Loss of cooling system pressure does not cause overheating. All it does is reduce the temperature at which the coolant boils.

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

Hadnt seen that type of cap but will check it out. I have been so focused on the temp needle that I did check the fuel gauge closely but will give it a try.
The radiator has no shroud and has no clutch and the fan belt is tight.
Thanks for all the feedback! I am sure it is helping more than me!
Cheers.

_________________
Psychics will soon lead dogs to your body!

1963 Dodge Dart 270 convertible

I wouldn't bother. They're a neat idea, but generally not well enough made to get closer than within the same three-state area as the ballpark as far as temperature accuracy -- but the bigger concern isn't the toy thermometer, it's the toy radiator cap!
Great, but I'm still not sure why people are throwing random answers like "Fan shroud! Fan clutch! Fan belt! Radiator cap! Pressure leak!" at this question. They're ignoring the kind of car you have and the symptoms you're describing. I'm not sure how they reckon this is helpful. :shrug:

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

I've got a Thermocap on my C7000. It's a piece of junk. When you twist it to install it the gauge inside will turn and be way out of line with the numbers that are printed on the face.

Neat idea, just poorly executed.

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Ok, I got it all back together and ran around the neighborhood this afternoon and it overheated right quickly.
I checked to be sure it was full of coolant to make sure there were no air pockets. Check.
Ran around again and the temp showed high, I went home and took off the cap and it was rattling and gurgling and raising hell! I checked the temp with my meter and it showed as ~200 degrees. I futzed around and around and it dropped a bit on the inside gauge and I took off the cap and it was bubbling and banging and make all sorts of racket.
I let it cool down and took out the thermostat and filled up water and ran around the neighboorhood for 15 minutes and the needle stayed right at above the lower "normal" temperature line on the gauge, it did not budge.
It looks like the Napa thermostat, a 195 degree one was giving me problems. I checked the old one I replaced and it was a 180 degree.
Looks like the new thermostat is bad.
I guess I will put the old one back in and give it a try, I only replaced the thermostat because I had pulled the housing to work on the mainfold.
yeck!
John

_________________
Psychics will soon lead dogs to your body!

1963 Dodge Dart 270 convertible

Optimal thermostat is a Stant SuperStat #45358, correct temp rating is 180°.

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

Thanks SlantSixDan.
Do you ever sleep?

_________________
Psychics will soon lead dogs to your body!

1963 Dodge Dart 270 convertible

Do I ever which now?

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

Just had a recurring problem with overheating myself. It was vacuum leaks. That means check every hose to make sure it's clamped and spray some carb cleaner around the intake and carb to make sure they are leak free.

This advice sounded "whatever" to me until I realized I was too lean because of leaks.

Well it gets crazy again.
I put the180 back into the car and the gauge went directly to way overheat on a short trip around the block. Got home checked the coolant and it was low so I filled it up. Drove around again and it was smack in the middle of the normal range on the gauge.
Came home let the car sit an hour or so and went to the locksmiths to look for key blanks to make a spare set of keys and the car overheated again and to top it off the locksmith was closed in the middle of the day I guess for Veteran's Day.
WTF? Nest Step? Get a new 180 degree thermostat? Get the radiator boiled and cleaned out? I hate the thought that it ran fine only with the thermostat out.
I will look for vacuum leaks but thought I got them all earlier.
By the way Thanks to all the Vets here!

John
USAF 67-72
Clark AB Philippines/Korea 68-70

_________________
Psychics will soon lead dogs to your body!

1963 Dodge Dart 270 convertible

Might be a little obvious, but are you installing the t-stat the correct way?
The pellet into the head.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Did you buy a new t-stat? The one SL6 Dan mentioned? If not, it would be a good idea....

How old are your radiator and heater hoses?

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I bought the car from a couple of service techs at a local hi perf auto store here and they had replaced the thermostat, water pump, fuel tank and radiator cap.
While I was replacing the warped exhaust manifold I got a new Napa 195° thermostat. Bad problems ensued.
Did not get the SuperStat #45358 stock NAPA thermostat and the thermostat is in correctly.
Can this sturdy engine be so persnikity? Vacuum leaks causing massive overheating, being so picky it doesnt like any thermostat but the SuperStat #45358? Crazy.
As far as I know the radiator is the original and has not been cleaned boiled or cored.
Looks like this is the next step to take after trying the SuperStat #45358 thermostat.
Sound right?
Thanks all.

_________________
Psychics will soon lead dogs to your body!

1963 Dodge Dart 270 convertible

Any 180° thermostat of the correct physical design will work. The 45358 is the best one on the market, is all.

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

Thanks that is my take, I would think that the /6 is such a robust engine that it would be able to handle lots of abuse and misconfiguration.
New 180° thermostat to be sure and radiator to the shop next week for cleaning.
John

_________________
Psychics will soon lead dogs to your body!

1963 Dodge Dart 270 convertible