Oil Pressure Gauge Issues

Daniel644

Well-Known Member
OK so Sunday Night I drove home and after backing into the driveway I look down and I see the "Check Gauges" Light, I look across the gauges and it wasn't the alternator (like it was the last time I saw that message) this time the Oil Pressure Gauge had dropped to 0, I know the gauge is a sorta BS gauge on these trucks (having watched May03LT's video where he straight unplugged the sensor and still had a reading years ago). Engine sounded normal but i shut it off for about 20-30 seconds then cranked it back up and the gauge went back to normal. How should I proceed from here? I replaced the VVT Solenoid and replaced all the stepper motors in the gauges about 5-6 years ago and have used Full Synthetic oil exclusively the whole time, is there a way to manually check the oil pressure to make sure it's not the oil pump or something else?
 

Matt

Silver Supporter
Have you replaced the sensor itself? I'd start there even though it's a PITA to get at if it's near the thermostat.

ETA: Please disregard where I said it was, thinking of two things at once.
 
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TJBaker57

Well-Known Member
How hot was the engine and what was the idle speed?

Know this much. The sensor circuit is normally closed and opens with adequate pressure. So if there were to be a short in the wiring a low oil pressure warning will result. Some folks say oil can leak at the sensor into the harness connector and cause this but oil is not a conductor so I kind of doubt that.
 

zaid3ssaf

Well-Known Member
Had same issue. I've replaced the oil pressure switch with OEM and haven't had an issue ever since. For the peace of mind you can hook up a gauge just like May03LT did.
 
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Mooseman

Moderator
Have you replaced the sensor itself? I'd start there even though it's a PITA to get at if it's near the thermostat.
What are you talking about? The oil pressure switch is located right above the oil filter. You're thinking of the temp sensor.

And yes, the switch is a known failure part that will do this. Replacing it will take care of this issue. A lot of times, you will find oil inside the the connector confirming its failure. On very rare occasions it's an actual oil pressure problem.
 
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Matt

Silver Supporter
What are you talking about? The oil pressure switch is located right above the oil filter. You're thinking of the temp sensor.

And yes, the switch is a known failure part that will do this. Replacing it will take care of this issue. A lot if times, you will find oil inside the the connector confirming its failure. On very rare occasions it's an actual oil pressure problem.
Right switch, wrong place...I'm an idiot sandwich.
 

TJBaker57

Well-Known Member
I installed a mechanical gauge in my 2002 years ago. I have noticed that when my oil temps go north of 200 degrees my idle oil pressure goes south of 10 PSI. I believe my issue is a pickup tube seal issue. Cold starts the pump is slow to prime but once there I have full pressure. This is why I asked about the engine temp above.
 
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Daniel644

Daniel644

Well-Known Member
What are you talking about? The oil pressure switch is located right above the oil filter. You're thinking of the temp sensor.

And yes, the switch is a known failure part that will do this. Replacing it will take care of this issue. A lot of times, you will find oil inside the the connector confirming its failure. On very rare occasions it's an actual oil pressure problem.
So unplug the electrical connector on the oil pressure "sensor" and look for oil on the electrical plug?
 
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Daniel644

Daniel644

Well-Known Member
How hot was the engine and what was the idle speed?

Know this much. The sensor circuit is normally closed and opens with adequate pressure. So if there were to be a short in the wiring a low oil pressure warning will result. Some folks say oil can leak at the sensor into the harness connector and cause this but oil is not a conductor so I kind of doubt that.
engines been getting a little creeping up in temps from time to time lately, it was probably 1, 1 and a half ticks past center on the temp gauge when I backed in. didn't check the idle rpm, it wasn't low or anything, I do occasionally get a dip in Idle RPM when shifting from Reverse to Drive.





Edit: Went ahead and ordered a new Oil Pressure Switch and the socket to remove it off Amazon (should be here Saturday), Ordered an Oil Filter from the parts store (so they can get it in the store for me to pickup) and gonna pick up some oil from Walmart in the next day or 2 so provided the weather is clear I'll do an oil change and swap the switch while i'm in there, should be easier to do while the filters out of the way.
 
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Mooseman

Moderator
engines been getting a little creeping up in temps from time to time lately, it was probably 1, 1 and a half ticks past center on the temp gauge when I backed in. didn't check the idle rpm, it wasn't low or anything, I do occasionally get a dip in Idle RPM when shifting from Reverse to Drive.
Check the fan clutch. It's the usual cause of engine temp creep.
How to test the electro-viscous fan clutch
 
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Daniel644

Daniel644

Well-Known Member
Check the fan clutch. It's the usual cause of engine temp creep.
How to test the electro-viscous fan clutch
I know a few years back I could stop the fan like in the video, the temp creep started a little over a year ago when driving back from the town south of me, I think it's the fan clutch but will see if the fan tries to move, it was a while back so I don't remember if it tried to keep going or if I had even let the engine warm up.

Also, I've been debating switching to an electric fan setup since I have a set of fans from my old 99 Firebird laying around anyway.
 

Mooseman

Moderator
Also, I've been debating switching to an electric fan setup since I have a set of fans from my old 99 Firebird laying around anyway.
I don't recommend this at all. Went through this when I was drinking the efan Koolaid. I had temp creep as well as poor A/C performance at idle. These trucks were not given the best radiator so they overcompensated with a huge mechanically driven fan.

If it is your fan clutch again, I'd recommend getting the thermal from an 08-09 and have the codes tuned out.
 
