What degree thermostat for 79 W72?
 

The temp is fluctuating from 210-230 on the 79.I don't think it was ever changed,and with 20k miles,I think it should.
I want to make sure I have the correct degree thermostat,is it a 195 degree?

With 20K miles you might want to take it out and see what is stamped on it.
Even if it is the original, I would remove the radiator and have it flushed. There's alot of gunk buildup going on over the years.

I would run a 180* at the hottest. I run 160*s

The original is/was a 195, as I recall.

As you only drive your car in the summer,a 160 will do just fine.

Thanks guys,I will check it,I was having a problem with the bracket that holds the line that returns gases...I believe.. to the charcoal filter.It turns everytime I loosen the first(closest to person) nut and bolt,and I don't want to break it,it's aluminum with radiused eges and holding the line whic starts to bend....Well here's a pick...just to the left of the insulated fuel line and at about 7 oclock to the waterneck...are these repro'd if i break it?
http://img443.imageshack.us/img443/2...pdTA19k139.jpg

For some reason I thought my 78 had a 205 orignally. I run an AC Delco 180 now.

Trans Am Thermostat
 

Hey Guys,

What about just simply REMOVING the thermostat altogether, & running the car without one...? It's only on the road in the summer anyway, right...?

I wonder if that might help keep your engine temperature down to a reasonable level...

Eddy
Ontario, CANADA

removing the thermostat has negative effect. Water is circulated to fast to allow for optimum heat transfer as it passes through the radiator.

Trans Am Thermostats
 

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Hi Larry,

I guess I'm just plain stupid here, & I don't get it...!

Following along with what you said (above), once the thermostat DOES open up --- no matter WHAT its temperature rating might be --- won't the coolant STILL "...circulate too fast to allow for optimum heat transfer" through the rad, as you describe...? And then at that point won't the temperature simply continue to rise, higher & higher...?

The DIS-ADVANTAGE to HAVING a thermostat under those conditions is that the coolant temperature will have been given an opportunity to reach 160F, 180F, 195F --- whatever --- BEFORE being allowed to at last move through the system...where it would do little good, by your explanation...

I'm NOT trying to be a smart-alec here, or anything like that, at all --- I'm just trying to get a logical handle on this so that even I might understand it (you see, my '78 T/A runs a tad too hot for my liking, too).

Eddy
Ontario, CANADA

If you are NOT a fan of thermostats,what you need to do is take the center section out of one & just install the outer flat ring/plate as a restrictor.

This will slow the coolant down enough to let the radiator do it's job properly.

Just for fun,you might want to install a 160 or 180 T-stat in your 78 & see if it actually DOES run cooler than with NO thermostat.

FYI: if your 78 came WITHOUT A/C from the factory,it likely came with a 2 row radiator.If you haven't upgraded to a 3 row,that would ALSO be a good idea.

(2 row offers only "marginal" cooling at best)

Trans Am Thermostats
 

Ahhhh...now that makes some sense to my feeble brain...

A system that is thermostat-free LOSES the benefit of the restrictive flow that it brings along to the party, thus not allowing the rad to fully "...do its thing" in the cooling department! Simple.

Yes, I really should investigate the merits of a lower-temperature thermostat, than the one that's in the car presently (190F, if memory serves me well).

My '78 may well have originally had just a two core radiator...it has no A/C, & the transmission is a stock T-10. The rad in it presently is a three core brass & copper unit, which was installed in the summer of '04 (I wish I had the spare cash for an all-aluminum four core model!).

I think my mistake here re. the car running hotter than I'd prefer is two-fold, i.e.:

(1) I SHOULD have replaced the coolant, and flushed the system, in '06 (a two year interval just like the owner's manual said to do), and,

(2) When I finally DID just that last summer, I used the newest generation of Prestone anti-freeze that has all of the "latest & greatest" additives to make it compatible with aluminum, instead of the old-fashioned straight ethyl-glycol blend. Indeed, whenever I tap off some of the coolant from the bottom of the rad, I can see a sort of a white, milky "residue" that (I believe) is designed to bond with aluminum, extending the life of that metal.

I recall that when I drove the car after getting the new rad & the old-fashioned "new" anti-freeze in '04, it didn't matter a whit if the outside temperature was 98F --- the engine temperature guage would barely register above idling temperature, even when I pushed the accelerator hard on the highway.

