Re: Oil Pressure Problems

Posted by Tim Cole On 2012/7/3 15:20:59

Dear Jim:

In the case of the DeSoto once the car cooled off the oil pressure came back up, but was always pretty rotten. Keep in mind that the gauge and sender weren't rebuilt, but that it started out okay and consistently got lousy as the oil heated up. You really don't need a lot of oil pressure to keep lifters quiet. Also, the owner thought this was a low mileage car and so he didn't like the low oil pressure at idle. The visual problem was that the oil pressure was too heavily correlated with motor rpm which indicates high mileage. Lifter noise in the Packard V-8 is a rather unique case because it happens at road speeds. I've seen known shot motors with quiet lifters, for example a Chrysler 318 with oil pump failure and quiet lifters.

For your car there is another possibility which has to do with the pick up. The drain plug on the Packard V-8 is in a lousy location and responsible for sludging. I've had machine shops tell me that the Packard V-8 is the dirtiest engine they have seen. Although I doubt they are old enough to remember the Chevrolet 235 six which would literally fill to the top with sludge.

Anyway, the oil pickup may be clogging from crap in the oil pan. So first step is overfill the oil level by one quart and retest. If no change then pull the oil pan. If the siutation is better suspect an oil pump issue.

Good luck with your car.