Engine temperature sender.

[Jas11n]

Anyone of you guys got the part number for the engine temperature sender that's located on the back of the engine, just below throttle body/ISV etc?
I've looked in the family album but can't seem to find it. Vag-com session on Sunday pulled up G62 - engine temperature sender when we dumped codes.
I've noticed the last week or so that the engine coolant temp getting way past where it used to be on the gauge before the fan cuts in. (fan now cuts in when needle is half way between 90 and 120 ) This seems the likely cause.

Thanks in advance

Jas

[gavs20v]

035 919 369m

[S2central.net]

Haven't checked PartNo, but G62 only connects to the ECU - it doesn't drive the coolant temperature guage. The temp guage signal comes from the MFTS (F76) under the water rail.

Check S2 central for details on when fans should be switched on, but yours sounds OK for that behaviour. The two 'overheat' switches are actually at the bottom of your main radiator - totally unrelated to G62.


Paul

[Jas11n]

035 919 369m

Thanks Gav, saving the day agin eh? you'll go to heaven one day mate

Jas

[Jas11n]

Haven't checked PartNo, but G62 only connects to the ECU - it doesn't drive the coolant temperature guage. The temp guage signal comes from the MFTS (F76) under the water rail.

Check S2 central for details on when fans should be switched on, but yours sounds OK for that behaviour. The two 'overheat' switches are actually at the bottom of your main radiator - totally unrelated to G62.


Paul

Thanks Paul will have a look

[Uukrul]

Anyone of you guys got the part number for the engine temperature sender that's located on the back of the engine, just below throttle body/ISV etc?
I've looked in the family album but can't seem to find it. Vag-com session on Sunday pulled up G62 - engine temperature sender when we dumped codes.
I've noticed the last week or so that the engine coolant temp getting way past where it used to be on the gauge before the fan cuts in. (fan now cuts in when needle is half way between 90 and 120 ) This seems the likely cause.

Thanks in advance

Jas

I do not think that there are any direct relations between temperature sender on the back of the engine, the coolant temp. gauge and the radiator fan.

The temperature sender on the back of the engine is used only by ECU.

The coolant temp. gauge uses the 3/4-pin multi-malfunction sensor on the coolant manifold.

Radiator fan uses thermo-switch on the bottom of radiator.

Of course, if ECU says "G62 error" - check the sender (do not forget to check the connector/wires - it gets pretty warm there).

[Jas11n]

Thanks for the replies, I'll change the G62 sender as it's coming up as a fault.
I'll also change the stat as I'm thinking it may have gone as I was getting temp readings of 2/3 notches above 90 on the motorway yesterday driving at around 90/100mph, which never dropped even when I left the motorway and got back down to 50/60mph. If the stat was duff, would it cause this? or would it just boil it's brains out and go pop?
I'll also give the whole coolant system a flush and refill with G12+

[PeteRR]

Would a failing M.F.T.S. ever give a slightly high gauge reading when the engine is fully warm?,
'cos thats what I'm getting and almost everthing else checks out ok

[Uukrul]

Would a failing M.F.T.S. ever give a slightly high gauge reading when the engine is fully warm?,
'cos thats what I'm getting and almost everthing else checks out ok

Well, on both my cars MFTS failure resulted in completely dead coolant temperature gauge (the same picture as if ignition was off).

Though it is possible to get different effects - the MFTS often gets flooded by coolant fluid (overtightening?) and that fluid does bad things to electronics. Especialy if you have 4-pin (the older over-engineered VDO design) MFTS.

BTW, what do you mean by "slightly high" ? 100C ? 110C ? I sometimes get ~100C when car is not moving fast, for example doing 0-60-0 several times with wide-open throttle. Different picture when speed is high enough - at 100kmh and more coolant temperature stays ~90C, but oil temperature goes up

[mcandmar]

Same here, totally dead gauge with the faulty MFTS. BUT when it was working it always read slightly higher temps than the new ones does. Not sure which was wrong but it sits 90 degrees fully warm, will goto 100 if sitting in traffic jams now.

Slightly off topic, any idea what the 4th pin did on the old design? New one i got was a three pin

I also remember someone on the 20v.org list talk about adding a ground wire to the casing of the sensor to cure erratic behaviour.

Mark.

Well, on both my cars MFTS failure resulted in completely dead coolant temperature gauge (the same picture as if ignition was off).

Though it is possible to get different effects - the MFTS often gets flooded by coolant fluid (overtightening?) and that fluid does bad things to electronics. Especialy if you have 4-pin (the older over-engineered VDO design) MFTS.

[gavs20v]

pretty sure the 4th pin was an earth

[Uukrul]

pretty sure the 4th pin was an earth

And I am pretty sure that 4th pin is +12V New MFTS is not so complicated and does not need +12V. Ground is the coolant manifold.

[PeteRR]

BTW, what do you mean by "slightly high" ? 100C ? 110C ? I sometimes get ~100C when car is not moving fast, for example doing 0-60-0 several times with wide-open throttle. Different picture when speed is high enough - at 100kmh and more coolant temperature stays ~90C, but oil temperature goes up

Not sure of the exact temp as the urq has a led digi-dash. It just shows one or two 'notches' higher than it used to/should after using 'Bars Flush' and new rads, stat, coolant etc,etc.
Everything has been checked/substituted/tested several times, all but the MFTS. I may just have to get a new one to eliminate it from the enquiries!

Would the flush compound effect the sender in any way?, I've run out of ideas why the temp. reading has changed.

[kwlw]

Not sure of the exact temp as the urq has a led digi-dash. It just shows one or two 'notches' higher than it used to/should after using 'Bars Flush' and new rads, stat, coolant etc,etc.
Everything has been checked/substituted/tested several times, all but the MFTS. I may just have to get a new one to eliminate it from the enquiries!

Would the flush compound effect the sender in any way?, I've run out of ideas why the temp. reading has changed.

Could you take picture of your digidash when you think engine is too hot. I will try to compare it with my digidash readings for AAN (with newer style MFTS).

Sau

[PeteRR]

Not sure its too hot, but the gauge will sit on the 'N', or one/two notches above the 'N'.

It should/did sit at one notch below the 'N' and rise to one over in traffic until the fan kicks in.

I should hopefully get the car back soon and will see if there is any difference in running temp. But they found nothing specific to cause it.

(Could it be the new stats. that make it run a fraction warmer?)