shikado

Background info:
2001 A6 2.7T with 77K mi. Need to do a 600-mi round trip in the desert next week.

Hi guys,
This is my second summer that I've been experienced with these issues. Under normal condition, my oil temp read out is always at 225 (a tick below middle) and my coolant is alway right in the middle.

During hot day when the temp. reach 95+ degree, my car will start acting weird.

1. A/C problem: Unlike older car that the compressor and fan will kick in when you drive and off when idle, my A/C will still blows air but the compressor will be off and on while driving. When idle, the A/C basically becomes useless (blowing out warm air).

2. LOPS warining: This also happen in a hot day. Once the engine reach the normal operating temp., if I happen to hit either traffics, slow moving in parking construction, or idling at a few consecutive red lights, both the coolant and oil temp will starting to creep up. When both guage get to the next tick (250 for oil and 5/8 mark for coolant), I get the Low Oil Pressure sensor warning. No overheat, just the LOPS warning. When it happen, I pulled over and let the car cool down. No problem afterward (providing the car is back on the move, not sitting idling).

When this happen last yr, I took the car in but the dealer couldn't find the problem and the problems kind of went away on its own due to weather being cooler. Now, it came back a few weeks ago and I'm a bit concern. I don't want to be strand out there in the desert. Any idea?

Just Me

1. the AC condenser
2. the radiator

maybe via leaves, etc.

I assume you have already checked the levels of both coolant and refrigerant?

Note that hot coolant will raise the temperature of the condenser to the point where it might become useless.

Those are my ideas ( guesses?) anyway.

Grant

Jonathant25

The low oil pressure warning is a common occurence. I'm in the middle of trying to diagnose mine right now! There are a lot of posts on the A6, 2.7t, and S4 boards about this, but none really root out the cause. I just changed out my oil pressure sender ($12 part)yesterday and instead of intermittent low oil pressure warning it's now on constantly although my pressure checks out fine. WTF? Next step is to drop the lower pan and check the sump screen.

Changing the oil pressure sender is a bit of a PITA. You have to drop the sway bar, move the intercooler hose out of the way and use some contortionist movements of your hand to get in there. I have an Audi pic of it if you want... Some people have had luck just changing this as it gets loaded with oil.

shikado

The smaller one on the inside is not.