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Hey guys need some quick info. I've got a 2005 Saab 9-7x that I just swapped another 5.3 into and thought I had low / no oil pressure problems. The sending unit was working on the truck I pulled it out of as the gauge on the dash read fine. Once I swapped it in the Saab however it is reading basically nothing. I'm thinking it was the sending unit all along though as I hooked a mechanical gauge up to 2 different ports in the pan and both read over 50psi cold at idle.
question is is this a good spot to get a reading? The oil filter is in the center of the pan as its front sump and awd. So it has 2 Allen plugs. I removed one checked it...then removed the other and checked...both had good psi. My GTO had a small cover in this spot and I drilled and tapped it to read oil pan on it...so I assume it would be a good spot for this vehicle as well. Should I just assume I have good PSI now and try to replace the sending unit? Or should I try to check it at the sending unit as well. I don't have a adapter for it through. Since it's like a 16mm thread.
I'm probably being over paranoid at this point. But just would like some input. The 2 plugs I'm pulling pressure off of are at the rear of the pan on this pic.
If they are after the filter then they are OK. If you have access to a shop manual, it will have an oil flow diagram. That is too different from a truck, I think, to give a definite answer.
Both of those tubes run directly to the filter so I know one is pre filter and the other is post filter I'm almost certain. So that being said. Bother were over 50 PSI I and within 5 Psi of each other. This was only temporary to check for pressure so I'm assuming I have a bad sending unit? I'm also wondering if there might be a difference from for gen 3 to gen 4 sensors?
This all started because I thought I had low oil pressure. Turns out the oil psi sender was not working or not the same as the one for my Saab 9-7x. The connector on both wet both 3 pins but they did look just a but different. Gauge on dash is working great now.
In review for the thread though. Those 2 plugs in the rest of the pan work well for reading psi. They are fairly easy to get to as well. Was reading 50psi or more on both. If I were actually mounting a gauge permanently it would make sense to use the POST filter one though. The factory gauge just has L and H but appears to be spot on with 50psi or so.
08-22-2018, 09:10 PM
Mechanical oil pressure gauge location?
