Temp warning light flashing but engine seems ok - Any ideas?

[tobyn]

Hi,

I've recently bought a T25 van, so am new to these vehicles and this particular one.

Can anyone shed any light on the following problem:

Temp warning light comes on and flashes after about 10 mins of driving. I stopped the van and looked at the engine, which was hot but didn't seem too hot (no steam etc). There was plenty of coolant. Left the van for about 10 mins and temp warning light still flashing when engine re-started.

Does this sound like a cooling problem, or could it be a dodgy sensor or gauge.

Please could someone advise me what to check.

Thanks!!!!

[kevtherev]

https://club8090.co.uk/wiki/Co ... ht_on_dash" onclick="window.open(this.href);return false;

[clift_d]

The LED on the temperature gauge is a coolant level warning light. You need to check the level of coolant in your expansion tank - this is the main tank under the engine lid, not the reservoir behind the number plate - you can see it on the right above the battery in this picture of a 1.6TD diesel engine. If the coolant level drops below a certain level in the expansion tank then the light comes on. When the engine is cool and you take off the blue 'dalek' cap, the expansion tank should be filled right up to the brim with coolant. If the coolant level is low just top up the tank and then run the engine to bring it up to temperature to see if goes off and stays off. You may have bigger issues if it goes off for initially but then comes back on after a bit, and when you re-check you find the coolant level in the tank has gone down again.

[tobyn]

More info on problem - can anyone fathom this out?

1 hour since last drive, so I'd like to think van is cool (although expansion tank warm to touch still). Temp gauge still off scale (to the right) and light above it still flashing.

Tried disconnecting relay 43 - Fault remains.

Tried disconnecting relay 43 AND disconnecting expansion tank probe - Fault still remains.


Any ideas what this could be or what to try next?

Toby

[marlinowner]

Sounds like a short to ground in the coolant temperature circuit, the light flashing means it "thinks" the coolant level is either too low (disabled when relay 42/43 is removed) or too hot. Disconnect the wire to the temperature sender which I think is on the thermostat housing. If the gauge then drops and light goes out, then the sender is suspect. If the problem is still there, look for a short to ground between the gauge and the sender connection.

[tobyn]

Hi,

Following the advice in previous post, please could somebody send me a picture that clearly identifies the sender unit (1988 petrol). I think I have located it, but not 100% sure and don't want to go round in circles with diagnosis / trouble shooting.

Thanks for all your help with this - Considering I've only owned the van for a week, I'm learning loads!!!!

[kevtherev]

Tell us what engine it is then!

[tobyn]

1.9 petrol.

Van = 1988 RHD

[clift_d]

The sender is the probe sensor on the expansion tank - it looks a lot like this one from Brickwerks:

http://www.brickwerks.co.uk/index.php/c ... ip-on.html" onclick="window.open(this.href);return false;

[marlinowner]

That's the coolant level sensor, the coolant temperature sender is different and they both lead to red light flashing, but if the gauge is reading high and pulling the coolant level relay (labelled either 42 or 43) has no effect, then its the temperature sender circuit that's causing the problem.

[kevtherev]

That's the coolant level sensor, the coolant temperature sender is different and they both lead to red light flashing, but if the gauge is reading high and pulling the coolant level relay (labelled either 42 or 43) has no effect, then its the temperature sender circuit that's causing the problem.

which is located on the thermostat housing, at the rear with two wires brown and red/yellow.
I would start by replacing the temp sender.
along with the O ring and clip
VW No 251 919 501

[tobyn]

Got it!!! Thanks.

Before I go ahead and change sender, are there some checks worth doing (resistance between pins etc)?

If I do buy a sender, please could you recommend a supplier.

[kevtherev]

Brickwerks
It's the Black sender
don't forget the new o ring and clip

[MidLifeCrisis]

Got it!!! Thanks.

Before I go ahead and change sender, are there some checks worth doing (resistance between pins etc)?

If I do buy a sender, please could you recommend a supplier.

Have you pulled the connector/wire off that temp sensor and confirmed that the needle does not now go to full hot (and the light does not flash) when you turn the ignition on?

[tobyn]

Cant seem to disconnect wire connector.

Does it just pull off, or do I need to release any clips?

Don't want to pull too hard, just in case there is something else that needs to be released first.

Also, now I've started twisting and pulling, water is dripping from sender housing. Is that to be expected?