Temp light worry or not that is the question!

[Novice in need]

Hi my temperature light comes on and does its self check thing... flashes 2-3 times and goes out which is all good, but then it comes back on and maintains flashing, this however only happens when first started from cold and if allowed to warm up then turn off engine then back on it stops

Water levels are fine Oil is fine also ... she obviously cannot be overheating as its from cols start first thing in the mornings only!!!

So am i to worry or not ?

[Ian Hulley]

Sort it because the one day you ignore it it will cost you a grand.

[Fin]

It'll probably be followed by the buzzer of doom in 500 or so miles
Sort it now - Mine does that - but I plan on fitting a new engine - so I'm choosing to ignore it for the moment
Now where's that AA subscription

[ermie571]

Novice,

does it do it from cold every time?

I am no expert here.....but the way to test it would be to look at the expansion bottle in the engine bay BEFORE turning the key. It should be brim full. Totally brim full. Undo the darlic cap and check. The light is triggered by the sensor in the top of the bottle...make sure the prongs are not green and furry. Make sure connections are good. I would have thought that what the red LED is telling you, is that when cold, water is low...but as it warms up and expands, enough water is present to fill the bottle, and allow the self check to go out.

Check the operation of your darlic cap...it should push water out as it gets hot, then as it cools suck it back in. Maybe its only going one way? People mention blowing and sucking on it - can't remember what it should or shouldn't do....but a quick search on here will tell you.

First thing is to find out whether that blessed light is telling the truth...or not. So, check your bottle....satisfied its full....key to stage 1....blink and go out...all good. But if it stays blinking and you know the bottle is full, you need to repost for some more help.

Hope that helps

Em
x

[Ian Hulley]

The coolant makes the circuit between the 2 'prongs' of the sensor thus extinguishing the light, try taking the plug off the top and insert a piece of wire into both terminals, the system should 'self-test' and go out (i.e. it believes the coolant is there) if it doesn't there's a wiring/dash pod issue. The sensors are known to fail but that doesn't explain the 'only when cold' part of the problem.

Ian

[Novice in need]

Thanks for replies

The light really does only come on when absolutelly cold ... the first time she gets started up in the mornings, all other times when running around here and there its all good and operates as it should.

Water levels i check very regularly almost daily and have done so when the light goes on in the mornings and the water levels are fine, full to the brim and between the lines etc

il do the check on the sensor as suggested Ian and report back

[StuM]

...the water levels are fine, full to the brim and between the lines etc

You need to check the header tank level as well as the expansion tank (behind the flap) - this has no 'lines', and needs to be brimmed.

Cheers,
Stu

[Novice in need]

The expansion tank level is to th brim, i double checked yesterday along with the header tank which has the level lines they was all good.
I even done the wire connecting the plug directly to the terminals and the light went on and off as its supposed to on a self test (this was done however when engine was hot) this morning taking kids to school i did not have time to re do the direct wirering test mentioned on here by Ian which i will do as thats when it always happens when very first started in the mornings whilst engine is cold, which is what it did this morning aswell.

Il report my progress hopefully tomorrow after i have done so, personally i think i need to trade the van in for a push bike

[jamesc76]

Might find that the sensor has a broken down internally and once warmed and expanded makes the circuit again?

[Novice in need]

Could well be... its certainly a suggestion that matches the nature of the problem, il just change it for piece of mind next week. Thanks for input

[Ian Hulley]

il just change it for piece of mind next week.

http://www.brickwerks.co.uk/shop?page=s ... ory_id=118

There's 2 kinds, depending on the terminal set-up ... they're both halfway down the page.

[Novice in need]

Hi thanks Ian,

Im on the hunt already found GSF ebay shop which appear to sell items for T25's which are all new for less than the prices on their own website and cheaper than Bricks and VWheritage, so im just waiting for them to answer me back on the sensor as its priced at £7 and visually it is exactly the same as what is already on the van.

I have recently brought a Ignition amplifier off then that had been advertised for a Jetta etc but only when going into the ebay page properly for th item did it list it assuitable for my 1.9 watercooled T25 result

[Ian Hulley]

found GSF ebay shop which appear to sell items for T25's which are all new for less than the prices on their own website and cheaper than Bricks and VWheritage,

I wouldn't do that if I were you.

[Novice in need]

O ... ok il give them a miss .. thought id got a result as they are GSF afterall and not just a unknown supplier etc

[Ian Hulley]

GSF are a great company ... our local branch staff in Derby (Theo and John) & Nottingham (Glynn) are exceptional, friendly, knowledgeable and all of them run VWs so they share our problems ... and they sell some great products, they also sell some budget items that are extremely questionable. Whole batches of their sensors are faulty and the cooling system parts and cheaper wheel bearings seem particularly weak.

Just my honest opinion, Ian.