Flashing Red Light/No Flashing Red Light??????

[thetattoomaster]

Hi,
I wondered if someone could advise me about the problem that I am having....
I am driving a 1986 T3 Camper with a 1900cc Diesel Non Turbo Engine.
The problem that I am getting, is that if I drive for around 10 miles then stop and turn off the engine for a few minutes, when I start the van again the Red Light in the centre of the Temp Display starts to flash, sometimes it will go out after a few hundred yards, today I returned after doing 12 miles, parked outside my garage turned off the van to unload somthing, then started it again and the red light was flashing, I parked outside my house some 50 yards away and had a look in the engine bay with the engine running, the temp was reading in between quarter and half, I tried taking off the conector to the the Pressure Tank and also the one to the Temp Sender on the rear of the cylinder head but it kept on flashing. The water in the Pressure Tank was hot and full( although when I removed the overflow pipe from the Blue Pressure Cap there was a few drops of hot water come out) I then increased the revs to around 2000rpm and filled the Pressure Tank right to the top.
When I checked the Rad at the front, both pipes were COLD (but the heater was putting hot air onto the windscreen) although the Camper had only done around 10 miles with a ten minute break after 8 miles.
It would seem that if the van is ran and not stopped the red light does not come on, if it is stopped after a run of about 10-15 miles then stopped, upon restarting after a few minutes, the red light will flash and keep flashing.
If the Camper is left to stand for around 15-20 minutes then the light will go out and stay out till you stop again.
Any ideas guys ???????, I have replaced the Thermostat, Rad Sender Unit and the sender that turns on/off the small water pump in the rear that circulates the water around the Oil Cooler.
Could this be an air lock in the system???? if so what is the correct way to bleed the air from these systems as I have so many different stories?????
If anyone has any ideas I would be realy greatful.
Many thanks for taking the time to read this.

[AngeloEvs]

My approach would be to determine which part of the cooling circuit is causing the LED to flash. Remove what looks like a relay marked 43 out of the fuse box and after driving a few miles see if the LED behaves. If the LED behaves as it should then the fault is in the coolant level circuit or the coolant level module 43 may be faulty. If the LED still seems to be a problem then either the coolant is too hot or you have an electrical problem with the Coolant electrical circuit. The LED flashes to indicate coolant loss but it needs the coolant module 43 to activate the LED. The LED will also flash if the coolant temperature is high and it will flash even if the coolant module 43 is removed. Flashing Red light problems are most commonly caused by poor earths in the coolant electrical circuit and/or poor comnections at the back of the dash. See how you get on with the module out of the fuse box.
Can't help with the bleeding as I have petrol...........

[thetattoomaster]

Many thanks for the reply Anglo, I will try that tomorrow and let you know what happens, I see you are in Upwell, nice to see someone from the same area, I am just near Newmarket.

[AngeloEvs]

no luck pop over some time...............

[thetattoomaster]

Will do Anglo, and many thanks....
Cheers
Dave

[thetattoomaster]

Hi Angelo,
I tested the van as you sugested today and this is the findings
My Fuse Board is as follows
Top row numbered 1 to 6 with Unit 42 in position 3.
Bottom row numbered 7 to 12 with Unit 18 in position 8, Unit 19 in position 10 and the Flasher/Hazzard Unit in position 12

1.It would seem that the relay that controls the heating side of things on the Diesel Camper is Unit 18 as this is the one that I have found the referance to on the Internet, and also through removing it from the van.
2. Removed Unit 18 and started van from home, Light went out.
3. Went to local shop...1.6 miles stopped, re-started van and Red Light went out after 3 seconds.
4.Drove 2.5 miles and stopped the van, re-started it and the red Light started flashing...replaced Unit 18 and the flashing stopped.
5. Drove 1.2 miles with Unit 18 in place and then stopped the van again, Red Light stayed flashing.
6. Stopped at cross roads after 1.5 miles with light still flashing, re started the engine and the light went out.
7. Got home after another 1 mile and stopped the van, re started and the Flashing Red Light went out after about 6 seconds.
That is as far as I have got at the moment, from 4-7 the Unit 18 was in the fuse board.
During this trial the Temp Gauge never went above the White Section on the Temp Gauge.
There was Hot Air from the Windscreen Vent so I should think that the water is getting that far at least.
I look forward to your reply, my email address is
stringfellowz@aol.com


All the best
Dave.

[AngeloEvs]

Its the one numbered 43 (some are 42 but identical) and same for all post '86 vans (Petrol or Deisel) that you have to remove. You took the wrong one out, take 43 out and re-try.

[leroiandjayne]

hi mate,dont know if its relevent but i had a problem with said flashing red light it kept coming on after turning the headlights off!, turned out that an earth connector had come off at them connectors on the left of your pic behind the fuse box,cleaned it replaced and no probs,maybe this helps. good luck leroi

[thetattoomaster]

Many thanks for that Leroi i will check that out tomorrow, also as you said Angelo, I will try your test with the correct relay out and see what happens...
Watch this space.

[AngeloEvs]

43 is an electronic module that senses coolant loss (though it looks like a relay), its this module that earths at the cluster thats why I suggested you remove it. See how you get on..........

[thetattoomaster]

Hi Angelo and Leroi,
I removed Unit 42 as asked and tried the Camper, done 1.5miles and light was still off, done a further 2 miles and stopped....re-started and light came on re-fitted unit 42 and the light stayed on....went a further 5 miles with stopping and starting and the light stayed on, I then thought of what Leroi said and turned on the headlights and low and behold the light went out, I tried this several times and it seems to extinguish the Red Light when I put the Head Lights on to Full Beam. Could this be as Leroi said, and a bad earth behind the fuse board??????.
Many thanks
Dave

[AngeloEvs]

Yes, since it was fine with the module out. The module is earthed at the cluster next to the fusebx and causes problems. You need to check them. There are quite a few and they either come loose, tarnish, or adjacent to earths that get hot like the rad fan earth. Just waggle them all, inspect them, any that look suspicious or feel loose need to be renewed. The LED is supposed to flash every time you switch the ignition on and after a few seconds go out. If you continue having problems then the earth fault is elswhere in the coolant level circuit, your coolant level is low or the module is faulty.

[thetattoomaster]

I removed all the Earth Wires behind the Fuse Board, fitted new Terminals on all Earths and cleaned up Earth Connectors, gave the van a run and still the same problem so I started checking behind the dash and found that the problem was caused by a faulty nut that holds the wiring membrane in place behind the Temp Gauge, have been on test run and now the Temp Needle stays in the centre of the guage and the van seems to be heating up better, rather than running at the edge of the white section(still took around 10 miles before the water was starting to heat up the pipe at the bottom of the rad) I also fitted a new Pressure Cap from Brickworks...excelent service 1 day turnround.
Thanks for everyones help and fingers crossed, we might be able to get away now.
If anyone breaks down in the Suffolk area, keep my Mobile Number 07733255517 and if I can help you back to mine or help get you on your way I will be more than happy to do so.
Cheers Lad's.