I installed my Cyberdyne coolant sensor in the throttle body hose and got some "interesting" readings this past weekend. (note: this was all with normal driving, no racing or even pushing the turbos too much)

I've had it installed for about 2 weeks now and never seen above 210 degrees F, but ambient temp has been <70.

This past weekend it was in the upper 80s and the water temp climbed up to 230! before going down to 205. I was driving, and it just started climbing up pretty quickly, then dropped just as suddenly. Within about 60 seconds or so.

Coolant mixture is approx 40% coolant 60% water. Have stock radiator, Pettit AST, no leaks or signs of coolant seal failure.

Any ideas what could cause this or if it's even something I should be terribly worried about? I've looked for kinked hoses, and didn't see any.

~Tom

 

air bubble in the system? fans kicked on? ioughno.

 

Possible air pocket as this will cause the coolant temp to increase. Also, if you just started driving after stopping for a while, the heated coolant will take a little bit to circulate and the temp will rise first then go down.

Seen this with my PFC.

 

Yep, I agree - air bubble. Or, double check your connections. I have sensors installed under both leading edge plugs and have never seen temps above 200F, and I live in freakin' Tucson!

 

Why isn't my AST taking care of the damn bubbles??
evot23: i think you might be on the right track with the stopped and start.

Another possibility....thermostat malfunction?
~Tom

 

Ron,
Did you tap the rotor housings yourself to be able to take temp. readings at the housings or are the holes already there to be able to do this? ? ? Jack