Sometime this summer it's my intention to flush-out the entire system, dump the anti-freeze that's in there now, and replace it all with the old-fashioned blend (I see it at the local auto parts place --- it sells for about $3.00 more per jug than the newer-styled stuff)...all this, and maybe put in a lower temperature thermostat, too.

Thanks for the info...

Eddy
Ontario, CANADA

OK F IT,I'm spendin mo money................

Wait a minute are you saying to run the new orange sht in my original radiator?
If that's the deal I will,but I thought I should stay with the green stuff.......?:confused13:

In my 79 Formula with a factory W72 400 4 spd.. I up-graded to a 4 row Radiator and a 160 thermostat.I did this because I was having problem's with the car running hot on the free way and in the city traffic.Once I made the change's I had no problem's at all.In 2005 I drove the car to the Gathering of bird's T/A show in Dundee,Mi. where the temp was 94 degree's when I left my house in Wisconsin.The car ran fine at 70mph all the way with one stop for fuel.The only time the temp gauge reached 200 degree's is when I got stuck at one of those damn toll booth's.I always use the green anti frezze.Never tried anything else on the older cars.

T/A Thermostats
 

Yes, I think that a 4-core radiator is THE best set-up for these cars --- even more so if the darned thing was to be made of aluminum, vs. copper & brass.

I STILL think that a LOT of people are missing something here, however, regarding anti-freeze: the traditional "day-glo" bright green-coloured stuff is no more...Prestone's newest generation of coolant is a washed-out, lemonade-coloured concoction, that I think is better formulated to be used in systems with aluminum rads, versus brass & copper.

When I went to the car parts place the other day, I seriously read the labels on the anti-freeze containers for content, and only one brand specifically said that it was formulated for "...older" cars (I assume that "older" means cars with iron engine blocks, & brass & copper radiators), and the emphasis was on its ethyl-glycol content, rather than "extra corrosion inhibitors for aluminum"...which I continue to believe is what that white, milky-looking gunk is that seems to line the inside of my rad hoses (and most likely is clogging-up the radiator passage ways, too!).

Someone reading this PLEASE tell me that I'm wrong! Otherwise, the anti-freeze companies are pulling a fast one on us with their "...one-size-fits-all" coolant pitch...

Eddy
Ontario, CANADA

I'm going to throw this one in here..

My car was cooling right at 160 all spring. Once the hot summer months hit it was running near 220. I replaced the thermostat with a new 195 as that is all the parts store had and it would warm up to 220 and not budge. I took the thermostat out completely and the car runs a notch under 160. Even sitting at a stop light in 95* summer heat it will barely get to 170 and then once I start moving it drops right back down again. Had the same issue with the '67 Bonneville I had last summer. That car didn't have a gauge but it would puke water everytime I parked it. Took the thermostat out and it ran fine, even when we had the week or so of 105* august days last summer.

Trans Am Thermostats
 

**************************************************

Hi Joe,

What you've just described (above) is darn-near, word-for-word, EXACTLY what I'm experiencing here with my '78 --- right up to the point where you removed the thermostat, that is...

...And THAT small detail shall be remedied by yours truly before the end of the week!

What have I got to lose, except for:

(A) The time it'll take to get under the hood & take the thermostat out, and,

(B) A nagging heat issue...!

Thanks, Joe. I only hope that my results here will be similar to what you've achieved there.

Stay tuned...

Eddy
Ontario, CANADA

That nut was bad about freezing up and the stud coming loose before you could get the line off. I have been able to get a thin wrench under the line bracket and hold the stud while breaking the nut loose.
A nut splitter might work if there is enough room to use one.
I think, I would cut the bracket before I would tear the line up, if I couldn't get the nut loose.
It would take some time but you might grind a side off the nut with a Dremel tool and get it loose.

Just caught this thread, hope it's not too late.

Not too late yet,I stopped before i did anything I would regret,does anyone repro this part?

The other bad thing is when I drove it last it shot up to 250 deg,I shut it down twice when it got that hot.
Driving at a 45-60 mph steadily left it at 200,but it climbed quickly at a stop.
Checked the oil and radiator fluid,no milk or bubbles,thank you Royal Purple,hope to God no damage occured,I'll go nuts if something happened over something so stupid as a fan clutch or thermostat.........