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Oil pressure sending unit, how many of you have had one fail? UPDATED...

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mpascino

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I have recently redone my whole motor, to the tee. I have had average of 40 psi oil pressure at warm idle [high volume pump]. Yesterday I was driving and noticed that idling, I had about 15 psi. I ran home and changed the oil with a slighty heavier wieght to find very little if any change. I really don't hear any noises in the motor that I didn't hear before. I am begning to wonder if my gauge is wrong, it is factory and is the orginal sending unit. When the motor is cold I now have 50 psi or so according to the gauge. My over all question is how many of you have had similar problems and found the guage to be toast. Guess I am just looking for some words to make me sleep better. Thanks in advance all,
Mike

You call that dirty!?<P ID="edit"><FONT class="small">Edited by mpascino on 07/18/01 11:33 PM.</FONT></P>
 
Re: Oil pressure sending unit, how many of you have had one fail?

I've had three take the big dirt nap - one read excessively low, one read around 70 all the time, and one read "0" all the time. All of these went south within a 3 month period too, with no warning at all.

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Re: Oil pressure sending unit, how many of you have had one fail?

My wifes Opel(also a GM product) started squirting oil out through the bras wire connection tab. It cost 6-7 $ and was simple to change once I got some good lighting and the car upp off the ground enough to work comfortably.

It's right next to the oilfilter, but you probably new that..
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Re: Oil pressure sending unit, how many of you have had one fail?

I had to replace one about 5 years ago in my '87 and now I'm pegged high again so it looks like I'm due.

Those who think money can't buy happiness don't know where to shop.
 
Re: Oil pressure sending unit, how many of you have had one fail?

My 87 Was pegged at 60 all the time. With a new motor you should have put a mechanical guage in there. Along with mechanical water temp guage also. I just put all autometer guages in my truck and now there is no guess work, I KNOW what my oil pressure is and I KNOW what my water temp is. Just a piece of mind for me. Those factory guages aren't worth a piece of horse crap. after putting my mechanical guages in, none of them read right, even with new senging units. Just my thoughts.
Ben 87 jimmy
<font color=blue>Rust=Bad</font color=blue>
 
Re: Oil pressure sending unit, how many of you have had one fail?

I've had 3 go bad. It does happen. A good mechanical guage would not hurt either. Just make sure you use good tubing going to it. I use braided stainless line for extra safety.

'83 GMC Jimmy 4x4 ZZ4 Crate Motor
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Re: Oil pressure sending unit, how many of you have had one fail?

Hey I think you should go with a mechanical guage too, but that reading sounds real similar to what I've seen in many motors in my life, even with a hydraulic/mechanical guage. If you live by the 10psi to every 1000rpm rule, you ought to be fine, but the sudden change would have me a little worried.
Try the sender first, though, they should be pretty cheap and it's pie to swap out. Maybe do a T-fitting with a hydro/mechanical guage on the T, so you can do an actual comparison between the two.
A buddy of mine that works at a Heep dealer in the hamptons called me the other day to tell me he just had a 2002 wrangler or something in for an oil pump. He just wanted to reassure me that even good ones go bad quick, since I'm having suspected pump issues right now...

If you go mechanical and your guage still shows low, maybe your new pump went south. No chance it's the bearings, right? I remember you saying you just had the crank machined, too.

BTW, when the sender cooked on my camaro, the guage went strait up and sat at the stop, like it stopped recieving voltage altogether.

Ratch
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Re: Oil pressure sending unit, how many of you have had one fail?

I've had two go bad but not yet on my K5.. one on my 300Z TT and one on my 88 suburban...
 
Re: Oil pressure sending unit, how many of you have had one fail?

Thanks for the input guys. Today I installed a mechincal guage. Turns out at cold idle I have 90 psi oil pressure. The damn old one was way off. Runs about 60 psi when warm at cruising speed. I will sleep much better tonight!

You call that dirty!?
 
Buy the GM unit!! I bought several no name imports from checker/advance/etc and they all failed in a very short time period. Some read low, others high and some never changed readings. The GM unit has been on the truck for over a year and no failures. Most of the imports failed out of the box or within a month.
 
It appears, from my "rattle tests" that a failed sending unit, when shaken, will rattle. I need to cut one open to see why, but not a pressing concern : ) Need to replace mine too...first one (used) would stick at 60 psi, then drop back to normal whne it felt like. Second one (used) bounces a lot. It rattled a tad before I put it in.

As to factory gauges being crap, I kinda take offense to that. I don't work for GM, but I like my truck, and think GM did a damn good job on these trucks. (why do we own them?) People complain about the car gauges as well, which are the same thing. What everyone seems to be forgetting is that some of them are now almost 30 YEARS old. Hell even 15 years is a long time for corrosion and wear to take place.

Factory gauges IMO were never meant to be totally accurate. They were meant to let you know when something has changed. It doesn't matter that your voltmeter reads 16 volts when its really only 12, what matters is that if you alt fails, that needle tells you that your voltage is dropping. There is NO reason to be super precise with oil pressure gauges...think about it..some people are running 90psi, some are running 10 psi. In either case, if the pressure drops suddenly, you've got a problem, right? Same with temp gauges. If the needle starts moving towards higher temps than what is NORMAL (again, if it reads 240 all the time, and suddenly starts going to 260, then there is obviously a problem)

On top of ALL of that, how do you know your aftermarket gauges work correctly? Because they are new? Ever gone to a store and looked at the thermometers they are selling on the rack? (think your house one is accurate? heh) Almost every single one of them reads differently.

By the way, there are two different oil pressure sending units for gauges, and the wrong one, matched with the wrong gauge, will produce varying results. (IE a diesel 80psi oil pressure gauge won't work anywhere near correctly with a 60psi sending unit)

Oh well, rant off, I just like my clean look interior. Ok, so theres not much interior, but still, nothing I had to add in. Don't have to look forward to oil leaks in the cab either. Those are ugly.


Dorian
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Accuracy is the only way to fly in my book. Facctory guages=Junk, autometer mechanical ones=Good.
Ben 87 Jimmy
<font color=blue>Rust=Bad</font color=blue>
 
Factory gauges = JUNK
Aftermarket Electric gauges = JUNK
Aftermarket Mechanical gauges = good

You can think whatever you want--but I won't trust the engine I built to anything less than a good mechanical gauge. I'd rather have oil in the cab than no oil in the motor and my electric gauge still reading 50 PSI when the motor just shot a rod through the oil pan.

Tim
'84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
 
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