i recently put a new stock radiator in my dart and a 180 degree thermostat. i left on a road trip, averaged 70 mph and she ran great, right at 180 for 9 hours.

at some point on the way home however, she started running in the 150 range. the gas mileage did not change, everything looked great with the radiator, the new hoses and thermostat. could it be that my temperature guage is shot? any ideas on what is happening or tests i can run?

also, what is the optimal temperature for a 225? will a 195 thermostat contribute to early engine wear? will the engine run more efficiently at 195 as opposed to 180?

Sounds as though your new thermostat might be sticking open. 180° is the optimal temperature, though 195° thermostats were factory equipment after about 1973—this was a desperation emissions measure, not necessarily picked for optimal engine life or performance. 160° is not the correct choice. My preference is for the Stant Superstat.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

what would cause a thermostat to stick open? particulates in the coolant?
can i get a stant superstat by name at the advance/autozone?

I liked the Stant thermostats until they changed their warranty....

I had a Stant thermostat for my truck (not sure if it was superstat), and the packaging clearly stated lifetime warranty (I kept packaging).... Well the last time it failed, I find that they no longer have lifetime warranty. Pep Boys gave me the new one free, but the replacement doesn't have a lifetime warranty...

To me a lifetime warranty on a car part means that I'll NEVER have to buy that part again. (As long as I have the receipt, which I don't have a problem with)... So the next time the truck thermostat fails it won't be a Stant. (BTW, I have the same issue with Raybestos brake pads.....)

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

A better description would be failure to fully close......

Have had that happen a few times. If you put it in boiling water, it will usually opens up like normal, but it when cooled it never fully seats...............


Well tonight mine did the same thing..........

Going up the hill the temperature was at about the 2/3 area (previously the highest it got was about 1 needle width above half-way mark (not counting the temp spike you get when the car has been sitting for about 5 minutes))....

After hitting the rest area at the top of the hill, the temp went back to normal, and then somewhere going down the hill the temperature dropped to about the 1/4 area and never went above the lower mark.....


What I think happens is that the wax that expands and opens the thermostat leaks out and causes both symptoms.......

Since some wax leaked out, there's not as much pushing open the thermostat, thus the higher temps under load.

But some of the wax stays behind on the wrong side of the piston that pushes open the thermostat and jams up the closing of the thermostat when it trys to close.


But since it has a lifetime warranty (and btw isn't a stant (see previous post)) I can't dissect it to find out what really happen when I take a look at it later............

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I've had that problem a couple of times, Stant used to be a good stat. I had one recently though that opened fine in the bucket test but when I removed it and it would shut it got 'hung up' on a spring coil and wouldn't seat all the way unless I stuck an awl in there then it would 'snap' shut.


They don't make stuff like they used to,

-D.Idiot

The part number for a 180° Stant Superstat for a /6 should be 45358. You should be able to just ask for that at the counter without them having to look it up.

By the way, Adavnce's website (part of PartsAmerica.com) still lists the Superstat with a lifetime warranty.

Steve G.

There is the regular cheapo Stant thermostat (which have not been good in my experience). Then there is the "Stant Superstat" which I've had excellent results with.

The easy way to tell them apart: the cheap version has a yellow package with blue stripes, while the Superstat has a blue package with yellow stripes. They come either carded or in boxes.

Steve G.

That's exactly what the marketeers who come up with dumb ideas like "LIFETIME warranty!" certificates want you to think.

It actually means you get to spend your lifetime exchanging parts under warranty. It's a marketing gimmick, nothing more, and certainly not a valid measure of a part's quality.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

"Lifetime warranty" in the parts biz, means 5 years. On average, most people do not own their vehicles for more then 5 years. When they trade/sell the vehicle the warranty does not transfer with the sale. After the 5 years the parts people can resell the part to you again...

After 30 some years, I doubt the factory gauges are anything close to accurate. My fuel gauge reads "full" at 12 gallons of gas. I have a 18 gallon tank. My temp gauge is usually in the middle. Sometimes, for no apparent reason, it's not. There seems to be an incestuous relationship between the gas and termperature gauge. It one is not accurate, it is a pretty good chance the other one isn't.

The rating of the termostat doesn't have much to do with the temperature of the coolant. That depends on the capacity and efficientence
of the radiator. You can think of the thermostats rating as the lowest possible tempurature, not the max. If you use a 160* thermostat and your radiator will only cool the engine down to 195*, then that will be your temperature, not 160*.

Ok, engine running cool problem can be thermostat, but in my case I never reach normal temp zone in gauge, always the needle stays in the 1/3 range, is that good or bad? I got manual tranny and seven blades fan, and factory thermostat

_________________
Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

Checked my thermostat, and it was actually stuck open, not the failure to fully close that I've seen in the past............


And the cause was some grit. I pushed it close (wasn't hard, but you could feel the grits grinding) with my fingers and cleaned it up with an old tooth brush and it works fine now (in the boiling pot of water).

The tolerances were just right on the engine side so that some fine grit gummed up the works.........


I now suspect that's your problem

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

That would be because they are both fed power from the same 5 volt regulator. See this article for ways to improve your gauges accuracy.

Steve G.

Already done that, didn't make a differance.