chirpy chirpyu cheep cheep. LCA

[haydn callow]

That all sounds good except for the voltage at the sensor screw.....It's too high @ 2.9 volts which means that the resistance from the screw to earth via the coolant is high....so...either dirty screw (new ones on the way) or very weak coolant strength or extreamly low coolant temp (below freezing.).

The alarm will "mutter" above 2.5 volts.....I would guess that the alarm is silent once warmed up...
The other possibility is a faulty componant within the alarm that is allowinf the volts to leak to the sensor....however if that was the case I would expect the fault to be permanant.

Put a new screw in and report back.

OK, One more question, you talk about the screw, singular? Mine has two, with a red wire and a black wire. It was fitted before I got the vehicle. You are not going to tell me that the black wire should go to earth I hope?

Yes it usually does stop when it warms up but Saturday was the exception, it sounded very quietly with a dim light all day.

You have 2 x screws...that is quite a old alarm as for the past 2 years we have only required 1 x screw.
SO...you have a TOP screw which is the coolant level screw and the BOTTOM screw, the wire of which goes to earth.
Replace both screws and report back....also note the voltage from the top screw to earth..

[Velocette]

Ah, OK. I've had the Bongo nearly two years.

[longhaul8]

Mine must be an old alarm too it also has two wires going to it.

just got to move my lesure battery out of the way so i can change the screws on mine too.

[haydn callow]

make sure you use the correct screws ??

[longhaul8]

I will do i have 2 screws you sent me when i bought a cube alarm from you

[bongobaz]

Mine comes on when cold 06 on head temp sensor, goes off {stops noise} at 11 usually 200yards or so. Level bang on dip stick level. Should i clean my screws? i also have a high level alarm.

[haydn callow]

might as well give it a try.

[Northern Bongolow]

Mine comes on when cold 06 on head temp sensor, goes off {stops noise} at 11 usually 200yards or so. Level bang on dip stick level. Should i clean my screws? i also have a high level alarm.

yours has newish red coolant baz and as haydn says , sometimes this can affect the alarm.

[haydn callow]

Yes..correct...."some" coolants, and the red 5 year seems to be the one most involved, When first introduced into the system...lay down a protective layer which amongst other things protects the metal beind eroded by cavitation bubbles around the water pump.
This layer also coats the Coolant Alarm sensor screws causing high resistance which pushes up the supply voltage to the screw...This higher voltage trips the alarm and OFF it goes....cleaning replacing the screws fixes the problem and once the new coolant is about 2 weeks old the problem goes away as it only lays down the proctive layer once when first introduced.

To clean a screw.....wait till system cold....remove tank cap and replace (to get rid of any pressure.....remove the screw and get her indoors to put a finger over the hole.....wire brush the screw or fit a new one.....no coolant should be lost ...job done

[Velocette]

Thanks Haydyn, the screws arrived yesterday and I fitted them this evening.

The alarm now sounds for two to three seconds then stops cleanly and the light goes off completely. I haven't tried driving it but will be doing so on Saturday.

The voltage readings are:

1.68 with engine stopped.
1.99 with engine idling.

Mine has the pink coolant too.

Cheers
Eric

[haydn callow]

That should be fine...the trip voltage is about 2.5

[Velocette]

Drove it for about four hours altogether to day. it came on sporadically now and again all day, for a few seconds at the time, usually quietly but one time it was quite loud but just for a few seconds or I would have stopped and checked the tank. It seems to be tripped by electical equipment, brake lights aircon fan etc. I am thinking of repalcing the alarm, but I will wait and see what happens after the hose has been replaced just in case. Engine temp was between 84 and 88 all the time so not much wrong there. I will check the water level in the morning.

[haydn callow]

I am pretty sure replacing the alarm will make no differance.....It sounds as though you have a electrical gremlin upsetting things....these alarms are quite sensitive to voltage fluctuations....It would be good if I could have a look at it and I would be happy to fit another if required....will you be at Stourport ??

[haydn callow]

Just noticed you are in Bristol...any chance of getting down to Somerton??

[Velocette]

Just noticed you are in Bristol...any chance of getting down to Somerton??

Yes, I am sure I could, I was down in that general direction today actually meandering back from Gillingham, got as near as Castle Cary!

Tomorrow I have a family birthday to attend so whenever elses would suit you really.