Help: thermostat install

[backyardbill]

Ok. I read the threads on the head stat VS the external stat. The head stat is not $5 at Autozone any more. Actually I remember buying one for $2.99 many years ago. Now they are $13.99. Cheesh.

I decided to test the original stat. Its a Wahler 80C. I boiled it and it opens correctly. I drilled the 1/8" hole as suggested. Put everything back together. Filled the system. Burped her real good. Ran the engine, warmed to about 195F and bingo, the fan came on! Waited until it cycled 3 times to make sure. The stat did indeed open at 180F as I felt the bottom hose get hot at that point.

I'm a happy camper now. Thanks all.

[TulsaSpider]

Wohoo!

[rlux4]

Bill, I'm a firm believer in drilling the hole in the stat. If you look at the way the bottom hose comes up to the stat from the radiator, there isn't anywhere for the air that is in there to go, (that leg of the stat is closed) so no amount of burping will make it rise to the top of the system. The hole in the stat allows water to dribble downward to fill that cavity, and solves the problem. FYI, the hole doesn't affect the stat operation, I've driven my car on 2000 mile round trips, towing a trailer and never overheated.
Ron

[divace73]

Bill, I'm a firm believer in drilling the hole in the stat. If you look at the way the bottom hose comes up to the stat from the radiator, there isn't anywhere for the air that is in there to go, (that leg of the stat is closed) so no amount of burping will make it rise to the top of the system. The hole in the stat allows water to dribble downward to fill that cavity, and solves the problem. FYI, the hole doesn't affect the stat operation, I've driven my car on 2000 mile round trips, towing a trailer and never overheated.
Ron

I agree with rlux4, makes me wonder why there isn't a hole from manufacture??

[rlux4]

Good question David. I guess the idea's been around for a while, but I didn't know about it when I changed out my stat for the first time and couldn't get that pocket of air out. Then I changed one on my wife's Dodge Caravan and it had a hole in it from the factory. After I puzzled it out what the hole was for I decided to try it on the Fiat, and a major PIA was solved. I came onto the forum with what I thought was a great original idea and found out it was a common practice amongst a lot of drivers. It's even on the International Auto Parts website in the tech section.
Ron

[So Cal Mark]

the potential problem is if the hole is too large. An oversized hole will cause really slow engine warm up and a heater that doesn't stay hot if the blower is on high speed. On some cars even 1/8" hole is too large

[rlux4]

Good point Mark. 1/8" works perfectly for my car, but any size hole would serve the purpose of letting water flow down through the stat. When I pulled the stat that came on my car I found that it had four 1/4" holes drilled in it! No wonder it wouldn't maintain temp.
Ron

[courtenay]

I got a thermostat from AutoRicambi which is not the same as the original equipment one or the one shown in the IAP bulletin. Does drilling a hole work with this model too?

[rlux4]

If it's the "Y" type replacement (external stat) then the principal still holds. Here's a pic of the one I did.

Ron

[courtenay]

Thanks, Ron. That looks like the one I installed. While I was successfully able to burp the system and it seems to be running just fine, when I take it apart to install the new alum rad I got from Mark, I will drill the hole.

[backyardbill]

courtenay: I also bought the one from Ricambi. It is not OEM for the Fiat Spider. The closed valve postion goes toward the bottom of the radiator. The problem with that unit is that port is a right angle to the valve, so you can't drill it from that port. Also, you can't get to the valve form the port that goes to the water pump either, because another valve is in the way. So I gave up on modiflying it and used an OEM stat, and drilled that one. Works perfect.

Maybe someone else has an idea for you on that Ricambi stat.

[BenjamminsFiat]

I've been following this thread and finally decided I had to at least share my experience. I've now drained the radiator and refilled it twice in the past three months because of other work. My experience might NOT apply because I do not know if my thermostat has the hole drilled in it. I just got the car over thanksgiving and just haven't had a reason to check because my car is NOT a pain to refill.

I had always heard of people having a hard time, and since I've been lucky these past two times I thought i'd at least share my experience. You can find the full procedure here: http://www.mirafiori.com/124/cooling.html
Essentially, you disconnect the radiator to coolant "T" hose and fill that up SLOWLY with water. When that's full, take the cap off your radiator and fill that slowly again. Patience is the key.

Leave the radiator cap off and start your engine. Let it get nice and warm which shouldn't take too long with the thermostat closed. When you start to see bubbles at the radiator neck shut the car off. Go have a drink or something, but leave it alone for 15-20 minutes. The instructions say to stop here, put the cap back on and go for a drive, but I usually go through one more iteration of the above. Run the engine with the cap off until you see some bubbling, then shut it off and wait 15 minutes. Put the cap back on and your thermostat should open now.

This has worked for me perfectly both times I've tried it and I've never had to jack up the car or anything. I have a '76 124 with the stock engine. The theory is that as long as you get the engine hot and wait long enough, the heat will simply conduct from the block to the thermostat and open it up enough to let the air out.

I'm a believer and I have empirical evidence to back this procedure up having done it twice now. However, the one disclaimer I must share is that I simply don't know if my thermostat was drilled by a PO. I don't think so, but I wouldn't want to mislead anyone.

I've gotten very lucky I think with this car. It seems to cool itself really well... something I'll appreciate this summer in Texas.

[courtenay]

Ben - I did much the same thing when I installed the autoricambi thermostat and my system is working just fine. And I know there is no hole in the thing because I didn't drill one!
Bruce

[divace73]

Drilling the hole eliminates having the patience......a little anyways......

[TulsaSpider]

Wow... you have more patience than I! I drill a small hole. Then the problem is eliminated!