expansion tank

[abw280]

Is the plastic expansion tank supposed to have a hole drilled in the neck.....mine has just below the pressure cap.

Net result is that water (and it's bloody hot!) squirts out of the hole when the car is really hot, just missed me today!

I would have thought that the pressure cap should let off the steam not a hole?

[mild2wild]

There should be a plastic pipe connected there which vents under the car, to allow any excess pressure to escape. You may be over filling the expansion tank, mine has a full mark about two inches from the bottom.

[danny hoffman]

If it looks like a drilled hole, maybe the moulded spout for the overflow pipe has snapped off?

Danny

[montegogt]

My expansion tank has an overflow into a windscreen washer bottle fitted below it. It also syphons expelled coolant back as the engine cools. Is this an owners mod?

Lee

[wedg1e]

If it is an owner's mod., maybe my car had the same owner, since there's a washer bottle plumbed into my expansion tank too...

Ian

[bobfrance]

My 1990 400SE has the same extra tank fitted to it.

Who was this guy who owned all our TVRs?

And why did he insist on fitting extra bottles to the expansion tanks?

[edward1]

My 350 also has the extra bottle, as I understood the header tank should be filled to the top and allowed to expand into the extra bottle thought the expansion pipe and will as has previously been stated suck it back in as it cools. I may be wrong though

[350zwelgje]

I have a "second" expansion tank als well. My 350i is a bog standard one (bought from first owner), so I assume the second reservoir came standard. At least nothing to worry about.

[danny hoffman]

My '85 350i doesn't have one

Danny

[montegogt]

Sounds like the extra container syndrome is spreading! Oh, you may be interested to know that, if the thermostatic fan switch dies, and you haven't got a manual over ride one, the boiling coolant over taxes the poor little overflow bottle, causing the plug bit to be ejected, with the tube in situ, this then flails around like a demented banshee (whatever that is) and liberally sprays the nearside part of the engine bay with a nice soothing blue coloured liquid...
Guess what I wired in this week? Oh, and don't ask what happens if you short out a test wire...

Lee