I have a 85 fuel injected 302 in my truck and it always used to run at about 3/4 the way up the oil pressure gauge. I recently changed my oil and now it runs just above low. I used that motor flush stuff from walmart before draining oil so a friend thinks I clogged up the oil pressure sensor with sludge and suggested cleaning the sensor. What do you guys think?

 

Most likly the oil filter is clogged with crap from the pan, Change the oil and filter.....

 

Flushing an older motor isn't always the best idea, sometimes the sludge is all that's holding things together!

Did it start with the low oil pressure right after you flushed it and changed the oil, or did it gradually drop off? Either way, you might want to change it again as Hemieater suggests, because there will still be loosened up gunk circulating through the engine. And it can't hurt to pull the sender off and clean it, or better yet, replace it with a mechanical gauge so you get a truer picture of what the oil pressure is doing.

What oil are you using, what weight?

 

The pressure gradually dropped off and I'm running valveoline 10w-40

 

yup sounds like the filter is clogged.

 

install a mechanical gauge and let us know what it reads, also what brand oil filter you using?

 

I'm using a Fram filter and I installed a mechanical gauge and it runs about 25psi. But I know it used to run more than that.

 

25 PSI hot at idle is what the standard pumps pump.

Jay@my5oh

 

When I first start my truck cold it runs 50psi then drops to 25psi. It used to start at 50psi and the gauge never moved so I think it used to run at 50psi.

 

Have you tried a new filter??

 

not yet I have to wait till this weekend for my paycheck.

 

I changed my oil and filter. I used Super Tech(Walmart) 10w-30 synthetic oil and a super tech filter. I started it up and it makes a weird almost knocking noise when first started up now. And it runs even lower oil pressure now that it did before.

I cut open my old oil filter and it was pretty clean so it was not a clogged filter.

Can synthetic oil and regular oil be mixed together to maybe thicken it or what should I do.

 

I drove my truck and at cold idle it runs about 50psi. When warmed up at idle there is 0psi and while driving at about 2500 rpm there is about 25psi. Would switching back to regular oil maybe a little thicker help?

 

Not a good sign my friend.....sounds like a bearing has gone bad.

 

I changed my oil yet again cause I thought maybe it was the syntheic. I used just regular old 10w-30. It dosen't make noise anymore. It runs 50psi cold as usual and after warmed up at about 3000rpm it runs 40psi or so but at idle it still runs 0-5psi.