What water temps are you all running with stock eninges? I just drove my 74 with L48 on a 2 hour drive and the whole time it ran 220 no matter if it was sitting still or going down the highway. I have a new fan, new fan clutch, new fan shroud, new radiator, new temp sensor (which appears to be working correctly). Just wondering if 220 seems too high for the stock motor.

 

220 is high-very little room for a higher spike. The only thing you did not comment on were the radiator and seals. Did you flush the radiator and go with something from 100% distilled water up to a 50/50 solution of distilled water and antifreeze? I went with 70% distilled water, 30% antifreeze and one bottle of Water Wetter when I went through my system at the beginning of last summer and my BB never gets over 190*. Also, ,make sure you have all of the foam all of the radiator seals in place to force the air through the radiator. That is one of the most important items a lot of people forget to do.

You might also have an air bubble in the water system. Finally, a number of folks recommend an infra-red gun to see if the sensor is correct.

Good luck with your project.

 

Sorry, yep, flushed out the antifreeze, and refilled with a 50/50 mix of distilled water, and antifreeze. I also added a bottle of the water wetter.
I don't remember any foam pieces around the radiator. I'll hav eto check and see if they are there, would I be able to see them with the radiator installed?

 

Check the sending unit you replaced. Need to get the correct unit for the gage in the dash. A 280 degree gage needs a 280 degree sending unit.
Also take readings with a IR temp gun to verify the gage.

 

Where's the best place to take the IR readings?

 

Regarding the radiator seals- Doc Rebuild has some great diagrams on his website that you should check out. There are two 4 piece kits for your year, and both are priced at $20. The difference is whether you have AC or not. The seals go between the radiator and the radiator frame on all four sides. You should be able to see the foal wedged between the frame and radiator. It forces the air through the radiator instead of having it seek the path of least resistance around it. BIG difference in cooling. Good luck!

 

Normally most C3s run between 200 and 210 F if they have a stock thermostat.

I you are running 220 virtually ALL the time, either your thermostat is opening higher than normal (190-195 stock) or your gage/sender calibration is off.

The fact that you don't run hotter in traffic indicates you have adequate cooling capacity - it would run cooler on the road if heat rejection was the problem.

If 220 bothers you put in a new 165 or 180 thermostat (2 bolts and a gasket) and your temp should drop to about 10 degrees over the thermostat setting. If it doesn't your gage or sender is not calibrated.

 

Mine has all stock cooling componets except the thermostat, its a 160* stat and my car normally runs between the "100" and the first mark(halfway to 210 mark). It almost always runs there on the highway and at idle unless I idle for a LONG time, like 20 mins or longer, then it creeps up some.

BUT, this past weekend I was running the AC and it does run a little warmer with the AC on, at idle it averages right at the halfway mark between 100 and 210 but I got stuck in a BAD traffic jam and it hit 210* due to the ac being on. A few mins later I parked it at Home Depot when I went in to get some stuff and when I came back out, it had puked over about a 4" round puddle on the ground(no expansion tank) so it must have gotten pretty hot when I shut it off.

I think my gauge reads lower temps then its actually running. When I stuck a thermometer in my radiator cap hole with it running and at temp, the water temp was 165* yet my car's temp gauge only reads barely above 100*...Actually almost halfway betwen 100* and the first mark.. Who knows...I need a laser heat gun.

I would think a completely stock car would have a 195* stat and run around 200-205* or so. With AC it would definetly hit 210*.

 

I am not able to see any pics. I get a "SafeImage Loading" message with a red bar underneath, but an image never displays. Am I missing some viewer plug-in?

 

I agree with BlueL36, the item most overlooked is the radiator foam seals, on sides and top. you need to force all the air thru the radiator. E-Z fix if that's the problem. good luck with it.

 

I think your problem is the thermostat.
get a 180 and try it.
Also on the thermostat, on the large flatpart of it you should drill two 1/8 hole in it so some coolant leaks past it all the time so if it does freeze up and stick closed you won't completely overheat and pop the radiator.
Don't be scarred to do it, i do it and have never had ANY problems!!!!!

 

You can take readings at the thermostat housing if it is not chrome...otherwise,just take reading on hose next to it...IR guns are vey handy checking coolant temps..and verfying your temp gauge..

I usually check as engine warms up...(you can determine when Stat opens),at same time verfying your gauge readings....after a drive you can get readings,but be aware there is a "heat rise" for a few minutes after engine is shut down....

Where I live,in 100+ weather,my 502 runs at 205 in traffic...got a clutch fan/180 stat,4 row C/B.....in prolonged idling stuck in traffic,it barely reaches 210...at highway speeds it runs at 200 F in same weather....

Rich

 

I had an interesting experience a couple of weeks ago. My temps are religiously at 180* but coming back home from work I noticed that the guage spiked @220* before returning to 180*. I drove a couple of more days and noticed that it kept taking longer to return from the 220* back down to my usual temps. My first reaction was that the t-stat was sticking and so I replaced it. I got kinda worried when the new t-stat didn't help. For whatever reason, I grabbed the fan to give it a spin and noticed that the fan clutch had a lot of side-to-side slop in it. I took an uneducated guess and replaced the clutch. Problem solved.

 

Some aftermarket fan clutches today last about a year,then begin to weaken...that is why Hayden dropped their life time warranty...

 

Wheres the best place to get a new thermastat?

 

i had cooling issues also after i bought my 78, replaced many items and couldnt cool it down and found that i was missing the air dam that forces air up into the radiator. sounds obvious but thought i would mention it anyway

 

At what temp was it running?