Coolant alarm magnet has become detached

That’s interesting, I fitted a VW tank half a dozen years ago & have never seen it referred to on a forum before. I doubt the stock alarm will work with the VW tank as it uses current flowing through the coolant whilst the stock circuit is a magnet & reed switch.
I built my own initially which was fine & would still be using it if an Australian box of tricks hadn’t appeared for the price of a packet of fags on eBay.
When I had the tf the magnet parted company from the float, I used a dental mirror to locate the hole & a pair cranked forceps to feed it back in.

my TF is also 2005 and I agree that the coolant alarm system and indicator became standard in late 2004. I agree also that the tank was assembled with the float inside .I have had the sensor part go faulty but that is a part which push fits to the bottom of the tank. I think that a complete tank with float is you're only option

Mike

I think about June 2004 was when Longbridge began fitting the TF with the wiring looms to to support a low coolant alarm together with modified instrument display which replaced the automatic gearbox warning light, which most TF's didn't require with a low coolant warning indicator. Curiously the early examples which had the wiring fitted, did not carry the sensor in the expansion tank! Presumably they were using up stocks of the old tanks before fitting the new design with the magnet sensor.
I put a new tank onto a mates TF which had this, and it worked great after fitting. I think anything made from September 2004 onwards had the sensor fitted in the tank.
My latest TF is a Jan 2005 model and it has the sensor fitted. My previous TF160 was a Jan 2004 build and had neither the wiring or the sensor. I fitted a contactless sensor on the outside of the tank and wired it to the unused gearbox fault lamp.
When I got rid of the 160 - or whats left of it after crashing on ice last winter, I removed the sensor from the expansion tank, its going spare if anyone wants a contactless level sensor that clips onto the outside of the expansion tank.

Sundance

Got round to reinstalling this today ( nothing to do with the fact that I lost it having placed it on my desk - turned up last week stuck to a treasury tag!).

The hole in the float is open at the top, so I made a tool with a length of small bore copper pipe, the bore of which is slightly smaller than the magnet. Bored it about 5mm deep so the magnet was a loose fit. Put the magnet in the end and sucked on the orher end of the pipe to hold it in, then positioned it over the hole in the float and pushed it in with the pipe.

If I push the float down and turn the ignition on and start the car the dash warning light stays lit, but if I start the car and push the float down the warning light doesn't illuminate. Is there a time delay on the warning light or some other sequence involved?

The coolant alarm should have a delay, so as not to give false alarms when the float moves suddenly over bumps, hard cornering, heavy braking, vigorous acceleration etc.

This seems a good time to recommend one of my low coolant alarms which works via an external sensor mounted on the outside of the expansion tank. I reckon they are more reliable than the original float technology. I'm sure most will have seen them for sale on ebay where they are a total bargain at just £33. Even better, contact me by private message here and I can offer a significant discount.

Admin, if this blatant promotion is not allowed, please delete this and slap me on the wrist

I have just fitted one of Bruce's low coolant alarms. Very simple and effective. The sensor is glued on to the existing expansion bottle, 10 mins for wiring. You certainly wont miss the sound of the alarm when the fluid gets low.

I've had one of Bruce's alarms for around the last 3 years, works very well.