Beware of Bargin Thermostats

[JAKEJR]

Okay, here's the story.
Living in Texas the temperature goes from 100+F in the summer to the teens in the winter.

In order to control cooling better, I've had to opt for the two thermostat method: a 195F for winter use, which I install in October and a 180 that I run in the summer.

For the past few years I've reused the same stats, so this past Oct I swapped the 180 for the 195. Up until last week everything was fine; the it gave up the ghost.

If you're like me, you keep tabs on the various dash readings and kind of get use to seeing certain numbers under certain driving conditions. My temp gauge would usually climb slowly until it hit right at 200, then drop; climb a few degrees again, then drop. It would finally settle on a 195-200 range and stay there - depending on how I'm driving.

Last week I was going to the HS to pick up my son and noticed the temp gauge climbed to 210 before beginning to drop. No drama, but not the usual. Couple of days later it did it again, but this time it didn't drop and on the way home it continued to climb.

At stop lights it would climb to 230/235, but when I drove off it would drop 10 or so degrees. Well, I knew something was definitely wrong and hoped I could make it home before it hit the shut off temp I'd decided on of 250.

I made it; showing 248 as I pulled into the garage. Shut it down for an hour (to cool) then restarted the engine and removed the radiator cap. No circulation.


So now I'm thinking water pump or thermostat. Always one to do the easiest fix first, I pulled the TB and thermostat housing.
Took the stat into the kitchen and submerged it into a pot of boiling water for 5 minutes. Took that sucka out and it was completely closed. Re-dunked it for another 10 and still it wouldn't open.

Then I held it with a pair of pliars and put directly over the burner flame. After about two minutes it grudgingly opened a tad, less that 1/4".

Found the culprit. So I stuck my 180 back in, topped off the radiator and packed it and things were back to normal.

Conclusion: My 195 was an AutoZone special (silver dollar style for lack of the correct name) and my 180 is a basket type SHAW.
Bought another Robert SHAW 195 basket job and I'm back in business.


Moral to the story: Don't try to save a few bucks by buying the El-Cheapo stat unless you want to chance revisiting this issue.

Hope this helps.

Jake

 

[evolution]

Wow. Good heads-up!

I thought the basic mechanics of a thermostat would be pretty hard to screw up. I stand corrected.

 

[safety_match]

I noticed a different type of thermostat when I purchased one recently. Apparently, in the event of a failure it will stick in the open position instead of closed. The idea being that it is better to overcool than overheat until you can get home / get it replaced.
I don't know if these are gimmicky or not...anyone know? If they work as advertised then they seem to be the way to go.

 

[DkBG]

Your absolutely right Jake ! Thats the worst place to go cheap . Cliff

 

[JAKEJR]

Your absolutely right Jake ! Thats the worst place to go cheap . Cliff

Yea, and considering I spent over four hours gapping my rings just to hit that last thousandths right on the head, didn't make a lot of sense to save two or three bucks on a stat..

Must have been brain-dead. Watch out for old age, Cliff. It's got a hold on me.

Jake

 

[vms4evr]

Jake,
Doing the same thing on my92. Most of the parts places like Autozone don't carry the style used in the LT1. I actually had a parts guy try to tell me a standard stat would work just fine. There were no special ones...
The factory one is 180. I bought the 160 with my chip upgrade. Very good quality. Before installing the stat I did like you have done. Dropped it in a pan of water with a baking thermostat in there so I could watch the open/close temps. When I swap I'll repeat that as a sanity check.
I also store the stat in the house instead of leaving it in the garage parts bin. So it lives in a nice 70deg house until its time to come out and take its turn
Graham

 

[resto75]

I also store the stat in the house instead of leaving it in the garage parts bin. So it lives in a nice 70deg house until its time to come out and take its turn

I leave my dog in when it's cold out but Graham is the only one I know who thinks of his themostat.

 

[vette-dude]

I noticed a different type of thermostat when I purchased one recently. Apparently, in the event of a failure it will stick in the open position instead of closed. The idea being that it is better to overcool than overheat until you can get home / get it replaced.

Safety Match

I would like to know the answer to that too. Has anyone used these?????

