TR2/3/3A Non Triumph cooling question

[RonR]

I have a car that overheats when stopped for short time periods, like at stoplights.
Radiator is full.
Electric fan works at idle

Since the car cools down once it is moving, I am assuming the water pump is working.
The temperature sendng unit is on the engine, not the radiator.

Thanks for your help.
Ron

 

[M_Pied_Lourd]

Well, with the car moving you are getting air/cooling through the rad...doesn't necessarily mean that your water pump isn't bad....

Have you done a full coolant flush lately? Could be lots of sediment in the coolant passages/rad etc.

Cheers
Tush

 

[Merlin63Tr4]

If it's a modern car, it could be the water pump's plastic impeller freewheeling on the water pump shaft.
They don't move much coolant when that happens....

M.

 

[TomMull]

Might help to know what the car is. Might also post under "Other Cars". Some cars, e.g. my BMW, have an electric fan in addition to the engine driven fan. Both need to be working properly or overheating at slow speeds will occur. On this car the engine fan is a viscous drive and those are prone to failure.
Tom

 

[CJD]

Look for bugs and leaves between the condenser and radiator.

 

[Geo Hahn]

Could also be a partially blocked radiator - can sometime be diagnosed by pointing an IR thermometer at various location on the hot radiator. This problem is more likely in a car with age & high miles.

 

[CJD]

Gotta love diagnosing an unknown car, sight unseen, with no clues!?!

 

[RonR]

it's a Honda DelSol.
it only has electric fans, one for the radiator and one for the condenser.
The condenser and radiator sit side-by-side.

A blocked up radiator is a possibility. I had a 1984 Civic where that happened.
Although a radiator cost a lot more than a water pump, it would save me a lot of time if all I had to do was replace the radiator.

The car has a air bleed screw, near the thermostate housing, for the coolant system. I think if I open this bleed screw after the engine is running, water should really shoot out if the water pump is working.

Thanks for the comments.
Ron

 

[TimK1955tr2]

I would check the radiator for cracks, I think those may have plastic top and bottom sections. I had a 1997 Civic develop a crack and it showed the same symptoms. A hairline crack would not allow the pressure to hold, reducing the cooling capacity especially once it gets hotter like at a light or stop.

I replaced with an Autozone one and it has been fine for the last year, I don't it cost more than $100?