www.jec.org.uk

I have ordered a new set of hoses for the beast, but am now wondering about the type of antifreeze to use. I have in mind that the more modern antifreeze is bad for older vehicles as it attacks the lead in the radiator. What is your recommendation?

I swapped from blue to orange "organic" antifreeze three years ago. No problems to report; I'd be amazed if anthing significantly attacked lead, it's pretty inert.

If you do consider changing, and actually even if you don't, you need to flush an XJS cooling system at least 4 times to get the old stuff out. And remember to clear out the atmospheric catch tank, or you'll contaminate the new coolant.

At the risk of causing apoplexy, I'll recommend adding Barrs Leaks if you change to organic. As it has a 5 year life, you don't want leaks or air entering the system. When adding Barrs, follow the instructions, and immediately take the car for a drive to distribute it at the the correct dilution throughout the engine; if you pour it in and then leave the car standing, I suspect the stuff all collects at the bottom of the radiator, potentially clogging it.

When adding Barrs, follow the instructions, and immediately take the car for a drive to distribute it at the the correct dilution throughout the engine; if you pour it in and then leave the car standing, I suspect the stuff all collects at the bottom of the radiator, potentially clogging it.

Sound advice there. Personally, I don't Barrs for that very reason (risk of clogging) but if you are going to use it, then do as Paul says.

Cheers, Rich

If you do go down the route of the OAT coolant, be absolutely sure that you have got rid of every trace of old stuff from every part of the system including the heater matrix etc. It will make an awful congealed mess otherwise and could destroy your engine.

I also thought there was something about certain engine blocks etc not being suitable for certain types of the modern fluid? There has been discussion here. One thread is:

http://www.jec.org.uk/forums/viewtopic.php?f=119&t=4039

It may be that it's a good thing to do on a completely empty and rebuilt system. However, I think you'll find that most restorers and service organisations stick to the old stuff on the basis that many owners are not doing huge mileage and the cars will be well maintained and coolant periodically changed. Perhaps a call to David Marks would be a good idea.

Also see here for discussion on Barrs Leaks fluid:

http://www.jec.org.uk/forums/viewtopic.php?f=49&t=2146

Good luck

Paul

I always ran on good ol Blucol, seemed to suit the car.

I'd be wary of Barrs Leaks, yes it's effective if your running a banger, but if your cooling system is being restored you shouldn't need it?
And it can clog up those essential little pathways......

TonyS

I always ran on good ol Blucol, seemed to suit the car.

I'd be wary of Barrs Leaks, yes it's effective if your running a banger, but if your cooling system is being restored you shouldn't need it?
And it can clog up those essential little pathways......

TonyS

though Jaguar actually sell and recommend Bars leak stop in the V12, in fact they say in the manual that two bottles should be added to a fresh system fill


BB

I think that I will stick with the old blue stuff. I am happy to change the ant-freeze every couple of years. Thanks for your advice.

Some related help please. I'm running my XJS (AJ16) on the yellow Jaguar coolant but have run our. Is there a substitute I could use which won't mess things up. It would be my intent to flush at some point (about 4 years overdue ) and re-fill with yellow.

Many thanks
Nick

Some related help please. I'm running my XJS (AJ16) on the yellow Jaguar coolant but have run our. Is there a substitute I could use which won't mess things up. It would be my intent to flush at some point (about 4 years overdue ) and re-fill with yellow.

I was going to write an response, but came across the following link which is much better:
https://www.hemmings.com/stories/2014/0 ... antifreeze