Radiator and thermostat replacement

[ComancheBSJ90]

I just installed a new radiator and thermostat. After installed, I filled the rad up through the top radiator hose. I did not bleed the system.

 

Now the engine wants to heat to the 125C (red line) mark and pass, if i were to let it. I get good heat, and the closed system bottle is filled appropriately.

 

The radiator is cold and the upper hose is cold but the engine is up to and past operating temp.

 

I used a new Super Stant thermostat. I was thinking that the cause was air in the system, but with what I said it must be a defective thermostat, Right?

 

 

thanks

[Eagle]

If the upper radiator hose stays cold, the thermostat is not opening. Either that, or you are SERIOUSLY low on coolant. But ... if the system is low on coolant, usually you don't get any heat from the heater core so if you have heat, I would suspect the thermostat.

 

I don't recommend anything but a factory Jeep thermostat in the 4.0L. I haven't yet found an aftermarket t-stat with the bleed check valve in the flange. The fact that so many aftermarket t-stats just don't seem to work is another reason.

 

You should bleed the system, though.

[wolfpackjeeper]

bleed the system, boil the Tstat.

 

I have had nothing but good luck with the superstats, I actually recommend them, but you may have gotten a bum one, or could you have installed it backwards?

[ComancheBSJ90]

The copper pellet towards the engine. I emptied about 7 liters into the radiator. I think the the T-stat needs to open to bleed the closed system that's why i think it won't accept anymore fluid unless I do what other have suggested to bleed.

 

I was playing with it (t-stat) before install and noticed that I could not manually resist the spring force to open it.... should have clued in...

 

I'll replace it with a Motor Stat from Canadian Tire.. Can I torch it open with a butane torch :)

 

 

thanks for the quick responses,

 

Mike

[james750]

pull out the thermostat and drill a small hole in the top, this will bleed the excess air out, that is what separates aftermarket thermos form OEM, OEM has a hole or check valve that bleeds the air out.

[BLHTAZ]

pull out the thermostat and drill a small hole in the top, this will bleed the excess air out, that is what separates aftermarket thermos form OEM, OEM has a hole or check valve that bleeds the air out.

Yes...that can be done, but in this case, the t-stat itself is not opening so it would be a waste of time ;)

 

Get the Mopar t-stat and be sure that the bleeder hole / check valve is in the 12:00 position when installed :thumbsup: .

[ComancheBSJ90]

I installed the cheap-o MotorRad Canadian Tire Thermostat and now the cooling system is running beautifully.

 

That's funny, when looking on the CT computer screen thermostats for Comanche came with or without a Jigger valve, I bought it with out not knowing its purpose.

 

Thanks for sharing the knowledge and timely responses :)

 

Mike