My 2001 XJR, 100k miles, is having coolant issues. I did two stupid things to my Jag:
a) put radiator leak fix in reservoir tank
b) added nondistilled water and Prestone antifreeze into system that already had some Jaguar coolant in it
I noticed I had no heat about two months ago but living in St. Petersburg, Florida it was not really an issue. About 2 weeks ago, I was getting a "Low Coolant" warning after adding antifreeze a few times I noticed my upper radiator hose?, near the thermostat, was soft and when I pushed on it with a screwdriver it split. I replaced that and everything seemed okay (still no heat) until yesterday. It appears my heater hose, on the passenger side by the firewall simply blew apart at the T. I believe this is part of the Octopus hose. This hose is difficult to get to though I have read some previous posts on how to get to it. My question is, can I flush my heater and just reattach it or do I have to buy the entire Octopus section? I would then thoughly flush the entire system and change the thermostat. Please don't yell at me dumb for things I did. Hopefully, others might learn from my mistakes.
Thanks,
Jan

 

Klasik,

Did you ever determine what was over-pressurizing your Supercharged V8?

 

Not sure if you will get much reply on a 5 year old thread.

However, first things to check if any coolant problems (and especially if the weather heats up):

- coolant lines on the expansion tank are mounted in a crossed configuration (which is correct but looks illogical),

- Thermostat working; take it out and check in boiling water, or replace it altogether, they are not expensive, and are very well known to get stuck on our cars,

- Check if the expansion tank cap holds pressure.

 

Yes, old post. I ran across it searching for a heater hose part number for my 2006 SV8 and it got me to thinking because I developed blow-by at the pressure cap and after I replaced it there was a serious leak at the forward heater pipe connection(s?) and I wondered if I might have an over pressure condition too.

The thermostat was replaced (tested first) along with the mechanical water pump and repairs were made to the electric auxiliary coolant pomp (new brushes) and the electric supercharger coolant pump (computer was not grounding the relay coil to activate it) to get them running 3600 miles ago and it was trouble free until the blow-by and the heater pipe connector leak. It made me wonder if I had just transferred the problem with the new pressure cap or if it was just coincidence.

Anyhow, the car now has a brand new upper radiator hose with a new heater pipe connector, and so far I found no leaks in a brief warm up to 199F. Test drive to follow today and I am hoping for the best but still have a nagging thought about high pressure. May be time to invest in a coolant sniffer to test for combustion gas just in case.

Oh..and I have a soft spot for Daimlers so the original post caught my eye.

 

Check the coolant overflow pipes to be sure they are connected correctly. See #23

 

This is the same way they were routed at the expansion tank when I bought the car. Look OK? Or did you mean some of the lower hoses?

 

Maybe you are in the wrong forum, Phil. Doesn't look like a X308 . . . . ?

 

No, sorry, it is a 2006 SV8. I was interested in the V8 over-pressure thread in case I have a similar problem on my V8 and was checking to see if the original poster ever determined the cause.