Coolant Alarm - high voltage problem

[Kincaid]

Hi

I've a Low Coolant Alarm - the one with two wires that plugs into the cigarette lighter.

After a full coolant change 9 days ago I reconnected the coolant alarm, next morning the alarm was sounding so I took out the screws cleaned them and all was well again. But then the alarm went off again this morning so I've repeated the process and it is now OK.

Before fixing it I measured the voltage from earth to the top screw, this was 3.65 during the alarm. I cleaned the screws, replaced and the same voltage measurement is now 2.85. I also used a wire to connect from the top screw into the coolant - this stopped the alarm condition instantly (and realarmed as I removed the wire).

I've read on the forum that the LCAs alarm once the voltage is above 2.4 on the older models so am really confused as to (a) why the alarm is not ringing now and (b)why the voltage is so high in the first place.

P.s. the power for the cigarette lighter is via a leisure battery using a Winninton kit. The earth for the coolant alarm sensor wire is taken from the starter battery earth terminal.

Any ideas as I'm running out of them

[rita]

Hi

I've a Low Coolant Alarm - the one with two wires that plugs into the cigarette lighter.

After a full coolant change 9 days ago I reconnected the coolant alarm, next morning the alarm was sounding so I took out the screws cleaned them and all was well again. But then the alarm went off again this morning so I've repeated the process and it is now OK.

Before fixing it I measured the voltage from earth to the top screw, this was 3.65 during the alarm. I cleaned the screws, replaced and the same voltage measurement is now 2.85. I also used a wire to connect from the top screw into the coolant - this stopped the alarm condition instantly (and realarmed as I removed the wire).

I've read on the forum that the LCAs alarm once the voltage is above 2.4 on the older models so am really confused as to (a) why the alarm is not ringing now and (b)why the voltage is so high in the first place.

P.s. the power for the cigarette lighter is via a leisure battery using a Winninton kit. The earth for the coolant alarm sensor wire is taken from the starter battery earth terminal.

Any ideas as I'm running out of them

Hi,
haydn callow is your man,he invented/developed these alarms(If it is the same one that you have)

Cheers..

[haydn callow]

The new coolant is the problem.....New coolant causes a protective coating to be laid down on the inside of the cooling system. It also coats the screw causing a resistance which "triggers" the alarm..
After a couple of weeks the coolant loses the ability to coat (it's all used up and done it's job).
and so the sensor screw after cleaning/replacement will be o.k.

Give it a couple of weeks and let me know if you want me to send a new screw.

The alarm is fine.

I would also suggest you move the power wire from the LB side of things to the IGN switched live........this would mean not having a perm live ciggy socket.....the type of LCA you have (now discontinued) is not suitable for a perm live ciggy socket and you lose the self test function.

[Kincaid]

OK. I'll move the unit to be powered from the switched live rather than the LB. Is there an antifreeze that is recommended for the LCA that doesn't cause this issue?

[haydn callow]

Good question.....this problem has only been reported (as far as I know) in the past 12 months.....perhaps a differant additive has been added......perhaps more peeps are now sticking new coolant in.......the alarms havent really changed and the one you have is very old...
Don't know is the answer.......new coolant seems to be the problem......and after 2/3 weeks it goes away after cleaning the screw or fitting a new one..
voltage fluctuations also cause "strange" things to happen......LB's are not good for alarms.

[mikeonb4c]

Good question.....this problem has only been reported (as far as I know) in the past 12 months.....perhaps a differant additive has been added......perhaps more peeps are now sticking new coolant in.......the alarms havent really changed and the one you have is very old...
Don't know is the answer.......new coolant seems to be the problem......and after 2/3 weeks it goes away after cleaning the screw or fitting a new one..
voltage fluctuations also cause "strange" things to happen......LB's are not good for alarms.

In case it helps, I've always used bog standard old ethylene glycol coolant and my Haydn supplied Mk.1 LCA (first production batch, now installed about 4yrs) has never given any problem (nor has the Bongos cooling system, touch wood). When the original LCA got going (in Oz?) and before Haydn worked (with the Aussies?) on a kit for the Bongo, I wonder if ethylene glycol was the most commonly used a/f in the cars where it was tested. It might explain why this problem was not unearthed (and maintenance notes put in the instructions) in those early days.

If I've got the history of the LCA development wrong, I'll ask for Haydn's forgiveness and he can give corrected thoughts.

[Kincaid]

Cheers Mike, I'd probably have gone for a blue EG 50/50 mix myself, but I asked the garage what they had put in after they did some warranty work the other day and they'd gone with the red. I fancy fitting a new thermostat over the next few months so will do a full drain and refill with blue.

[haydn callow]

Whatever the reason for this to have started to happen in the past 12 / 18 months, the fact is it does happen and in most cases it seems to be with the RED longlife 5 year coolants....These lay down a strong protective coat (have a look at a stat housing or water pump impeller/housing...you should not clean this coat off by the way) problem is it also coats the LCA sensor screw......there is nothing we can do to prevent this, this coat when it covers the screw increases the resistance of the screw and the alarm compensates by increasing the supplied voltage untill the "trigger" voltage is reached...
We could increase the trigger voltage but that would desensitise the alarm !!
Fortunatly it is a temporary thing as after a couple or three weeks (depending on use) the coolant stops laying down the coating...

[TonyBee]

Thanks for that info Haydn as I am just about to flush out my system to fit an inline temperature sensor in the radiator top hose, change the stat and re-fill with red longlife coolant.

Tony