Topic: Is 225F a good temperature to run at?
in Forum: C3 Cooling and Heating Systems
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OK. The new Dewitt rad is in place and the water pump works fine (a Stewart Hi-Flow, in aluminum too).
The engine holds the temperature pretty well whether on the highway or in the traffic.
Except that the thermometer on the dash shows 225F. It used to be 210F with the old rad before it got clogged. The thermostat was changed too (supposedly195F).
At least, I don't fear the traffic anymore (before I changed the rad, it would go to 250F in a few minutes in traffic).
I checked the temperature with a laser thermometer, just after shutting down the engine.
Thermostat, water pump, intake manifold at cylinders 1 and 2: 225F
Intake manifold to cylinder 7: 230F
Intake manifold to cylinder 8: 270F !!!!!!!!!!
Intake manifold to other cylinders: 250-255F
All these seem quite high to me. Especially on cylinder 8.
Any comment?
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I think you need to check those temps with the engine running, not shut down. Especially the radiator outlet on the manifold and the top of the radiator where the hose connects to it.
Also just curious as to why you chose a 195* thermostat instead of the preferred 180*.
|UPDATED|10/10/2015 1:06:39 PM (AZT)|/UPDATED|
Also just curious as to why you chose a 195* thermostat instead of the preferred 180*.
|UPDATED|10/10/2015 1:06:39 PM (AZT)|/UPDATED|
F4Gary said:
I think you need to check those temps with the engine running, not shut down.
Good point! I'll do that next time.
F4Gary said: Also just curious as to why you chose a 195* thermostat instead of the preferred 180*.
I started a thread on that subject a couple weeks ago and I came to the conclusion that the original spec was not such a bad choice. I just don't expected the temperature to go to 225F instead of 210F.
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Christian said:
OK. The new Dewitt rad is in place and the water pump works fine (a Stewart Hi-Flow, in aluminum too).
The engine holds the temperature pretty well whether on the highway or in the traffic.
Except that the thermometer on the dash shows 225F. It used to be 210F with the old rad before it got clogged. The thermostat was changed too (supposedly195F).
At least, I don't fear the traffic anymore (before I changed the rad, it would go to 250F in a few minutes in traffic).
I checked the temperature with a laser thermometer, just after shutting down the engine.
Thermostat, water pump, intake manifold at cylinders 1 and 2: 225F
Intake manifold to cylinder 7: 230F
Intake manifold to cylinder 8: 270F !!!!!!!!!!
Intake manifold to other cylinders: 250-255F
All these seem quite high to me. Especially on cylinder 8.
Any comment?
I'm a little confused as to why you are measuring temps like this. On the intake manifold, the rearmost cylinders do not have a coolant crossover as the front does. Temps on the manifold there will be higher than the front. Without coolant flow, the static temps after shutting the engine down will obviously go higher for short time, since there is no coolant flow.
Using a 195* thermostat will have the coolant at a higher temp before it opens, so actual coolant temps will likely be in the 205* range before the coolant even starts circulating thru the radiator to be cooled.
What does your temp gauge show while driving down the road in no traffic? If the engine was actually running 250* before it would have been puking coolant, unless you have a higher rated rad cap than normal.
Something strange happening here....
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Adams' Apple said:
I'm a little confused as to why you are measuring temps like this. On the intake manifold, the rearmost cylinders do not have a coolant crossover as the front does. Temps on the manifold there will be higher than the front. Without coolant flow, the static temps after shutting the engine down will obviously go higher for short time, since there is no coolant flow.
Using a 195* thermostat will have the coolant at a higher temp before it opens, so actual coolant temps will likely be in the 205* range before the coolant even starts circulating thru the radiator to be cooled.
What does your temp gauge show while driving down the road in no traffic? If the engine was actually running 250* before it would have been puking coolant, unless you have a higher rated rad cap than normal.
Something strange happening here....
I'm a little confused as to why you are measuring temps like this. On the intake manifold, the rearmost cylinders do not have a coolant crossover as the front does. Temps on the manifold there will be higher than the front. Without coolant flow, the static temps after shutting the engine down will obviously go higher for short time, since there is no coolant flow.
Using a 195* thermostat will have the coolant at a higher temp before it opens, so actual coolant temps will likely be in the 205* range before the coolant even starts circulating thru the radiator to be cooled.
What does your temp gauge show while driving down the road in no traffic? If the engine was actually running 250* before it would have been puking coolant, unless you have a higher rated rad cap than normal.
Something strange happening here....
Yes, you are right. I should have let the engine run while measuring the temperature, which I did since. I still find 225 in the front but "only" 250 in the rear. No I don't have a higher rated cap and the engine is not puking coolant.
The gauge reads a steady 225 whether in the traffic or on the highway. Overall, it works fine. I just wonder why 225F and not 210F. I am not sure a 180F thermostat will help much. It will just start cooling sooner, which doesn't mean it will prevent the system to reach it's working temperature which appears to be 225F. The only thing I changed is the rad (Dewitt Direct Fit).
Before it got clogged, the original rad (re-cored) was providing a good 210F.
I sealed the opening between the rad and the shroud (between 1" and 2" on the upper long edge of the radiator). Side seals were in place already. Temperature at the radiator & thermostat
- Before sealing: 225F.
- After sealing: 215-ish. Gauge says the same.
At least, I am making progress. Next step, I'll change thermostat for a 195F Hi-Flow (said to let 50% more coolant through). Same setting point but more flow rate to better match the performance of the radiator and of the Hi-Flow water pump.
Sounds logical, no?
Sounds logical, no?
The correct operating temperature is 210. I don't like to run hotter than that but I don't want to run too cool either.
I don't use the car for very long drives, so I don't want the car to take ages to warm up. A 180 stat would simply extend the warm up time.
I use a summit racing thermostat, it has shunts installed in it to never let it completely close, I hade my oem brass
radiator rebuilt and it seems to work very well with this thermostat. I also use a high flow water pump.
A big block corvette is probably no place for a 195 thermostat. Did they even have 195's in the early seventies??
in Forum: C3 Cooling and Heating Systems
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