Alternate thermostat setup

[JammerX19]

I saw a couple cars at FFO this weekend that were running with a T-stat in the head and the water pump going straight to the lower radiator hose. I can see some benefit to this setup (two fewer places for coolant to leak, two less hoses to buy), but I would like to hear from folks who have done this on their car. For comparison's sake, mine is fuel injected.

Exactly what thermostat was used?
Did you have to change anything else?
Is there a difference in the way the car heats and cools?

[pastaroni34]

You can do this just using the earlier cooling system components, no problem. You probably will not see a difference as far as cooling behavior etc.

That being said, there are a couple of reasons Fiat changed the cooling system:
1. External thermostat is easier to change, just loosen a few hose clamps rather than 4 bolts in the head.
2. Cooling is more even/consistent with the external thermostat.
3. Burping/bleeding is easier with the tee at the front of the engine.

If you're on the edge of your engine's cooling capacity, I recommend the external, otherwise it makes no difference really.

If you want to go to the early style, you'll have to change the coolant spout, thermostat, upper and lower hoses. You may have to come up with a special lower hose though, depending on if you have an a/c compressor mounted on the exhaust side etc.

[JammerX19]

Good information, thanks. I believe my cooling system (being entirely brand new except for the t-stat) is working perfectly, so I'm not necessarily looking to go this way just now. Just looking to be educated on it.

[bradartigue]

I saw a couple cars at FFO this weekend that were running with a T-stat in the head and the water pump going straight to the lower radiator hose. I can see some benefit to this setup (two fewer places for coolant to leak, two less hoses to buy), but I would like to hear from folks who have done this on their car. For comparison's sake, mine is fuel injected.

Exactly what thermostat was used?
Did you have to change anything else?
Is there a difference in the way the car heats and cools?

FIAT did this for a reason, there is even a service letter on it (that I've read but never scanned) described the change from in-head to external for the engine series. There was a specific problem with uneven cooling in the head, due to the position of the t-stat. The external placement resolves whatever issue it is.

In owning something like 18 of these cars from virtually every series the one area I've never had problems is the cooling system with either type, internal or external. I say go with however your car was designed - which unless you have an AS Spider is external. It works well all the time.

[JammerX19]

Agreed, Brad. Ran my car at 80mph+ this weekend at FFO and had no issues at all.