Oil pressure 04 lesabre

rcl153

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I have a situation. A week ago my car was making noise, like lifters or rocker arms. It would last ten minutes then go away. The oil pressure on the dash read 55 lbs. I had the engine flushed , and the motor quieted way down , it sounds good. Then I was driving it and the reading on the dash gauge started fluctuating and went down to zero, the oil light came on, but the engine still sounds good . The mechanic last week tested the oil pressure and said it was ok. Sometimes the dash gauge reads in the seventies and seems stable. My question is, would a bad oil pump have readings like that or is it most likely a bad sending unit? It seems to run good, if the pressure was zero , wouldn't it be noisy? Does the oil pump on these cars go often? My gas gauge doesn't work, and neither does my speedometer, tach works sometimes. Thanks!
 

MelsRegal

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If the mechanic tested the oil pressure why wasn't the sender changed at that time, it has to be removed to run the test.
How often do you change the oil?
 

rcl153

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The dash gauge wasn't really acting up at that time. At least I wasn't aware of it. I change the oil every 4k MI. Do the oil pumps on lesabre's have problems?
 

Alan 55

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The dash gauge wasn't really acting up at that time. At least I wasn't aware of it. I change the oil every 4k MI. Do the oil pumps on lesabre's have problems?
It has been my experience that the oil pump on the 3800 engines are very reliable. It is a standard gear type pump. If a person uses a good quality engine oil and filter and changes it per maintenance schedule
the pump is good for a very long time, perhaps the life of the engine.
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rcl153

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Thanks Alan ! That's very helpful! I'm believing now it's the sending unit, because the engine seems quiet and smooth.Most of my gauges don't work too good, I think I can drive it.
 

Mad_Coachman

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Thanks Alan ! That's very helpful! I'm believing now it's the sending unit, because the engine seems quiet and smooth.Most of my gauges don't work too good, I think I can drive it.
Make sure you get an appropriate socket to do the job as there is very limited space to do it. It's a specialty socket specifically for oil pressure sending units. The sender is right above your oil filter and is a common failure point on these old engines.
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BuickGirlFromMars

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sounds like your IPC is having either class 2 issues with PCM, ground issues for the cluster, cluster internal failure, or some other issue. does your car report tach, gas, speed reliably on a scan tool? If so, I would usspect your cluster has some issues or wiring to it that are causing the reading issues not a sender. your engine is 99% likely fine, it cant just have 70psi and then none and be cruising kind of thing. he tested the pressure at idle which is where it could be 0 and it was good. i wouldnt suspect a sender unitl the nature of the cluster problems are found
 

Mad_Coachman

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sounds like your IPC is having either class 2 issues with PCM, ground issues for the cluster, cluster internal failure, or some other issue. does your car report tach, gas, speed reliably on a scan tool? If so, I would usspect your cluster has some issues or wiring to it that are causing the reading issues not a sender. your engine is 99% likely fine, it cant just have 70psi and then none and be cruising kind of thing. he tested the pressure at idle which is where it could be 0 and it was good. i wouldnt suspect a sender unitl the nature of the cluster problems are found
It's actually just good sense to replace the oil sender on an old car. A failed sensor can lead to loss of oil if it breaks. I had one break on my 2nd Oldsmobile (1998 Eighty Eight). I noticed a puddle of oil below the car when I parked on the street in Brooklyn. The oil wasn't dripping from anywhere but when I started the engine it was spurting out. I had to call a tow truck to get my car home where I could change the sender. I got lucky. He should change the sender. Cheap insurance against possible catastrophic failure and it's easy to change with the proper socket.
 

rcl153

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I'll get it done. The car seems to run fine. When I start it , it reads zero pressure till I get rolling about a minute later , then it climbs to 50 and sometimes 70. I can't believe the accuracy of any of these readings.
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Mad_Coachman

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I'll get it done. The car seems to run fine. When I start it , it reads zero pressure till I get rolling about a minute later , then it climbs to 50 and sometimes 70. I can't believe the accuracy of any of these readings.
I changed the sender in my current Buick and my last one due to them both reading 130psi. The same thing happened to my brother's '04 Lesabre at just 90k miles.
 

rcl153

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What's involved in changing it? How do you do it? Can you change it from above the car or do you have to get underneath? What is involved with the wire? They have them on eBay for $30
 
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Mad_Coachman

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What's involved in changing it? How do you do it? Can you change it from above the car or do you have to get underneath? What is involved with the wire? They have them on eBay for $30
You can get the sender and the socket to remove it on Amazon for less than 50. I used Standard part #PS309T and an OEM tools socket.
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rcl153

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Can you do this job from above the engine or do you have to get underneath?
 

Mad_Coachman

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From underneath. If you can change your oil and operate a ratchet you can do it. BTW I answered this question already in post #15 which referred you to post #8. Now let me ask YOU a question. Have you changed your own oil or do you take it to Jiffy Lube?????
Edit: Judging by your posts since you joined I'm guessing the latter.
 
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rcl153

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Actually I don't change my oil. The car is heavy, and I don't like to crawl under it. For some reason I didn't see your previous answer. My bad.
 

rcl153

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What's the best way to jack the car up? Using the tire changing jack? Can you get a jack stand underneath it if you use that?
 
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