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Overheating issues.

AuSpecVr4

Well-known member
Joined
Dec 1, 2010
Messages
107
Location
Brisbane, QLD
Hey guys

I will make this as quick as i can.

Cooling:
Evo 3 Racing aluminum radiator
78 degree thermostat (now removed)
Coolant and no blockage or airlocks
Stock radiator fan shroud (Not sure)

Stock TD05 turbo 3" stainless downpipe and turbo dump
Ceramic coated inside and out EVO 3 manifold.

My problem, on a average day, not ridiculously hot, with a 78 degree thermostat it seems that when i'm at the lights or stopped for a period of time. Coolant Temps would reach 100 degrees and continue climbing? Fan is on and working, i don't know if it is the stock fan, it may not be spinning fast enough, How can i test this? i took the thermostat out and ran that, it wouldn't get to operating temperature when driving around, it was until i am stationary temps would climb, fast. The only way to bring temps down is to drive around, idling makes it worse. I don't have a heat shield on my exhaust manifold but i want to get a second hand one from somewhere but still that doesn't explain why it gets so hot on idle.

Any information to help me sort out this problem would be much appreciated.

motor was built 15,000kms ago 2.4L, stock head, cometic head gasket.

Cheers, Brock
 

brisvr4

Well-known member
Joined
Feb 13, 2004
Messages
955
Location
brisbane australia
Ground out the rear temp sender on the thermostat housing and the fans should both run on high Brock.
Give me a shout if you want me to have a look at it for you.
 

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,165
Location
Toronto, ON, Canada
Why on earth have you removed your thermostat altogether? Didn't we establish in a previous thread that your 78deg C thermostat was too cold for the engine? Removing the thermostat entirely will actually make the problem WORSE because the coolant is circulating at such a high rate it is unable to dissipate its heat through the radiator. To make it a double-fail whammy the radiator is an aluminium radiator which does not has as great heat transfer properties as the original bronze cored unit.

You need to put IN a thermostat, and it NEEDS to be the correct temperature of 88C.
 

AuSpecVr4

Well-known member
Joined
Dec 1, 2010
Messages
107
Location
Brisbane, QLD
Thanks for the help, I was just throughing up ideas why it is overheating, I put the 88 degrees thermostat back in and it gets to temp, still slowly climbs on idle but never reached 100 when stopped. Thermo fan kicks in around 93-95, is there a slow speed before this? My fan is either on or off? Is this right? And with the stock radiator fan (don't think it's the stock one) the battery tray has been bashed the crap out of to fit the shroud in? Before the aluminum radiator? On top of the fan it has a/t on top, do you want me to take a picture? It doesn't seem right :/

Cheers Brock
 

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,165
Location
Toronto, ON, Canada
there should be two fans - one in front of the radiator blowing air through the air con condenser radiator and the engine radiator, then the other fan behind the radiator in front of the gearbox sucking air through the other side. The fan in front comes on/off with the air con however if the engine is over-heating the air con fan will turn on constantly - the sensor/switch for this is on top of the thermostat housing. The fan behind the radiator should turn on about 88-90degrees as measured in the bottom tank where the sensor/switch is next to the radiator bottom hose outlet. You can check the circuit is running by unplugging the loom from the radiator and bridging the two pins with a paper clip.

Fans are only an on/off, no speed steps like the later 8G Galant or 96-on Lancers have.

Sounds like a fan off another vehicle has been adapted to fit onto the aluminium radiator - it should be alright so long as the fan and the shroud covers about 1/2 to 2/3rds of the radiator core surface and that it runs at a sufficient speed.

Does it get any higher than 100 degrees? Where does the temp gauge needle register when it's at 100 degrees? Mine always sits dead on just a smidgen under the half way mark and will always remain there constantly whether it's hot/cold outside or if the engine is under load/on motorway/idling in traffic etc.

