As I get older, my obsession with fluid replacement remains unabated. I tend to change all the fluids in my cars usually much in excess of the manufacturers recommended intervals. I work on the basis that fluids are cheap, whereas components such as engines or gearboxes are expensive.

So, after an engine oil and filter change a few months ago (1500 miles since the last one), over the past few days I've flushed the brake fluid in the Teves system on my AJ16, and today I did the coolant and the autobox fluid.

It's a bit of a pain pulling the bottom "octopus" hose on an AJ16 XJS, so I decided to try a different way.

I started by syphoning as much coolant as possible via the remote header tank. As that enables coolant to drain back from the top hose and the top part of the right hand radiator tank, I was able to extract 3.3 litres this way.





I then removed the top hose and, with a bit of wiggling managed to get a syphon tube down the right hand radiator tank to the bottom. I then slowly syphoned a further 5.5 litres as coolant migrated its way across to the right hand tank.











With a total of 8.8 litres removed, I checked the Jaguar figures. It states that a drain and refill involves 9.9 litres. So I decided that 88% of the Jaguar drain figure was a pretty good result without detaching the bottom hose! And as I change the coolant every 2 years anyway, it's in very good condition anyway. I can't remember exactly how much I drained when I last disconnected the bottom hose as it gets quite messy when the hose comes off!

I then slowly filled the system via the remote header tank. I left the top hose disconnected at this point to aid flow and avoid air locks. You'll need to reconnect the top hose just after 5 litres as the right hand radiator tank will start to overflow just after that. With the top hose reconnected, I continued to fill through the remote header tank until I'd put a total of 8.8 litres back.

All in all, I think it's a better, cleaner way to do it, especially with the frequency that I do it.

Paul​​​​​​​

 

Hi Paul

Great idea! I'll have to do the same

Though no update from me tonight as I have discovered an expensive little problem that needs sorting out

Alex

 

Grant gave me a similar tip Paul. I undo the (equivalent of as I have a different cooling setup) banjo bolt on the RHS top of the rad, and then insert a thin tube that goes right down to the bottom of the tank. Then syphon out the coolant which takes about 8 hours as the tube has to be so narrow to get through the banjo hole.
On OEM V12 rads there is a stopcock at the bottom of the tank, but sadly not on my ally one. This tip has saved me loads of mess too.

 

Greg,

I'm able to do similar on my Range Rover where there's a blanking plug in the top right corner of the rad. As you say, a very thin tube cab be inserted down that tank and a slow syphon achieved.

Wouldn't it be easier if we all had nice simple block taps on the engine to drain the coolant?!

Cheers

Paul

 

Good idea! & I share your passion for frequent and thorough fluid changes in old cars - there is something satisfying about it.

Disconnecting that lower coolant hose is a truly awful job. The only advantage I can see from it is that the sudden thunderous loss of coolant I guess might dislodge/carry with it more pieces of rust/crud if you have any sitting in the system.

I have a cheap 12v electric vacuum pump I used on the transmission fluid but IIRC it says to use it only with oily substances, not water (presumably for lubrication reasons) - was yours the same/does it still work fine?

 

Hi guys.
I have one of these vacuum extractor pump things and it’s brilliant for removing liquids. I went in to the radiator on my car through the banjo and managed to remove most of the old coolant from there. If you have a clean system and just want to change the coolant definitely worth the £ss to have in the garage.

https://www.ebay.co.uk/itm/123531232...mis&media=COPY

Rob.