Each of my two still have extra water aboard. Clean containers so as to be fit for human or machine.


I go far enough back to the days of the canvass bag filled with water hung off the hood emblem.


Somewhere around here, I have/had one!!!


Carl

 

Always good to see a question you were going to ask (which direction the flow doth flo'th) has been asked and debated at length long ago.

 

Start from cold. Select max heat and shoot each heater spigot with a laser temp gun at the firewall. should see a slight difference. This is what I would do. Ian

 

Heater Flow comes from an outlet on the engine head water rail and returns to the bottom of the radiator on the V12. I am sure most engines work this way, so to see where the source of the hot water is on the engine, see where the feed to the water valve comes from. The outlet side from the valve will disappear into the heater unit through the firewall.

 

Does it matter in theory. After warm up, all the water is hot.... that is all that is needed at the heater matrix...

 

Yes, Carl it matters.
If the water has gone through the radiator first, it loses so much of its heat as to be nearly Useless as a heat source on a cold night.

I can tell you how I learned that and what a mess it was to reverse the hoses - Again. But I was young and dumb at the time.
(';')

 

Bender box in back in the car. Diagram provided explains most things, hot water in from the top rail via the heater valve thingee and down to the lower core pipe and then out via top core pipe back to the lower rail tap on the side of the engine. Are there any special no-return values that should be inserted at any point in the passage of the water?


so hot flows in at bottom and out at top

lower railer and under rail with taps for the heater.

 

Nope.

Only valve, for want of a better word, is the heater tap, which is Vac controlled, ON or OFF, no partial opening at all.

NO Vac = full on.
Vac = OFF.

 

Elinor:

With my usual respect.
1. I meant at the heater spigots. In and out reversed. matrix still gets water from te hot engine, not the cooler radiator.
2.I am contemplating your explanation. Agree. Water from the "cool" side f the radiator Is cooler. But, still plenty hot. How much cooler? Now at 200? Just short of boil at ambient pressure?

Please I do not want to open a controversy !!!!

 

The heater system in my Series 1 is about as useful as a screen door in a submarine.

I'm banking on "global warming" to get me thru future winters.
Trouble is, when the next "ice age" arrives, I'm gonna be stuffed!

 

funny because the previous 2 Jaguar models, the S type and the 420, had excellent Heaters.
The XJ arrived with lame wipers and Heaters.

make sure the Heater Tap is a Normally Closed, Opens with Vacuum tap. The oem tap is useless and appears to be restrictive, use one from a 1965 Ford Galaxy. Plastic, Made in China, cheap and works better.

if no cigar, then the heater matrix or "core" might be clogged. Time to back flush it.

Last, the blower motor is lazy. Replace with a more powerful motor so that High is really High.

 

Great tips, thanks Jose.

Yes, the heater motors are geriatric. And noisy. I tried new brushes & a commutator clean, but no joy.

Hoping some spare motors I acquired from a Series 2 can be adapted to fit. I know the impellers (?) are a different size.

Regards.

 

redtriangle. finding and adapting a modern 12v fan motor can't be so difficult, or fitting the squirrel cage to the shaft. just go to a salvage yard with a bag of tools and start pulling fans out of cars and trucks, if they are accessible.

I did drive a Series 1 XJ once and I agree, the blower motor had no energy.