Since I'm changing out my anti-freeze in a few days, I figured that I might as well replace the thermostat. My Olds is a cruiser, not a racer, so I was figuring on staying with a standard 180 degree part since I've never had any over-heating problems. But I've seen two types out there, one is your normal everyday thermostat, and the other is this new "Hi-Flow" one.


Has anyone out there used the new thermostats and do they work any better. I know that in the grand scheme of things this is not an expensive part ($4.50 vs $11.50). I'm just curious if there is a difference.

 

Chip, I will relate my adventure with these.

72 Chevy, original, funked up radiator. Stock gauge going to 250 on open road in summer. Did not know if it was gauge or overheat. Bought a mechanical gauges and a 160 deg stant superstat high flow. Installed all parts.

Mechanical gauge matches stock gauge to within 10%. I will remove mech gauge this spring. Temperature dropped an average 20 degrees across the board. Where the car would typically roll around town at 210, do highways at 230, and be taxed at 250, it now rolls around town at 180, highways at 200, and I may see 220 once in a while.

My application may not be the same as yours. I have the original radiator, slightly bowed from a collision in 1986, and it is surely funked up. This was the original, low flow, low emissions, high temp stock thermostat. It helped me a lot, it may not help you as much, but I highly recommend high flow stats for our classics, regardless of the temp, and I personally prefer low temp ones.

Whenever this comes up on here, I feel obliged to mention the following. Ideally, the radiator can outcool the engine, and the thermostat regulates the temperature by opening and closing based on its temp setting. This is why, with new cars, with good radiators and low resolution gauges, that temp needle is ALWAYS at dead center, no matter if idling in winter, or blasting in summer.

Our old cars, the radiator gets funked up, and the thermostat goes way open, and can no longer regulate the temp, as the radiator cannot out cool the engine. Granted, as temps in radiator go up, the cooling efficiency gets much better (it's from the temperature gradient between operating temp and the ambient, which is why cars "run hot" but don't overheat, and why cars don't overheat in winter). So, you end up with a 160 degree stat wide open, and the car fluctuates between 180 and 200 depending on what you are doing, and how hot it is that day. The radiator is simply doing the best it can.

Ideally, we'd all have radiators in good shape, and run 180 degree thermostats. I have a funked up radiator, so I run a 160 high flow to get as much coolant through there as soon as possible just to get a good thermal reservoir going to offset any load I am about to put on the engine. I keep an eye on the gauge in the summer, and I don't push the thing hard until warm in the winter.

 

I prefer the Stant Superstat 180* thermostat.

 

What's the difference? I thought all "regular" thermostats were basically the same.

 

The brand has been around since I was a kid and I've never had an issue with any I've installed. All thermostats are not the same as the opening mechanism can differ.

 

I was just reading some reviews of the Stant and a few people stated that they had to drill a 1/16 hole in it to allow some coolant to weep through. Did you have to do that also?

 

^^^This. These cars didn't overheat when new with the stock regular flow t-stat. Why do you think you need something different now, especially since the OP says he does NOT have an overheating problem?

 

When you add hp you add heat.
When you rebuild and bore a block you take metal away,
age and water jackets scale.
All things that when new you didn't worry about.


Wouldn't a 190-195* help these engine run more efficiently?
For my daily's I use the ones that fail safe (open) .

 

I have used the fail-safe stats in other cars, they only last about 2 years, yes they fail in the open position but they do always fail after about 2 years.

 

And you are to change out your anti freeze at what time table?
boom -mic drop.

 

Sometimes 5 years.... bottom line is they don't work for me.

 

Every bottle of peak or prestone green has listed 24 months.
That I've used, Sure in some of my junk it had stayed longer.
I've had the reg t stat sick closed, it tends to make a mess.

 

Hey, do whatever you want, there is no wrong answer. I prefer the 180, remember the thermostat starts to open at 180 give or take 10-15*. Living in Texas once the thermostat opens it stays open in the summer. The 180 is plenty enough to give me heat in the winter.

 

Thanks for the reply, but do what you want doesn't answer the question I "put out there"
Knowledge is king.
Other engines use the hotter T=Stat rating to get better mpg out of them.
I figured someone might have tried to do the same with an olds engine.
What was they rated in the last cutlasses? I don't know off hand.


Every T-Stat I put in my personal vehicles I test in a pot of water. they are fully open by the rated temp, but that might be because there is no water flow through it to change the temp to cycle it back closed, In use in an engine I can see it taking a higher than rated to open fully.


I only asked about if it help or hurt efficiency, as I will be daily driving my olds all but winter and any gain here is a wonderful thing.

 

Wow...I did not mean to start an argument. I thought that I was asking a fairly simple question. Has anyone out there used the "hi flow" thermostats, and do they perform any better?

I'm talking about a stock Olds Rocket 350 4bbl with a/c and with only 46K miles on it, under normal driving conditions.

 

I answered your question....

 

Yup, and thank you. I was looking at the rest of the string.

 

No argument, the question was answered. It boils down to personal preference and what people have found that works. Like I said there is no right or wrong when selecting temp ratings. There were a few offerings for thermostats from 160-195 from Oldsmobile. You can google best engine temps and see a variety of discussions.

 

What will you mix your antifreeze with tap, well, distilled water or premix antifreeze?

 

I usually just get the pre mix 50-50. I've never had any issues with it.

 

I had the same experience with one in my Jeep. One day the engine wouldn't heat up, I pulled the thermostat and it was stuck in the open position. These are not "fail safe" designs, they are "stay open permanently" after a temperature excursion above the set point. I don't see how that is very helpful as a regular thermostat would be fully open anyway if the engine overheated, then it would function normally after the overheat situation was resolved. With these POS devices, you have to pull the thermostat and replace or "reset" it, which is additional work.

Sorry for the thread hijack, I just wanted to add my experience with this inferior, gimmick thermostat design.

 

That's OK. In a weird way, it is interesting. And as I've said before, I always seem to learn something new on this site.