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I have a 1966 3.8S, the engine has been rebuilt and the radiator has been recored. Even on a short drive (to my daughters school and back) it is losing about half a litre of coolant, I'm wondering if I have the wrong radiator cap, it says 7lbs on it.

HAs anyone got any advice?

cheers

Hello Brent,

you didn't mention what temperature the engine is running?
There are different lengths of radiator caps, just ensure yours is suitable for the radiator, 7 lbs sounds OK.
Do you have a remote header tank or is it like the Mk 2 with none. If you overfill the radiator, it will always lose coolant until the level drops sufficiently for expansion to take place when it warms up. In other words don't fill the radiator to the top.

Alec

The temp gauge sits around 70 from memory, and no, no header tank on mine.

I'm just very paranoid as the engine rebuild was due to it cooking itself before.

I do understand that it expands, but half a litre? Can a header tank be added easily?

Hello Brent,

the Mk 2 manual gives total coolant as 11.4 litres so half a litre is not a lot. I would run it without adding any more, keeping an eye on the water tempertaure gauge, and see if it continues to lose coolant. If the gauge actually drops to a low reading it means the coolant is now below the sensor so is a good warning sign.
I'm assuming that there are no obvious leaks and that it is being lost from the radiator overflow?

I believe that it is quite easy to fit an overflow tank, using the overflow pipe from the radiator to couple it, using pressure hose and clips.which will need to have a pressure cap (of a type which can open as the engine cools and allows coolant back into the radiator) fitted and just a closure cap on the radiator. The alternative and less complicated is simply to fit a catch tank.

Alec

Yes there are no obvious leaks, the company that rebuilt the engine just bypassed the heater system as well so a bit less there to worry about in terms of leaks. More to worry about though in getting the heater working now. :/

I'm a bit worried about the accuracy of the gauges I must say, I have ordered a new wiring loom as the existing wiring is pretty bad