I was trying to identify a material that would be readily available and would be a good choice for making a float booster like Spurlee's prototype. First attempt (below) not so good. But this one I think is better.

The material is called HDPE (high density polyethylene). It is the stuff used to make, for example, motor oil bottles and is easily identified by the recycling symbol "2" on the bottle. (The number is enclosed in a triangle.) The stuff floats, should not be attacked by coolant mix, and can withstand the temperatures needed.

I tested with a bottle cap and it does indeed float and hold its shape in boiling water. Easy to cut to desired shape. Did not test in antifreeze.

I hope this is of some value in the float wars.


[edit] Below ... a first attempt, looking at the material Surlyn. I left this here just as an FYI. Surlyn is no good because melting point is too low.

A possible material for use as a float booster ... SURLYN - DuPont Surlyn Sheet - Order Online

It is commonly used to make the skin of golf ***** (but probably not the driving range variety). This material should be stiff enough to hold its shape if formed into a "c" shape ala Spurlee's prototype.

 

I'm back...got behind at work.

My cooling system is solid, no leaks or bad hoses - just the very, very regular cycling of the Low Coolant message - once each cold start. I had suspected my float was at fault and since others have reported saturated floats I went down that route. But even with a booster float in place I still had the problem.

Right now I'm thinking that the expansion tank really is getting low. I'm hindered by not really knowing how the Expansion tank (the black one with the sensor and cap) and the Degas bottle (what regular people call the overflow tank, down by the front wheel) work together.

I had thought the fluid was being drawn into the system though the little tube that comes across the engine into the top of the expansion tank. Now I don't think that's how it works at all. I think fluid is being sucked down the lower tube, out the bottom of the expasion tank and can't be replaced fast enough from the Degas bottle. I presume the tube at the back of the expansion tank pulls fluid from the degas bottle.

In this engine Jaguar uses a two stage cooling setup. At a cold start initially about 1/2 of the fluid is cycled past the bores then, later (I presume after the thermostat opens) the balance of the coolant is cycled throughout the entire engine. I got this from Nigel Thorley's book. I don't know if this plays into anything at all, but it is coincident with my Low Coolant cycling.

What if it is simply that my degas bottle is empty and there is just not enough antifreeze to filll the expansion tank until the final 1/2 of the cooling system comes on line...

I'm waaaay over my head here. I need to look at the JTIS and understand how the plumbing works.

 

Time to walk away and clear your head.

 

Spurlee, You're getting off track. The problem is the float won't float and it won't hold the magnet. Nothing else is a problem. The float not floating is the only problem you have had causing the low coolant light to come on. You did a great job finding that problem. Don't get sidetracked. Thanks for a job well done.

 

+1

 

Occum's Razor!

 

Thanks, all.

My youngest daughter is getting married tomorrow so I'll take a break and attend to that sort of stuff. I'll get back on this Monday...

 

The floats I have will not sink!

 

OK Gus. Don't keep us in suspense. What are we talking about? What is it made of?
And is it a boster or replacement of the original? We know that the float Spurlee has will not float under all conditions which is why when cold it does not. He has actually see that happen and described in earlier post.

Looking forward to your response as I would like to fix mine.
Thanks Gus.

 

I am testing the two floats that I have and they will not sink, I want them to sink so I could work on the problem.

 

Frustrating isn't it Gus. When I sucked down the coolant in my tank my float seemed to float pretty well. But the magnet had also come out. In Spurlees' case he actually observed very marginal floatation as he described. I have some PVC foam at my airplane hangar that I used in construction of my bird. When I get over there and remember it I will try a piece to see how it works and stands up to coolant. Also my XJ6 has the exact same system and has worked great for 17 years. Who knows what the Brits did to us on these cars.

 

How about adding some ballast (fine wire solder?) until they're only just buoyant ?
Interesting that buoy is one of the few words Americans pronounce correctly as boo-oy while the brits say 'boy'
Do you say 'boyant' though?

 

No it floats, whut ya tink, it all based on what part of the states you live in! Moved to the south 30 years ago and still having problems. Lets go have a pint, i mean a beer. Jim

 

I just can't let this issue go....

Recall that my Low Coolant message somes on regularly and reliably for about 5 minutes at cold start then extinguishes, not to reappear until the next cold start...

Yesterday I decided to "overfill" the expansion tank just to see what happens. I filled it to the very top and took off on a 100 mile trip. Guess what - the Low Coolant light came on and stayed on for 95 of the miles. This is new and different behavior!

To see if I could change the behavior I removed most of the coolant from the expansion tank, taking it to well below 1/2 full. Yep - the condition went right back to normal - a short period of Low Coolant message and then it goes off and stays off.

Is there such a thing as having too much fluid in the expansion tank? The storage bottle has an overflow drain so you can't overload the entire system.

Looking back to post #41 I noted that the reed switch will close (and send the Low Coolant signal) when it the magnet is very low on the post - or very high. The theory is that the expansion tank accepts hot fluid from the block as it expands and passes it eventually to the storage tank in the wheel well. Getting a low coolant message when this is happening is counter intuitive to me.

But could it be that there is too much coolant entering into the expansion tank causing the float to rise really high on the lost and trigger the reed switch? Perhaps later the fluid is then sucked into the storage bottle and the float drops to it's normal level. Or maybe the route to the storage bottle is restricted and the expansion tank temporarily fills too much.

I know this whole idea is really a stretch, but it does fit my observations. The car is with my GF this week but I will try pulling out more fluid when I get it back...

 

Questions: Are you running with your float booster? Do you beleieve the float is doing its job, i.e. floating, reliably?

On float position: My experiments moving the float manually indicated that any float position at or below some critical level = low coolant warning. Any position above that level = no warning.

This is devilish.

 

Spurlee - why not (no I'm not mad) snag your float with a small fish hook and very fine nylon line which you use to hold the float up and trap with the cap.
Then the little blighter can't move and any errors you get are for another reason.

 

Going fishing in the coolant system - I love it....

Just don't eat any rainbow trout you happen to catch in there....

 

I say paint the float it will close the pores on the float and see what takes place. If that does not fix the problem then go fishing and bring the beer…

 

That is a very clever idea!

 

I am not using the booster float right now, I experienced the same problem with it as without it so I sort of abandoned that idea for the time being.

I'm going to have to try and replicate your experiment on float position. You're certainly correct and my idea about too much fluid is most likely wrong. I can try my own test when I "go fishing" in the coolant as I trap and hold the float to try that test...