1990 c1500 with many problems

I didn't think you guys wanted a hloe lot of new threads so I am condensing them. You'll have to forgive me, I'm a complete newbie to mechanics.

My truck is a V8 5.0, automatic transmission with O/D, 130,000Km.

1. My A/C clutch pulley is making some crazy noises, like grinding metal so I'm thinking the barings are gone. I don't use the A/C so I was hoping there was a way I could remove that, keep the same pulley system and add a different pulley that has nothing to do with anything. Basically a space filler that allows me to keep the same pulley system. Maybe it's called the drive belt system, I'm not too sure. If there is another part I could use, could you tell me where to find it?

2. My truck stalls sometimes when I am at an idle. Only when the engine is hot and the oil pressure is very low(that's another problem). Something like taking a 20 minute drive and then stopping at a red light and all of a sudden there it stalls. When I'm at the light idling it's like an up and down. First it will idle ok and then it gets real low almost stalling and then it's like someone gave it a shot of gas and revs a little high and then repeats that cycle until either I stall or I go. My step-father told me I needed to change my fuel filter. Maybe that's what it is.

3. The last thing is my oil pressure. When the engine is cold it's fine but once It starts to warm up the oil pressure drops considerably. I'm using a K&N filter with Castrol Syntec 5W50(it gets cold here in Canada) :biggrin:

Thanks in advance, I hope you guys can help.

Wow, all these mechanic wizards and no one has anything to say. Not even "could you explain better" or "this forum is for people who know there stuff".

Well, thanks for taking the time to read my post. I guess I will have to look somewhere else for the answers.

Your idle problem could be a lot of things. I'd first check for vacumm leaks around the throttle body area and also clean out your fuel injectors by buying some fuel injector cleaner. Flush some of that stuff through a couple tanks. A truck with that many m/km's could have a number of things wrong with it. The A/C pulley is gonna cost some $ anyway you look at it, except for one way.... You might be able to bypass this pulley and buy a belt that is made for trucks with no A/C. I'm not sure if that would work, but logic would say it would. That could save you some serious $ if that works <---- :cool:

As for your step-father's opinion, the fuel filter may be what's causing it, but I considerably doubt it since it only happens after the engine warms up. Something you might consider to save you $ is to raise your idle a couple hundred RPMs to keep the engine's revs from jumping up and down at stops.

If the problem persists I'd go ahead and take it to a mechanic to see what the deal is, but feel free to post another message with more information you've found out.

thanks for your help Andyman8282

I will look into the things you talked about

No problem, hope it goes well

Have you checked/replaced the oxygen sensor yet? That could be the problem, especially because of the miles. A fuel filter is most likely not the problem because it does not take much fuel to keep an engine idleing and an extremely dirty fuel filter would affect more of the upper rpm. Because it is surging I would start with the O2 sensor, then move onto the egr system.

One thing you need to check also, is the compression of all your cylinders. If your oil pressure is dropping dramatically, it could very well be because your bearings are getting wore out and the same with your compression rings. Another thing to check on is the manufacturer's suggested oil grade, because with todays close bearing tolerances, it is very critical that you use what they suggest. Hope I have been some help! Rex

if you pull your air cleaner off and you hear a very loud hissing noise your idle air control may be out of calibration ask gmmerlin how to adjust it. you may need a scanner for this job. my oil guage went funny on my truck. when cold it was ok, but when it warmed up it would wander all over. i replaced the sending unit and it still did the same. finally i pulled the oil pan off and the oil pump mounting bolt had the head broken off and it was laying in the bottom of the oil pan. i replaced the bolt but i also checked and replaced the main bearings on the crank. that was at 63000, now it has 177,000 miles.