thermostat temp range options for 455??

Can anyone share some knowledge with me on what choices we have for 455 thermostats in regard to temp operating range? Do they make one less than a 190/195 degree one? Part #'s, prices, and vendor info would be most helpful. Thanks!

 

Sure, Stant makes 160*F, 180*F, and 195*F t-stats. It's the size of the t-stat really, not what some dumb auto parts store computer SAYS is the right one. Don't quote me on this, but I think 57 mm is the right size.

160* is probably way too cool for a street car. the optimum temp is about 190*F, for best efficiency and power, in general.

As far as range goes...in my experience, when I ran a 160* t-stat on the street, it ran at 160* until I was on the highway, then it creeped up to 210* max

With the 180* t-stat I have now, it runs at 180* until I get on the highway. The it should go up to...exactly the same temp as before. It's been cold, I've seen 190* max

A 15 psi system like most Buicks from our era have will give you a boil over point of 247*F. Your engine should see no damage due to high temp up to 230*F, if I recall correctly.

The t-stat shouldn't really control a 'range' of temps, per se. The full 'range' of a properly working system will alwys be from 0 to whatever it's rated to. If you're worried about an overheating problem, I'd suggest looking at the radiator cap before the thermostat as a culprit. Overheating will be caused by a bad thermostat rarely, compared to the other possible causes.

The Stant 180* t-stat I put in 2 weeks ago with a 'jiggle' valve cost about 8 bucks and change, I think. Got it at AutoZone

 

Now that I have the auxillary gauges in, I'm looking closer at operating temps. I have I believe a 190 or 195 degree stat in the car, and on a warm day recently, I saw highway operating temps range from 208 to 212. This was on an 85 degree GA day with high humidities about a week ago. Was that operating temp range too high? It stayed pretty consistent too in that range from city vs highway driving. I asked the Poston rep over at the Reynolds event about this (last Friday) and he said not to worry that those temp ranges were acceptable. He said not to worry until it starts getting around 225 or so. Just wondering if I may need to try and lower stat in the car and what effect it would have. BTW, I have the stocker type 3 core radiator on the car and to the best of my knowledge, the fan clutch is working. Am I overreacting? Thanks!

 

210 or 212 degrees will not cause damage or overheating. When you shut off the engine, and the temp gauge shoots up, do not worry. It is an incorrect reading, the probe needs coolant to flow to get a proper reading. I would say you are just over-reacting. before you got the gauges, the engine was running at that temp anyway, you just never knew exactly the number...now this high number scares you, is all. 230 is too hot, 212 is ok. Your coolant will not boil at 212*F unless it is at atmospheric pressure-which it shouldn't be.

OK, the anti-freeze will allow a slightly hotter boil over temp. But it's not the anti-freeze that makes your system operate over the boiling point of water at atmospheric pressure. (Also this is why it's called anti-freeze, not anti-overheat, lol) This is the function of your radiator cap. It keeps the system at higher than atmospheric pressure. This raises the boiling point, in your case, to 247*F if you are using the right rad cap (15 psi, I beleive). At atmospheric pressure, a bit over 212*F will boil you over. At the correct pressure, 247* is your boil over point.

A cooler t-stat should not lower your operating temp. Once the t-stat is open, it's open, no matter the rating.

Buick's water pumps are not the best design, the bushings wear out, happened even when the cars were new.

You do not have an overheating problem, in my opinion, and I feel I have a LOT of overheating experience. I run a 4 core radiator and I see temps just slightly lower than yours in 90*+ days, very high humidity. I have never overheated with this set up, on a daily driver, even in summer Boston traffic.

If you are using an overflow tank (so that when your radiator purges-it is a standard function- it will not draw in atmospheric pressure- the overflow does not just hold "extra" coolant, like some folks seem to think), and if your radiator is in good condition, the engine is tuned properly, your radiator cap is ok, the fan and clutch work, you use the right fan shroud, and there are no air bubbles in the system (the pump can only pump liquid, not air) you should have no troubles. I cannot dream of a situation where 212 or even 220* F will damage your engine or cause overheating.

 

Thanks Chris. Your explanation gives me some peace. One less thing on the GS to worry about!ou:

 

With my 4 row rad, any air temps below 60* and I must put cardboard in front of the rad to get even up to 180*.

In really cold weather I need to almost cover the entire thing to get it over 160*.

But it runs nice and cool in the summer. Can't have the best of both worlds I suppose...

 

Well, I guess I did oversimplify the thermostat, Larry:grin: you're keeping me honest

 

Yardley, it sounds like your thermostat is stuck open. A good thermostat will bring the engine up to temp regardless of the cold, (simply bypassing the radiator) unless it gets down to something ridiculous like 80 below. :eek2:

I'd take a look at it, continually running cold can really hurt the life of an engine.

James

 

Yardley you may indeed have a defective thermostat.In my experience they are not uncommon.I had to replace two new ones before I got one to work properly!I now have one from NAPA and it works fine.Hard to believe you could get two bad ones in a row but that is just my rotten luck.I had the same problem of the motor not coming up to temp except in extreme heat.Another thing you might look at is where your sensor is located-if it is in the manifold opening near the right rear of the motor(at least on a Performer) you will get inconsistent readings on the guage.This is not a "through"passage.Hook up your heater hose here and have the guage sensor hooked up to the front water passage.Makes all the difference in the world.I personally had always used a 160 t-stat but have changed over to a 180 which I feel is better for efficiency but as has been said watch out for detonation if you were marginal to begin with.Play with jetting and/or timing to stay clear of trouble.Hope this is helpful.Rod

 

Mr Gasket t'stat ?

 

Thanks Larry. I'll look for it locally but if not, I can order it. I may try both the 160 and 180 degree settings and do some controlled testing.

 

Hey Evans, in my 70 I'm using a 180* and a 3 core rad. The hottest temp I saw this summer was 205* but, it normally runs 190*-195*.