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I have a 2003 GMC Safari AWD. I'm 99.9% sure the sending unit needs replacement. Any ideas where it's located? I know somewhere behind the engine, but can I access it from above or do I need to get under it? Thanks!
 

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What makes you think you need to replace the oil pressure sending unit?

You access it from above. You'll have to pull the doghouse.

It's circled in red below - the thing with the white clip, not the evap metal line and plastic hose. You unscrew the sending unit - with the correct socket or a wrench - from the right-angle adapter fitting that screws into the engine.

IMG_3537.JPG
 

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Liz said:
It does stop bouncing for the most part, then drops to zero on occasion and when braking.
I don't know that it's your oil pressure sending unit... mine does the same thing, so I did a little research, and if my memory is correct this is a somewhat common issue and it's actually caused by the gauges themselves. I would search the forums a bit to be sure.
 

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I'd attach a manual oil pressure gauge (the old-fashioned kind) in place of the sending unit and see if it agrees with the vehicle's gauge.

I've never had the bouncing and dropping to zero on any of my Astros.
 

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Liz said:
Thanks! I believe this is the problem because the gauge bounces all over yet there is oil ...
- and the vehicle isn't making any strange sounds.
And can you describe or repeat any of the sounds that the Van is not making ??

LOL - just had to laugh - brought to mind/seems like the usual... , " sounds like marbles in the hubcaps, followed by an old bear yawn with crinkly sounds, like the can opener..."

In reality, I have been around here 5 years and I have never heard of...
- or read of anyone replacing the Oil Pressure Sending Unit.

Mike
 

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sixsix said:
LOL - just had to laugh - brought to mind/seems like the usual... , " sounds like marbles in the hubcaps, followed by an old bear yawn with crinkly sounds, like the can opener..."
Oh, that's just your bearings! :p That made me think of the AAMCO TV ads I've been seeing recently. There's a video on YouTube, "AAMCO - We Can Fix It All - Weird Car Sounds Video" that is what I am talking about. :p

As for the oil sending and gauge... I've definitely seen mine drop low when idling or breaking (sometimes a little below 40 -- but never 0), then spike when I accelerate (up towards 60, but about where 50 would be). I figure the drop and spike is expected behavior with more oil being moved as the engine does more work. I really only started paying attention during the last few years (when I started to care about this stuff given the sentimental value of my Astro). I feel like the dip and spikes are more noticeable now -- but, as I said, I only recently paid attention.

Is it possible that the OP could possibly have a gauge that is no longer calibrated, or has gone bad, or bad wiring? I guess a manual gauge in place of the sending unit would help indicate that?

Also, could oil type or viscosity affect the pressure, or read values? I believe up until the last year or so (when I made the big repairs) the van either had regular natural oil or part-synth oil. I've started using 100% synthetic Mobil1 and I noticed that the gauge doesn't seem to idle as high as it had used to (I feel like it was consistently near 60, but now rests closer to 40).

I've definitely never seen mine flutter like this, however:

(Hopefully I'm not hijacking. I figured I'd should add something, or ask more questions, instead of just posting some witty remark about hearing sounds. :p )
 

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Thanks! I believe this is the problem because the gauge bounces all over yet there is oil and the vehicle isn't making any strange sounds.
Hi, did that work? I have a similar problem with my 2001 GMC Safari. It bounces the gauge from the center to one forth, even when there's plenty of oil. It doesnt go to zero but goes to at least one forth of the gauge.
Im considering on replacing that sending unit.
 

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Hi, did that work? I have a similar problem with my 2001 GMC Safari. It bounces the gauge from the center to one forth, even when there's plenty of oil. It doesnt go to zero but goes to at least one forth of the gauge.
Im considering on replacing that sending unit.
Replace the sending unit. They're not that expensive and replacement is pretty straightforward.

The original poster hasn't logged in for 2.5 years, good chance she's not coming back.
 
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