Before I purchased, a previous owner switched the engine coolant to the green and away from the pink (dex-cool). My engine temp runs 194-197 degrees max now. What should it run at, and does the dex-cool make it run cooler? Thanks.

 

kbeachy I have the same Engine/Trans as you in my 07 XK and run dexcool. My max temp has been 197.4 degrees and typically run the same as you.

 

On my 04 XJ8 the temp averages 195. Will creep up to 198 on a hot day or stopped in traffic with dexcool in the system.

 

What is it about dex-cool, then, that makes it advisable for our Jags?

 

Improved compatibility with the materials used in modern engines, extended coolant change intervals.

 

My code reader shows 190-198 usually, with 209 max. Started monitoring the temp after electric cooling fans began running for a few minutes after the engine was switched off. The coolant reservoir tank has a small leak and I suspect that is why the electric fans are running, and maybe why the temp spiked to 209 degrees.

 

Dont forget you cannot/should not mix the two! You will get a gel formation that will block the cabin heater matrix at the very least.