Clarification on engine temperature 1967 327/350
 

An initial comment: over the past few weeks I read quite a number of the posts on engine temperature and initially thought I would add my question to one of the many threads. But most of those posts/threads seek advice on what to fix or replace next, and I didn't find a thread that tried to address the basic issue I tried to lay out below. So I am posting this question as a new thread. I hope this falls within the posting guidelines for this forum:

I recently purchased my '67 coupe, and it consistently runs 200 - 210 F in moderate climate, 70 - 80 F outside temperature. Whether I run the car hard or just cruise, it hasn't yet exceeded 210 F. I verified the temperature with an IR gun at several locations. The thermostat housing, for example, reads around 215 F on the gun when the temperature gauge reads around 210 F.

There were a few things that I addressed - replaced the lower radiator hose to one with internal spring reinforcement, replaced the thermostat with a high-flow 165 F unit, and flushed the cooling system - but after addressing those items, the temp still runs exactly the same, 200 - 210 F.

While my motor-head friends say 210 F is too hot for '60s era 327 engines, and most of the innumerable temperature-related posts on this forum seem to agree 210 F is too hot specifically for C2 327s, the Owners Manual for the 1967 Corvette says the engine temperature gauge will, in fact, read 210 F under normal conditions.

Before I take more invasive steps with the radiator, water pump, and maybe electric fan swap, I want to make sure I understand whether there is, in fact, an issue.

So the basic question is: why is a running temperature of 210 F thought to be too hot by most folks, while the Owners Manual says that is precisely the temperature at which the engine will run?

(As additional information on this car, the engine was reportedly rebuild 10,000 - 15,000 miles back, so should have addressed valve seats and bearings. But the prior owner had no paper to support the rebuild.)

Thanks in advance for any insight...

You're working on a problem that doesn't exist. GM put 210 in the middle of the gauge range for a reason in 66/67 Corvettes. When I get to my computer, I'll post a technical bulletin from GM on how they "fixed" the 65 overtemp complaint of 210 degrees.

My ‘67 327/350 runs 210 all day long.

Your car is fine. Drive on.

Steve

Check your timming and vacuum advance and if they are in spec your fine

:iagree: Car temps are best at 180* for the same reason that engine oil has to be change at 3000 miles.

Welcome to the CF. Please check your spec information about the thermostat. I believe it should be a 180*. :cheers: Dennis

are you missing any of the seals around the radiator?
have you checked whether your fan clutch is properly engaging?

Thank you all for your replies, especially 65GGvert for the Chevy TSB, very insightful. Timing, fan clutch, radiator seals, etc are good to go.

I appreciate you all taking the time to respond and saving me a lot of time and headache.

One small item that is often overlooked is the surge tank cap. Should be a 15# cap. Be sure it's sealing correctly so that your cooling system can function correctly.

I thought small blocks got a 13# cap and big blocks got a 15#

Small blocks with factory AC got 15# caps. Not sure about BB caps.

'64-'65 SB w/A/C and all '66-'67 SB got the AC Delco R26 15# cap. '63 all and '64-'65 w/o A/C got the 13#

when my original radiator in the 66 started leaking I went cheap and replaced it with a brass one. My temps ran at least 20 degrees hotter than the original aluminum rad. Then I spent the money and replaced it with a Dewitts original style unit and the temps came back down where they originally ran. I know some guys say brass is better but in my case the aluminum was the way to go.

A Dewitt's radiator will hurt your feelings and your wallet - but only once...:thumbs:

It’s your fan clutch. My original 1965 on my L76 gave up on a road trip. I did not change it out until I got home, and the replacements (tried 3) all had my car idling 20* warmer.

So so instead of the 180-190 it ran at all the time, it’s now 200-210.