thermostat housing orientation

[rlux4]

If there is air in the hose from the bottom of the radiator your stat will never open. I could never understand how burping will purge this air trap. As you fill the system the first place the coolant goes is out the bottom of the radiator and up towards the stat. Without a hole drilled in the stat the air being pushed by the coolant has nowhere to go, it's trapped at the bottom of a closed stat. The hole will allow it to seep past the stat and also allow coolant to seep down from above and fill any air pocket that may be under the stat. Assuming the system's other components are good, two things will cause the car to overheat; air in the system or a bad stat. If the stat is new the most likely culprit is air.
Ron

[jcp]

Wow, I guess it really was air. And a lot of it. Jacked the car up and ran it with the radiator cap open. Squeezed the cool lower radiator hose as much as I could, and sure enough, a lot of bubbles and gurgling and the level of coolant in the radiator dropped quite a way.

Now I understand why the orientation is so commonly mistaken. With the OEM one being different than the modern aftermarket thermostat, and the whole issue with air in the system, it's easy to think it's a problem with the thermostat direction.

I also have the style of thermostat where it's impossible to drill a hole, as the plate is buried further up inside the unit. So I'll just have to be very diligent about keeping the system free of air...

[rlux4]

Good for you.
I remember driving my car up a 45° bank once to fill the system before I drilled my stat. Next stat you need get one you can drill, I don't even have to burp my car when filling the coolant.
Ron

[giuliot60]

Can't wait to flush and refill mine.

[jcp]

After a few days of running the car on and off, it looks like I'm still running a bit hot. The needle stays straight up, around 200, and occasionally goes to 205 or 210 under heavy load. Verified with the IR thermometer. I doubt it's the thermostat or air pockets at this point. The fan goes on reliably around 190.

Should I look into buying a new radiator before next summer? The one I have is looking pretty rough, and it's been flushed with the garden hose twice. I don't really know what else it could be.

[courtenay]

Those temps don't sound too bad - I certainly wouldn't call 210 "overheating" - particularly if it's happening when you are stopped or in slow traffic. If it's happening when you're driving on the highway, maybe. The important thing is that your fan is kicking in at 190.
If you're looking for a new rad, check out Mark Allison's unit. Pretty good price and several here have installed it and are happy with the result.

[RRoller123]

just for giggles, make sure your fan is Pulling air through the radiator and not Pushing it through. I believe that these DC fan motors can run backwards if wired in reverse.

[Jrlovvorn]

I am having the same troubles with my 79. Fan coming on really late.

Tried burp, which made it better, but not right.

Replaced the fan switch, and the thermo.

Doesnt work, water never getting to bottom hose.

Can someone confirm that the orientation of the thermo posted by Mbouse on Dec 21, 2009 is correct?

I dont want to change this thing three times, if I can avoid it.

Thanks!

[4uall]

http://wwwe.fiatspider.com/f08/viewtopi ... on#p151872

http://www.youtube.com/watch?v=m5Xnrfjc ... ature=plcp

http://www.youtube.com/watch?v=-BqyZ3_r ... plpp_video

[Jrlovvorn]

Awesome. Thanks.

[Jrlovvorn]

Well, that didnt work.

Drilled hole, installed with proper orientation, bled the system, and the thing is not getting any hot water to the bottom hose.

Well, maybe a little. But its heating up to 230 without the fan coming on.

Totally fed up.

The damn thing runs so hot, can I just rip the thermo out and run it straight through?

I have a hard time imagining any day cold enough for that to be an issue where I feel like driving a convertable.

Thanks for any insights.

[giuliot60]

You may have already done so, but have you checked the Thermostat in a bowl of hot water?

I'm no expert, but you could probably run it without it. Just don't push it until she's warm. At least you'll know if the rad/fan/cooling will keep it cool.

[Jrlovvorn]

Thanks. I will pull it out and test it next.

It's fresh out of the box.

The old one was opening late IMO, and this was supposed to be an improvement.

But things are much worse. Something is wrong, and I think its the stat.

I would say the new fan switch, but the bottom of the radiator is barely warm.

[fiat218]

you can also use a flashlight instead of wrapping your lips around the coolant-tainted t-stat

Hahaha.

[Jrlovvorn]

Bypassed the thermo with a bunch of pipe fittings from home depot.

Confirmed the new thermo is defective.

Fan comes on right on schedule.

Seems really odd the part was defective out of the box.

Anyone have a better source for a replacement?

No thermo is fine for now, but when it drops below 70, it could be an issue.