I know the manual states DOW-D542 coolant for these early cars, which I believe is yellow, and replaced the green coolant installed from the factory (D985?). My cars coolant is green, but I have no idea what it actually is so I intend to fully flush the cooling system by doing several changes (to water) and then adding the appropriate volume of coolant.

Is there anything within the early engines which will suffer from using normal red OAT coolant? This is recommended from 1999 onwards for the 4.0l supercharged engine.

I understand Jaguars recommendation in-period would be to avoid people mixing coolant types and causing warranty claims, hence recommending what was installed at the factory, however I'm keen to understand if there were copper or brass parts in the early engines which were phased out with the coolant change and might cause me headaches. It would be great if I could keep the fleet to a single coolant type.

Thanks

 

Dexcool and all its clones don’t attack brass or copper it’s another old myth, they’re a little more aggressive against solder which isn’t used anywhere on these cars.

I’d upgrade to the recent VW and Volvo coolant (G64/G65) and if you can’t find it go with G40. I was able to get the new Volvo green colored one from the local dealer for a good price.

 

Just like oil I think it is more about flushing the coolant on schedule more than anything. I don't buy lifetime coolant anymore than I buy 10-15K oil changes or sealed for life transmissions. Fluids will become contaminated and break down.

 

I flushed out my dexcool and went with good ol prestone green. 06 STR

 

There were changes in the early cars .... my 98 VDP was switched out by the dealer. The X300 was blue. They finally all came with the Ford orange in late 2000 (I think) It's easy to get -- my last came from Amazon (Ford Gallon) The OE Jaguar container was 5L -- so it had enough to do a complete switch.