Randy

 

[Bob Yates]

Jake .... Are you just rotating your stats and not putting in a new one every time you change. I'm from the old school and was told never to reuse a stat once it's been in use. They will in time stick closed when put back in service. Now when a stat goes bad and has never been removed it generally sticks open. A lot of the times it's the chemicals in coolant that causes the problem over time. Even after it's removed the air causes changes in how the spring contacts . I have and 86 C4 like you. I purchased it in August of 02. Here in Louisville when I was in traffic it would go to 225 the fan would kick on it would go down to 210 . When on the open road it would go down to 190. When cold weather came I'm talking in the 30's the temp would only get to 150. The heater didn't work very good . I took the stat out it was a 195 I replaced it with a bridge port 180 and that did the trick. The weather now has turn colder to the single numbers and it still runs about 189. I will be keeping an eye on it this summer. I do have aluminum heads so I don't know if that makes a difference. It more than likely does. In my 37 years in auto repairs the 180 stat is the best all around one to use on a small block. A trusted brand is always best to buy. I know alot of the guys like to put 160's in but I think that's to cold for a small block and really not for winter weather. But I think those guys put thier vettes up when the temp drops below 80. And only drive on sunny days . That's OK if you think that way but I like to drive my vette all the time. That's what I'm into . I'm getting away from the subject so I best move on. Take care....Bob

 

[Corvette-Pilot]

I hear you on this !

I had a Toyota truck and I bought an Auto Palace Thermostat. When I first started the truck and it warmed up it would keep going and going just up to the red line. Finally it would open and run normal.

I figured it was bad and returned it for another one. Same deal.

I went to Toyota and bought one. After talking to the parts guy he showed me that the Toyota brand has a tiny hole that allows anti-freeze to flow slightly. The AP version did not have this. I think it stayed closed and the hot water in the block didn't flow to the thermostat so it wouldn't open.

Ya, not worth 2 buck for all the trouble it causes.
By the good stuff

 

[mvftw]

I only use Stant and drill two 1/8" holes in them , just in case...but next week I'm replacing my water pump, stat, hoses, clamps, I'm going to get the stat that stays open when it goes bad

 

[JAKEJR]

Jake .... Are you just rotating your stats and not putting in a new one every time you change. I'm from the old school and was told never to reuse a stat once it's been in use. They will in time stick closed when put back in service. Now when a stat goes bad and has never been removed it generally sticks open. A lot of the times it's the chemicals in coolant that causes the problem over time. Even after it's removed the air causes changes in how the spring contacts . I have and 86 C4 like you. I purchased it in August of 02. Here in Louisville when I was in traffic it would go to 225 the fan would kick on it would go down to 210 . When on the open road it would go down to 190. When cold weather came I'm talking in the 30's the temp would only get to 150. The heater didn't work very good . I took the stat out it was a 195 I replaced it with a bridge port 180 and that did the trick. The weather now has turn colder to the single numbers and it still runs about 189. I will be keeping an eye on it this summer. I do have aluminum heads so I don't know if that makes a difference. It more than likely does. In my 37 years in auto repairs the 180 stat is the best all around one to use on a small block. A trusted brand is always best to buy. I know alot of the guys like to put 160's in but I think that's to cold for a small block and really not for winter weather. But I think those guys put thier vettes up when the temp drops below 80. And only drive on sunny days . That's OK if you think that way but I like to drive my vette all the time. That's what I'm into . I'm getting away from the subject so I best move on. Take care....Bob

Thanks for that, Bob. I'd never considered the cause may have been due to my continuing to reuse the same stats year after year. You are probably on to something too with the reaction of the chemicals in the coolant and air.

You can bet your boots that I'll use a new one each time from now on.

I agree, too, with the 180 stat being the all around best. I've tried a 160 and the engine ran too cool, even in the heat to summer. I'd run one year round except my temps run so low in the winter that getting heat inside the car is a problem. Swapping them isn't a big job tho; I've done it so often I've gotten the time down to 15 minutes.

I appreciate the advice.

Jake

 

[Bob Yates]

Hey Jake ..... I have found that stats having the same temp can sometimes have larger opens. Like a Bridge port 180 when open allows more coolant to flow than a Delco 180. Maybe a delco might work for you in winter and summer. Just a thought ....Later..... Bob

 

[JAKEJR]

Hey Jake ..... I have found that stats having the same temp can sometimes have larger opens. Like a Bridge port 180 when open allows more coolant to flow than a Delco 180. Maybe a delco might work for you in winter and summer. Just a thought ....Later..... Bob

I went with Robert Shaw's because that's exactly what they claim; flows more than others.

