Hi,

As some of you may be aware I am working to resolve some rough idle and high fuel consumption issues on my XJR6. As part of this I have replaced the thermostat and lost some coolant, which looks pretty dirty.

I am going to flush the old coolant out and replace.

Do any of you have any recommendations of what to use?

I am in the UK so brands maybe different. I know a lot has been written on forums about coolant, however from what I can see:

There was a change in 1997 to use Jaguar branded DOW D542 coolant, which is expensive, but I can source. Earlier vehicles in the VIN range 720001-803241, could use this too.

Some people say use G-O5 coolant which is a H.O.A.T. coolant and is a similar spec?

Others are saying to only use a silicate based coolant and replace every two years, which wouldn't be a problem.

This is a bit of a minefield, I don't want to use anything that will damage the engine longterm.

Thanks,
Nick

 

I suppose a lot depends on what colour the coolant was that came out. Green and orange do NOT mix. If you are unsure then it probably means a complete empty and flush until you get clear water flowing out then replace with your own preference, I ran 50% water/Glycol in my AJ6 and am using the same in my AJ26 S/c as that is what the repair shop used when they replaced the tensioners prior to my purchasing the car.

 

Nick, the original was BLUE, WHICH WAS NO GOOD.
Jag found out they were eating away at the heater core.
They went to orange after that, not green.
Red was a gm that was only good for their cars.
Orange or green are good but don't mix.....either or.
Did we do the gtjoey tune up yet?
GTJOEY

 

My mechanic is very specific that I use this stuff

Total - Glacelf Auto Supra, very long life antifreeze/coolant organic
Comes in a 5 L

It’s orange

 

Hi All,

I drained the coolant today and flushed it three or so times with de-ionised water. Each time there were lots of what my daughter called bronze glitter in the water (rust I presume). After three flushes it had decreased substantially and I had run out of water! So in went the coolant. I used the Jaguar D542 coolant which replaced the green coolant that apparently was damaging the heater matrix.

Let's see what happens...

Nick

 

Well... the coolant cools the car and all seems good, so i'll stick with the Jag D542 coolant from here on.

 

Sounds good to me .

FWIW, I ran my XJR/6 for 171k miles using old fashioned, off-the-shelf, green "Prestone". Nothing bad ever happened. Well, not with the cooling system, at least!

Cheers
DD