Both true. Water ALSO make it more efficient at heat-transfer - the primary task, after all.

Then too, there are minor 'clotting' concerns with certain type of contamination, plus now and then seals or hoses that don't like concentrated glycols...

All that said, the give-ups are - for ME anyway - rather minor compared to NOT circulating a fairly efficient electrolyte insofar as the 50% water share.

Wasn't an original approach on my part BTW. Dad picked it up from aero-engine gurus whilst working as NACA, Langley, in the early thirties.

We've applied it to tractor, gen-sets, trucks and cars ever since. Never had a single problem beyond the rare hose softening earlier than it might otherwise have done, ordinarily strain and re-use the coolant when changing hoses and such, so it can actually end up cheaper than the 50-50 mix if one runs long enough.

Still - not 'recommending' - just onpassing our own experience.

Do your own due diligence, of course.

ESPECIALLY if still under warranty. Most wars are best won by not starting them.

 

The problem continues and I believe it is my fault. I installed the new thermostat (bought at Advanced auto) and was unable to get enough of the coolant in after flushing and flushing until the water ran clear. The car ran great, all the lights went out for and then I drove it. About 15 minutes into the drive it started to rise in temp.

2002 super 8

 

I need to be a little more descriptive. I drained and flushed the cooling system as much as possible with the Tstat housing open and the plastic screwcock at the bottom of the radiator until the fluid ran clear. I also installed a new Tstat. The Tstat was a $12 part at Advanced auto that met the specs for the super 8. The orange fluid was Jaguar spec and called for 12.6 litres. I put 6 litres of distilled water in first and then was only able to get in about 3 litres of orange coolant before it filled up. I started the car and everything ran well but after I drove it with a full AC in the florida heat it started to get hot after about 15 minutes. I left it alone and the next day I checked the coolant level and I was able to put about 1/3 liter of coolant in the tank. It reacted the same way, so I drained fluid out of the radiator and put in just coolant. It went longer before it started to tick up in temp. Turning off the ac, turning on the heater drops the temp back down but I let it sit overnight and add a little more coolant. Any ideas here? Could it be the Tstat or is it the mixture?

2002 Super 8 103000

 

It could be the Thermostat - did you fit it with the ' giggle pin' at the top to allow air to bleed?



The most likely scenario is you still have air in the system which would explain why you couldn't get the full capacity on the refill.

This might sound like lunacy in Florida but put the heater on MAX hot to circulate coolant through the full system including the heater matrix. Sitting in the vehicle during this torture is optional!

Graham

 

as it has not been mentioned explicitly in post#23, you have to *bleed* the cooling system ... not just fill it ... and the SC version requires that both the engine and SC cooling circuits be bled. bleeding with the ignition in the run position with the the engine off is helpful as the intercooler and auxillary heat pumps are activated and draw the coolant level down.

 

What do you guys mean with "bleeding"?

 

The cooling 'circuit' has a point or points that can trap air. If not gotten out, a/the trapped pocket(s) of air impede coolant circulation, leading to hot-spots.

Among the worst of examples, ever, were early BMW inline slant-sixes. Coupled with a poor head casting design and technique to begin with, quite the industry arose in replacement heads - many of 'em welded-up. Some rather badly.

 

What is the proper way to bleed these cooling systems? I am hearing to let the car run for a bit with the heater on high and another says to turn the key on but leave the engine off which allows the fluid to run through. At what point do I open it back up and add fluid?




2002 Super 8 (supercharged Vanden Plas)

 

Haven't personally 'been there' yet, so don't know if it is in the manual.

BMW had a bleed-screw on the uber-complex dual-thermostat housing.

BTW - learned long ago that whenever replacing a thermostat, if it did not ALREADY have a tiny hole in the disc, (as some do...) ..to drill one.

Has near-as-dammit zero effect on the fluid or actuating point, but can help save yerazz as far as trapped air, if/as/when.

 

My experience is that the X-308, both SC and NA are filled perfectly fine by more of a burp. There is old Jag-u-wah lore of some need to bleed, burp evacuate or some other voodoo. That just ain't true on the X-308 NA. It ain't a BMW, it ain't a slant 6, and it ain't a Jag V-12. It has bypass hoses and does not need any such BS.

The JTIS manual is very clear

<quote>
Refill the cooling system with a 50% solution of water and Jaguar Antifreeze / Corrosion Inhibitor ESD-M97B49-A.

Fill the cooling system at the header tank until the level stabilises at the top of the breather neck.Allow at least 2 minutes for air to purge from the system.

Top up the header tank as required and fit the pressure cap.

Switch on the ignition, switch off the climate control system and start the engine.Run the engine at between 1500 and 2000 rpm until the cooling fans operate.

Switch on the A/C system, set to maximum heat, and check that heat is coming from the heater at the fascia vents or the footwell outlets.

Switch off the engine and allow it to cool down.When cool, remove the pressure cap and top up the system as necessary at the header tank.

If necessary, fit new seals to the pressure cap.Remove both O-rings from the pressure cap.

