Re: TOY: Temp help part 2

[Roger Brown <r.c.brown@xxxxxxxx>]

>   Ok everyone, I've got a weird problem here that I hope someone can help
> me with.  I have a newly recored rad, new thermostat, new water pump, new
> rad cap and tons of coolant.  What happens is generally (but not always)
> on startup the truck warms up like normal but the temp guage keeps
> climbing.  I jump out and check the rad and it's cold - the tstat isn't
> opening I suspect... which is why I've replaced the thermostat.  Still the
> same symptoms.  Find that when I crack the rad cap, instantly the temp
> drops to normal and stays there (and can feel heat entering the rad)... so
> replaced the rad cap.  Still the same symptoms.  Sometimes if I play with
> the heat level control it'll sort the issue out (sliding it to cold is
> sometimes the cure, sometimes sliding it to hot) and the coolant will
> start to flow to the rad.  Since this happened on 3 different thermostats
> now, I can't believe I'm _THAT_ unlucky.  
>   So what do you think?  Air trapped in the system is my only guess... but
> how can I get it out if that is the problem?

Sounds like the classic temperature overshoot problem:
	http://4crawler.cruiserpages.com/4x4/CheapTricks/index.shtml#Thermostat