could my car be overheating...temp gauge shows displays needle past middle marker
 

Hi,

Maybe someone can tell me whats going on with my car. The temp gauge needle sits almost near the next marker after the middle marker and oil temp is right on the marker (225 degrees) before the 250 degrees marker. Could it be overheating?

Scenario 1
Outside temp around 80 degrees. This also happened during the winter time when its very cold, but it takes a lot longer for the needle to move past the middle marker.
When I leave work and drive for roughly 15 miles (highway), with no traffic, and then stop at a stop light for roughly 3 min, I notice that the temp needle starts to creep up past the middle marker, once i start driving again, ~15 sec, it goes back to the middle marker. The oil temp is right on the 225 degrees marker. If I'm moving, then the temp needle stays in the middle and everything seems normal. During stop and go city traffic, I see the temp needle go past the middle when stopped and back to the middle after driving.

Scenario 2
Outside temp is cool and not blazing hot.
I drive roughly 15 miles or so and then stop at the store to pick up something. Before I shutdown my car I notice that the temp needle is in the middle like it should be. I turn off the car, and return in less than 5 min, and start the car back on. The temp marker now goes past the middle marker and starts to creep to the next marker. If I drive for a few min, it goes back to the middle. I hope this all makes sense. I'm just trying to describe the issue.

Should the oil temp be around 225 degrees while driving for only 15 miles or so. I don't drive agressive and the outside temp is not hot.

Any help would greatly be appreciated.

Re: could my car be overheating...temp gauge shows displays needle past middle marker
 

I forgot to mention that my car is an A4 2.8 2000, with 99k miles.

I could be wrong but I don't think I've ever seen either of my 30V's oil get that hot
 

even punishing them with several hours of 100+ MPH driving in summer temps.

Re: could my car be overheating...temp gauge shows displays needle past middle marker
 

and I don't run the AC since I'm afraid that it will heat up faster than normal.

Couple of things
 

Could be thermostat, temp sensor, fan sensor switch
Also make sure you have not lost fluid
Have the car checked for codes.

Heatsoak? when you are idling is the a/c on?

Typical for an older car whose cooling system is losing efficiency.
 

The gauge is designed to read dead center over a range of normal operating temperatures. So when that gauge moves past the center mark, you have a problem brewing.

What's going on is that the cooling system can no longer keep up with the demands of the engine. Typically the source is a partially clogged radiator (calcium and other deposits will slowly clog the channels inside). Debris trapped between the fins on the outside of the radiator can also contribute to these symptoms. A less likely scenario is that the thermostat doesn't open fully.

Assuming you're giving this to a garage to do, I would bundle the cooling system work with a timing belt job. Have them replace the timing belt, tensioner, rollers, water pump, thermostat, and yes, I would recommend the radiator based on what you're saying. Independent shop will probably charge $1500 give or take for the whole thing.

Re: Heatsoak? when you are idling is the a/c on?
 

No, the A/C is always off. Just afraid to use it as it causes the temp to go up.

temp guage shows needle past middle
 

OP, did you ever find the root cause / solution to your issue? I have a B5 S4 and am experiencing the same problem. I have a VAG but don't exactly know what I should be measuring and what values to be looking for. Any help would be GREATLY appreciated as I haven't been able to find many posts describing the issues I am having as well as this one does.

Dude, this post is three YEARS old.

Why not do a search or start a new thread?

Search for thermostat and coolant temp sensor.