4.2 engine running hot

[Harveysearle]

Hi guys
Just finishing off full restoration on my 2+2 4.2
Road testing but car seams to be running hot.
Tested head gasket has no leaks at all.
Any ideas , the engine has been rebuilt,
Pressure quite high .
Thanks

[gtjoey]

What Radiator
What thermostat
What electric fan and how soon does it come on....

[Simonpfhc]

Also, what makes you think it is running hot? You can’t rely on just the temp/sender gauge as they aren’t always accurate.

You could always remove the gauge and temp sensor and test in a pan of warming water with a thermometer.

Do you have an IR temp gun?

[politeperson]

Harvey,
Test far air in the system by by doing the heater connection at the highest point and see is you can get more coolant in. They can be susceptible to air locks.

Then, with the car running, check the circulation of hot coolant with your hand from cold. When the thermostat opens you should feel the top hose get warm then you should feel hot water circulate across the radiator and back into the engine. You will also be checking the operation of the thermostat by doing this.

If you cannot feel circulation, you may have a water pump issue. Unlikely if it is a new pump,unless the wrong one has been fitted with a small impeller.

If it is getting hot on a run you may have and old rad or lock of cooling fan issue.

On old engines you can have a silted up block issue. Unlikely in your case.

[colinevans]

I would start with the gauge/sender test and if ok check coolant circulation assuming the rad/fans are good.
Good luck, been there myself recently!

[Harveysearle]

Thanks james and guys for your help
Will try all of that.