I wish to attach a coolant storage container(bottle) to recirculate the overflowing coolant. Has any done it or are there suggestions as to how it can be done.

 

As I understand it, it gets pretty hot in parts of India. The Mark V has the traditional radiator with a cap at the top, and space has to be left for coolant expansion. If you're getting coolant coming out, either you've overfilled the radiator, or, the car is overheating, and the radiator is in need of attention.


Jaguar exported these cars to hot countries like yours, and they seemed to be OK, but of course that was then and radiators do lose efficiency by silting-up. Is the radiator the original ? If you want to put in an expansion tank, you'll need to seal the radiator cap at the top and tap in a pip to run to the expansion tank. However, if you have an overheating problem, an expansion tank won't solve the problem.


Other thing if coolant is being forced out is a possible head gasket failure. This can be checked using an instrument that detects combustion gas products in the coolant

 

Thanks Fraser for your very useful reply. No the radiator is not original, also the engine has been rebuilt. I have put an extra cooling fan in front of the radiator. I am using 4 lit of coolant and 8 lit of distilled water. It is after the engine is switched off that the coolant is thrown out. Please suggest the reason for the same. We have flushed the engine block and radiator twice. The water pump has been rebuilt and is properly working. Yes the temperatures in Ahmedabad during summer is on an average around 41 degrees centigrade.

 

Hi Vijay
At 41C = 105F, a Mark V is going to struggle coolant wise. I had a look on the SNG Barratt web site and couldn't see anything to indicate the system is pressurised, so it will be atmospheric pressure only.


SNG Barratt - The Ultimate Jaguar Parts Specialist


What would seem to be happening to your car is that when you switch off, the heat build-up in the engine is such as to cause the coolant to boil, because the cooling via the radiator and fan has been suddenly removed, so the temperature rises and boiling occurs. A big nuisance ! Mitigation is possible, by letting the engine idle slowly until the residual heat has been reduced and the engine can then be switched off.


With a correctly-specified pressurised system the pressure cap prevents this boiling.

So what can be done ? As you suggest, fitting an expansion tank with a pressure cap on it and sealing off the radiator cap is an option. This would then allow pressure build up after switch-off to occur without boiling.


I pulled out my copy of Paul Skilleter's book on the Jaguar saloons to see whether there was anything on overheating in the chapter devoted to the Mark V. There is a hint of difficulty on Page 153 where Paul inserts the experience of a UK owner, who said that cooling and braking were rather marginal, stating that the car wouldboil-over quite readily in traffic or when climbing hills. No damage was apparently caused !


Paul then makes the comment that the system was non-pressurised, and a number of owners apparently sealed off the radiator cap, and inserted a 5lb pressure valve in the overflow pipe.
So what you are proposing to do was clearly needed all those years ago, and if it were me, I would be proceeding to install a suitable modification. I would think the main problem is finding a suitably sized expansion tank.


Here is one as fitted to the XJ Series 1 and 2, and early Series 3 saloons


SNG Barratt - The Ultimate Jaguar Parts Specialist


It is steel and would obviously look better in a Mark V engine compartment compared to the modern plastic type.

 

Radiator Overflow Can - JEGS High Performance


Jegs sells many options that look cool. I think what looks clean is the narrow diameter ones that you can get however long your space will allow.