Original thermostat?

[Douglas C.]

Pulling my intake, 69 L-68, to clean it up, and in taking the water neck off I find a 180 degree thermostat, marked DELCOSTAT CF on the top ring, below shows 180 marking and on the side tab HRD.

Car ran very cool for a BB and I wonder if it is the original thermostat, car has 72k miles.

Should I just put it back in?

[Joe L.]

Re: Original thermostat?

Pulling my intake, 69 L-68, to clean it up, and in taking the water neck off I find a 180 degree thermostat, marked DELCOSTAT CF on the top ring, below shows 180 marking and on the side tab HRD.

Car ran very cool for a BB and I wonder if it is the original thermostat, car has 72k miles.

Should I just put it back in?

Douglas-----


All 1968-69 Corvettes were originally equipped with 195 degree thermostats. This was connected to the fact that all 1968-69 Corvettes were equipped with AIR. However, many folks choose to replace with a 180 degree and I expect that's exactly what happened in your case. Basically, there is not a lot of advantage offered by 180 degree thermostats since thermostats only control the lower temperature the engine will operate at and Corvette cooling systems, especially for big blocks, have a difficult time maintaining a 195 degree temperature. Nevertheless, I use and recommend a 180 degree thermostat for most Corvette applications.

[Douglas C.]

Re: Original thermostat?

Douglas-----


All 1968-69 Corvettes were originally equipped with 195 degree thermostats. This was connected to the fact that all 1968-69 Corvettes were equipped with AIR. However, many folks choose to replace with a 180 degree and I expect that's exactly what happened in your case. Basically, there is not a lot of advantage offered by 180 degree thermostats since thermostats only control the lower temperature the engine will operate at and Corvette cooling systems, especially for big blocks, have a difficult time maintaining a 195 degree temperature. Nevertheless, I use and recommend a 180 degree thermostat for most Corvette applications.

Thanks Joe. Yes, 180 did seem kind of low for a factory setting, but even though it probably is quite old as it seems to work well I guess I'll just put it back in.

Doug

[Joe L.]

Re: Original thermostat?

Thanks Joe. Yes, 180 did seem kind of low for a factory setting, but even though it probably is quite old as it seems to work well I guess I'll just put it back in.

Doug

Doug-----


Many Corvettes were originally equipped with 180 degree thermostats. It's just those equipped with AIR that got the 195 degree.

Also, thermostats are a maintenance item. If yours is old you might do well to replace it.

[Joe R.]

Re: Original thermostat?

Douglas,

I agree with Joe, go ahead & replace it. By the way, you may want to get the Robert Shaw Flowkooler 330-180. It will not stick closed.

Joe

[David L.]

Re: Original thermostat?

Enclosed is a pair of photos of my NOS 3156298 195-degree thermostat that is in my 1970 Camaro SS350 parts collection. The top is stamped "CF" and "DELCOSTAT" and the bottom is stamped "195" and "HRD".

According to my 1966, 1967, 1968, 1969, 1970, and 1971 Chev. Parts Catalogs it is listed for the following models:
66-69 ALL A.I.R. (8 cyl.)
66-69 ALL (6 cyl.)
66-69 Corvette w/A.I.R. (8 cyl.)
70-71 ALL (exc. S.H.P.)

Note: "ALL" includes Chevrolet, Chevelle, Camaro, and Nova models but does not include the Corvette.

GM # 3156298 was discontinued in May 1972 and replaced with GM # 3015490 as per Chevrolet Parts History. I assume in factory equipment on the models listed above.

I had several NOS 3156280 thermostats (for 70 Z28's and other models) a few years ago that were similar in appearance but were stamped "CF" and "DELCOSTAT" on the top and "180" and "HRD" on the bottom packed in the same Delco Harrison boxes. GM # 3156280 was discontinued sometime between Jan. 1976 and Dec. 1981 as per GM Parts History.

Dave

[Douglas C.]

Re: Original thermostat?

Douglas,

I agree with Joe, go ahead & replace it. By the way, you may want to get the Robert Shaw Flowkooler 330-180. It will not stick closed.

Joe

O/k Joe, I'll do the Robert Shaw. The Delcostat I have will look cool in my parts collection.

Thanks,

Doug