So I just recently bought my K5 and I did an oil change today.

I noticed, after changing the oil, I started the K5 and it was idling at approx. 50 PSI cold, then when I turned the engine off, the PSI gauge sits at 30 PSI.

Is this normal? Should the gauge be sitting at 30PSI when I shut it off or should it drop to 0?

 

I just went out to see what my 94 would do with a cold start just to make sure my thinking was right. When I got in, the gauge was sitting at around 30 psi, when I turned the ignition to the on position the gauge dropped to 0 then moved back up when I started it. When I shut the engine off it fell very slowly to about 40 and just sat there. I'd say your gauge is just fine, no worries.

 

I'm not so sure. Here's a video.

Gauge reads 60PSI in park, 30 in gear and moves from 30 to 60 while driving or revving engine.

http://s252.photobucket.com/user/add...60e58.mp4.html

 

Just unplugged it and checked..it reads the same. Must be bad.

Is this the oil pressure sensor?

 

Thats the temp gauge sensor. What year Blazer? The oil pressure sensor should be by the distributor, drivers side.

 

I have a slightly different problem cold start gauge preforms normally. After everything warms up and at idle it drops down to 0 PSI and the check gauge light come on. With a slight increase in idle and and PSI gauge comes right up

 

I found that out the hard way...I removed the temp sensor and the coolant started spewing out. Put it back in, filled it back up with coolant and called it a day.

I did notice the last couple of threads where quiet a bit tougher to get into the block when I put the temp sensor back but everything seems strait and it's cast iron..so I seriously doubt I cross threaded anything.

I'm just going to run the rig to the shop tomorrow and get the pressure looked at lol.

 

Doxadan

That does sound bad. High mileage engine? Plenty of oil? What rpm does your truck idle at? What viscosity oil do you run? Could be a hundred things, I would hate to speculate without seeing it. I know you would like to get some kind of answer but it could be anything from low oil level, bad sending unit or gauge to needing engine rebuild and I would hate to give bad advice on that one. Try checking the oil level, make sure theres no water/coolant in the oil, things like that. Someone on the forum may have had a similar problem. I would start a new thread and ask there, its hidden in this post and I think you would get more/better help that way. Just be sure to list what year, model, engine size, carb/tbi and any work/ upgrades thats been done to it. That info can help alot.

 

I took it to a shop, got a cat put in, had my temp sensor replaced and had them check the oil level. They claimed it seemed normal and didn't seem to have any issues.

 

It idles low around 500 rpm bring it up to 1000 and the pressure rises some. While driving it is in the normal ranges. Using standard oil don't remember what it was had it changed 4 months ago and the trucks been sitting for the most part. I have been told it may be the sending unit or the cam barrings.