1999 Mitsubishi Mirage • 75,000 miles

Hi, I have a 1999 mitsubishi mirage with 75k on it. The previous owner drove it hard. After driving on the highway 60-70mph and then off the highway: the lifter makes a loud ticking noise. I changed the oil 5-30 (maybe I should have used synthetic) I put a little stp in there too. The oil pan has a crack where it leaks a minor amount of oil: but could this result in low oil pressure on the highway? Just driving around town 35-45 mph no problem (no noise whatsoever). Any suggestions? I am not a mechanic. Thanks ahead of time for your help!
August 30, 2012.

Hydraulic lifters hates additives if I must say from personal experiences. The problem is not with synthetic oil or not. If the engine is heavily sludged, the lifters would be affected.

If the oil level is low, high speed driving would have a problem with oil pressure as there is insufficient oil for the pump to work. Likewise if the engine is heavily sludged, the stariner would be partially cloggged and this would result in oil flow problem whereby the pump is not able to work fast enough to provide sufficient oil for lubrication.

Since the oil pan is cracked, you need to either repair or replace it. While ther, check the oil strainer for blockages.

Aug 30, 2012.
Thanks KHLow2008, when I had the oil changed I believe they put in 4 quarts instead of the required 3.2 quarts. Could this cause the engine to be heavily sludged (even though I just changed the oil) and yes, I will have to check the oil strainer. Thanks & GB

Aug 31, 2012.
No, sludge is caused by long term use with far and few oil changes in between and addition of additives.

A little excess of oil does not cause the problem.

Aug 31, 2012.