Pape

So got my coolant flushed about 6 months ago, got the waterfall for a while and disappeared at some point.
Fast forward 2 weeks ago weather started to warm up, heater no longer required.
In the morning when starting cold the temps will climb to around 230 and than go down really fast (30 secs) to 19X.
Only happened 3 times to my knowledge and all of them was within 5 minutes from a overnight cool start.
The radiator fan kick in at 215 on speed one and will switch to speed two somewhere passed 220.

since my temps will go down really fast and it always only happen on first radiator opening of the day (when it happen) my guest is a bad rad cap, any one can confirm or instruct how to test it?

Also since the JK is having 115K KM, the radiator is not at is best anymore and I noticed a direct relation in engine temp and oil usage as oil consumption is really low in the winter and higher in the summer.
Therefore is replacing my Rad cap with one opening a little earlier (around 180) is a good idea or I'm looking at trouble ? especially in the winter where most of the engine heat is evacuated by the CAB heater.

Thanks

Jiblet

I think you mean thermostat, not radiator cap.

The old school way to test one was to put it in a pot of water with a thermometer and heat the water to see when/if the thermostat opened.

If you go through the trouble to take put the old one, I'd just replace it.

It's not a good idea to use a lower temp thermostat in the JK. There are other components that operate based on the computer knowing the temperature and you want to get up to operating temperature anyway.

For the oil consumption, have you changed the PCV valve yet?

Jiblet

When you had the coolant flushed, was it replaced with the required HOAT coolant?

Mixing coolants can cause sediments.

Pape

Ya, sorry the thermostat, for a weird reason I always confuse it with the radiator cap, probably the spring in both lol.

flush was done at the dealer, I strictly demanded coolant for my year, the good thing is the part guy know what I was talking about when I did that request.
Noted about the extra work for a couples dollars.

The PCV is on the agenda for a while now, I guess I'm having bigger priority when it come to jeep time
Anyway I guess I will throw a thermostat on the list of the pre season maintenance

Thanks

CombatDiver

Once upon a time the thermostat and cap were one and the same...or am I just imagining this (I know it's not the case now, but in my previous life as a mechanic over two decades ago I could have sworn that was the case).

ronjenx

I've never seen the cap and thermostat be one and the same, but I do remember seeing a thermometer in the radiator cap.