Temp Gauge Flashing Light

Post by **Illboy** » 15 May 2006, 09:00

So the little red flashing light, which I believe comes on when the keys are in the ignition, then after a few seconds, goes - appears to be the warning light for over heating ?
My T25 destructions are in German, hence the stupidity, but in all the times we've driven it, we've had no flashing lights, until now. The temp gauge goes straight up to the top and this certainly hasn't happened before, water and oil levels appear to be fine and there doesn't seem to be any leaking under the vehicle. The petrol gauge is in the red/orange, if that would have any link.
I've been stuck in traffic jams and the gauge has never gone over about 3/4 up the gauge, so I'm a little puzzled why this is happening, any thoughts on this ?
My experience with all things technical comes down to knowing flashing red is not a good thing

Post by **Horza** » 15 May 2006, 09:54

Probably better off posting in technical for this, you'll get more replies (perhaps Louey or someone will move it?).

Did it actually over heat or was the gauge the only sign?

Was the water getting to the front still? Did the heater make hot air?

Stab in the dark at this stage, it could be your thermostat. Stops the water getting to the radiator which sorta foils the cooling system and prevents cooling. The Wiki or any heynes will have descriptions of diagnosing this.

You'll be wanting to tell them waht engine and age of bus in technical too, the folk who know things (as opposed to me

) like to know these details.

Post by **Hacksawbob** » 15 May 2006, 12:27

flashing res like sirens and buzzers are bot generally good things. The temperature guage is working which is a good thing, but what it is telling you is a bad thing. I take it cos you have not said that the fan is not coming on (at the front behind the radiator) you can hear it. It may be that you have been driving round with a broken fan and not noticed it, they come on in standing traffic. take the top grill off the front of your van and feel the radiator at the top when your van is hot this should be hot right to the top. if its not the suspect thermostat as Horza says or perhaps an air lock.
have a look here for radiator bleeding. http://www.club80-90.co.uk/wiki/index.p ... ing_system

Also here for new owners guide
http://www.club80-90.co.uk/wiki/index.p ... _questions

Website · Post by **dbroada** » 15 May 2006, 12:33

there is another thread over in tech atm (something like possible overheating).

The red light flashes on start-up as a self check. After that its primary function is as a low coolant warning rather than an over temperature warning. When it starts flashing it is a good time to check! However it will flash if there is a broken wire (guess how I know).

The temperature gauge is driven by a sensor in the thermostat housing and its possible that a wiring fault here would show a high temperature. The cooling fans are driven by the radiator temperature.

As Horza has said, are you sure it overheated or is it just your gauges? I would check the wiring under the engine cover for stray leads first. Give them a wiggle, they tend to fail just inside the connectors.

Post by **Mocki** » 15 May 2006, 15:47

the red LeD is Water low, AND over heating signal, so could be caused by either, but temp gauge is either sender fooked, or wiring fault if it isnt boiling the water..... shorting the temp sender wire to ground ( earth) will make the gauge go right over, so look for metled wire insulation if nothing else......

Post by **Tallbird** » 16 May 2006, 15:18

We have a T25 and have had this problem as well - driving along, all is well and then the temp needle rockets up and the light starts flashing.

Usually if you turn the ignition off and on a few times it seems to 'reset' itself.

Unfortunately we had a real temperature emergency the other week (fan belt broke) and to start with we thought it was just the guage again, it was only when the steam started belting out of the back that we realised otherwise!!

Since fixing it, the guage is still a bit temperamental, but there is definately no overheating going on.

It's very unsettling though - and is the next thing on the list to be fixed.

Website · Post by **dbroada** » 16 May 2006, 17:22

Tallbird wrote:Unfortunately we had a real temperature emergency the other week

been there too! I got the flashing light, checked the circuit diagram and decided to check the wiring. Broken wire (while on holiday). The day I bought the bits to do a temp repair, but before I could do the repair I got a split pipe.

Post by **thewibbit** » 16 May 2006, 19:53

Just read this thread and I feel quite glad.. my '82 Aircooled doesn't have a temperature guage let alone any flashing lights. I just have to rely on whether it's running or not, funny smells etc. which is nice! It's worked for me for the last 7 years.
This one time, me & the wife drove to the top of a mountain (in the Pyrenees) on our way through to Spain, and on the way down it was so steep and I was on the brakes for about 20 mins. I noticed this funny smell and realised that my brakes were cooking. We pulled in at this little clearing bit and I couldn't touch the hub caps they were so hot. Oh the fun we have in our camper! Needless to say we made it to Spain the next day.

Post by **Illboy** » 02 Jun 2006, 14:55

Thanks for all the help, the result :

One of the 2 water tanks was a little low, which I thought I had checked, but the pipe between the two was blocked, hence the red light freaking out. It wasn't hot, but we got it sorted, so all's good and we're off tomorrow somewhere near Brizzle ...