White smoke from under radiator cap after stopping

[patdugan]

I have a 99 Wrangler Sport and started noticing coolant loss a few weeks ago. My commute to work is about 20min and when I'd come home in the evening the top of the radiator would be wet with coolant which looked like it was also hitting the belt and spraying onto the rest of the engine.

I tried replacing the cap first but the issue continued, so I assumed it was the radiator itself (was the original radiator) so decided to refresh the whole cooling system.

I ended up replacing:

1. The radiator (with a mopar)
2. Radiator cap (also 18lb mopar)
3. Both hoses connected to the radiator
4. Both hoses running to the heater core
5. Thermostat housing + gasket
6. Thermostat (stant)
7. Temperature sensor
8. Line running to the overflow reservoir

I then flushed the system with distilled water and filled with 50/50 G-05.

Since having done this, the temperature gauge hasn't gone above 190 (was running around 210-220 previously), but about 1 minute after stopping and killing the engine, a slow trickle of white smoke (possibly steam?) starts to come out from underneath the radiator cap. Not a lot, and not noticeable without the hood popped, but definitely there.

Any ideas? Possible the system is losing pressure somewhere even though otherwise it seems to be running fine now?

 

[pagrey]

Are you still loosing coolant? New components like your radiator will give off all kinds of shit as they are heat cycled the first few times. If you are still loosing coolant that's probably a different deal from what you are seeing at the radiator.

 

[Gilaguy23]

The system should hole pressure for some time after you've stopped driving and have shut it down. Next trip after its fully warmed try squeezing the top hose a few nims after you have shut down and it should be hot and not easy to squeeze by any means like a pumped up ball. remember the system will hole 15+ lbs or pressure is its OK. If after a few checks after the shut down the hose can be easily squeezed obviously you have a problem. Considering all the new parts everything should be tight and good to go. Whats going on with the overflow bottle when you shut down and see the steam? Are you losing coolant at all? regarding the 190 vs 210 all I'll say is same temp thermos dont seem to run at similar temps in my experience. personally I dont care for Stant stuff anymore due to excessive cycling or what your seeing.

 

[patdugan]

The system should hole pressure for some time after you've stopped driving and have shut it down. Next trip after its fully warmed try squeezing the top hose a few nims after you have shut down and it should be hot and not easy to squeeze by any means like a pumped up ball. remember the system will hole 15+ lbs or pressure is its OK. If after a few checks after the shut down the hose can be easily squeezed obviously you have a problem. Considering all the new parts everything should be tight and good to go. Whats going on with the overflow bottle when you shut down and see the steam? Are you losing coolant at all? regarding the 190 vs 210 all I'll say is same temp thermos dont seem to run at similar temps in my experience. personally I dont care for Stant stuff anymore due to excessive cycling or what your seeing.

I'll give this a try. I've only driven 3 times since rebuilding the cooling system and haven't noticed any drop in coolant since then. Re: the thermostat, I'm using a Stant Superstat at the recommendation of another forum member.