joe audi

Hello, I'm a new member and old Audi owner! I have a 2000 A6 4.2L quattro. Just last week the engine oil and coolant temp gauges started to read anywhere from 25-50 degrees hotter than normal. This in turn has caused my ac to blow hot air. I should also mention that at 45mph up to highway speeds both run exactly where they are supposed to and the ac blows cold. I was told the condenser sits behind the radiator and causes the ac to blow hot when the other temps are high, so I am trying to find out if anyone has any ideas of what could be causing the sudden change in engine oil and coolant temp. Again, it doesn't overheat, at least not yet , just wondering if this is another common issue and if I should be looking for a sensor, thermostat, fan, or fuse issue? Thanks for any insight you can offer!!!

Airbag

just a guess but i would say if BOTH your coolant and oil are runing warm they really are and it is a mechanical/ electrical issue and not a sensor . I would just make sure your fans are working right off the bat ..

uberwgn

Joe, welcome aboard! First thing I'd do is verify all cooling fans are working.

GTA_Driver

Got enough coolant? If so, something is blocking its flow. Maybe the thermostat (not uncommon). Or maybe something else (though unlikely there'd be blockage in plumbing).

Airbag

i thought of that too but he says at highway speeds it is normal means he might be getting enough cooling from airflow without fans .. and besides .. in for a stat .. petty well in for everything no ?

GTA_Driver

When my fans weren't working on the 4.2 A6, the only time the temperature would climb up was in stop and go traffic. As long as the car was moving, it was fine.

Not sure I got your comment about "in for a stat" ... :|

Airbag

if im replacing the stat .. im replacing the water pump .. and the timing belt , and the rollers ....

so figured checking the fans may be a good start

2.7Lturbo

check oil... does it look clumpy/milky?

joe audi

Thanks for all the input! Just had an oil change, and didnt see the old, but the place put the wrong oil weight in first and had to drain and refill, so it got an unplanned flush also! I'll try checking the fans first i guess and go from there, just hate the idea of tracing electrical in this beast. Btw, my motion sensor and trunk release buttons on the b-pillar have switched, i now have to press the motion sensor to pop the trunk, and the bose system keeps blowing fuses, any ideas on that! Like i said, not looking forward to electrical diagnostics on this beast!!! Thanks again!

GTA_Driver

It's not that much different from any electrical diagnostic on any other modern car, in fact, probably better

First, switch the buttons ?

You will do well do acquire VAG-COM / VCDS from Ross-Tech if you at all want to get anywhere in diagnosing anything with this car. Without it, you're at the mercy of (in)competent mechanics.

And where did you take it for an oil change? Find a good independent mechanic that works on Audis.