient when stationary/slow.

good thought on this, my dad said that its not the water pump as it was definitely moving the coolant,

cant be the fan as it was moving air ALOT more than the factory setup..

when it happened I was stationary, but I can definitely hear the fan running loud..

1 thing i haven't mentioned was the position of the thermofan resistor pack.. its in direct position of where the airflow is..

Have you remembered to plug every thing in this time?:tongue_smilie:

funny man but yes i did remember as otherwise my engine would've ended in catastrophe

 

[VOLK]

Ahh k so it wasn't a terminal overheat where the temp needle was reaching for the sky, just slightly above the norm then stopped hmmmmm....

Check actual temps.

 

[naughtika]

Also, fire up evoscan and check the actual water temps.

that's next step..

 

[naughtika]

Ahh k so it wasn't a terminal overheat where the temp needle was reaching for the sky, just slightly above the norm then stopped hmmmmm....

Check actual temps.

nah.. the temp had risen for about 15mm from the usual position.. stayed on that and it never did get any higher..

i pulled over to a servo and parked the car properly just in case.. kept the engine running and so did the fan..

turned the a/c on and off for a few minutes a a time.. temp stayed the same..

 

[TME_Steve]

But you don't drive it hard.... so.... Your car is stuffed. Fans blowing the wrong way?

 

[Schneider]

Curious, with the fans did you test the airflow with them mounted on the radiator?
Could be a case of them providing higher airflow but not enough static pressure. Also agree with Steve, perhaps double check they are blowing the right way.

 

[Blue legnum]

SH...T! 15mm above normal is quite abit when you descibe the type of driving, weather etc..

Just a long shot... If the fans are flowing the right way n all, What gauge wire was used on the thermos?
They might not be getting full current through the wire to run the fans full speed?

 

[TME_Steve]

15mm would be around 140degree water temp from what I've seen

 

[naughtika]

But you don't drive it hard.... so.... Your car is stuffed. Fans blowing the wrong way?

stop being a hater, it is blowing the right way at this stage, i dont care if the engine blows as I have a spare one that'll be ready soon...

Curious, with the fans did you test the airflow with them mounted on the radiator?
Could be a case of them providing higher airflow but not enough static pressure. Also agree with Steve, perhaps double check they are blowing the right way.

i did test both fans individually while it was sitting on a step ladder and turned it on via direct connection to a battery.. and each fan seemed to push more air compared to the oe ones together

SH...T! 15mm above normal is quite abit when you descibe the type of driving, weather etc..

Just a long shot... If the fans are flowing the right way n all, What gauge wire was used on the thermos?
They might not be getting full current through the wire to run the fans full speed?

what ever wire that came with it.. spliced it with the oe wiring

I think, for a solution i will tap a thermoswitch on the bottom near the return hose.. wire it in with a few relays.. get my dad to do it..

 

[Kenneth]

Carsten has the same problem with his, though he is running both fans in push + full alloy radiator.

One possibility is that at low engine speed with the bigger radiator there also isn't enough turbulence (water speed) through the core to get optimal heat transfer, also contributing to a slightly high temperature.

Carsten has been running his like that for ages, I wouldn't be overly concerned. If you are, get a electric booster pump to improve your idle water flow.

 

[Rabit]

Hi Christian, Have you checked that both fans are moving the air in the correct direction, that is from the front to the rear. They are DC motors and its easy to plug them in with the polarity incorrect. With one in front and one on the back of the radiator they need to be connected with opposite polarity so that one pushes and one pulls the air through.

 

[TME_Steve]

I have a40mm radiator and it works fine.... These fans, do they floe more but against less static pressure perhaps? Do they move lots of air though the radiator out just out in the open? Also, what are the shrouds like?

 

[brackenridgevr4]

U need to have both fans pressurising your radiator or she won't work 2 blowing one way or 2 pulling either or