Bongo Fury

Hi all, some Haydn coolant alarm help please. 1996 diesel AFT 4WD.

Van has one installed, was done by a previous owner, so don't know much about its install. Was working okay when I first got the van in September 2020, but the coolant was in very poor condition. Drained, flushed and refilled the coolant with red antifreeze, Triple QX and changed tank screw, thermostat, water pump, cleaned header tank and fitted Rusty's bleed kit at the same time. Within a week of running it, the alarm came on, as expected with fresh coolant. Took screw out again and cleaned it, made it go quiet for another week. Done that numerous times until it now makes no difference.

A couple of months on, the coolant alarm stays on when van first started, if you rev the engine it will go off, but then come back on when idling again. It's like that until fully warmed. Now it is even worse. Sometimes comes on when fully warm and driving along.

If it comes on when warm and driving along, if you turn on the rear heated window it goes off, for about 5 seconds then comes back on. You can do that repeatedly. If fully warm and driving along and the alarm is not on, I can make it come on by using the windscreen washers!

It goes without saying the level is fine, and the screw is clean. I have done some tests now, all with ignition on but engine off. I can confirm that:

The alarm does not go off:

• After the self test

• If I add a jump lead from the block/head direct to the battery

The alarm goes off if I:

• Earth the screw direct to the battery

• Earth the water in the tank direct to the battery

• Earth the water in the tank to the engine block/head

• Earth the water in the tank to any exposed metal part on the car

My thoughts are that there is a poor earth somewhere. I've checked and cleaned as many earth's as I can find. However seeing as I can silence the alarm by earthing the water to the head, I assume all earth's are okay.

Could it be the coolant has lined the inside of the engine so well the circuit won't complete??

Fresh out of ideas here, help please!

Have you tried earthing the engine to the body/chassis? If that isn't it I am sure Haydn will be along soon with some advice.

Hi, yep sure have. Using a jump lead. I have actually replaced one of the earth cables from the engine to the chassis as it was showing bad corrosion.

Cheers Phil

Has the battery been tested and or the alternator, the alarm is very susceptable to lowered voltage, like when the glow plugs are still on after starting etc or the position of the live to it is not as advised in Haydn's instructions.

Battery condition is fine, it has the winter twin battery set up still, no starting issues for the entire time I've had it.

I don't know where the power is taken from. I'll have a look and check connections. The oil warning cable was attached, which I disconnected, insulated the end and stored away. I assume that's okay?

My Haydn Alarm can grumble at times esp once weather turns cold and damp. Luckily its never stayed on big style and like you if i do something/operate an electrical device it tends to kick it iff. I've got used to it now but at first I found it unsettling. I put new screws in a few years back and maybe that helped a little. I use original ethylene glycol type antifreeze which maybe helps (I'm thinking the original Ozzie LCA design probably dates from when cars used glycol a lot more). On the plus side, my LCA was fitted 15 years ago as one of Haydns first pre-production batch (its a 2 screw model) and its pluses (its saved me twice) have greatly outweighed its minuses. But it would be nice if its grumbling was easier to diagnose!

Hi, contact Jo at our HQ, ask for a new extra large screw, tell her ‘dad says ‘. Google Haydn Alarms or link below

Thanks! I have got a replacement screw from Jo recently, assume the extra large is longer? I'll try that, many thanks...

If that doesn’t work then look at electrics as suggested above.

Thanks. Screw ordered after a slightly awkward conversation!!

Will update, as always good to know the outcome!

Well it would be awkward, asking my daughter for a ‘Long Screw’ on a Saturday morning with her husband listening!

I was trying not to go into detail!!

Appealed to my school boy sense of humour, too.