stat in the head or the tee?

[124JOE]

does it cool better with the stat in the head or on the tee

i see pics or our spiders with the stat on the head as one of your mods
and newer rads
mine is fine.should i go big?

im not over heating or any thing,just wondering.

[rrrrob]

Hello joe,

The older versions, I believe carb, are in the head. Along about the time the FI was added the sensor was moved to the T. I don't believe it was a matter of working better other than the design change of the FI system caused the need to re-locate. I'll bet most haven't even tried to change from one setup as posed to the other. Their may be a slight lag in the rise in temp due to the location difference but once the thermostat opens and the system is in balance (at full temp), then the temp is the temp. The system isn't big enough to show much of a difference unless it isn't working properly. Then you would be having bigger problems.

; )

Rob

[4uall]

I had a really tough time trying to trouble shoot an overheating issue until I discovered the T stat was stuck closed in the head.

http://wwwe.fiatspider.com/f08/viewtopi ... =5&t=16398


Why she was overheating by itzebtze, on Flickr

[manoa matt]

The external 3-way stats allow coolant to flow around the head and block, until the stat opens and directs coolant to the radiator. With the internal stat, coolant can not flow until the stat opens, it just churns around the pump by the #1 cylinder. Most of the wear on an engine occurs in the time between the initial start up and when the engine reaches operating temperature. The design of the external 3-way stat allows for a faster/shorter warm up phase, and produces a more even coolant temp across the cylinders until the operating temp is achieved. The external stat design allows the engines to last longer due to lessened wear.

The internal stats are much cheaper, come in a range of temperatures, and "clean up the engine bay". You just need to be more careful when pushing the car until its fully warmed up.

[So Cal Mark]

Fiat changed to the external stat as the engines got larger because they flow more than the internal stat. The radiators didn't get larger until the 2L motors came out, so more cooling was needed for the 1800s

[Raze]

I'll echo observed evidence of everything said so far in this post because I had to replace a HG due to having BOTH a stuck/sticking t-stat in the head, with an external t-stat conversion done by the PO, at the same time, no wonder I couldn't bleed the system properly...

With the head t-stat removed and only using the external t-stat warmup is much faster, and I'm not seeing a delay between the temp gauge and when the radiator starts heating up. Also, with the head t-stat removed and a fillter-t added at the heater hose at the firewall I can fill the system correctly first time, every time...

[124JOE]

this is great stuff thanks to all

i will stick with the external one