Metal sleeves in coolant expansion tanks

Post by **FireFox31** » 12 Sep 2023, 00:08

Is the top nipple on a coolant expansion tank supposed to have a thin metal sleeve inside it? I removed my original tank from June 1999 which has the sleeve and installed a junkyard tank from June 2006 which does not have it. The tank I bought from FCP in 2021 also didn't have the sleeve.

On the bottom nipple, is it ok if that internal metal sleeve has some rust and corrosion? That sleeve on my 2006 tank has corrosion buy the 1999 does not. Do you think I could swap the sleeves without destroying the nipples?

Thanks. I'm glad to have that badly cracked 1999 tank removed but I hope this 2006 one will be reliable.

Post by **MoVolvos** » 12 Sep 2023, 00:45

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Don't attempt, the sleeve is designed in fear of potential clamp over-tightening. Meant for pressure rather than strengthening the entire nipple. Having the metal piece will causes all the force/movement/pivot to be where the tank and nipple meet. Volvo probably figured out it was not a good nor necessary feature besides extra material and extra labor cost in manufacturing.

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Post by **abscate** » 12 Sep 2023, 01:08

I wouldn’t try to move it. You are missing your reminder label to “disconnect the level sensor “ to save you $50 when you forget...

V50M66 · Post by **V50M66** » 12 Sep 2023, 10:46

Just buy a new expansion tank. They are cheap, and it's not worth the headaches of cooling system issues to save $30. Everything I have over 15 years old gets a new expansion tank (and all the other plastic bits) no matter what.

Post by **FireFox31** » 12 Sep 2023, 12:30

Thanks, I'll ignore the sleeve. Perhaps this question was silly.

Speaking of level sensor, how does that thing work? In Geronimo, the level sensor wiring has pulled out of the shaft which resides in the tank. Yet, it doesn't leak. How can the wiring sense the level when it doesn't come in contact with the fluid?

Yes, I have a replacement level sensor to replace this broken one. Would have installed it when the coolant was drained but I didn't think to bring it.

Post by **abscate** » 12 Sep 2023, 14:52

The level sensor is a magnetic reed switch, triggered by the magnetic float in the bottle.

Sometimes you can stick the wires back into the hole and it will work, otherwise, it’s another FCP return for user error.

FCP pre checks thst box for me on the RMA sheet

Post by **FireFox31** » 12 Sep 2023, 17:13

Interesting, thanks. This failure was a previous owner problem and yet another dash light I'd like to extinguish.