Coolant level alarm

[dandywarhol]

http://www2.partstrain.com/store/?D=coo ... 5610&Nty=1

So that one is connected directly to the cap overflow and isn't pressurised - you wouldn't be wanting that on the Bongo though . The majority of systems I've come across incorporate the tank as part of the pressurised system.

[haydn callow]

Thats what I was saying earlier in this topic......You need a pressurized tank....2 inlet/outlets...etc.etc
I thought the "simple" expansion tanks were quite common

[haydn callow]

All modern (since about 1950s) are pressurized Haydn - I don't see the relevance to the float type

I would be concerned about getting a good seal with a 16mm hole in the side of a pressurized tank (no worries in the simple overflow tanks) and also getting the float located via the inside of a Bongo tank with all those baffels. Still...If Grahame has managed it and it's been o.k. for so long it is obviously food for thought.
It would be interesting to know exactly how it was done....ie...was the tank removed to fit the float ? was a bleed required ?? etc

[Grahame at work]

This is what I did:-


The bits


The hole


The modified part of the bracket


Assembled

I have to admit that I may not have 100% seal as I have lost about 300ml over the year - including the trip to Poland. And before you ask Alan - no I have not had it pressure tested yet - I intend to next time its in the garage for something.
Although its always dry I can see a 'drip stain' down the side from the hole when I look using a mirror - but as I say its been fine for some 9k miles.

regards Grahame

[missfixit70]

The issue I would have is possible weakening of the pressure vessel with a hole that large, I wonder if the pressure cap would relieve the pressure before anything gives way on the float switch/hole/seal?
I guess it's not too much of an issue if it's survived 9k though.
Illustrates nicely the staining into the plastic on the cut area.

[bongalo]

Had a look at that switch looks just the ticket did you just drill the tank on the low level line and pull it through from the inside

[dandywarhol]

Good looking job - I'd be amazed if the sensor popped out with a bar of pressure - look at the thickness of the tank wall, and it's screwed in!

Some cars have a radiator fan sensor switch in the side of the radiator and its kept in purely by a tapered rubber seal which grips the sensor and is about 17mm diameter. Same pressure of system to the Bongo.

[bigdaddycain]

Illustrates nicely the staining into the plastic on the cut area.

I thought the same thing... Isn't it freaky?

[haydn callow]

Looks good....couple of questions....I assume it is positioned at the back of the tank because of the size of the device and the position of the baffels within the tank.....Would it be possible to position it a little higher in the tank between the web of the mounting bracket ??...(the thinking being the higher it is the more warning you will get should coolant be lost and less chance of air getting in via the top outlet spigot)....also ...how is the device held in ?? You cannot access the inside of that area...there are "3" plastic nuts and a rubber sealing washer. ... unless you tapped the hole I cannot work out how it is held in.....you couldn't pass a nut through the hole.
All in all it is a very neat installation...

[bigdaddycain]

I know the system is supposed to be 100% sealed,and no coolant at all should be lost, but the reality is i do have to top mine up occasionally, i'm guessing around a cupfull per every 6 months or so.

[spout]

I know the system is supposed to be 100% sealed,and no coolant at all should be lost, but the reality is i do have to top mine up occasionally, i'm guessing around a cupfull per every 6 months or so.

Global warming

[Grahame at work]

Hi everyone,

Answers to the various questions –

The level switch is fitted from the outside and when the nut is tightened it compresses the ‘T’ shaped sealing washer which deforms into a ‘U’ shape seal either side of the wall of the tank. As can be seen here: -

http://www.relayspec.com/catalogs/006720/0416/7.pdf

I have just noticed that the minimum operating temperature is -10C - may have to watch for that in this weather – but that is the actual operating switch rather than the seal – I think.


The switch certainly does alarm on low level, as I pull around the round-about outside my house every morning I get 2 – 3 beeps as the cold coolant surges to the nearside of the tank (despite the baffles). It will do this if the coolant is up to temperature and I do a very hard right turn or emergency stop. When the level drops slightly (<5mm) then I get more than 3 beeps in the morning as I go round the round-about.

I check the level regularly and this drops over time – the 300ml I quoted is slowly over the 12 / 18 month period.

The position was chosen as the ONLY place I could fit any of the options I was looking at. The height was chosen to ensure that it would always revert to ‘open’ position (no alarm) when the level is just below the ‘MAX’ mark on the tank. As the data sheet states there is a fair hysteresis in the change from open to close to open.
In fact there is not much chance to move the level switch either up or down without affecting the operation.

Regards Grahame

[haydn callow]

I think I understand now how the seal works...cannot get your "link" to work. We did try somthing along those lines in our early days without much success (they had some sort of captive nut inside which compressed the seal as you tightened it up) I have one lieing around somwhere. Not quite the same as yours though.
I will fit one the same as yours to a spare tank and pressure test it. If you are interested in the results I will pm them to you.

[teenmal]

I think I understand now how the seal works...cannot get your "link" to work. We did try somthing along those lines in our early days without much success (they had some sort of captive nut inside which compressed the seal as you tightened it up) I have one lieing around somwhere. Not quite the same as yours though.
I will fit one the same as yours to a spare tank and pressure test it. If you are interested in the results I will pm them to
you.

Hyden,try this https://www.relayspec.com/catalogs/006720/0416/7.pdf

[haydn callow]

That worked...thanks....all is now clear.