Andrewembassy

I am currently in Armenia where there are no Audi servicing centers with scans, so your advice will be highly appreciated. 2000 Audi A6 Sedan Quattro 2.4l gas. Do not have any tech manuals with me.

It is hot summer here. The engine runs stable most of the time, keeping coolant at 90 C and oil at about 100 C, with tachometer at slightly above 500 rev when the car is not moving.

Problem 1. When does the radiator's electric fan usually start working? Never seen or heard it working. Note that the outside temperature is now around 30 C.

Problem 2. When outside temperature jumps above 30-35 C, the engine, after some driving, sometimes unexpectedly gets flooded : a) it either would not start, and then, after cranking for some time, it would slowly pick up producing lots of smoke until cleared, or (2) it would start on high rev, about 1200, as if in warm-up mode (though the engine is hot!), with very low power - so the car hardly moves. After the engine cools down a bit, it goes into normal mode again. Some say the coolant temperature sender (4 pin) gets crazy and sends low temperature signal to the computer, which in turn gives the engine a very rich mix and floods it. Note that when it happens, the coolant temperature gouge sometimes shows above 90 C - up to 100 C. I am confused - does this flooding happen because of the sensor or the fan not working, or something else?

QCRAZY

...regardless of how hot the engine gets!!

Andrewembassy

OK. Thanks. But the fan NEVER operates.

Cont. on engine flooding: In addition to no-start problem, I've noticed that the engine is very responsive in the morning, after the first start. However, after some daytime driving in the hot, the response unpleasantly slows. When it is extra hot, the engine sometimes even goes into EPC mode upon the start and hardly moves. Re-starting produces the same result. When the car cools down EPC signal stops lighting and things go into norm. Anybody have a clue what's going on?

QCRAZY

...but it's possible that the electric fan also works as the after-run fan. Meaning when the car is hot this fan will run to cool it down and keep it from getting even hotter AFTER the car is shut off.

I would investigate why your electric fan doesn't run and see what you find. Maybe it's just a blown fuse!!

Andrewembassy

The A/C appears to work OK when driving. When not moving, the compressor goes on and off all the time even in "LO" mode and practically does not cool, though the car could be as hot as frying pan after standing in open sun...

You may be right in thinking that the fan also plays as after-stop cooling fan too. I noticed that after I stop the engine, and then start it again after a few minutes, the temperature gouge shows higher than usual 90C - sometimes up to 100C. If the fan worked after shut-off, it probably would keep the temp at normal level...

QCRAZY

...should cycle on and off. That's normal.

Here's something you can try next time your car acts up. If the car isn't running correctly then shut the car off. Then turn your key so the accessories all start up (but the car doesn't start). This should turn the cooling fan on. Let the cooling fan run for a few mintues to cool the car down. Then try to start it and see if it acts normally.

I don't know what would cause the problems your having but if it is related to high engine temperature this may tell you.

Good Luck!!

Andrewembassy

Got all problems resolved finally:

1. The fan did not work because of the blown fuse under the dash - replaced. Now has a "siren sound"... bearable, though.

2. Engine flooded: finally found a mechanic with a matching scan tool at Skoda dealership. The coolant temp sender showed on scan -48C - Siberian cold. Accordingly the engine was running on super rich mix. Got the sensor replaced the same day and things are OK now.

Thanks everyone for suggestions and help.

Andrew