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Water Temp Sender Woes!!

Saul

<b>SCN Admin</b>
May 21, 2001
4,194
0
The coolant level sender probes are bonded into the header tank - these ones scale up and cause a false reading, especially when it's cold (and I assume the coolant contracts, so the level drops a bit). These ones give the three beeps on startup and flashing red light.


i had the three beeps and red light with the failed coolant temp sensor (i did scrape the 'prongs' for good measure though)
 

petay_pan

Full Member
Oct 27, 2005
97
0
The Coolant temp sensor (G61) is the one that is commonly replaced with the "green top" sensor, this one that relates the engine temperature to the ECU for the cold running/warmup cycle. When the black top sensor goes, the car runs rich...

The Temperature Gauge Sender (I think it's G62) is in the thermostat housing and feed the temperature gauge. This one causes the gauge to rise and fall 0-90'C or sit at 70'C.

The coolant level sender probes are bonded into the header tank - these ones scale up and cause a false reading, especially when it's cold (and I assume the coolant contracts, so the level drops a bit). These ones give the three beeps on startup and flashing red light. Clean the probes by scratching with a screw driver, or replace the coolant bottle.


Feel... top info! seem to me that my problem is the bottle and that sensor thingy! :lol: the coolant beeping not something I need to worry about till the winter but I'll give that screw driver thing a go later on. Will have to see if the parts garage is open tomorrow.

Cupra_UK am I right in thinking I need to ask for the O-ring as well as the sensor?
 

Cupra_UK

Correction Cupra"R"
Dec 24, 2007
217
0
Near Gatwick
What Feel is suggesting is the problem and what I’m changing are different things. But if you order the part from Seat/ VW/ Audi ask them if the O-ring is included. I bought a genuine part from elsewhere and it didn't come with the O-ring. They're only £1 from Seat but you could probably use your old one.

When I drain the coolant I’ll have a good look at what the prongs in the expansion bottle look like. Will give them a clean too if needed.
 

Bosher

Active Member
The Coolant temp sensor (G61) is the one that is commonly replaced with the "green top" sensor, this one that relates the engine temperature to the ECU for the cold running/warmup cycle. When the black top sensor goes, the car runs rich...
The Temperature Gauge Sender (I think it's G62) is in the thermostat housing and feed the temperature gauge. This one causes the gauge to rise and fall 0-90'C or sit at 70'C.

VAG list G61 as a knock sensor and G62 as the 'green top' ECT Engine Coolant Temperature sensor

Cupra UK... just seen a 'how to do it' guide on ECT sensor replacement... they recon you'll lose 1 litre of coolant, but i'd have a bit more to hand just in case.. :D
 
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petay_pan

Full Member
Oct 27, 2005
97
0
I had a look at the prong before but despite the size of the bottle there not much of a hole. Would be interested to know whats going on.

Might have a poke about with VAG-COM later see what I can find. dam thing just want it to play nice! Hope all your bits go well though mate. Will go get that sensor tomorrow if I can be nice to get this one solved!

Last quick Q: what does the G61 and G62 refer to? - ignore just been answered :p
 

Cupra_UK

Correction Cupra"R"
Dec 24, 2007
217
0
Near Gatwick
VAG list G61 as a knock sensor and G62 as the 'green top' ECT Engine Coolant Temperature sensor

Cupra UK... just seen a 'how to do it' guide on ECT sensor replacement... they recon you'll lose 1 litre of coolant, but i'd have a bit more to hand just in case.. :D

It's ok, I lost about 95% of it yesterday and plan to do the flush & Change this evening so bought two 1.5l bottles.

Fingers crossed!! :blink:
 

Feel

Veedubya 'velle
Jun 12, 2003
4,918
2
Midlands
Ah, okay G61 etc was all from memory...

If you do your coolant sensor when the car is cold, I don't think you'll loose any - I didn't.

From memory, O ring and C clip are different parts - I would make sure you get them, C clip is easy to break/loose.
 

petay_pan

Full Member
Oct 27, 2005
97
0
Ok just been out with the camera to have a look.

the coolant bottle prongs look ok to me:
P1000722.jpg



And I assume this is the sensor thing? Mine already green, I found it on the passenger side just underneath the smaller plastic engine cover.
P1000720.jpg



Doesn't look like too much hassle but see what you mean about the C clip thing looks flimsy.
 

Bosher

Active Member
As far I'm concerned it's the one shown in the lower pic Petay Pan uploaded.

Mines in a slightly different location as mines a 16 valver and a lot more difficult to get at.. [:@]

That's wot I'm replacing as soon as I can get one.
 

Feel

Veedubya 'velle
Jun 12, 2003
4,918
2
Midlands
we have two possible explanations for the temp gauge hanging at 70, 80 odd

feel says a sensor in the thermostat housing, others the blk/grn top sender in the coolant pipe...

which is it?:whistle:

or are both things the same?:blink:

Nope they ARE different., and the one that is the gauge sender IS IN THE thermostat housing on the 1.8T

As far I'm concerned it's the one shown in the lower pic Petay Pan uploaded.

Mines in a slightly different location as mines a 16 valver and a lot more difficult to get at.. [:@]

That's wot I'm replacing as soon as I can get one.

The one in the lower pic is the coolant temperature sender. Maybe it's different on a valver, but on a 1.8T this does NOT control the temperature gauge.

steady now, you do want to make 5000 posts dont you :p

Yes Sir. No Sir. Sorry Sir.
 

kieran

Guest
Nope they ARE different., and the one that is the gauge sender IS IN THE thermostat housing on the 1.8T



The one in the lower pic is the coolant temperature sender. Maybe it's different on a valver, but on a 1.8T this does NOT control the temperature gauge.

I have the problem with the erratic temperature gauge, sometimes it sits at 0 then shoots up to 90, other times it floats around other temperatures, but doesn't overheat, so i'm guessing my issue is with the gauge sender in the thermostat housing as you suggest.

My question is, how hard is it to replace this? Is there a guide anywhere? I've seen how to replace the coolant temp sensor as pictured above, as i thought this was the issue, but i get the impression i should be changing the sensor in the thermostat housing?
 

petay_pan

Full Member
Oct 27, 2005
97
0
^^^ what he said! :confused: :D

why they have to have sooo many sensors just for the temp! need to get to bottom of this.
 

Muttley

Catch that diesel!
Mar 17, 2006
4,987
31
North Kent
Feel, I've looked at all of the diagrams for Leon engines and they all have the coolant temperature gauge sensor (G2) in the same unit as the coolant temperature sender (G62). The VR5 and VR6 engines have this composite sender screwed into the thermostat housing, but all the 1.8t engines (APP, AJQ, ARY, AYQ) have the unit screwed into the coolant manifold attached to the cylinder head.

Now, it won't be the first time that the drawings are wrong, so can you tell me which engine you have and what makes you think that the temperature gauge sender is in the thermostat housing?

One easy way to tell if the unit you are looking at (green or black) contains one or two sensors is to count the number of wires going in to the connector. If it's more than two (could be three or four) then you have two sensors in the block.