Fit and fully seat new O-rings to the pressure cap.Fit the pressure cap.Remove the paintwork protection sheets and close the engine cover.
<endquote>

If it is a SC, you should probably fill through the tank with a intercooler hose loose until it has some coolant running out, BEFORE you run the engine so as to not run the intercooler pump dry.

If you don't believe the service manual, then I suggest sacrificing a virgin at midnight under a full moon and pouring her blood into the engine to be sure there are no bubbles.

 

'Her'?

Sexist....



Otherwise .. sounds straightforward.

I'd add checking it each of the first day or three after the do.

Trapped air (non) issue aside, now and then a hose-clamp gets overlooked and one simply loses coolant too slowly to notice carpark footprints.

 

bleed, burp ... whatever you want to call it, and however you want to do it ... get the air bubbles out of the system. the Jaguar V8 cooling system is just particularly obstinate.

the technique described by Motorcarman is the one I prefer.

 

plums:
Do you refer to this from bob?
"When ever I top up an XJ8 cooling system I always fill it to the top, place my palm over the top of the reservoir and squeeze one of the radiator hoses to displace some coolant into the catchment tank in case it is low. If some spills on the floor then I know it is FULL."
If bob recommends any other steps, I would sure try and follow his way.

 

That's the one. Works a treat too. He is also into massaging the hoses. I find the right side (upper) hose the most effective in combination with having the pumps running. If you get a rythmic sloshing action going you can get the level to drop an inch or more from when you start. Top up, slosh some more until you can't get it to drop.

 

I can't get this car to drive more than 15 minutes without rising in temp. It can sit in the garage running forever without rising. I start to drive and can't go 10-15 minutes without it getting hot. I've run the heater ad nauseum and filled it to the neck as much as possible. It's not getting any better. Could it be the thermostat is in wrong? What else should I try? This is absurd. When I turn on the heater the temp drops and it drops quickly when I stop and turn it off but not driveable. I've been playing with this for 2 weeks now.





2002 Super 8 (supercharged Vanden Plas)

 

Curtiss:
I sense frustration! And I don't blame you, but lets get to facts on YOUR CAR. How do you know it is hot? Is the guage moving up above half scale? Do both of the fans run while this is occurring? Do you have or can you borrow an infrared thermometer?

If the guage is indeed showing hot, and it really is hot, and water is blowing out, then either 1) coolant is not being circulated by the pump; 2) coolant is not being cooled in the radiator; or 3) the engine is developing too much heat.

For #1 the impeller could be broken on the water pump, or the thremostat could be in backwards (I am not sure if that can happen on the XJR).

For #2, you say the fans run, so this is not likely

For #3, serious blowby or valve timing errors can cause this, but I would expect drivability would be so bad you would never notce it running hot!

So, my advice would be to pull the water pump and have a look. If it is OK, then take the thermostat out and make sure it has no deformity caused by improper installation, test it in a pan of boiling water, then make sure it is installed right.

You ain't got an airlock, and the type of fluid is not the problem, assuming you have described what you have done correctly. My bet is the water pump impeller.

 

LOL.....yes frustrated indeed. Thank you for your help!
This car has never shown any movement on the temp dial. Now it slowly moves up and one time the red light came on before I caught it rising (first time). Yes, above half scale. For the last four years since I've owned I sometimes wondered if it was stuck there but it starts out on C and always moved up to the same place. Yes both fans start running when it starts to rise. No I do not have a thermometer but it smells hot.

I do not see any water blowing out anywhere. I am starting to believe the tstat is in wrong. Which way does it face? It could have fit either way but it seemed that the Oring fit better in one way than the other. Drivability is fine except I have to turn on the heater to high to keep the temp down.
How hard is it to pull the water pump? Seems like there is a lot of stuff in front of it on this car. We can rule out #2 because fans run strong.

2002 Super 8 103k mles

 

Add collapsing hoses to the list of potential suspects. Typically the one running to the thermostat, that's the "lower" hose.

The thermostat is fitted with the spring part towards the engine, bleeder valve or hole at 12 o'clock, and the o-ring goes around the flange of the thermostat. It does not sit separately. If you need pictures see some of the recent posts this week about thermostats in this section.

Short of a aftermarket gauge, the alternative to monitoring the temperature in motion is a OBD scanner or tool that displays coolant temperature. The stock gauge tells you almost nothing.

 

Here is the procedure for any supercharged XJ of the X308 variety. Follow it to the letter, it works well. I have just done it in the last few days. Pay special attention to the sound of the intercooler pump, if it is surging and going up and down in revs, it is purging air. Once it settles down, it will be a steady sound and you will be able to feel the water going through the intercooler hoses. Then take it for a spin and be ready to add a little bit once it cools down. You'll need a 19 mm allen key for the SC bleed port.

What part number thermostat did you get? The pointy end of the thermostat should be facing you in this picture.
[IMG][/IMG]

 

See if this makes it clear:
If it is in right, bring a pot of water to boil and drop in the thermostat. It should open wide.

Make sure the little hole in the valve plate is oriented to the top when you re-install. Removal of the water pump is fairly easy on this car, after removing the serpentine belt.