Radiator 1962 3.8L

[richard btype]

I have just completed a comprehensive servicing of the cooling system as the car ran pretty hot even in the winter (my only experience of the car as purchased last November).

When I removed the 'thermostat manifold' the 'slot' to the side of the thermostat was almost completely closed with calcium. Once removed I then had the damaged alloy ground away and re welded/machine skimmed.

The head was removed and further alloy around the galleries was treated in the same way (as above) after being acid dipped, the head was skimmed.

All water hoses/clips were replaced, the radiator flushed and refitted. A new expansion tank, temperature sensor, thermostat, otter switch fitted along with a new Copycat motor and multi bladed fan.

So it has been a bit of a surprise to find the gauge reading as high as 100 even with the cooling fan running, but the engine did not appear to be boiling...

My questions are:
1) Could this be the temp gauge i.e. are they known to give imprecise readings?
2) Should I change the water pump? it is not leaking but have no way of testing its performance.
3) Should the radiator be replaced or overhauled as it looks like the original?

Richard

[PeterCrespin]

The bypass slit being full of deposits would not hurt cooling - quite the reverse if it largely blocked off the bypass route to rapid warm-up.

The radiator is the prime suspect and it is inconceivable that it will be clean inside if it's original, unless it was reconditioned pretty recently. If you did all the other work and not the radiator, then that is your next job regardless of what the gauge says.

However, yes, the gauge may not be accurate. They are not laboratory instruments, they give a rough guide and what you look for is changes, not absolute values. That's why they stopped putting actual numbers on the scale eventually. Check (or have checked) the true running temp with an infrared thermometer on the inlet pipe of the rad (not the rubber hose), or stick a normal thermometer in the expansion tank while warming up from cold and compare it to the gauge.

Pete

[richard btype]

Peter

Many thanks for your suggestions - I have just spoken to a local radiator repair shop and they will test for 'cold spots' and take it from there but can fit a new core to the existing rad if it comes to that.

I will complete this phase before proceeding with temp gauge and will post the outcome...

Richard

[38E]

I doubt they understand the construction of a 3.8 E-Type radiator since it's practically impossible to just 'fit a new core' to those aluminum crossflow rads. Passable reproductions are however available.

It is however surprising that a 50-year-old aluminum rad is still free from corrosion leaks though. If the cooling system is not boiling over and continuing to puke ( ie., past the normal expansion space requirement) I'd say it's not actually overheating.

[richard btype]

Clive

My car does not have the original fluted (side) rad fitted - probably just outside that production period. However a further investigation last evening before removing the radiator allowed me to discover a couple of brain disengaged errors on my part - there is an oft used term in the golfing world along the lines of "most of the problem tends to lay in the 6inches between the two ears" Is it not maddening to spend ages trying to sort a fault only to find it occoured during a lapse of concentration!!!!

Firstly I had not secured the earth wire to the chassis bolt (by the brake switch) secondly the copy cat fan I fitted was wired for negative earth and my car is positive earth so these two errors combined were causing erratic running of the fan (due to earth wire touching now and again) and secondly the new fan was spinning the wrong way achieving diddly squat of cooling air where needed.

Have since rectified and from first test the fan is controlling the temperature spiral, however need to check further this evening as the otter switch does not seem to be causing the fan to cut in.

I did also check back over the previous owners notes and only a few months before I purchased the car he recorded a rad flush - more checks to be done....

Richard

[andrewh]

Talking about radiators. Can anyone tell me which radiator I should have on my October 62 car. 860897? Should it be the fluted type?

[richard btype]

Andrew

I cannot know for sure (as I tried to find this out recently with my car March 1962 build - 860403) but it would seem it was not the fluted type except on the very earliest cars.

One can find both types are available - perhaps the answer will be found by the style of the existing (if you feel sure it is the original one).

Richard

[andrewh]

Thanks. I cannot say whether the existing radiator is original or not but it is not the fluted style. I will go with the conventional type although not sure about alloy or steel. Cheers.