[JLMounce]

I work at home 90% of the time, so there's not much reason for the wife and I to have two "daily" cars when I've got my bird that is reliable enough to be used in a pinch if we didn't plan ahead for me needing our Jeep.

Fast forward this morning and we wake up to a dog in severe pain. I call the vet and get an appointment and that means taking the bird. We had a cold front come through yesterday and the drive to the vet was in about 20 degree weather.

Although the drive is not far, I did allow the car to idle and warm up for about 5 minutes prior to leaving. Between the warm up time, drive time and then heat transfer to the coolant for the half hour I was at the vet, I couldn't get the car above 130 degrees. Driving the car, actually resulted in the temp lowering further with an average driving temp of about 115-120.

Not ideal for the comfort of it's passenger, but certainly not ideal for burning off any condensation in the oil etc. Additionally, the FiTech will not jump out of open loop operation until 150 degrees. Still drives fine of course, but it's fairly flat in the tune.

Previous to upgrading the radiator I had installed a high-flow 180 degree stat. It's pretty clear based on my situation that it's passing enough fluid prior to it's temp rating to keep the car cool below the minimum.

I'm wandering if this is typical for such a thermostat, or if mine has possibly failed in general.

Considering these things are cheap and pretty easy to replace, what are you guys using with good success in the colder months?

Once the temps outside get to about 50 degrees, the car will stay at about 173 unless it's sitting and idling for a long time (which I'm still trying to get corrected)

[Scott Thelander]

car aside for now ..........

hows the pup ............... ?

[AIR RAM]

Hope the pup is ok...

I used to place a piece of cardboard in front of my radiator during the winter months. I would only block off 1/2 of the radiator and it was easily removed if the temps where to get to hot... they never did. It worked great in getting the coolant warm enough to blow good heat. You could try just placing a small piece of thin plastic behind the grill openings during the winter months. You could just use Zip Ties to hold it in place. You would still get a decent amount of air from the lower openings. This may allow the radiator to warm up without the fear of closing it off to much.

I plan to experiment with different ways to build up heat once the car is back on the road.

Good Luck,

SPEED SAFE, NICK

[72LuxuryLeMansLa.]

Originally Posted by AIR RAM

Hope the pup is ok...

I used to place a piece of cardboard in front of my radiator during the winter months. I would only block off 1/2 of the radiator and it was easily removed if the temps where to get to hot... they never did. It worked great in getting the coolant warm enough to blow good heat. You could try just placing a small piece of thin plastic behind the grill openings during the winter months. You could just use Zip Ties to hold it in place. You would still get a decent amount of air from the lower openings. This may allow the radiator to warm up without the fear of closing it off to much.

I plan to experiment with different ways to build up heat once the car is back on the road.

Good Luck,

SPEED SAFE, NICK

You always see the truckers using zip up covers over their radiators in the winter. Sounds like a reasonable fix.

[dataway]

Yes, how is the doggy??

Thermostat would definitely be my guess. Obviously the cooling system is working fine.

A heater on high in 20 degree weather will remove a LOT of heat from the engine, with a well tuned engine ... possibly enough to keep it below the thermostat setting at idle.

If driving lowered the temps ... then the thermostat is malfunctioning in some way (is it drilled?). Obviously coolant is flowing through the radiator if driving lowers the temp.

[Formulajones]

Thermostat isn't operating properly.

What ever the temp rating is on the thermostat, it will force the engine to run in that general range no matter how cold outside. Water does not circulate through the radiator to cool the engine until that thermostat at least cracks open a pinch. So something funky going on there. Even the small bypass holes I drill in my thermostats don't affect the operating ranges they are designed to run in.

So if you're running a 160, it would not be uncommon in really cold temps to see the engine temps stay around 155 degrees, as that's about where that stat will start cracking open. And if functioning properly, you will see the temperature fluctuate back and forth just a few degrees as the stat closes and cracks open again. When ambient temps are that cold, the thermostat will likely never fully open, and cycle back and forth.

I don't bother to change our stats in the classics and we drive them daily. Nothing for us to have ambient temps in the teens at night and then warm to 50's during the day. Especially through Jan and Feb months. I leave the 160 stats in place and they generate plenty of heat to keep the passengers warm, typically running right around the stat rating on the really cold days, and in the 170's to 180's on the hot days during the summer months, depending on which car we are talking about.

[Scott65]

Sounds like a scenario where an electric water pump thermostatic controlled would be beneficial.

[70GS455]

I often wonder about those that say "Aw hell, 230 deg F is fine" when they read about situations where folks drive around in freezing azz weather and the cooling system obviously has enough cooling capacity to maintain coolant temps at or under t-stat rating

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[JLMounce]

Thanks for the concern everyone. Pup is okay. She's starting to show her age a bit and mixed with a bit of arthritis she may have tweaked her back a little roughhousing with her brother. She's on some meds and bed rest for a bit. So far she's obliged to do so.

The thermostat is only a couple years old on this piece and it's a Mr. Gasket model. Not altered in any way, no holes etc. Just the high flow version.

