Thermostats

[Bluedot]

On another thread, I had asked for electric fan advice, and reported on what I learned and ended up with. I am happy with the Flex-A-Lite 238. But even tho it does a good job, quietly, the temp still acted strangely at times. At slow speeds or idling, even with the fan turned on (manual switch), the temp would quickly climb to near 240º before the fan was able to bring it back down. So I started researching additional remedies: that coolant additive stuff that's supposed to lower temps all by itself (e.g. "40º Below"), high flow water pumps (e.g. FlowKooler), and thermostats. Opinions on forums, just like with any subject, were all over the place. What I came away with:
(a) Reviews of the additives like 40º Below seemed to run hot or cold (sorry!), with little in between. Some swore it worked, some said it gunked up the cooling system and did no good.
At $30 a dose and possible problems, I put this one on hold.
(b) The FlowKooler water pump got mostly very good reviews. The bulk of the opinions seemed to be that more flow made for cooler temps. This looked like a good bet, but in the process of researching water pumps, I began to pick up quite a few T-stat comments. So before ordering a water pump, I started researching T-stats alone.
(c) Now you’d think something as trivial as the T-stat would be pretty much a no brainer, drawing little controversy. Wrongamundo, kemo sabay! Holy crap. Cold stats, hot stats, no stat, on and on. But what I noted was a parallel of more flow = colder temps between the T-stat comments and the water pump comments. Many saying taking the stat out altogether will often make the engine run too cold, ie, never warming up properly, to evaporate condensation in the crankcase; sludge city. Also that the pump needs some resistance to slow flow and avoid cavitation. That began to make sense. (Aside: There were a few who said with higher flow, the water doesn’t have enough time in radiator to give up heat, making the engine run hotter, not colder. That theory was pretty much debunked. Less time to give heat is also less time to pick it up in engine.) The best commentary I read said that engines (older ones anyway) run best tat 180-200º.
A few stat comments spoke of a “RobertShaw high flow thermosat”, which I was not familiar with. I knew RobertShaw makes temperature controls for buildings, but did not know for cars. Apparently their T-stat design flows significantly more than standard cheapie stats. Anyway, a stat costs a lot less than a water pump, and an easy change out. So I bought a 180º one from Speedway (they modify them for even a little better flow when open) and installed it. Wowee – what a difference! I’ve only had it on two short drives so far, but the gage never broke 200º, even without running the fan. Like a different car.
MORAL OF THE STORY: Try the simpler and cheaper solutions to a problem before throwing a lot of time and money at it. And the RobertShaw high flow stats are easily worth the extra money ($19). Lesson learned.

[TPogue]

My dad has always run 160 thermostats with out a problem.
I always use 180 myself and have a Mr. Gasket hi flo one in my 34.
That said I know what you say about different opinions on water pumps, t-stats and even radiators.
For what it is worth several years ago I machined a water pump pully for a guy using an aluminum radiator in a 34 Chevy with a blown big block and air. He was having problems keeping the temp down on it and the radiator company said he needed to slow the flo down. machined a bigger pully for him,don't remember now how much this was 30 years ago, and he said he could set with the air on and would not get hot.

[Crab]

I just put a 160° thermostat in the Corvette yesterday. The last time I drove it, it spiked at 240 and I headed back for the shed, and as soon as I made a curve, the temp came down quickly, so I guess it was stuck. The old one didn't look gunked up or anything, but it was an easy swap. The car did fine when I drove it yesterday. I do have a big aluminum radiator and an aluminum waterpump to help with the heat issues Mid Year Corvettes are known for.

CRAB

[grancuda]

I like a 180* super-stat from NAPA with an 1/8” hole drilled in the flat area beside the opening for a little flow around too keep water on the thermostat at all times. That’s worked well in various makes of old V8s for daily driving in summer. If the termostat is really sealed off well when shut it can create an air pocket under the thermostat & not allow it to open at the right time.