I've notice when I drive on the highway with high altitudes - that I get a fault code - " High Temp Engine fault " this gas been going on for two years - I replaced the thermostatic & the reserver which had a leak - the code will go away but it will come back only when I drive in high altitudes / strange cause I checked the engine & it's ok the fans are working fine - when this happens I usually pull over - open up the reserver - turn are on & put hear on blast for 5min this was told to me by a jag tech to push air pockets out - what do u guys think? I hope some one can shine some light on this problem -

•I use peak 50/50 anti freeze green liquid
•All original hoes / no leaks or burns
•the thermostatic is from auto zone duralast
•04 xtype 3.0

 

Juan, if I had to take a guess, your thermostat is running a few degrees warmer than it should so when you are at the lower altitudes, there is more pressure on the water and therefore makes it harder for the water to boil, therefore allowing the engine to be properly cooled. But, as you go up in altitude, the pressure drops and it is just enough to cause the coolant system to start boiling which is leading to the over heat condition. I would say to try replacing the thermostat and seeing what you have at that point. Granted, it could also be the water pump with too much gap, leading to too much turbulence and the low pressure on the backside of the impeller can be leading to the water flashing to steam and causing cavitation (leading to a loss of flow).

 

Also, you say you're using green antifreeze. Oem antifreeze was orange. These two different types of antifreeze have been known to interact creating a thick sludge that can cause blockages in the smaller coolant passages.

If when the change from orange to green was made, the system was not thoroughly flushed, you could have local narrowing of the arteries!

 

Sounds great - you guys know your jags -
• I'm going to change the thermostatic to a oem the one I have is durlast universal

• is I change back to orange what's the best steps & best type of liquid - the reason I'm using green cause the last owner had it already in car

 

Juan, if you are changing colors of coolant, it is best to do a really good flush and get as much as you can out. They say that they are for the most part compatible. But, some of us have seen some strange things in the overflow bottle when you mix the two.

 

Ok will take note of it

What would u suggest ? Not sure if this is a serious issue that must be delt with now or pay for it later -