Club 80-90 Forums

My 1984 DG engined van has got the dreaded coolant flashing red light syndrome.

It only happens when the van has been laid up for a while. To begin with it takes anything up to 20 minutes to go out but eventually after using the van regularly it is back down to its normal 10 seconds.

All water levels in the two tanks are correct and I have bled the radiator.
I have checked all the connections to dashboard and sensor but the wiring diagram shows a "Cool Low Lvl wrng cntrl unit". Where is this unit on my van (1984) as I would like to check the connections to it or replace it? Incidentally does the water level sensor switch ON (make contact) when full of water or OFF. Mine is off (no current passed through) at present?

My van has the earlier type of fusebox with only two relays in it. I can see that on the later van's it's in position 3 but this is no help to me.

Could it be the one fastened to the body behind my fuse box under the dash or is it the one in the black box at the front of the engine compartment?

Trundletruc.

I had the same problem on our Scirocco, tried many things, changed level sensor, pipework, header tank, plus other things, nowt worked, the only thing that did work... driving it, regularly.

If I leave it for a couple of weeks, it flashes again, so we use it!!

Sorry cant be more helpful.

Munnyella

The water sensor in the coolant tank is not a switch, it relies on the small (milliamps) current that will flow through water.
T

The coolant level control unit looks like a relay similar in size to those in the fuse box. In post 86 models it is in the fuse box, in earlier ones it is probably in the dash somewhere but exactly where I do not know. It contains an electronic module that detects the presence of coolant. If there is a loss of coolant it injects pulses into the guage circuit which activate the coolant led. If and when you locate it it, simply remove it . If the coolant light continues to flash then the problem is in the temperature sender wiring but I would also expect to see the temperature guage reading high for the LED to be activated. If the coolant LED behaves normally with the coolant level control unit removed then the fault is in the level control circuit. Poor earths, faulty coolant level unit (in the coolant header) or the module itself is faulty. The control unit is earthed at the earth cluster next to the fuse box and this too will trigger the coolant led. The coolant led can also be triggered by a duff voltage stabiliser and an excessive antifreeze mix.

AngeloEvs wrote:The coolant level control unit looks like a relay similar in size to those in the fuse box. In post 86 models it is in the fuse box, in earlier ones it is probably in the dash somewhere but exactly where I do not know. It contains an electronic module that detects the presence of coolant. If there is a loss of coolant it injects pulses into the guage circuit which activate the coolant led. If and when you locate it it, simply remove it . If the coolant light continues to flash then the problem is in the temperature sender wiring but I would also expect to see the temperature guage reading high for the LED to be activated. If the coolant LED behaves normally with the coolant level control unit removed then the fault is in the level control circuit. Poor earths, faulty coolant level unit (in the coolant header) or the module itself is faulty. The control unit is earthed at the earth cluster next to the fuse box and this too will trigger the coolant led. The coolant led can also be triggered by a duff voltage stabiliser and an excessive antifreeze mix.

and also low voltage will cause it , so bad connections in the engine bay and or poor earths in the engine bay will cause it to trigger.......

The control unit is relay "43". Chances are if you only have 2 relays this is one and the other is your flasher unit, usally "21". Flick the hazard lights on and remove the one that isn't clicking.

The one mounted on the van body is probubly the rad fan 2nd speed.