I have a 1998 Audi a4 1.8T Quattro with the sage 2 tuning (Scorpio dual pipes, permantent air filter, Chipped) with 187,000 miles. The timing belt, v belts and all other maintance has been taken care of recently. But yesterday when I was driving it (45-60 mph) it overheated. I didn't think it was a huge deal so I let it cool down and finished my drive, by the time I got back it had overheated again. The car had been sitting for awhile (hadn't driven for awhile) do I though the thermostat might be sticking so I bought a new one and replaced it. I also put new coolant in it just because I hadn't in a little while and I was already under the car. Well i drove it today hopeing that fixed the problem. It didn't, it still overheated in about 5-10 minutes of driving. The oil temp. Gauge says around 250 but the other temp. Gauge goes past H and starts flashing on my dashboard. I have no idea why it's doing this so if you could help me that would be great!

 

Have you nothed if the fans are coming on when the engine gets hot? Are the drive belts OK?

 

Plastic water pump impeller failure?

 

What year is your car?

Jason

 

All belts look to be working and good condition

The front fan (the one on the driver side comes on, the left doesn't but I think that's the ac fan)

What is a plastic water pump impeller and what are signs of its failure?

And lastly it's a 1998

 

The check engine light is now on and doesn't go away when I unplug the battery and replug it in. Also te dash says "service oil" but the oil level and color are fine

 

Now that the check engine lamp is you should get the ECM scanned and see what it is complaining about. Much easier and cheaper than throwing parts at the problem.

 

Audi A4 Service light reset:
Turn off the ignition
Press and hold the button on the left hand side of the display while turning the ignition on.
Service oil will be displayed.
Pull out the button on the right side of the display until the service prompt is cleared.
The display should now read ---

If the above procedure does not work, outlined below is a alternative procedure.

With the ignition off, push the right button.
Turn the ignition on and then pull the left button.
This should clear the warning message
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As far as the plastic impeller goes - did you replace the water pump?

The OEM water pumps (as well as a lot of replacements) have a plastic impeller that can split and slip on the shaft - causing overheating. Being a 1998, there's a good chance the pump was replaced, but it could have been replaced with a plastic impeller model and not a metal impeller model.

 

I'll try to take it to an autozone do they can read the code

And in regards to the water pump how would I know that's the problem? The left side of the engine always feels really hot, the right side is not that hot not sure if that means anything

 

Coolant should be circulating in the expansion tank.