Club 80-90 Forums

Hello All,

I know that there's been another thread on this topic, and I've looked at the Wiki, but has anyone else experienced the following.

Van's been running with no problems and water levels in tanks have been all O.K. Yesterday, started van and red light blinked in the temperature gauge and went out as it should. A short time later it started to blink constantly just before driving off. I checked water levels and everything was OK. I even poked around a bit, fiddling some wires (I'm very technical!?). Re-started engine, red light blinked shortly as it should, then stopped and didn't come on again. I got to my destination, stopped, parked, moved on and parked again, and resumed driving (no problems). About half way home, the red water temperature blinking light came on again, and the car was not overheating according to the gauge's needle, also the heating worked. I got home, turned the engine off and on and the red light still continued blinking. Today, I thought I'd try things again, I wanted to check if the fan would come on if the engine got hot while the light was apparently(?) malfunctioning. Anyway, I ran the engine (while parked) until it got to running temperature. The red light was still blinking. Before the engine got warm enough for the fan to come on, I had to leave the van briefly, so I turned off the ignition. Within 5 to 10 minutes later, I turned on the ignition again, the red light blinked briefly, then turned off as it should. I continued to run the engine (still while parked) and the light did not come back on. I ran the engine for some time, waiting for the fan to come on, but the gauge's needle stayed well within the centre of the temperature gauge. I think it was too cold for the fan to come on, and the thermostat was apparently doing its business as it should. So, has anyone else experienced this and how did they sort it out? I presume that if this is a sensor malfunction, or a wiring problem I can still drive safely until I can get it sorted?

Ta ra,
Sal

That light also blinks when the coolant level in the coolant tank is too low.
(Note that it is the coolant level in the coolant 'expansion tank', not the coolant level in the 'top-up tank' that you can see through the number plate hatch).
The coolant level is either low or the coolant level sensor is malfunctioning (they get 'gunked up' as they are permanently dipped in the coolant).

MidLifeCrisis wrote:That light also blinks when the coolant level in the coolant tank is too low.
(Note that it is the coolant level in the coolant 'expansion tank', not the coolant level in the 'top-up tank' that you can see through the number plate hatch).
The coolant level is either low or the coolant level sensor is malfunctioning (they get 'gunked up' as they are permanently dipped in the coolant).

My water level in the expansion tank is up to the brim, where it ought to be, so how do I actually get to the sensor to see if its gunked up?

The sensor is screwed into the top of the tank - you should see an electrical cable/connector going to it;
Yank the cable off it and it should unscrew - its a bit of a faff to get to but not impossible.

FYI - do make sure the engine/coolant is cold before doing this as that is a pressurised system.

Thanks, I've just had a look, and I see it is a bit of a faff!!

But another question - Assuming (as I suspect) that my problem is a sensor/electrical issue, should anyone presume that their engine is overheating if the temperature gauge flashing light comes on but the needle in the gauge does not go to the left, but stays where it should for normal driving, ie, in the approximate centre of the guage, upright. This, of course, is presuming that the water level is full to the brim in the expansion tank, as it should be. Hmm?

In theory the red light flashing means that one of two bad things is happening;

1) The coolant temperature is very high - (red light flashes and temp needle is off to the right) - therefore you need to stop immediately.
2) The coolant level in the van is low - (red light flashes and temp needle may/may not do anything) - therefore you need to stop immediately.

The problem is that you can never 'presume' that the coolant level is correct (unless you are actually staring at it, which you won't be doing if you are driving).

I am not sure what the temp needle would do if you had lost so much coolant that the temp sensor was no longer touching coolant - maybe it wouldn't read a high temp? Hence why we have the flashing light to show that the coolant is escaping....

The problem with the coolant level sensor flashing the red light is that it tends to 'cry wolf' all too often as it is very sensitive so in the end people stop trusting it !!

MidLifeCrisis wrote:I am not sure what the temp needle would do if you had lost so much coolant that the temp sensor was no longer touching coolant - maybe it wouldn't read a high temp?

It wouldn't, reliably. It'd just show the temperature of whatever's surrounding it. That might be hot coolant, it might be steam, it might just be air.

Also worth remembering that if the charge light comes on, it might be down to the alternator/water pump belt having broken, so the water pump isn't pumping - so the coolant temp gauge wouldn't be reliable. The water'd be being heated locally, but not circulating to the sensor, which'd still read normalish, whilst the coolant LED would remain off...

"Also worth remembering that if the charge light comes on, it might be down to the alternator/water pump belt having broken, so the water pump isn't pumping - so the coolant temp gauge wouldn't be reliable. The water'd be being heated locally, but not circulating to the sensor, which'd still read normalish, whilst the coolant LED would remain off...[/quote]"

I don't understand. If the alternator/water pump malfunctions, then presumably the water wouldn't flow through the system - to the radiator - and its temperature would increase, indicated by the gauge initially, and only by the 'flashy' light when it gets very hot, yes - no?

salgarfi wrote:I don't understand. If the alternator/water pump malfunctions, then presumably the water wouldn't flow through the system - to the radiator - and its temperature would increase, indicated by the gauge initially, and only by the 'flashy' light when it gets very hot, yes - no?

It'll get very hot - but not at the thermostat housing, where the sender is. It'll get very hot in the heart of the engine itself. Some of that heat will conduct towards the sender, but not all, and not quickly.

I had a broken alternater belt, with that I got a flashing Temp light & battery light. Have also had the flashing temp light, with low to mid temp needle position, turned out it was a dodgy earth connection on the earting crown behind the fuses & relays.

Hope this helps,

Bob

have same problem............check plug going to ribbon cable on back of clocks..this was my fault// also check out earth crowns...................my light flashes when i put side lights on
verat25

I had this problem when I fitted a non-OEM sensor in the expansion tank. Only the tips of the two sensor probes were exposed (about 0.5 inch of metal), the rest was protected by hard plastic. On the Brickwerks ones the probes are fully exposed (about 3 inches of metal). The light on the dash would often flash. When I put in the Brickwerks sensor it stopped.

Also, there's a Coolant Level Control unit, "Module 42" on the relay plate/fuse box. Check that it is properly seated. If you have access to one, try swapping it out.

Thread in the archive here: http://archive.club8090.co.uk/viewtopic ... 00&start=0" onclick="window.open(this.href);return false;

Good luck!

I should have written earlier, but I solved this problem by cleaning the sensor heads in the expansion tank. To my surprise, they had lime scale on them. This shows that before I got Honoria, she was being driven in areas with a lot of geological lime. Here in Mid-Wales, our water is soft, and we never get lime scale, so I guess that this can be a problem with people who live in areas of hard water!

ta ra!