Daimler V8 radiator - allowance for expansion.

[MDA]

There does not seem to be allowance for coolant expansion on my Daimler V8. Unless there is a tank that I cannot see? The top of the radiator has the filler cap but no means of seeing the coolant level in the radiator top (Unless its full). Is this the same as the mk2 or is it unique to the Daimler?

[PPV]

It is the same as the Mk2 in that there is no expansion tank. That is why you just fill to about 1" below the top of the filler point. I have added a catch tank to the overflow as sometimes when extremely hot mine does eject some water but when it cools it takes it back. Never found the reason why, thought it was the radiator cap but changing that made no difference and it has a new radiator fitted also.

[piman]

Hello all,

I'm progressing with my rebuild and one thing I am pondering about is to fit a sealed expansion tank to the cooling system.
Are there any views on the pros and cons of fitting one? It is an easy modification so if it doesn't work it's also quite easy to revert to the original set up.
However I would appreciate some input especially if your car has one?

Alec

[Dave Eynon]

I would say other than originality there isn't a downside to modifying the system to incorporate an expansion tank. It would certainly save the slightly embarrassing little wee on someone's new drive after a spirited drive with a heat soaked engine. My Daimler V8 doesn't have one and will release coolant if I have topped it up slightly too much, and it is also awkward to gauge just how full the radiator top tank is. My slightly later XJ6 S1 has an expansion tank and life is much simpler with an easy check on coolant level. A friend with a 3.4 Mk2 fitted an expansion tank as part of preparing his car for continental touring, I don't think he would ever consider removing it now.
Hope this helps.

[B87UL]

This subject has recently been discussed on another Forum, my input is repeated below as it mirrors the other Forum.

This thread is quite interesting from a terminology view as well as the actual arrangement. No one has commented but two different systems are described: -

1. A simple overflow system where the radiator is pressurised but the overflow pipe and overflow container are at ambient pressure. Used in fact, myself on my own car and for the last 55 years as a fleet engineer, worldwide, on hundreds of various cars and trucks.

2. A system that has the complete overflow system fully pressurised including the overflow pipe and tank, effectively this is a radiator header tank extension. This system was original used by manufacturers to enable packaging of lower front ends whilst maintaining header tank height and accessibility. In the case of Rover, they used the pressurised overflow, unusually without excessive height on the Rover 2000 TC to make up for loss of coolant by inserting the oil cooler in the bottom radiator tank.

Both systems will allow coolant overflow and reversal coolant flows, but the fully pressure system No 2 can be potentially dangerous, depending on the header tank location and the hose and clipping arrangement. This system also does not allow the radiator cap to be depressurised unless the system is cool.

I have system No 1 with the metal header tank under the left wing (fender) but with that expansion tank overflow pipe outlet well below suspension height, avoiding any coolant or steam egressing over the disc brake.

Although I utilise the MG overflow tank it is fitted with a flat cap whilst the radiator has a 7lbs normal pressure cap. This maintains the cooling system completely full and under bonnet access is completely standard and safe.

System No 1 will allow the radiator to be filled to the brim and the overflow tank to ¼ full, with a 7 lb cap on the radiator and blank cap on the overflow tank, the system will operate very well.

In the early 60’s I operated a number of cars running between England and Milan in Italy. The round trip was done in either 7 or 10 days, including driving over the old Gothard pass. All these cars, including the odd Jaguar MK X were converted to system No 1 and ran very successfully.

Has anyone thought about these two slightly different systems?


Norman

[piman]

hello both,

thank you for the response.

I like the system 1 idea and will probably go that route.

many thanks,

Alec