Coolant - reminder needed.

[Cuppa]

During the process of replacing a coolant hose on the car yesterday I of course lost some coolant. I topped it up, ensuring that radiator, & the 'pressurised overflow bottle were full as well as ensuring the non pressurised section of the bottle was up to the max line. I then brought the car up to temp by leaving it idling for a while. Left it overnight & the levels were the same this morning. Just did a 10km round trip into Lockhart (no more leak - yay!) & on return the pressurised side of the bottle is down (as in pic). I'm having a senior moment, unsure whether to top up the bottle or leave as is. Can someone advise please.

85863

[BrazilianY60]

I would just complete it and never loose my sleep over it.

[Cremulator]

I don't know the official procedure here either, but I would be concerned about over filling it and as the liquid heats up and expands, it could potentially blow a hose. [emoji2369]

[Cremulator]

Out of curiosity Cuppa, when you brought it up to temp, did you check the levels when it was hot?

[Cremulator]

For reference, this is my coolant level cold. Just fully replaced after a service a couple of weeks ago. (And a new overflow bottle as the factory one was getting chalky and brittle).http://www.nissanpatrol.com.au/forums/images/imported/2022/08/86.jpg

[Cuppa]

Thanks Cremulator , your pic was helpful. How much were new bottles, mine have seen better days too, especially the overflow one which has turned white at the top.
I asked because I was concerned like you about overfilling & blowing a hose , but thinking about it the worst that could happen would be the overflow bottle filling & overflowing.

As it is I think I'm just observing the coolant system 'settling down', purging air from the system resulting in the 'pressure bottle' level dropping. Have now topped it up to look like yours (without the nice clean & new appearance of course).

[pollenface]

A quick search on google reveals $120, probably worth doing. Mine was replaced at 170,000kms (went brittle & leaky)
https://www.allfourx4.com.au/epages/shop.sf/?Locale=en_AU&ObjectPath=/Shops/allfourx4/Products/DET0045&ViewAction=ViewProductViaPortal&CATARGETID=720017010000134731&CADevice=c&gclid=CjwKCAjwgaeYBhBAEiwAvMgp2qdqC0QOhMFURDEloY8p xu4PMyINCFew7RlkSYxUxW1rgHYricd1URoC_OsQAvD_BwE


My non pressured overflow bottle is always empty. I fill it and a week later it's empty again. I don't worry too much about it.

[Cremulator]

Thanks Cremulator , your pic was helpful. How much were new bottles, mine have seen better days too, especially the overflow one which has turned white at the top.
I asked because I was concerned like you about overfilling & blowing a hose , but thinking about it the worst that could happen would be the overflow bottle filling & overflowing.

As it is I think I'm just observing the coolant system 'settling down', purging air from the system resulting in the 'pressure bottle' level dropping. Have now topped it up to look like yours (without the nice clean & new appearance of course).Mine are top and bottom genuine Nissan replacements, as the mechanic recommend better to get genuine for these components. They were around $300 for the two tanks and hose that runs between them from memory.

[Cuppa]

Well I have ended up buying new tanks, but went for the cheaper Dayco tanks which are advertised of being OEM quality. $115 on ebay. Dayco DET0045
https://www.ebay.com.au/itm/194103908435

For what it's worth I found the following through Google. I am sharing it as I have gained the impression, not just from this thread but past conversations also that the twin expansion & overflow(recovery) tanks are not well understood. They certainly weren't by me. https://www.mishimoto.com/engineering/2019/05/tech-coolant-tanks/ Both work similarly but do slightly different jobs - one sealed under pressure, the other at atmospheric pressure

In short Expansion tank = less fluid loss over time, higher temps possible & better for the environment. The overflow tank becomes an 'emergency catch can' in very high pressure situations. At least as I understand what I read.