Audi S2 ABY Radiator

[Crasher]

The car has AC so it made things very tight

[Solfella]

POGO Gen 3 65mm radiator fitted (a lot of “adjustments” required) almost requiring Vaseline

Sorry to resurrect and old thread, but came across your posts and wondered about the scope of those 'adjustments'. I have the 52mm version in the shed waiting to go in at some point. I hope this won't need vaseline.

[Crasher]

They never did seem to register on any car but when digital, always.His other 5 are the same.

[johne]

I wouldn't get too excited over the oil temp gauge, the one that came with my car originally was just the same. Way back I changed the aux gauges to aftermarket ones with white faces to improve things but basically oil temp tracks water temp (with a little lag on warm-up) and that's it.

[Crasher]

POGO Gen 3 65mm radiator fitted (a lot of “adjustments” required) almost requiring Vaseline with BEHR temp sender, genuine thermostat, new FTE oil pressure sender and now sits at 92 rad kick in BUT drops to an indicated 87 (thermostat threshold) on the cruise; but I think the oil temp gauge is FUBAR, never moves and new sensor on the new pump.

[JayCab]

That's an obscene amount of money to pay for such a simple sensor.

Supply and demand I guess. You could always try digging out the thermistors ;-)

[Nuvo]

That's an obscene amount of money to pay for such a simple sensor.

[JayCab]

I have ordered one of the BEHR senders with Pete but he says it is 3 pin, not 4.

Yes, that was the last available OE sensor. My original one (1999) was a 3 pin sensor. The OE 4 pins ones pre date my car. It was 3 pin from new. If anyone is interested, I can confirm a 1999 Cab still has the 4 pin harness with the +12v feed.

[Crasher]

I have ordered one of the BEHR senders with Pete but he says it is 3 pin, not 4.

[JayCab]

I have two 1995 ABY S2 Coupes which both behave exactly the same (both are standard cars and have AC. Aux Rads are still fitted and both have Wahle thermostats fitted).

In traffic the temperature will move up to an indicated 90 and the moment it edges above that, the fan will kick in for a short while. The fan is never continuously on and it never stays on for long, even in hot weather and irrespective of whether AC is on or not. The after-run pumps also work on both but are heard very rarely indeed and not for long.

When cruising on a motorway the indicated reading on both is 80-85, it never gets to 90 until I sit in traffic. It seems previous owners noted this and the thermostats were changed in both cars with no change to the above operation. I have read on here that on the ABY S2, the rush of air over the temperature gauge sender causes it to read slightly low and attempts have been made to insulate it etc.

I am remiss in not having taken an OBD reading of coolant temperature (and in any case the User Manual is nebulous in what forms a correct reading of all the gauges) but the situation has not really concerned me enough to warrant it. Certainly the cars are not in danger of over-heating, They may or may not be running slightly cool on a run but seemingly with no problem.

I also have a 1987 B3 90 quattro. This sits at 90 all the time when warm. In traffic the neelde will move to the centre point on the gauge and then the fan kicks in until it gets back to 90. The after run on this car runs nearly every single time on the 90 whereas it is very rare to hear it on the S2s.

I can confirm that my cooling system behaves similar to hashluck's vehicles,. Mine is a 1999 AAH cabriolet, so shares the key cooling components and control logic, minus the turbo aspects and the aux rad, but with an auto gearbox adding a heat load to the system as well.

However,;
- my vehicle reads 88-90C on the dial at cruise / high airflow, depending on ambient temp and cruise speed.

- my vehicle reads 100-102C at absolute max on the dial in blazing sun at idle after a slowdown from the motorway. At idle, the first stage fan will drop the temp at the needle to about 96-98C before turning off. I think the needle moves slower than the coolant cycle speed simply by being a slow analogue needle. The radiator top is untouchably hot just before fan kick in, and touchably cool at fan shut off.

- if it's one of our 30C + days, and the engine is hot with A/C running as well, it will sometimes run 2nd fan speed (which you really hear)

- my coolant temp at the dash is normally between 90-100. A crack under if cruising in cold air, a crack above if idling in blazing heat.

- behaviour is similar with A/C on, but with the cycle speed slowed down because the fan runs at constant A/C speed (slower than speed 1 triggered by the rad thermoswitch - sounds very quiet). When A/C is running, the cycle is generally between A/C speed and fan speed 1, on a slower cycle, with occasional fan speed 2 on a really hot day.

- I have never heard fan speed 2 with the A/C off on my car, but know the system will do this in hot countries with the same hardware.

I have:
- Brand new genuine thermostat (can still get from Audi - strangely)
- Nissens radiator (the behaviour was identical with the OE rad before it corroded, with all other components being the same)
- ERA 2 stage radiator fan control switch (if someone can get me genuine OE, please reach out :-))
- Genuine original MFTS (have also swapped for BEHR MFTS - with identical behaviour)
- Flushed cooling system refilled with genuine pre-mix G12 Evo coolant

[JayCab]

That's the sad part with MFTS's that there are no good suppliers left any more. I tried Vemo sensor and it was lying right out of the box. Showed way higher temps than they actually were. I hope you have more luck than I did. Ended up putting back the old Behr one.

Original BEHR MFTS can be obtained from Pete at Quattro Corner. It comes in a blue BEHR box, not an Audi box, and is identical to the original minus the Audi rings. It's over £100 though.
--> Note, I have purchased and installed this, and confirm it behaves identically to the original one. It's probably from the same production line as the original, sans Audi rings.

[Crasher]

Yes, it was VEMO and every one of the versions shown on TecDoc are 3 pin.

[ert]

I will have to check my spread sheets at work but I have a vague recollection of it being a 3 pin VEMO.

That's the sad part with MFTS's that there are no good suppliers left any more. I tried Vemo sensor and it was lying right out of the box. Showed way higher temps than they actually were. I hope you have more luck than I did. Ended up putting back the old Behr one.

[Crasher]

I have ordered a Pogo radiator and genuine thermostat but I can’t remember where the coolant temp sender came from, I will have to check my spread sheets at work but I have a vague recollection of it being a 3 pin VEMO.

[hashluck]

I have two 1995 ABY S2 Coupes which both behave exactly the same (both are standard cars and have AC. Aux Rads are still fitted and both have Wahle thermostats fitted).

In traffic the temperature will move up to an indicated 90 and the moment it edges above that, the fan will kick in for a short while. The fan is never continuously on and it never stays on for long, even in hot weather and irrespective of whether AC is on or not. The after-run pumps also work on both but are heard very rarely indeed and not for long.

When cruising on a motorway the indicated reading on both is 80-85, it never gets to 90 until I sit in traffic. It seems previous owners noted this and the thermostats were changed in both cars with no change to the above operation. I have read on here that on the ABY S2, the rush of air over the temperature gauge sender causes it to read slightly low and attempts have been made to insulate it etc.

I am remiss in not having taken an OBD reading of coolant temperature (and in any case the User Manual is nebulous in what forms a correct reading of all the gauges) but the situation has not really concerned me enough to warrant it. Certainly the cars are not in danger of over-heating, They may or may not be running slightly cool on a run but seemingly with no problem.

I also have a 1987 B3 90 quattro. This sits at 90 all the time when warm. In traffic the neelde will move to the centre point on the gauge and then the fan kicks in until it gets back to 90. The after run on this car runs nearly every single time on the 90 whereas it is very rare to hear it on the S2s.