Just checked the coolant level in the expansion tank and it had dropped to 1/4 of the way between the bottom and top level/markers within the Cold Fill Range; and there was a teardrop weep from the bleed screw (no undercar leakage or obvious leakage anywhere else on the expansion tank).

The car was given a few good high tempo runs yesterday to test the stability of the coolant level. Temp guage remained at a steady 12 o'clock throughout and on garaging the car at about 9pm last night, a check of the expansion tank showed the level of the Cold Fill Range marker to be as described and as seen a few minutes ago; and there was no weep at all from the bleed screw when parking the car last night.

The orange fluid that sits to the top of the expansion tank shows no obvious air bubble now/ maybe just one pinhead size area of white amongst the orange fluid.

What I have noticed, on the last 2 mornings, is that when the car has been sitting completely cold overnight, the bleed screw has capacity/ needs to be closed/tightened more (I'm being careful and I'm definitely not overtightening it). However when I checked the bleed screw when the car was at operating temperature last night, the bleed screw appeared to have no play to tighten it further)?

Have just topped the expansion tank up to the top level of the Cold Fill Range with 50/50 coolant/water mix and the engine is currently running to find out if the bleed screw weeps and/ or the coolant level drops again.

However, what I've noticed is that when the engine is running in the garage to get the car to operating temperature and even when I rev the engine after it's at operating temperature, the bleed screw has not weeped. It's only after driving the car on the road, parking it and returning later that the teardrops seem to have weeped from the bleed screw

Any thoughts welcome/ thanks.

Hmm interesting....

As I said when I topped mine up the levels kept dropping for a few days. It should stabilise when all the air is out. Can't explain the weeps though.

I can't imagine enough coolant would leak out to affect the levels though through the bleed.

Try the ptfe idea to totally seal it and see if the weeps continue? There is nothing that can't be fixed with a hammer😜😜
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MD very helpfully contacted me twice yesterday to offer advice and offered to deal if I take the car in but it's a fair way for something I'd like to 'learn' how to sort myself and which might just be a couple of days worth of topping up/ minor adjustment so I said I'll monitor for a day or so and take it in if it doesn't settle.

I'm fairly satisfied with my limited technical knowledge that the answer sits around the bleed screw. I take it there should be no concerns about the PTFE tape melting around the thread/ screw hole etc (can't imagine there would be given the tape is designed to go around metal that gets very hot)?

Thanks

as you know ptfe tape is used on central heating systems and water/pipe temperatures can go up to around 80c so i reckon yours will be ok. ... - .- -.




Y. O. L. O.
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Yes, cheers Stan, have also since spoken with brother in law (plumber) who says no issues using PTFE tape on this.

There's a definite albeit minor 'shift' with this bleed screw's ability to stay at a constant fully closed position between the expansion tank being hot and it being cold (expansion/ contraction). Makes me query the design of the tank screw hole and/or the bleed screw and obviously Dan @ Duckworth's previous posts about the designs having changed is interesting. Not sure if mine is the original tank or not but it looks 'as new'.

Last edited by pld118 on 17th Oct 2013 8:46am. Edited 1 time in total

Ptfe should be fine.

It is round plastic after all, which would melt at a similar point to ptfe.... There is nothing that can't be fixed with a hammer😜😜
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Having experienced continuing weeps from the bleed screw and noting that the screw's closed position would alter dependant on whether the expansion tank was hot or cold, yesterday morning, when the engine was cold, I carefully wrapped a small amount of white plumber's PTFE tape around the thread of the plastic bleed screw. I then tightened (or closed) the screw taking care not to over tighten it so as not to damage the bleed screw head or the actual screw hole on the expansion tank.

Then left the [PTFE wrapped] screw in the closed position for a few hours whilst the engine was cold. No further weeps. Then ran the engine whilst the car was static and on the level for over an hour. No weeps. Then took the car for about an hours worth of normal, local, stop start driving. No weeps.

Parked the car overnight on the level and just checked, the coolant level remains stable, there are no weeps from the bleed screw or anywhere else and something else I noticed is that now, when pressing a finger down on the newly wrapped bleed screw, no fluid bubbles emerge from the 'seal' where the bleed screw butts up to the expansion tank hole (before wrapping the screw, when pressing a finger on the screw, bubbles did emerge).

For info, the bleed screw on ours did not have a rubber o-ring on it anyway when I first started this process. Not sure if it should have had one or not?

I've since also stumbled across this Britishparts UK advert last night for a similar looking bleed screw for £4.29 GBP (not sure if main dealers sell them based on Dan @ Duckworths previous post):
http://britishparts.co.uk/products/5633-bleed-screw-PEI000010

Although the entire situation is covered by warranty, I'm hopeful that the matter is now dealt with and that the PTFE wrap is a sound, common sense permanent fix. Hopeful...

I will have a look at mine and see if there is an o ring on it to see if yours is missing  There is nothing that can't be fixed with a hammer😜😜
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Yes. Mine has an o ring squashed at the top of the screw.

I have a couple of big boxes of rings.

If you PM me your address i will pop a couple in the post.  There is nothing that can't be fixed with a hammer😜😜
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Thanks very much. PM sent

A couple of assorted sizes are on their way. There is nothing that can't be fixed with a hammer😜😜
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Thanks again... My wee dilemma is that for 2 days now all is looking spot on, stable and the bleed screw seems air tight thanks to the PTFE... So, despite now having o-rings that I could put on the bleed screw, should I leave well alone for now so as to avoid upsetting the stability of the system and only look to put the o-rings on the bleed screw if the expansion tank starts misbehaving again?