G62 temerature sender alternative

L

luftube

Member
I had the engine management light on intermittently with the common 17664 coolant temp open or short fault. I bought a new sensor and fitted it, everything was ok for about a week then fault came back iv'e cancelled fault twice now but comes back after 2 or 3 days, the wiring all looks ok and the connector is clean.
Ive read on other forums that you can get a more relable updated version of this sender that is green in colour (mine is black with 4 terminals) they say VW / Audi ones are interchangable across the range, I don't know if this is true of A2s.
The problem I have is that the green one Audi offered me that they said was for my car (indentified with the reg number) would fit into the hose ok but the electrical plug was the wrong size and couldn't be fitted.
Has anyone had any experiance of this better alternative G62 sensor. Or am I missing something and is there's another fault that can generate this fault code.

1.4 TDI SE 75hp 2004
 
I'd have thought your 2004 car would use the green sender already...? I was under the impression that the 2-pin black version was phased out during 2001.

Tom
 
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Mine is a 4 wire black sender with a flat bottom (coolant end) the green one they offered me had an extention about 20mm long at the coolant end and a 4 wire connection for the plug but the socket for the plug was about 2/3rds the size of mine so you couldn't get the plug on. I wondered if there was a green one that would fit my plug.
 
dan_b said:
Are you 100% sure you're looking at the coolant sensor?
Click to expand...

Ah, I do seem to remember Dan confusing it with the fuel temp sensor, or something like that...?

That's correct: there should be 4 wires as the later, green ones have 4 pins. They also have a 'nipple' at the coolant end. I'd have though that, for a 2004 car, you'd have been supplied with a green one. My 2002 A2 uses the green one.

Tom
 
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Indeed so - the easier to see and reach one is the fuel temperature sender and is a black 2-pin unit (well it was on my 2003 TDi). The harder to see and reach coolant temperature sender is the green 4-pin one.
 
My sender is in the bottom hose at the radiator its easy to get to if you take off the under shield I don't think there is another coolant sender anywhere else as iv'e looked round the engine and on the Etos parts manual it only lists one temp sender for my engine which is a BHC engine, the exploded view in the manual shows it in that position.

Thanks for your input
Roger
 
That's a different sender to the one everyone else is talking about then.
The coolant temperature sender that is used to send a set of signals to the ECU and another set of signals to the dashboard is located round the back of the block, on the right hand side. You can't actually see it directly but it's there nonetheless.

Which radiator is this sensor next to - the small thin one on the left, or the bigger wider one on the right? You might well be looking at the charge temperature sensor for the turbo monitoring.
 
Which engine does luftube have? I seem to recall that the coolant temperature senders were in different locations on the TDI versus the petrols.
 
The BHC engine uses the same cylinder block, head, etc as the AMF engine, so its coolant temp sender should be located around the back of the engine, as Dan describes.
 
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No its definitly in the bottom hose connection to the radiator of the cooling system there is a plastic housing on the end of the bottom hose that connects to the radiator (offside bottom of the radiator) and the sensor fits into it with a plastic clip to retain it. The description on the elsa win is 'G62 coolant sensor' I will have a look round the back of the engine but as far as I'm aware there is only the inlet manifold and turbo round there.

Thanks Roger
 
When I look round the back of the engine (I could use a mirror) is this sender you talk about directly in the block or head or is it in a hose or housing for the coolant system.
Before I go out I could have a look at the elsa win diagram for the AMF engine to get an idea where to look. It will be at least a couple of hours before I can look as my wife won't be home till then but I will post my results later.

Thanks for your suport. Roger
 
Ok, I've just been outside to have an investigate... I have parked outside my house at the moment both a BHC-engined A2 and an AMF-engined A2, so was able to compare.

BHC engine: There is a 4-pin sensor at the very bottom of the radiator, on the near-side, that's plugged into a small section of tubing that runs longitudinally, at 90 degrees to the radiator. On the off-side, adjacent to the intercooler, there doesn't appear to be any water plumbing whatsoever.

AMF engine: The 4-pin sensor mentioned above, at the base of the radiator, is also present.

This is not the coolant temp sender that is responsible for sending information to the engine ECU and temp guage in the instrument cluster. Given that both the AMF and BHC engines appear to have this radiator-sited sensor, I can only assume that both have the sensor around the back of the engine as well, which is the sensor you wish to replace.

Tom
 
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dan_b said:
Check out Spike's photo

http://www.a2oc.net/forum/showthread.php?3208-Temperature-gauge-woes&p=80965#post80965

You're looking side on at the back right corner of the engine if that helps orientate - there's the sensor mounted pointing slightly upwards.
There's usually a cable/pipe retaining bracket on the right hand side of the block which is worth removing to make access/visibility easier.
Click to expand...

Good find, Dan. This settles the matter.

With the help of the photo that Dan has linked, I was able to run outside and have another look at the BHC engine. Surely enough, there's the coolant temp sender!
I can see how Dan confused the fuel temp and coolant temp sensors when he did this job; they're quite close to each other. The coolant one is located slightly lower down and further to the back of the engine. It has 4 pins, whereas the fuel one only has two.

Tom
 
Thanks for all your efforts sorry I' getting my offside /near side mixed up mine is exactly the same setup at the bottom hose as you describe. I assumed that because this sensor is a 4 wire one in the coolant system that it was the right one to replace. Now I will locate and replace the one round the back (green one). I see now why even though the green sensor Audi supplied fit in the socket at the radiator the plug would not go on.

Thanks again for all your help Roger
 
No worries. Before you swap this sensor, you may consider detaching the coolant expansion tank and lowering it down towards the gearbox. When you remove the sensor, coolant will start pouring out and you'll have to be ready with the replacement sensor, but you'll minimise your loss and make the job of getting the replacement clipped in properly much easier without the pressure from the expansion tank.
In case you're unaware, the tank is held in place with just one 10mm nut, below its rubbery mounting points.

Cheers,

Tom
 
Thanks for all your help again looks like I should get a new sensor first so I can swop them as quick as possible to minimise coolant loss (Iv'e only just changed the coolant along with the oil and filter). It will have to be weekend when I can get the sensor and do the job I'll report back if its a success

Thanks Roger
 
It's very easy to drop the clip down the back of the engine too with the stress/ pressure of trying to secure it quickly to prevent coolant gushing out!
You can help prevent this by tying a piece of wire around it and looping the other end around something first.
 
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