My engine likes a bit of heat in it. Give it it fresh, cool air and about 185-190 degrees of water temp and that's her sweet spot. So I run the 180 degree stat which gives me some head room there.

All the HVAC components are in the car, but it's a former AC car and I've never bothered to correct the harness, so no blower motor operation. The headers put off enough heat that around 45 degrees ambient, it's really not too bad in the car with a hoodie or light jacket.

Sounds like I need to look into a new thermostat.

[Navy Horn 16]

Just because your water temp isn't going above 120 degrees doesn't mean that is the highest temp your oil is going to see. It just means that your radiator is getting water really cool before going back into the motor.

Your cylinder walls and other surfaces that are being lubricated within the engine are going to still be WAY above 120 degrees. If you have a laser temp sensor, your heads would be well above that temp.

Even if it was only 120 degrees, what happens to water on a 120 degree sidewalk? It goes away pretty quick.

[JLMounce]

Originally Posted by Navy Horn 16

Just because your water temp isn't going above 120 degrees doesn't mean that is the highest temp your oil is going to see. It just means that your radiator is getting water really cool before going back into the motor.

Your cylinder walls and other surfaces that are being lubricated within the engine are going to still be WAY above 120 degrees. If you have a laser temp sensor, your heads would be well above that temp.

Even if it was only 120 degrees, what happens to water on a 120 degree sidewalk? It goes away pretty quick.

I am reading water temperature from the cross-over, which should be post block and heads. If that's not correct my apologies, but if that's the case, I would be taking readings at a point where the water should be near it's hottest. Some cooling post head could be done through heat transfer in the intake cross-over.

You do bring up a good point that the oil may still be above that temp. I have no way to verify that as I don't run an oil temp gauge.

[ZeGermanHam]

T-stats tend to fail in the open position, causing the symptoms which you are experiencing. I had the same thing happen in my BMW. Should be an easy fix.

[72projectbird]

Originally Posted by JLMounce

All the HVAC components are in the car, but it's a former AC car and I've never bothered to correct the harness, so no blower motor operation. The headers put off enough heat that around 45 degrees ambient, it's really not too bad in the car with a hoodie or light jacket.

Sounds like I need to look into a new thermostat.

That's how my 71 is. The headers keep the floor warm, but it gets brutal around late November.

[Schurkey]

1. You have a failed thermostat. Replace with a QUALITY brand thermostat.
2. "Mr Gasket" thermostats (last I looked) seem to be Chinese knock-offs of the Robertshaw design.
3. Thermostats can fail open, or fail shut. They can fail somewhere in the middle, and just never move from that position. Or they can be sticky; refusing to adjust water flow until way above or way below the proper temperature. There's no telling how a thermostat might fail.

[steve25]

X2 get that Stat out of the motor before it free's its self up some and then really screws you by sticking in the closed position!

[TedRamAirII]

Fire it up cold, and look down the radiator. If you see coolant moving through the core tubes, the thermostat is bad.

[68 Firebird]

I humbly recommend 180 superstat.
Very accurate. Even when I drive my
Car in cooler months she stays at 175 minimum.
Gerry.

[chuckies76ta]

Originally Posted by JLMounce

The thermostat is only a couple years old on this piece and it's a Mr. Gasket model. Not altered in any way, no holes etc. Just the high flow version.

My engine likes a bit of heat in it. Give it it fresh, cool air and about 185-190 degrees of water temp and that's her sweet spot. So I run the 180 degree stat which gives me some head room there.


Sounds like I need to look into a new thermostat.

Go to Napa and get yourself a Premium Stainless thermostat and never look back. Those Mr. Gasket stats are junk. Just another tidbit of info. Drain the rad down half way to replace thermostat. Before putting new stat in, fill rad so you can see antifreeze in thermostat water cross over. That way all the air will be out of the heads. Install you stat and housing and top rad off. Start engine circulate coolant and top rad off again.

[antique69lemans]

I ran a high flow stat and had the same issue. I believe the problem is how they are rated. The high flow starts opening before rated temp, earlier than a regular stat. The engine could not maintain operating temp.

[Formulajones]

They all pretty much start to open before the rated temp. I've bench tested a bunch of them when I was experimenting with them years ago. The rated temp on these things is just a "range" there is nothing accurate about them.

A 180 generally will start to crack open around 175 to 177 degrees and they aren't fully open until 182-183 or so.

In most cases, if you have a car with a good cooling system capable of doing the job the engine will stay right in that temp range on hot days. On the really cold days you'll see the engine running around 175 degrees or just below the 180 rated thermostat setting because when these things start to crack open, that's enough flow to keep things cool with ambient temps in the 20's, and even ambient temps in the 50's, which is exactly why the poster in post #17 is seeing 175 degrees on cold days with a 180 stat. But by no means should you see the temps running 120 like the OP. That means the thermostat is stuck open in some way.

Think of thermostat ratings as being the coldest temp the engine will run, but it doesn't mean it will stay there on hot days if you don't have a cooling system capable of doing the job.