Engine Performance problem
1993 Nissan 240SX 4 cyl Two Wheel Drive Automatic 168000 miles
Hello, I own a 1993 Nissan 240SX w/168,000 original miles. I purchased the car new and know that the car/engine have not been abused.
I've noted (for a few years now) that the cylinder 2 spark has oil - not only on the pug tip area, but also on the base of the plug. The other 3 plugs look good.
I ran a compression test (following Nissan manual guidance) and came up with very low results:
Cylinder - PSI - PSI after adding a little oil
1 - 110 - 135
2 - 105 - 130
3 - 105 - 115
4 - 110 - 130
The Nissan (1993) manual says that PSI should be 179, minimum - 151, and max difference between cylinders - 14.
The car runs fine - no stumbling, missing, etc. It burns/loses virtually no oil. Performance may be down somewhat - but it is not significant. (I drive the car mostly in town, drive the speed limit, no jack-rabbit starts, etc, and as the car has aged - so have I - not " Speed Racer" or the like.)
My questions are:
1. How concerned should I be about the abnormally low compression?
(My goal is to continue to own/drive the car sensibly - without experiencing serious mechanical issues.)
2. If the cylinders continue to lose compression (over the next several months/years) - what symptoms/issues will I most likely experience with the car?
3. Outside of pulling apart/rebuilding the engine/head - are their any additives/products you would recommend I look into to help restore (some) lost compression?
I've seen various products at the auto store advertising their ability to restore lost compression, etc, though I confess to being a skeptic.
Mark. McKamey@us. Army. Mil
Thursday, May 8th, 2008 AT 7:00 AM