Something I'll keep in mind tho when I change it again.

Thanks, Jake

 

[vms4evr]

I like the idea of drilling a small hole in the stat body so that some coolant will flow all the time. I guess that makes a nice safety measure. I've found that the GM 180 stat for my LT1 opens closer to 195 and closes at 180. The custom chip I have turns the fans on at 200 and off at 190. So most of the time I keep the 160 stat in there. But it does make the engine run about 165 most of the time. The 180 stat keeps it around 195. So maybe with a couple of small holes it would keep the temp a few degrees cooler???

Roy, I don't have a dog so the stat gets its place, and it gets along well with the cat

Graham

 

[JAKEJR]

I like the idea of drilling a small hole in the stat body so that some coolant will flow all the time. I guess that makes a nice safety measure. I've found that the GM 180 stat for my LT1 opens closer to 195 and closes at 180. The custom chip I have turns the fans on at 200 and off at 190. So most of the time I keep the 160 stat in there. But it does make the engine run about 165 most of the time. The 180 stat keeps it around 195. So maybe with a couple of small holes it would keep the temp a few degrees cooler???

Roy, I don't have a dog so the stat gets its place, and it gets along well with the cat

Graham

I should have mentioned that. I've done all that already (drilled the holes), several years ago when I first read about it in TPIS' Secrets book. My PROM had been reprogrammed too. Fan on at 190.

I also plugged the by-pass hole at the passenger side of the water pump (the lowest hole of the three). Still, in 102*F + summer heat, idling with the A/C on, the coolant is hard pressed to remain below 230.

I installed a Derale oil cooler in front of the radiator (behind where the front license plate bolts on) and another fan mounted in front of the radiator in place of the small, stock Z51 fan that threw a blade. Installed a new radiator too, which did help some, but I'm dealing with some extreme heat conditions during the summer.

I'll see this summer if the two extra fans make the 20 degree difference I'm looking for.

BTW, oil temps were really high because of the siamesed bore of the 400 block I'm running. The Derale made a huge difference.

I'm convinced it's an airflow issue because once the car is moving, even at low 30 MPH speeds, the temps drop to acceptable ranges, even with the A/C on.

Jake

 

[vigman]

A great post ( A/C fan trick )

It's the combo of feild experience & day to day observations that brings all this SUPER info together. I never cheapout on a stat..learned my lesson in high school on a FIAT!

I 100% agree with this post!

BTW I run a 190 stat and the car hovers between 195- 205 Sunny/rainy A/C on or off.

And for those of you who have A/C try the following trick.

This will work reguardless if your A/C is charged or not!

You do not have to engage the A/C!

On the High side line of the A/C (the small aluminum line) ther are 2 pressure switches on that line, of the two there is a smaller 2 pin plug...near the aix box... remove it. This issues an A/C fan request since it thinks the switch is OPEN due to a High pressure build up in the system.

The ECM will think the A/C's running and engage the MAIN fan... 2-10 seconds after the car started.. and the fan will stay on until 30 (ish) MPH.

TADA!

Vig!

 

[Bob Yates]

Whoa..... vig your way out there for me.... Jake o'boy I think the two fans ought to do it. I had a Z28 once that wouldn't behave and that did it . Your charging system needs to be in tip top shape but you probably now that already. We'll have to wait for those hot summer days yet so let's just keep that heater on...vig... I'm going to study what you've said maybe an old dog like me can learn new tricks...Me and my check engine light don't get along.

 

[SPANISHVETTS]

Why do we spend thousands of dollars on heads, cams, intake, exhaust, pistons, cranks, machine shops, custom chips, etc., and still expect the factory cooling system to do the job?

You have an engine that I would cut off my right arm for and your are using 19th century cooling technology. I do not want to start another fight with the GM crew, but when you demand max performance from a internal combustion engine water based coolant just can’t do the job.

Waterless coolant is not a new idea. Anybody else out there as old as me will remember when airplanes had liquid cooled piston engines. These engines had to operate at +100+degrees on the ground to -30 degrees at 20,000ft. These extreme changes took place in less than 4 min. The cooling systems contained no water.

Have a look at the ¨waterless¨ systems. I could be full of $#!%, but what have you got to lose. A good night out cost more than the conversion.

If you do go waterless please let us know the results.