Just curious what is considered a normal coolant temp for a big block C3? 200degF maybe? What is considered too hot? 225degF? 250degF?

Thanks,
Steve

Mine runs pretty solid at 190. Just remember that there is no guarantee that either your gauge or your sender unit is accurate. Use an infra-red heat gun to check the engine and hoses to get a more accurate reading.

Mine runs at 190 when driving, even in hot weather. I was just in the parade in Hershey and mine never went over 210 even for that period of time. The other 2 71 big blocks that were with me in the parade were almost at 250 at the end of the parade, so I guess they can run at different temps. I also agree with Glenn that the gauges in the C3's are probably not the most accurate things in the world.

Tom,
I really wonder whether you consistently run so much cooler since you have your headlamp shields out. As the parade showed -- you were 40 degrees cooler than Dave & I -- even when we had the heater on (frying our legs off!)
~ Joe

PS -- THANKS AGAIN for the posters!

Hi

A good supplementary electric fan helps the big block to stay below the 210 F mark.
I don't think that 235 is too hot as the late C3 secondary fans only came on in that range.
Before I removed the useless engine fixed fan and installed the dual electric fan setup, my 68 big block hit the 250 F mark during stop and go drivings .
Think about it, at very low RPM, 800 or son how much air is this engine fixed fan pulling.
A electric fan always brings the same high flow.

Get it done and you can forget steering at that gauge.
Gunther

I am a Professional cooling system mechanic. I agree with WESCH. Your car as a rule before electric fan were installed should run at thermostat temp, or at least close to 195-200. NEVER run straight water in cooling system as the boiling point is only 213 deg. 50/50 coolant raises it to 260deg. I would never let my car run above 230 degrees. If it climbs to 260 look behind you, your motor may be laying in the road after it takes a dump............

Well? I was on earlier in October seeking similar information; seems that I have changed my therostat to lower 170 degree to get circulation going - but like many still have problems and fixed fan in 77 stock engine. Not sure, but it seems there's a lower "dam" missing it sits on the valance - does tis make sense? this might be part of my cooling problem? AND the hoses I replaced with new thermo and radiator, too. but new hoses don't have coil inside hose. Can't remember does hose with reinforcement (coil) go to lower or upper? Best turn it over to the pros... anyone?

I did two things........first is to install a 160 degree thernostat. Secondly I added an engine oil cooler ; oil absorbs 40% of the engines cooling load , thus the coolant had an easier job. Also my 68 came with triangular metal stone shields behind the front wheels, which I removed allowing more hot air to escape the engine room. I think GM took these panels off in later years anyway. Mine is an L-71 (solid lifter-11:1 compression) & usually run 165-185 degrees.
Hope this helps........Dan 68

Need to re-iterate that the thermostat does nothing in controlling how high your engine temp goes. All it controls is how quickly the minimum operating temp is attained (which is the temp setting of the thermostat).

So if your operating temp is consistently too high there is something not functioning correctly in the cooling system. Collaped hoses, dieing water pump, clogged/corroded radiator core, missing radiator/frame 'weather stripping' - the list is rather long. But putting in a lower temp thermostat alone will not solve your high temp problems long term.

I agree with Big Jim. Do not lower stat temp. from what factory requires. Your only asking for problems. The idea of a stat is to allow coolant to remain in radiator long enough to transfer heat. Lower temp stat may cause coolant to circulate constantly and not stay in rad long enough to pull heat out. Result , temp. will keep on climing. The front end design of a Vette and many other cars with no grill as per say DEPEND on the air dam to be in place to force air up through the rad. If missing it will cause overheat at higher speeds. other than that you also have fan clutch. Very important its working correctly. make sure you have a clean internal cooling system, espically rad. And the coil is in the lower rad hose to keep waterpump from sucking hose shut. I am a pro, any more questions, Terry