Hi All...
I am talking about a 1989 Chevy K2500 4X4, 5.7 ltr. V8 (350 TBI), VIN code "K".
About two years ago, the truck started to have low oil pressure. Being a pretty good wrench myself, I thought this was odd. Oil pumps generally don't go bad. At this point the motor had about 140,000 on it. I switched out the oil pressure sending unit, and bada bing... back to normal. Well, after about 6 months, the pressure drops again. I figure better safe then sorry, and switched the oil pump out, and a new sending unit. Holy cow.. pressure is way up now. Before the pressure trouble started, she ran between 32 and 45 PSI, hot or cold. With the new pump, the pressure pegs over out of sight (I figure 65 PSI) until it gets good and hot... then it'll settle down to about 50 to 55 PSI (Still almost out of site on the gauge). This still bothered me though, and I pulled off the oil filter housing to check the oil pressure relive valve. It wasn't stuck or anything, so now I'm stumped. Is it possible that I got the wrong pump? I got it from the dealership. I didn't pull apart the old pump to see if it was bad or not... dumb me I know...
Thanks in advanced.
HDS