Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: tcs on 26 February 2011, 18:05:21

Title: Erroneous "Coolant Level" Display
Post by: tcs on 26 February 2011, 18:05:21
Hi,

I have just staretd getting an erroneous "coolant level" display on my V reg 2.0 Omega estate (X20XEV engine).

Wiring across the sensor plug removes the alarm. Wiggling the wires around the plug seems to have no effect, i.e. they seem sound. The float floats fine - right up to the top - and when it does you get a connection on the sensor pins. I have played around with this extensively and can't find any suspect connections and the float is as free as a bird.

But - I still an alarm.  What am I missing? Does the alarm need some kind of reset?

Any ideas gratefully received.

Regards.
Title: Re: Erroneous "Coolant Level" Display
Post by: Jimbob on 26 February 2011, 18:08:18
these go faulty every now and again, sounds like youve ruled everything out, so its new header tank time, at about £35 new.
Title: Re: Erroneous "Coolant Level" Display
Post by: fiend61 on 26 February 2011, 23:08:26
and a plus to the new header tank is they look nice aswell    nice and clean and you can see the red antifreeze   :y
Title: Re: Erroneous "Coolant Level" Display
Post by: tcs on 28 February 2011, 12:55:17
Well, I know it's "only £35" but that's quite a few bottles of Theakstons when I haven't been able to prove where the fault lies.  I think I need to tap into the wiring while it's all assembled to see what's going on. (One of the bug-bears of being a test engineer - just can't give up that easily)
Title: Re: Erroneous "Coolant Level" Display
Post by: Andy B on 28 February 2011, 13:04:15
Quote
Well, I know it's "only £35" but that's quite a few bottles of Theakstons when I haven't been able to prove where the fault lies.   ..........

it's the float switch that's goosed. trust us!  ;) You only need to bridge the connector underneath the header tank for a day or two to prove it all, if it doesn't give low coolant then you've proved that it's the header tank

............ but we all know that now  ::)
Title: Re: Erroneous "Coolant Level" Display
Post by: TheBoy on 28 February 2011, 13:04:53
Short out cable under the bottle to prove.

Also, check if float sticky due to poor coolant servicing in its life.
Title: Re: Erroneous "Coolant Level" Display
Post by: Jimbob on 28 February 2011, 13:05:12
yup, unplug sensor, use a paperclip as 'replacement sensor' and you will have proved the fault  :y
Title: Re: Erroneous "Coolant Level" Display
Post by: tcs on 01 March 2011, 16:54:51
But this is what's bugging me - I have done everything suggested by everyone:

Shorted across the plug - alarm goes away.
Checked the float - as free as a bird (fairly new coolant as well).
Put a meter across the sensor while filling the bottle with water - switch closes once the float starts to rise.
No corrosion at all at the plug - almost looks new.

Given that this is effectively a 2 part problem and both parts appear to have been eliminated it is a bit frustrating.

However, I might just have to take your advice and splash out on a new bottle - then stay sober for a week or two  :'(

Thanks for all the advice. Let's consider this closed and I'll try to remember to let you know the outcome.

Regards.
Title: Re: Erroneous "Coolant Level" Display
Post by: Chris_H on 01 March 2011, 20:00:51
I've had two expansion tanks on mine , the second one bought used.  Buzzed out ok but failed pretty soon after.  They must be reed switches and I suspect go too high impedance or something.  I wondered about slapping a transistor in there  ;D but settled for the shorting link.
Title: Re: Erroneous "Coolant Level" Display
Post by: Agemo on 01 March 2011, 21:15:59
TCS Where are you? There may be a breaker who has one for loan/sale.  :y
Title: Re: Erroneous "Coolant Level" Display
Post by: tcs on 02 March 2011, 15:47:48
I guess the chances are that a used tank will suffer the same problem very soon.

The comment from Chris_H seems very likely. It is obviously a reed relay and I guess it's quite possible that even a fairly low resistance will cause the alarm to trigger, depending on the circuit used.

If I have a worse job to do this weekend which I would like to avoid then I might take some accurate readings and have a play with a parallel resistor - just for fun.  Sure beats cleaning up the garden.  :)
Title: Re: Erroneous "Coolant Level" Display
Post by: tcs on 21 March 2011, 22:24:29
OK, I gave in and got a new bottle.

I ripped open the old bottle because I had reached the conclusion that the magnet had seperated from the float but it hadn't - rock solid. So I remain totally baffled but with a new bottle. Ah! well - next problem?
Title: Re: Erroneous "Coolant Level" Display
Post by: smurfdjman on 25 March 2011, 10:17:14
hi guys, how do you short the sensor? and will this make the coolant level warning disappear?
Title: Re: Erroneous "Coolant Level" Display
Post by: Jimbob on 25 March 2011, 10:26:38
Quote
hi guys, how do you short the sensor? and will this make the coolant level warning disappear?


unplug the socket from the bottom of the bottle.
Insert paperclip into socket
warning gone  :y
Title: Re: Erroneous "Coolant Level" Display
Post by: Andy B on 25 March 2011, 11:15:46
Quote
Quote
hi guys, how do you short the sensor? and will this make the coolant level warning disappear?


unplug the socket from the bottom of the bottle.
Insert paperclip into socket
warning gone  :y

If you're just using a paperclip I'd suggest using insulating tape around it, or use a  bit of sheathed wire  :y