Dumb question from me, what is N.O.T.? No Open Throttle?

Anyhow, I am lucky to get 15 @ idle hot and 40-45 @ idle cold on my 4.3 with 138,000 on it. I don't know what oil they used and I know it is a cheap filter on it (oil was changed prior to me owning the truck)--haven't changed it yet.

I generally use 10w30 oil ---what ever is cheapest (currently Napa brand--which is Valvoline) and I use Napa Gold Filters (which are Wix filters) exclusively. I have also used the good Puralator filter too, but those are the only two filters I will use.

I am hoping the pressure comes up a bit when I change the filter and oil because it's a little too low for my liking. But the reality is it is within specs so I don't over think it for now. I may do what a friend of mine does and run a thicker grade in the summer months to boost the pressure.

 

Normal operating temperature. Sorry.. I should have just typed it.

Yeah.. I mean 40-60 seems normal, but just wanted to see what others run. 60 a little high for my liking..

 

58 psi cold start, 40 psi when cruising down the highway, and about 20 psi idling warm.

I run synthetic 5W-30 year round. I don't believe in changing viscosity just because of a temperature change in modern day engines.

 

I don't believe in changing viscosity just because of a temperature change in modern day engines.

I normally don't switch at all either, but I like it to be a little more pressure. But some engines just have what they have. I am going to put 10w30 in it like I put in all my other vehicles and see what happens. I am not crazy about 5w30, just seems to thin for me. I know it's a little old school thinking, but gotta do what works for me I guess.

And the basic rule of thumb is 10 psi for every 1000 rpm, so seeing 15 at idle isn't horrible by any means, but 20-25 makes me feel better.

 

Yeah.. I was thinkin' since engine has some miles on it and had loosened up switching would be good, but I'm not happy with the increased psi. These engines were built for 5w-30 so I guess I shouldn't bother over thinking it.

I'll probably wait a bit to change oil back.. Shit isn't cheap haha

 

40psi cold start/idle, only about 10-15 idling warm, which concerns me. But it comes up when I get going. Probably getting 30'ish cruising on the highway. I need to check what filter's on there because I just had the oil changed at the shop last time along with some top-end work & IDK what they did down there, seems like the pressure has been down since. 138.000 miles on a 2002 4.3.

I don't like other people doing my oil changes, grr.

 

I got a 01 4.3 with 136,xxx and I think my gauge is messed up. Cold start will be 40 and will not go over. Warm idle in hot weather will be 0-5. No motor noise or no shavings in oil. I run Mobil 10-30 with a WIX filter


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212k never had nothing but 5w30....pressure still good

 

I also heard the sending units that measure the oil pressure in these engines are known to be faulty or not accurate. So maybe some of you that have really low oil pressure have bad sending units or it's just really that low.

If I wanted to raise my oil pressure, I'd be using Lucas Oil Stabilizer to do so. But, the owners manual does permit using 10W-30 so you're not hurting anything by using that viscosity. The only thing you're changing between the two oils is the viscosity when the oil is cold. 5W-30 and 10W-30 should be the same viscosity at operating temperature.

 

Yeah.. the first number is the weight at cold and second number is weight at operating temp right?

This was my fourth oil change since I've owned the truck, and it is the first time I'm using a WIX filter and 10w-30 Pennzoil High Millage.. So far, besides my oil pressure slightly above before, my engine is a LOT quieter and smoother. At first I was nervous about the pressure, but now that I've been driving a couple of days I'm very happy with the sound and feel..

 

I have a 94 s10 4.3 Z code TBI. I just rebuilt engine. Got it running around 3am. It had 423,000 original miles on it. Only thing I had previously done inside engine was install a timing chain set when the water lump went out at 260,000 miles. It was running a steady 40 psi. With Penzoil 5W30 high mileage oil and Wix filters. Now after rebuild with Penzoil 5w30, all new bearings,camshaft, rings, and a new Duralast oil pressure switch ( broke off original pulling engine) . It runs 60 PSI cold and runs 40 PSI warm at idle goes back up to 60 PSI when above Idle. I did put a newer crankshaft, rods, pistons, harmonic balancer, and flywheel from a 1993 S10 with 160,000 miles and no wear on journals.She is running good ,so far. Put 200 miles on it today going to work and back.

 

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