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Old 3rd June 2019, 09:20   #41
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Quote:
Originally Posted by T-Cut View Post
It's the flat washer that 'seals' the tank. The o-rings serve a different purpose.
What is the different purpose TC?

I always thought the flat washer seals the neck of the expansion tank and the O-rings ensure the '140' pressure cartridge comes into play.

https://www.the75andztclub.co.uk/for...d.php?t=245285
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Old 3rd June 2019, 14:20   #42
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Quote:
Originally Posted by Blink View Post
What is the different purpose TC?
Have a read through this and see if you have any further insight. The mechanics of the cap/tank are all accurate, but I suspect my interpretation needs a little more refining. Any new perspective is welcome.

Click (Revised link to version without PhotoBucket images ransom): https://the75andztclub.co.uk/forum/s....php?p=2529527


If you have any comments, maybe best add them to the associated thread rather than complicate things further here.

TC

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Old 3rd June 2019, 15:19   #43
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Of course the O-rings seal. That is what they are there for.
They force the liquid/gas to go through the cap, so that the valve inside the cap will work.
The flat rubber on the top seals against the outside, so a seal both ends, and the parts inside the cap can do their stuff.

As for the O-rings being damaged by one solid close, nonsense.
Damage will take place, but that is a long term process owing to abrasion and plastic deformation.
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Old 3rd June 2019, 15:52   #44
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Of course the O-rings seal. That is what they are there for.
They force the liquid/gas to go through the cap, so that the valve inside the cap will work.

..... As for the O-rings being damaged by one solid close, nonsense..
Yes, that's what I meant in post 41.

The O-rings on a brand new cap were flat after one solid close, and they've stayed flat - so it's not nonsense.

As TC suggests, I won't complicate this thread by posting more here.
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Old 3rd June 2019, 16:24   #45
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Quote:
Originally Posted by Blink View Post
Yes, that's what I meant in post 41.

The O-rings on a brand new cap were flat after one solid close, and they've stayed flat - so it's not nonsense.

As TC suggests, I won't complicate this thread by posting more here.
They might have been a bit out of shape, but they would still seal. That is the defining point. If it was a cheap Chinese product, then maybe. That could have been made out of pasta, for what it is worth.
I always close mine rather solidly, and my caps last me, I guess, 5 to 6 years, if not longer!
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Old 6th June 2019, 14:39   #46
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Hi Simon,

New cap seals arrived today and fitted.

Ran up engine.

Air con switched off.

Temperature rose to 110 with no response from the fan, it stayed off.

No sign of any water loss from the cap.

I switched on the demist which called the fan on and temp returned to 96 and stayed there.

Any thoughts?

Phil
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Old 6th June 2019, 14:51   #47
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Ran up engine.
Temperature rose to 110 with no response from the fan, it stayed off.
Any thoughts?
Hmmm.
Was the car stationary with the engine just idling when the temperature rose to 110 degrees? How long did it take?

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Old 6th June 2019, 15:22   #48
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Yes it was stationary.

I fired it up, let it idle to 80 degrees.

Gently revved at around 2000 until it reached 95, then left it and watched the temperature rise on idle.
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Old 6th June 2019, 15:24   #49
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The whole thing took around 15 to 20 minutes.
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Old 6th June 2019, 16:29   #50
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Phil, check THIS out, hope it helps.
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