Typical oil pressure for a 4.3L chevy?

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Okay, folks. My parent's have a couple, and have had several, of the 4.3L V6 engines that come in the S-10 pickup and blazer. My dad's S-10 seems to run with lower oil pressure readings than the blazer, but I don't have much experience as to knowing what may be typical or abnormal.

After the truck is at operating temp, while idling, the PSI hovers around 20. My dad thinks that is low, is it? This vehicle needs the lower intake manifold gasket replaced, if that affects anything here.

Just really trying to get input from others that have worked with/drive that particular engine as to typical oil pressure, especially while at idle. Coasting yields 30-40 PSI, moderate/light acceleration is around 45-55 PSI. Full throttle goes 60-70. It's a typical stock GM oil pressure gauge that reads up to 80 PSI.
 
Originally Posted By: Chris142
If your using the stock gauge that's probably your problem. The stock gauge is extremely inaccurate.


Oh, I see. I do know that we've had a 2000 blazer go wacky with the fuel gauge on the instrument cluster. Was there ever a recall on those?
 
Quote:
while idling, the PSI hovers around 20


That's really okay.This has a functional pressure gauge so its normal that it drops lower when idling.
I see a lot with 10-15lbs at idle even 5lb will keep the engine lubed fine at idle.

Ford went to an on/off type fake gauge because of complaining just like in this situation about low oil idle pressures and needle variation.
Customers expected and wanted a steady needle in the higher range and they got it,an idiot light with a needle for looks.

Edit: BTW the gauge sounds like it is following the normal oil pressure variation fairly close.I think the gauge is okay.
Its normal to have variation in engines and gauges,what is important is knowing what is "normal" for this particular engine by keeping mental track of pressures the engine usually makes.
 
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My 98 is around 55 at cold idle or under any load at all, and hot idle is around 25.
 
both of my Blazers run @55-60 at start up, 45-50 hot run and 20 hot idle in gear. running 10/30 oil.
nothing wrong w/your gauges although as mentioned above they're not terribly accurate. but that aside your pressures look "normal" to me. the 91 was bought new and the 01 was used bought in 04.
the LIM gasket won't change any thing been there done that.
 
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Originally Posted By: JHZR2
My 98 is around 55 at cold idle or under any load at all, and hot idle is around 25.


I'll second that!
 
Originally Posted By: Chris142
If your using the stock gauge that's probably your problem. The stock gauge is extremely inaccurate.


Listen to Chris142 on this one. Those gauges are useless and only get worse with age.

Hook up a mechanical gauge to it if you are worried. But at hot idle in gear, anything above 10 is more than enough...
 
I used to have an 89 S-10 Blazer with the 4.3 and digital dash. Ever since I owned it it would show an extremely low oil pressure, then toward the end of owning it, it would barely show any oil pressure, to where the dummy light would be on, but there was no knocking. Ended up being the sending unit.
 
Originally Posted By: cchase
Originally Posted By: Chris142
If your using the stock gauge that's probably your problem. The stock gauge is extremely inaccurate.


Listen to Chris142 on this one. Those gauges are useless and only get worse with age.

Hook up a mechanical gauge to it if you are worried. But at hot idle in gear, anything above 10 is more than enough...


Agreed! On my Trailblazer the oil pressure gauge would stay at 40 at idle (hot or cold) and go up to about 60 at high rpms. Over at Trailvoy we found that there wasn't a true sensor for the oil pressure just an on/off switch. The PCM "told" the gauge what to read. So while at first glance it APPEARED to be a working gauge it was basically worthless - a slightly glorified "idiot light."

Just as an example - one person ran their engine 6 quarts low on oil (the I6 engine holds 7 quarts) and blew it up - all the while his "oil pressure gauge" was showing 50 - 60 lbs!
 
Wow, interesting light shed on this subject. Thanks guys!
thumbsup2.gif
 
The 00 s10 I'm using shows 20 at hot idle and only a little more while at 2k rpm. My 96 blazer shows at least 40 all the time and 60 while driving.

Currently there's a lot wrong with the 00 s10 motor and I'll most likely end up replacing it.
 
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