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Daniel644

Daniel644

Well-Known Member
If it is your fan clutch again, I'd recommend getting the thermal from an 08-09 and have the codes tuned out.
Can you still drive it till you get a chance to get the codes tuned out or does it put the truck into a "limp mode"? Also do you know part numbers I should search for? I assume that would also be a good time to do a water pump?
 

Mooseman

Moderator
HAYDEN 2851 was our go-to however, the ACDELCO 1540144 on RA is just a couple bucks more so worth it IMHO.

For the pump, that's up to you but if it's never been done, I'd replace it. ACDelco is also recommended. I've had bad luck with others. And if you're in that deep, might as well do the t-stat and temp sensor.
 
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Daniel644

Daniel644

Well-Known Member
HAYDEN 2851 was our go-to however, the ACDELCO 1540144 on RA is just a couple bucks more so worth it IMHO.

For the pump, that's up to you but if it's never been done, I'd replace it. ACDelco is also recommended. I've had bad luck with others. And if you're in that deep, might as well do the t-stat and temp sensor.
the Hayden is $20 plus the cost of Shipping cheaper on Amazon or Summit Racing.

I've owned the truck the last like 7 years and 30-35k miles and know very little of the service history before I got it, but it had over 200k miles when I bought it and i've been smelling coolant after driving for a while but haven't managed to trackdown the source. Lets just assume it's all original except for the Thermostat, Transmission, Spark Plugs, Fluids and Alternator as i've replaced or had all them replaced.

Whats the best option for the tool for removing the fan clutch?
 

Matt

Silver Supporter
Can you still drive it till you get a chance to get the codes tuned out or does it put the truck into a "limp mode"?
You can drive it, no problem. The only thing that will happen is your cruise control won't work. I replaced mine with the thermal a number of years ago knowing that I was getting a tuned PCM from @Mooseman at a meet a few weeks later.
 

Mooseman

Moderator
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Daniel644

Daniel644

Well-Known Member
@Mooseman OK, so I just loaded the truck up on the ramps so I can jump straight to doing an oil change when I get up tomorrow and I let the truck idle till it got up to temp, used a towel to stop the fan from spinning and every second or 2 I would feel a light "tug" of the fan trying to get going again, it's not a very strong tug, but enough if i'm just lightly holding a fan blade it will make my fingers move, would that mean the fan clutch is still working right or is that to weak of a tug and it's "wearing out".

I did find A coolant leak finally, got to sniffing around the motor trying to find where the strongest the coolant smell was and at first it seamed like the water pump but then I looked down and just beside the radiator cap neck I noticed this (been leaking for almost 2 years now and I finally found it, LOL), so time for a new radiator, are there any performance radiators that make e-fans an option?


Side note there is this chirping sound that happens ever few seconds, gets less noticeable as the engine warms up, definitely not your typical belt squeal but maybe a pulley/tensioner somewhere?
 

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Mooseman

Moderator
Another test for the fan would be to jump the relay to give it full 12v. It should go into full engagement and pull a ton of air.

I have found this full aluminum rad which might work with efans. However, this won't help with poor A/C performance at idle unless you use a really powerful fan(s) or add another pusher fan.

 
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Daniel644

Daniel644

Well-Known Member
Another test for the fan would be to jump the relay to give it full 12v
you got a guide on that?

Oil Change and pressure switch DONE, Oil Pressure Switch electrical connector was FILLED with OIL, it was like pulling out the electical plug on a failed VVT Solenoid or a coil pack when the spark plug tube seals go out in the valve cover (another thing I need to fix), Anyone near North Georgia wanna come help me do a valve cover gasket job, LOL?????????
 

Mooseman

Moderator
Already linked.
How to test the electro-viscous fan clutch
A few posts below the first one however I didn't give full details. The relay leg you need to jump is the same one that feeds the white wire to the clutch.
 
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Daniel644

Daniel644

Well-Known Member
New radiator on the way now. Should be able (weather permitting) to swap the rads next weekend.

Also noticed the AC Compressor Clutch engages regardless of temperature setting when the air is blowing on the windshield, is there anyway to disable that?
 

Matt

Silver Supporter
New radiator on the way now. Should be able (weather permitting) to swap the rads next weekend.

Also noticed the AC Compressor Clutch engages regardless of temperature setting when the air is blowing on the windshield, is there anyway to disable that?
No, the air will run when on defrost, it's programmed into it or something.
 

Mooseman

Moderator
That's is correct. The A/C is forced on while in defrost or defrost/floor settings. Only exception is when it's below freezing. In winter, I pull the A/C relay since it's extremely rare that moisture removal is needed. I've experienced those conditions just once or twice in my lifetime.
 
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Daniel644

Daniel644

Well-Known Member
That's is correct. The A/C is forced on while in defrost or defrost/floor settings. Only exception is when it's below freezing. In winter, I pull the A/C relay since it's extremely rare that moisture removal is needed. I've experienced those conditions just once or twice in my lifetime.
OK, will do the same and pull the relay, truth is I rarely ever used the AC in the first place between how rarely I drive the truck and I usually roll the windows down and just let the breeze keep me cool unless it's like 90*+ outside.

It mainly just spooked me a bit because I had just changed the Oil Pressure Switch and the next weekend when I'm out driving I notice a massive puddle on the ground after blasting the heat on the windshield, made me think I was leaking oil then when I looked at the puddle and knew it wasn't oil I pop the hood and I see drops coming off the heater core hoses over beside the exhaust manifold and I'm all like "F**k" then I look up and it's just the condensation dripping off the Dryer and it's lines (it was a very humid night).
 

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