Hi there everyone, had a question I’m unsure of with my x300.
I’ve been on a long trip (couple hundred miles), got back and parked up, next day checked levels and all fine. Next day did a 5 mile trip, got back parked up and noticed antifreeze pouring out under the car, lifted the bonnet and it’s running out from the bottom of the expansion cap.
Phoned a mechanic friend and he said firstly try a new cap as it may be faulty, he says if air getting in then the boiling point of the system is lowered plus its likely to be the cap as it was forcing out the bottom of it as opposed to the top? At no point did any warning lights come on or did I notice the temperature gauge climbing, although I can’t guarantee I would have noticed.
Now the system is low on antifreeze I need to top it up with a litre or more but unsure what antifreeze is in there, I know these cars originally had the green stuff but this car had a new radiator before I bought it, it’s got the pink stuff now, I’ve seen online that Prestone do an antifreeze they say can be mixed with any other coolant, any one recommend this stuff?
Many thanks in advance for any help!

 

Probably not what you want to hear....but here's what I'd recommend:
First, obtain a coolant pressure test kit. Check the system and the cap (old and new...or just old if you haven't yet obtained a replacement) per the instructions on the tester. This will ensure you have identified and mended the leak(s).

Next, obtain at least 12 gal distilled water. Set about flushing your cooling system with it: Run it up to operating temperature, shut down, drain the radiator at the radiator drain ****. You'll get about 2 gal out. Replace that with distilled water and repeat the process. Continue this "lather, rinse, repeat" until the coolant you are draining looks more or less like clear water. (my experience is that will occur once you've poured 10-12 gal of distilled into it, 2 at a time.) After your final drain, top up with the uncut coolant of your choosing. The distilled water that didn't drain from the system will give you your 50/50 mix (so don't use pre-mixed coolant).

I once added the Prestone mix-with-anything coolant to a 2003 S-type containing factory-installed pink coolant, back in the early days of Jaguar ownership. Took the car to Motorcarman some weeks or months later to mend some unremembered problem that vexed me and I couldn't solve, but that was likely not related to the coolant. He noticed it, scolded me sharply, flushed and replaced it with the proper spec stuff.

I should further reveal, I used to think pressure-test kits were for sissies who couldn't be bothered to crawl around on and under their vehicles, getting their hands dirty elbows deep looking for the source of a coolant leak.....til I bought one! Best and most useful tool since the flexible constant tension clamp pliers!!!

The cheaper alternative: Add distilled water to top up your system, then check it with hygrometer to make sure you have freeze protection adequate for your locale. I would not mix any coolant in until you can identify what is already there. And you don't want to go to the expense and trouble of a flush/replace if you are not certain you've mended the leak.

 

 

Forgot to mention: When you run it up to operating temp each time, make sure you have the HVAC control set to "Hi" or full hot. This will ensure the coolant is circulated through the heater matrix and associated piping, rather than leaving a trapped slug of old coolant in there.