Coolant Alarms

[Bongolia]

It was Northern Bongo I was referring too.

[haydn callow]

I suspected that!!!

[Northern Bongolow]

steady on guys, it not a one man show, its a forum, lets all help here. even teenmal with his vast knowledge but preferably without the mechanical genius bit.

[Bongolia]

Luv the banter

[Weeduggy]

If you cleaned it and the problem is still there ...... I would suggest you have another problem ..... If you have a multi meter ... Put it on voltage ... Touch a probe to the head of the sensor screw and the other probe to earth.....report the measurement recorded back here..... Do it twice....ign on no engine and engine running

Voltages were as follows.
Initially with engine stone cold

Ignition on 2.6V
Engine Running 2.74-2.75

After running a while
Ignition On 2.69
Engine running 2.74-2.75

I did a few times in between with pretty much the same result. Hopefully that helps.

[rita]

Weeduggy ,it might be worth checking that the alarm is working as it should ,the only way to do this test is to remove coolant from the header tank to below the sensor screw to make sure that the alarm is functioning as it should.



Good Luck

[haydn callow]

You can check the alarm is o.k. By unplugging the bullet connector in the sensor wire near the alarm 'cube'

Your voltages are far to high at the sensor screw, the trigger point is 2.5 volts and if all is well the reading should be about 1.6 volts.
So, you have either got :-
A dirty screw. ( I wish )
Contaminated coolant ( your new red mixed with some old rubbish)
Or
A electrical fault.

That trigger voltage is reached when the resistance in the circuit rises for whatever reason...ie..no coolant covering the screw.....dirty screw etc

[haydn callow]

Mixing coolants can turn the result acidic, this attacks any alloy to n the engine and results in a grey sludge that coats the screw very quickly.

I still favour a electrical gremlin in your case.

[Weeduggy]

Sorry for the delay in replying, Been away at Download festival then had to work. I have noticed the coolant seems pretty cloudy after its been running. Perhaps a good drain and flush will help. When i first installed it it all worked ok with no spurious alarms so I'm guessing at dirty crappy coolant. Whats the best way of flushing the system? Is it best just to drain, fill with plain water, bleed repeat until it all runs clear then drain and fill with correct coolant. I did a brief search and there was talk of using a hose and hot water but that's not going to be a goer for me. I assume that's to keep the stat open in order to clear the system.

[Bongolia]

Have you checked the earthing from the engine to chassis is OK?
If you are sure the connection are all good and the screws are clean then why not send the actual alarm unit back to Haydn for testing?
Then you can be sure the unit is not the problem.
In answer to your question though it depends how thorough you want to flush or how contaminated. Quick flush with a flushing agent will normally suffice but if you want thorough flush check out my post regarding flushing cooling systems.
Not sure how you find it ashamed to say

[haydn callow]

Not much point in sending it back although you are welcome to do so. These alarms either work or don't, there is no half way.
The fail rate is less than 0.5 %. If they work they work forever.
We weed out the odd one before sale. They are tested 4 times during production and again before dispatch.