Just bought an 02 C5 coupe with manual trans, 24,000 miles and totally stock engine. I have had it for a week and took a long wknd trip this wknd putting around 1,000 miles in all. Im in Colorado, so I was really pushing it on some the winding mountain roads. Lots of inclines and cornering and some temps in the 90s. It ran fine except two things

1-climbing Pikes Peak, I was in first/second gear behind slow traffic going up the steep road for at least 2 miles. Near the summit the clutch was on the floor and basically useless. I let the car sit for a while and have had no problems since. This happened half way into the trip, so I did a lot of driving after that with no issues. Is this a heat issue? or something more worrisome. The engine/coolant temps were running normal and no warnings came on the info center. I usually shift around 3-3500 rpm if that matters.

2. Tonite as I was driving home from dinner, the low oil warning came on. I checked it and it certainly was low. I know there are postings of the C5 being oil hungry. Is this just something to live with or is it a result of the type of driving I did over the wknd? Again, Oil pressure and temps were always within normal ranges. The driver info states 44% oil life remaining. Does anyone know how altitude affects engine performance? Obviously less O2 but enough to make a difference in airflow/performance?

Sorry if these are questions of ignorance, but its new to me. Thanks for any input. Nick

 

One more thing....clutch fluid level was normal/full and no sign of leaking as far as I could tell with the car on the ground.

 

Unless you are running the car on the track back off shifting at 3000 to 3500 rpms on a regular basis. Some engines use oil if you buzz them to those rpms under low load conditions. Top off your oil and on the way home monitor the oil level to see if it still drops with the modified shift pattern.

Not sure what conditions cause the sticky clutch issue but some people think it is heat. Check Ranger's posts on this issue. Personally, I have driven C5s on the track and street for 11 years without ever encountering a sticky clutch.

Bill

 

low oil light is sometimes a common situation that will naturally go away after sitting on a level surface. You can get this warning light after changing oil and being full just fyi.

If it is truly low add oil and smile.

 

As far as your question ....

Does anyone know how altitude affects engine performance? Obviously less O2 but enough to make a difference in airflow/performance?

Yup .... the higher the altitude the lower the air pressure (density) so the lower the performance of your engine. At 6000 feet multiply your "sea level" HP by 0.8 ... so your 350 HP engine is putting out about 280 HP.

Your engine has a MAF sensor (Mass Air Flow) that measures the mass (weight) of the air flowing into the engine. The PCM uses that data in calculating how much fuel to inject into the engine, which means the PCM is able to adjust automatically as the altitude changes.

On the LOW OIL issue ... are you sure the oil level was at FULL when you got the car ?? It is possible it was close to the LOW warning point and the 1000 mile trip used enough oil to triggr the warning ??

If you search for "sticky clutch" you will find hundreds of threads, all filled with vitriolic disagreement, on the causes and cures for this "problem". General agreement seems to be it is heated related, but others blame it on high engine RPM, others on clutch design, others on combinations of these. I believe there are still a couple of holdouts for the sunspot theory.

 

Suggest you change / flush your clutch fluid, and brake fluid while your're at it. I'll bet it looks dark and has absorbed lots of water over time, since brake / clutch DOT 3/4 fluid is hydroscopic. Water has a lower boiling point, and your fluid, which includes a lot of water got hot enough to boil, and bubbles don't work so good in brake / clutch applications.

Engine oil..........not all that unusual to burn some. Either add a quart, or change oil and filter, then monitor and see how much you are using.