Wierd Oil Problem... Viscosity related?

Spartan · 11-12-2009, 07:57 PM

Heres the issue my Buddies BII is having, I'd like some confirmation on weather or not Im on the right track.

Its an 89 XLT, and it has the infamous tapping problem. When first started up, it DOES NOT TAP, and has great oil pressure. After driving for about 10-15 minutes or after it has warmed up, it taps like a sunovabish. Also, when you let off of the gas and coast, oil pressure (again according to the gauge) dropps completely off into low range, and then bounces a bit near the cutoff for no to little pressure.

The oild HAS NOT been changed by my buddie, as he got the truck a few months ago and have been slowly scrapping my 89 XL to make one good truck. We had to replace the brake booster, seats, instrument cluster and other stuff. The oil has unkown milage on it, and is dirty as hell. My theory is that since when you startup and until it is warm there is no tapping and no pressure issues, we are seeing viscosity breakdown as the oil heats up. When it heats up, it gets thin, causing low oil pressure and not enough oil getting to the top of the motor to keep it from tapping.

Am I on the right track here? Saturday morning we are changing th oil regardless, but I fuigered id ask here to see if I'm thinking right.

Thanks

kevin

11-12-2009, 07:57 PM	#1
Spartan Wannabe Elite Explorer Sun Prairie WI 92 XLT Join Date: Sep 2009 Posts: 53 Vehicle Specs (Original Poster)	Wierd Oil Problem... Viscosity related? Heres the issue my Buddies BII is having, I'd like some confirmation on weather or not Im on the right track. Its an 89 XLT, and it has the infamous tapping problem. When first started up, it DOES NOT TAP, and has great oil pressure. After driving for about 10-15 minutes or after it has warmed up, it taps like a sunovabish. Also, when you let off of the gas and coast, oil pressure (again according to the gauge) dropps completely off into low range, and then bounces a bit near the cutoff for no to little pressure. The oild HAS NOT been changed by my buddie, as he got the truck a few months ago and have been slowly scrapping my 89 XL to make one good truck. We had to replace the brake booster, seats, instrument cluster and other stuff. The oil has unkown milage on it, and is dirty as hell. My theory is that since when you startup and until it is warm there is no tapping and no pressure issues, we are seeing viscosity breakdown as the oil heats up. When it heats up, it gets thin, causing low oil pressure and not enough oil getting to the top of the motor to keep it from tapping. Am I on the right track here? Saturday morning we are changing th oil regardless, but I fuigered id ask here to see if I'm thinking right. Thanks kevin