91GPSTE Posted November 27, 2006 Report Share Posted November 27, 2006 I was just wondering, those who have 3.1 GPs, what is your oil pressure gauge reading when the car is idling? My doesn't seem right because when I first start the car, the pressure jumps up then slowly drops down to almost red line. When I give it some gas, it shoots up again then comes back down. Same goes when I am driving. Is this normal or should I be worried? How hard is the oil pump to replace? Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted November 27, 2006 Report Share Posted November 27, 2006 http://www.w-body.com/forum/index.php/topic,51537.0.html Quote Link to comment Share on other sites More sharing options...
91GPSTE Posted November 27, 2006 Author Report Share Posted November 27, 2006 Thanks for the link. That helps a bit I suppose. Is the stock pressure gauge in psi? Mine only has 3 readings on it 0, 275 and 550. When it idles, it shows around 68 on the gauge. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted November 27, 2006 Report Share Posted November 27, 2006 USA gauges are on PSI....canada are in kPa. As for changing the oil pump, the pan has to come off, thus you'll have to pull the engine or lift it up a bit. Other than that, shouldnt be that bad. However, most stock gauges aren't that accurate, especially if the sender hasn't been changed in a while. For reference, USA gauges only have three numbers, 0, 40 and 80 psi. Quote Link to comment Share on other sites More sharing options...
91GPSTE Posted November 27, 2006 Author Report Share Posted November 27, 2006 I am guessing the sender is in the oil pan as well? Quote Link to comment Share on other sites More sharing options...
Supreme Cutlass Posted November 27, 2006 Report Share Posted November 27, 2006 The pressure sender is right next to the filter. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted November 27, 2006 Report Share Posted November 27, 2006 The pressure sender is right next to the filter. Yeah, it'll have an electrical connector, and the sender itself is usually silver (bare metal) colored, about 3in long. It just screws into the block, next to the filter. I think it takes a 7/8" wrench to get it off. Quote Link to comment Share on other sites More sharing options...
91GPSTE Posted November 27, 2006 Author Report Share Posted November 27, 2006 Ah, nice. That makes it easier, I will just swap one from my old motor when I do an oil change. Quote Link to comment Share on other sites More sharing options...
White93z34 Posted November 27, 2006 Report Share Posted November 27, 2006 best off to buy a new one, the old ones do nothing but FAIL. almsot any early 90s GM car that i'm in has the same issue you just described. Quote Link to comment Share on other sites More sharing options...
turby Posted November 27, 2006 Report Share Posted November 27, 2006 best off to buy a new one, the old ones do nothing but FAIL. Very true. When the one in my 89 GP failed it allowed oil to get out where the switch is pressed together. I didn't lose pressure until the motor was cooked. One minute I had pressure the next I had an awful bearing knock. Gauge still showed pressure though. Quote Link to comment Share on other sites More sharing options...
91GPSTE Posted November 27, 2006 Author Report Share Posted November 27, 2006 Did any new GM cars use the same sending unit? Today I went to look for one and there are 2 different type, 1 for the gauge and 1 for the light. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted November 27, 2006 Report Share Posted November 27, 2006 You want the more expensive one that says something like "with gauge" Here's a pic from Advance's site: http://www.partsamerica.com/ProductDetail.aspx?mfrcode=GPS&mfrpartnumber=OPS125&parttype=417&ptset=A Quote Link to comment Share on other sites More sharing options...
turby Posted November 27, 2006 Report Share Posted November 27, 2006 And make sure they give you one for the right year. The threads on 88-90 were1/8"-27 and in 91 it changed to 1/4"-18. Quote Link to comment Share on other sites More sharing options...
Supreme Cutlass Posted November 28, 2006 Report Share Posted November 28, 2006 I HIGHLY reccomend getting an oil pressure sender socket to get the thing out. I tried using all kinds of things and got it out, but it's way easier just to buy the special socket. Quote Link to comment Share on other sites More sharing options...
91GPSTE Posted November 28, 2006 Author Report Share Posted November 28, 2006 I did an oil change just now and tried to get that thing off. What a pain in the ass! I think I remember removing it ones before a few years back and I think I had to take off the starter. What size socket goes over that thing or is it a special one that I gotta buy from GM? Quote Link to comment Share on other sites More sharing options...
Supreme Cutlass Posted November 28, 2006 Report Share Posted November 28, 2006 Did you read my post?? Get the special one, but you can easily get it from autozone, etc. Quote Link to comment Share on other sites More sharing options...
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