1962 340 hp thermostat

[Dino L.]

Searched the archives and could not find definitive answers......

1. Did the car originally come with a 170 or 180 degree thermostat?
2. What is the part number for a delco stat , a robertshaw, or a mr gasket? For original temp spec?

[David L.]

Re: 1962 340 hp thermostat

My 1963 Chevrolet Parts Catalog (Oct. 1962) lists GM # 3136185 in Gr. 1.246 as the thermostat part number for the 1962 Chevrolets Pass. & Corvettes. The description is 180 degree (poppet pellet type).
GM # 3136185 was replaced with GM # 3156280 (also 180 degree) in March 1964 which was then replaced with GM # 3033780 in Apr. 1977 and then replaced with GM # 3041388 (180 degree) as per Chev. & GM Parts History.

My 1981 Corvette Parts Catalog (Nov. 1981) lists GM # 3033770 (170 degrees) for 1953-1962 Corvettes and GM # 3041388 for 1953-1964 Corvettes. GM #3041388 is described as 170 degrees (error in parts catalog) as it is actually a 180 degree thermostat.

Dave

[Joe L.]

Re: 1962 340 hp thermostat

Searched the archives and could not find definitive answers......

1. Did the car originally come with a 170 or 180 degree thermostat?
2. What is the part number for a delco stat , a robertshaw, or a mr gasket? For original temp spec?

Dino------


The current GM OEM thermostat part number is GM #10207381. It's also known as Delco #131-75.

I prefer a Robertshaw thermostat but these are getting harder to find. The part number is 330-180. You can get this thermostat from Summit Racing. It's more expensive than the GM, though, but I think it's worth it.

[Stuart F.]

Re: 1962 340 hp thermostat

A Mr. Gasket thermostat almost cost me my rare 63 L-76 Engine. A brand new 180 degree piece bought from Auto Zone failed (stuck closed). Lucky I have a bypass on my engine. These are, of course, made in China.

Stu Fox

[Dino L.]

Re: 1962 340 hp thermostat

Dear David and Joe...thanks so much for part numbers! I am guessing that 62's originally came with 170, then were superceded over time to 180's.....any one have a bowtie 62 that had an original Tstat?

[Duke W.]

Re: 1962 340 hp thermostat

1. Did the car originally come with a 170 or 180 degree thermostat?

The answer is in the AMA specs.

Duke

[William C.]

Re: 1962 340 hp thermostat

Not according to the 1963 Parts manual, P/N 3156185-180 degree Changed to P/N 3156280 for '63 up also 180 degree...

[David L.]

Re: 1962 340 hp thermostat

Dino,

I did a bit more research and found that the "Engine - Cooling Section" on page 7 (dated 10-23-61, revised 3-1-62) of the AMA Specifications for the 1962 Corvette shows that the thermostat starts to open at 167-172 degrees. The radiator cap relief valve pressure is 13 p.s.i. +/- 1 p.s.i.

Based on this I would say that assembly line 1962 Corvettes has a 170 degree thermostat. Why didn't I look there first? Sent me a PM if you want more information about the AMA Specifications.

Dave

[Joe L.]

Re: 1962 340 hp thermostat

Dino,

I did a bit more research and found that the "Engine - Cooling Section" on page 7 (dated 10-23-61, revised 3-1-62) of the AMA Specifications for the 1962 Corvette shows that the thermostat starts to open at 167-172 degrees. The radiator cap relief valve pressure is 13 p.s.i. +/- 1 p.s.i.

Based on this I would say that assembly line 1962 Corvettes has a 170 degree thermostat. Why didn't I look there first? Sent me a PM if you want more information about the AMA Specifications.

Dave

Dave------


There were originally TWO different thermostats cataloged by GM for 1962 Corvettes. However, no information was provided as to what determined which applied to any car. My "interpretation" is that there may have been a change during the model year or for some other reason and one found out which by removing the old thermostat. The 170 degree thermostat was GM #3138868 and the 180 degree was GM #3136185. The 180 degree 3136185 went through a series of part number changes eventually becoming the GM #10207381 available today. The 170 degree 3156270 also went through a series of part number changes eventually becoming GM #3033770. That part number "disappeared without trace" from the GM parts system many years ago.

I don't think a 170 degree thermostat has been available from GM in years. I don't know if other manufacturers still supply this rating.

If it were me, I'd install a 180 degree thermostat in a 1962 Corvette.

[Duke W.]

Re: 1962 340 hp thermostat

In the late fifties/early sixties GM transitioned to "permanent" (ethylene glycol) type antifreeze and higher cap pressures. The older alcohol based anti-freezes usually had 160 thermostats to prevent boiloff of the alcohol with the typical 7 psi caps.

It could be that they originally increased the 160s to 170s, but testing showed that 180 was okay, and, of course, they then went to 195 for emission controlled engines with basically the same setup - ethylene glycol and 15 psi caps.

A 50/50 blend of glycol and water with a 15 psi cap boils at 265F.

Duke

[Dino L.]

Re: 1962 340 hp thermostat

delcostat1.jpgRobertshaw Tstat.jpgThanks David, Joe and Duke....I have learned more about Tstats that I thought you could!.....I know people talk about Robert Shaw being High Flow....forgetting about the fail safe feature, they sure look different from a Delcostat...does anyone know the specs on flow and does it make a real difference in cooling?

[Duke W.]

Re: 1962 340 hp thermostat

I would take "high flow" with a grain of salt. The quoted temperature of a themostat is the point that it begins to open, and it usually takes another 20-30 degrees F to open fully.

If you want to do a science project, you can drop a thermostat into a pan of water with a meat thermometer, turn on the burner, then observe when it starts to open and measure the flow area every 5 - 10 degrees higher until it is full open.

Duke

[Dino L.]

Re: 1962 340 hp thermostat

Isn't it simple thermodynamics...at constant pressure, the opening or physical size of the thermostat pass through opening will either pass more or less water flow...the question is...is one thermostat bigger than the other and what impact does that have on cooling? or is it moot!

[John D.]

Re: 1962 340 hp thermostat

I have great success with installing a Stant 180 degree thermostat in all 57 to 65 FI restorations. Never had a complaint about the part. Made IN USA. I buy them from NAPA, etc.
None of the auto stores sell a 170 thermostat.
Gaskets: The best gasket to use is the GM gasket as it has a sealant on both sides. The contour of it is very nice. Problem with the gasket though is it is black.
Car Quest sells a really nice thermostat gasket as far as color and configuration goes. But no sealant. Lap the bottom of the water outlets on a grantite surface plate with course paper.
You didn't ask David. But why doesn't someone make a correct repro top water outlet stud. I see judges are looking for this and dinging a ton of car owners. As they should be. Sorry to rob your post. John

[Dino L.]

Re: 1962 340 hp thermostat

Studs are being dinged because they are plated and should be raw steel? or is their a dimple in the top? what is it?