Mild Overheating

[1967coronet]

It is good to get that thermo temp gun and check against your cars gauge.
You will then know at what point on the gauge is what temp.
All the things posted are good to check over. It is also possible you have another small problem. After the pump and thermostat swap that sounds like needed done. You may have a air pocket in the engine that has not bled out. Open your radiator cap to the 1st notch ,open your cabin heater control to hot, car parked with the front end up a little , start it and let it idle for awhile after the thermostat opens. Keep a eye on the temp gauge.
After you shut it down and it cools off some recheck you coolant level.
Also a good time to replace the radiator cap with a new 15 to 16 lb one. Something that simple can raise the temp.

 

[Eggo]

ran it with the rad cap off to make sure there’s no air in there and then the gauge was reading here after about 15 mins of idling with the fans on. higher than it normally would be as normally it’s bang on the C line. not 100% sure where i should be pointing the infrared thermostat and also couldn’t get it to show F even though was pressing the button, but would this maybe indicate that the gauge is wrong?

 

[Bird 426]

I would say that normal operating temp is where your needle in the picture is. Personally, I would never use electric cooling fans and all that goes with them on my old cars, but that just me.

 

[Eggo]

I would say that normal operating temp is where your needle in the picture is. Personally, I would never use electric cooling fans and all that goes with them on my old cars, but that just me.

will take it for a proper test drive tomorrow and see if it creeps up further when i accelerate. have bought a 180 thermostat instead for it so will swap that over when it turns up if the issue is still there. the electric fans are mega effective usually, like previously when the temps have increased a bit and i’ve put them on it’s brought the temps back down really quickly

 

[steve340]

With some load on the engine the cooling system will have to work a bit harder and the temp gauge may creep up a little.
At idle the engine is not making much power and if your fans move enough air a problem will not necessarily show up.
I still vote radiator partial block.

 

[Don Frelier]

Idling in the driveway particularly with the hood open is not a good test. (Idling for long periods is kind of a bad thing to do)
You need to drive the vehicle normally.
With the IR gun it's good to check the inlet(top) and outlet (bottom) where the hose connections come out of the radiator.
The difference between the 2 numbers is the key.

 

[Eggo]

With some load on the engine the cooling system will have to work a bit harder and the temp gauge may creep up a little.
At idle the engine is not making much power and if your fans move enough air a problem will not necessarily show up.
I still vote radiator partial block.

will try take that in somewhere to be checked out before swapping thermostat around

 

[Eggo]

not sure if this is a dumb question, have googled it and can’t find anything to say i can’t/shouldnt, but i have a rad in my C10 with the hoses in the same place that’s a similar size to the one in my satty. if it is the radiator that is the issue could i fit this temporarily until i can get the one in sorted?

 

[1967coronet]

If the hose locations are the same the short answer is yes, but..... could that radiator be 1/2 plugged up also?
You have transmission cooler lines to route. Mounting holes will be mis matched. Double ck the height of the c 10 radiator.
Just thought of this..... Is it possible the electric fan is slowing down ?
Were your running the temp shown on the gauge is not bad if the gauge is working.
That's pretty close to 160/170 were it's pointing.
The new temp gun. Most want you to be 10 or 12 inchs back. Shoot the thermostat housing itself. Also shoot the water pump near the hose.
What the thermostat housing reads is going to be close to actual engine temp, that is the outbound coolant.

 

[steve340]

Probably better to just fix the one in the car. Why introduce another potential issue.
The other one may be in a worse state and cause engine damage.

 

[Eggo]

so thought before pulling the rad out the chev and trying that (brand new rad only ran a handful of times), will swap the thermostat that i bought from rockauto. bought a 180 thermostat and new housing. probably my mistake for not checking properly but have found that the 160 i bought from a place in the UK is actually a 195 and the 180 i’ve bought from rockauto is a 160. Have put the one from rock auto on and it seems absolutely fine now so thinking the original one was maybe stuck and the 195 was way too high. thank you everyone for all your advice, have definitely learnt my lesson to double check the parts bought before fitting them

 

[Don Frelier]

160 is actually too low.
They were designed to run at 180 -190 Deg. F
You get more wear running too cold.

 

[RJRENTON]

I would say that normal operating temp is where your needle in the picture is. Personally, I would never use electric cooling fans and all that goes with them on my old cars, but that just me.

If there are no numbers on the temp gauge how is the comparison made? How is the thermal comparison made?
BOB RENTON

 

[1967coronet]

If there are no numbers on the temp gauge how is the comparison made? How is the thermal comparison made?
BOB RENTON

Well Bob
the way I checked my 67 was I let it idle in the drive until the temp gauge needle got to the 1st line past cold.
I then took a reading off the thermostat housing with my temp gun.
Mine read 167 degrees at that 1st line. The needle in the center, my car is at 185.
I've seen the needle between the center of the gauge and the 1st hot side line.
That was in very hot weather in a creeping line of cars at Good Guys. I did not have a chance to get a gun reading at that time, best I can figure the engine was near 200 degrees. It has never boiled or lost coolant. That is how I made my comparison .
My wag only.

 

[Ron H]

Lots of good advice, some of the simpler things to check I was going to mention, have been. Another is the condition of the lower radiator hose, they can get weak from old-age and collapse when hot. Form-fitted hoses are best for this connection. When I had some overheating problems after engine rebuild with some added performance, did a bunch of things to lower the temp. Using a temp gun found my dash gauge was pretty accurate. In my case the gauge was reading nearer to ‘H’. Added a 7-blade fan, found an OEM shroud and a top-seal for the rad (factory options on my car it didn’t have). Also reduced the coolant mix from 50/50 to around 30/70 as a higher ratio of coolant can retain heat. Added wetter. (Don’t drive my ride in winter and it sits in a heated garage.) Another thing I stumbled across when researching engine heat gremlins, was the oil viscosity, I was running a higher vis racing oil that I didn’t need, noticing high press on the oil pressure gauge I had added. I’ve since run 10/30 racing oil. Got the desired results.