Thermostat housing difference between 3711268 & 3827369

[Dan B.]

Here's a question that I'd appreciate some clarification on. What is the difference between the 3711268 (55-62) cast thermostat housing vs the later 3827369 cast housing used on the 63 and up low hp cars?? Other than the numbers, they appear the same from what I can tell from the pictures. According to my GM parts book from the early 80's, apparently 3827369 was the number used for BOTH applications. So why the need for a different part number?? I also noticed that some of these housings don't have EITHER part number stamped on them, just "GM" and that's it. Thanks in advance for your replies, Dan.

[Joe L.]

Re: Thermostat housing difference between 3711268 & 3827369

Here's a question that I'd appreciate some clarification on. What is the difference between the 3711268 (55-62) cast thermostat housing vs the later 3827369 cast housing used on the 63 and up low hp cars?? Other than the numbers, they appear the same from what I can tell from the pictures. According to my GM parts book from the early 80's, apparently 3827369 was the number used for BOTH applications. So why the need for a different part number?? I also noticed that some of these housings don't have EITHER part number stamped on them, just "GM" and that's it. Thanks in advance for your replies, Dan.

Dan------

As you mention, the GM #3711268 was used for most 1955-62 Corvettes and the GM #3827369 was used for certain 1963-69 Corvettes. The GM #3711268 was discontinued from SERVICE in May, 1965 and replaced by the GM #3827369. So, any P&A catalog published after that time will only show the 3827369.

Exactly what the difference, other than embossed part number, between the two is, I have not yet been able to determine. Certainly, GM considers them functionally equivalent or they would not have replaced the 3711268 with the 3827368. My strong suspicion is that the difference is something to do with the casting and might be something that's not even be a visible difference (e.g. an internal casting difference) or a slight angularity difference that's difficult to measure.

I have seen examples of both outlets which lack an embossed part number and have only the GM trademark. In fact, later GM SERVICE pieces even lacked the GM trademark. I expect the reason for this is that the outside supplier that manufactured them for GM wanted to sell some into the aftermarket and, because by that time the sales volume of this piece was so low, they didn't want to produce some with the GM logo and some without.

[Dan B.]

Re: Thermostat housing difference between 3711268 & 3827369

Joe, thanks for that excellent detailed reply. The NOS outlet I dealer purchased back in the 70's just had the GM logo cast into it and I only recently noticed it had no part number stamped, so that explains it. I guess the lack of a part number with the GM logo only would be a judging deduction as well. In those days, this type of information was not readily available, so we relied heavily on the GM parts book to get what we thought were correct parts.

If anyone else knows of any physical differences between the 2 parts, please elaborate. Dan