Heat Buildup

[zedbear]

I've noticed that when I get stuck in traffic or sit somewhere in drive at idle for awhile in hot temps with the a/c on (80's or more), the engine temp will climb up steadily to around 215F until stabilizing (as read from scangauge II). It doesn't take long, maybe 5-7 mins. As it approaches 212F the fan clutch begins to kick in fully. But at idle it doesn't seem to matter. Normally the truck runs around 190F. The waterpump and tstat is newer. Behaved this way last summer before I replaced those parts. Is this normal? Once I start moving the temp drops right back down. I know 215 is still well within operating temps but a 25 degree jump from idling for a short time seems excessive to me.

 

Interestingly, the a/c automatically switches to recirculate when coolant temp get near 212F. Less heat load I presume.

[Debo511]

This is normal opperation.

[txab]

This is normal opperation.

+1

[zedbear]

Another interesting thing I noted is the scangauge indicated 215F at one point yet the insturment panel gauge still sat in the same spot it always does once the truck is warmed up, which is just below 210. Another indication the factory temp gauges are BS as far as being a "real" gauge.

[Badbird2000]

I have a tuner on my F150 that i can also monitor water temp.. mine does the same thing. It can go from 192 driving on the highway, highest so far i have seen was 210 sitting in a drive-thru in Geogia last month..idiot gage never moved. I guess it's so people don't freak out when they see it move around.