To be honest 100 degrees isn't too bad at all, it's in the range of where the engine is the most efficient. The engine temp will always be higher than what the thermostat temp is generally. The reason the cooling system is pressurized and why anti-boil is run is because temps will often get to the boiling point when coolant is not under pressure - pressurizing the cooling system will increase the boiling point another 10 degrees or so.

Have you checked the condition of the radiator cap itself? Is any coolant spewing out of the over-flow reservoir?
 

ozyvr4

Well-known member
Joined
Mar 5, 2007
Messages
160
Location
Brisbane, Australia
I have been playin with the coolin system on my RS. So far I have found that low speed single fan turns on at 97deg & high speed both fans is 110deg. I have a suspision that the alloy radiator being as effecient as they are is cooling to much though the core so when the bottom ( wehere the low speed switch is ) is to the correct temp the top tank is 15-20deg warmer. The switch in the bottom is a 85deg on from memory. What I have done at the moment is to wire the radiator side of the lower switch (green wire ) to the high speed trigger ( the blue wire on the intake manifold side of the thermostat housing). This brings both fans on at 99deg and brings the temp back down to 95deg. At the moment it cycles between 102 & 95deg. I am looking for a fan switch to replace the 1 in the thermostat housing that will turn on 95deg & off at 90deg.

I would this simple mod first & put the thermostat back inas it will take too long to get to temp.

I would also check the fan blade is the correct way as the aftermaket fans sometimes can be changed and make sue the wiring is coorect. These fans will work in both directions. I did find on my car after the clutch was done the wires were backwards at it did what yours is doing.
 
Last edited:

AuSpecVr4

Well-known member
Joined
Dec 1, 2010
Messages
107
Location
Brisbane, QLD
Thanks ozyvr4 for the tip, i was told once to move that temp sensor to the top but never thought of doing it until now.

There is two fans, one in front of the condenser and one behind the radiator. The a/c one comes on when the air con is turned on, not sure if it turns on when it gets hot.

Quote:
Sounds like a fan off another vehicle has been adapted to fit onto the aluminium radiator - it should be alright so long as the fan and the shroud covers about 1/2 to 2/3rds of the radiator core surface and that it runs at a sufficient speed.



The fan does cover half the radiator, i've never looked at another galant (stock) to see if the fan assembly is the same, it could be off another car, someone have a picture of what a stock fan looks like? width aswell?

Quote:
Does it get any higher than 100 degrees? Where does the temp gauge needle register when it's at 100 degrees? Mine always sits dead on just a smidgen under the half way mark and will always remain there constantly whether it's hot/cold outside or if the engine is under load/on motorway/idling in traffic etc.



Since the thermostat is back in, it just scrapes 100 when idle for a long time or turn the car off and start it within 10 minutes, did not get hot under driving conditions. The needle sits directly in the middle all the time unless it starts to get really hot (115 degrees)


Quote:
Have you checked the condition of the radiator cap itself? Is any coolant spewing out of the over-flow reservoir?



I have not checked that, the reservoir sits around half way so it is taking water/coolant from there when it needs it.

Here are some pictures of my fan, is this stock? i searched the numbers on the top and the motor and did not find anything?











Look at the battery tray beside the shroud? i don't think that's factory?

Cheers, Brock
 

ozyvr4

Well-known member
Joined
Mar 5, 2007
Messages
160
Location
Brisbane, Australia
looks like factory fan. The second fan turns on when the sensor in the thermostat housing gets to the determined tenp. Its normally quite hot. If you take the sensor out it will say the temp on the base where you tighten it.
 

brisvr4

Well-known member
Joined
Feb 13, 2004
Messages
955
Location
brisbane australia
Hmm, those fan shots don't look like the Aspec fan that I have here.
The fan should be a straight bolt up fit on most alloy radiators. Your's looks like it doesn't cover the whole core Brock.
 

AuSpecVr4

Well-known member
Joined
Dec 1, 2010
Messages
107
Location
Brisbane, QLD
Yea Tim the radiator brackets broke so I fabricated my own. It all did line up but the old radiator and fan were pretty beat up
 
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