turver

Just installed a new thermostat in my 2001 xj. Filled up the radiator afterwards, turned the heat on full blast and watched the overflow tank. I let it run for about 10 minutes, but the temp gauge in the dash isn't going up. The heat is working and there are no leaks.

Does this mean the thermostat isn't opening?

Quick edit: Forgot to mention that the electric fan turned on, which it never has before.
Second edit: I'm just a dumb ***...problem solved.

djb383

U need to let the motor idle with the rad cap OFF and keep the coolant level full in the neck of the rad while idling. Once the stat opens, coolant/air will burp out the rad. Install a new rad cap and check coolant level in both the rad and bottle MOTOR COLD for the next several days.

turver

Will do the next time this happens, thanks for the reply

djb383

It's a good idea to frequently check coolant level in both the rad and bottle, motor COLD.

Roler

Curious how you solved the problem though

I'd say, leave the cap on there. No need to check the radiator time and time again and release the vaccuum again and again, if your overflow system is working properly, your fluid level in the overflow bottle is correct and your radiator has been checked and filled up after the first warm up cycle.

Although the importance of proper 'burping' the system can not emphasized enough, I have always had my radiator flow over w/o any significant airbubbles coming out of it while it was warming up. I then decided to let it warm up, put the cap on there once the coolant would expand and level came up, and never had any issues with this. For a closed system like in the 'newer' XJ's, the sytem should be 'self-burping' by design. The FSM also advices against checking via the radiator cap for that same reason.

And to answer the question wether your stat wasn't opening: a non opening stat will cause your engine to overheat....the fact that your gauge is not coming up (regardless of other causes why this would be), would actually mean that your stat might be stuck open, if anything.

Just my two (aus) dollar cents...

XJRed96

you forgot to plug the temp sensor back in didn't you? lol

cruiser54

C'mon turver, tell us what happened.................

We won't beat up on you too bad. Promise.

BTW, welcome to CF.

djb383

Newer XJs have a closed system? I'll continue to remove the rad cap (motor cold) on our late model open system XJ to be absolutely positive that the cooling system is full. The rad cap is key to the open type system recovering coolant properly. The rad cap can unknowingly fail and the bottle can appear to have the proper level of coolant while the rad is low on coolant. Takes no more time to check coolant level in the rad (motor cold) than it takes to raise the hood. Closed system XJs r the only ones u can be positive the system is full of coolant by viewing the bottle.

Roler

Meant newer have open system, my bad.

turver

Caught me haha....that's exactly what happened. Did everything right, but forgot that one step.

XJRed96

yea happened to me too when i did the drive belt, went to start it and it acted like it was flooded.... took me all of two seconds to realize my idiot mistake