Oil Pressure problem
#1
01-08-2008, 01:50 PM
Oil Pressure problem
Hello everyone!
I have a 1992 Camaro RS 305/5.0L with 211,000 miles on it. The engine has been meticulously maintained, and the only major repairs it has ever undergone is having the fuel pump replaced at 190,000 miles, the water pump replaced at 165,000 miles, and the heater core replaced at 130,000 miles.
The engine and transmission run as smooth as new. However, the oil pressure gauge will eventually drop all the way down to Zero at idle after the car has been running for about 20-30 minutes (regardless of driving speed and conditions, etc). When I tap the gas it immediately goes back up to and stays within a normal range (needle in middle of gauge) while driving, its only when I completely let off that it drops to zero. It doesn't do this all the time, just most of the time. The rest of the time the gauge reads normally even at idle.
Again, the engine runs and idles like new, no unusual noises, knocking, pinging, rough idling, etc... this is why I am hoping that despite the high mileage, it could be something relatively minor like a bad oil pressure sensor... or at least I want to try that before just assuming that the engine is worn out.
However, despite being a reasonably intelligent person who is capable of doing his own routine maintenance, I have no idea what the oil pressure sensor looks like, where it is, or what would be involved in replacing it (I am not someone who works on cars as a hobby). Is this something that a "reasonably intelligent" person can do himself? Where is the sensor located? What does it look like? I've seen other posts describe it as being "near the distributor", and buying a replacement sensor would solve the mystery of what it looks like, but I still don't know exactly where to look for it, how much a new one costs, and whether replacing it is within my ability.
Any help would be greatly appreciated!
Meniscus
* * * *
I have a 1992 Camaro RS 305/5.0L with 211,000 miles on it. The engine has been meticulously maintained, and the only major repairs it has ever undergone is having the fuel pump replaced at 190,000 miles, the water pump replaced at 165,000 miles, and the heater core replaced at 130,000 miles.
The engine and transmission run as smooth as new. However, the oil pressure gauge will eventually drop all the way down to Zero at idle after the car has been running for about 20-30 minutes (regardless of driving speed and conditions, etc). When I tap the gas it immediately goes back up to and stays within a normal range (needle in middle of gauge) while driving, its only when I completely let off that it drops to zero. It doesn't do this all the time, just most of the time. The rest of the time the gauge reads normally even at idle.
Again, the engine runs and idles like new, no unusual noises, knocking, pinging, rough idling, etc... this is why I am hoping that despite the high mileage, it could be something relatively minor like a bad oil pressure sensor... or at least I want to try that before just assuming that the engine is worn out.
However, despite being a reasonably intelligent person who is capable of doing his own routine maintenance, I have no idea what the oil pressure sensor looks like, where it is, or what would be involved in replacing it (I am not someone who works on cars as a hobby). Is this something that a "reasonably intelligent" person can do himself? Where is the sensor located? What does it look like? I've seen other posts describe it as being "near the distributor", and buying a replacement sensor would solve the mystery of what it looks like, but I still don't know exactly where to look for it, how much a new one costs, and whether replacing it is within my ability.
Any help would be greatly appreciated!
Meniscus
* * * *
#2
01-08-2008, 04:15 PM
RE: Oil Pressure problem
ORIGINAL: meniscus
Hello everyone!
I have a 1992 Camaro RS 305/5.0L with 211,000 miles on it. The engine has been meticulously maintained, and the only major repairs it has ever undergone is having the fuel pump replaced at 190,000 miles, the water pump replaced at 165,000 miles, and the heater core replaced at 130,000 miles.
The engine and transmission run as smooth as new. However, the oil pressure gauge will eventually drop all the way down to Zero at idle after the car has been running for about 20-30 minutes (regardless of driving speed and conditions, etc). When I tap the gas it immediately goes back up to and stays within a normal range (needle in middle of gauge) while driving, its only when I completely let off that it drops to zero. It doesn't do this all the time, just most of the time. The rest of the time the gauge reads normally even at idle.
Again, the engine runs and idles like new, no unusual noises, knocking, pinging, rough idling, etc... this is why I am hoping that despite the high mileage, it could be something relatively minor like a bad oil pressure sensor... or at least I want to try that before just assuming that the engine is worn out.
However, despite being a reasonably intelligent person who is capable of doing his own routine maintenance, I have no idea what the oil pressure sensor looks like, where it is, or what would be involved in replacing it (I am not someone who works on cars as a hobby). Is this something that a "reasonably intelligent" person can do himself? Where is the sensor located? What does it look like? I've seen other posts describe it as being "near the distributor", and buying a replacement sensor would solve the mystery of what it looks like, but I still don't know exactly where to look for it, how much a new one costs, and whether replacing it is within my ability.
Any help would be greatly appreciated!
Meniscus
* * * *
Hello everyone!
I have a 1992 Camaro RS 305/5.0L with 211,000 miles on it. The engine has been meticulously maintained, and the only major repairs it has ever undergone is having the fuel pump replaced at 190,000 miles, the water pump replaced at 165,000 miles, and the heater core replaced at 130,000 miles.
The engine and transmission run as smooth as new. However, the oil pressure gauge will eventually drop all the way down to Zero at idle after the car has been running for about 20-30 minutes (regardless of driving speed and conditions, etc). When I tap the gas it immediately goes back up to and stays within a normal range (needle in middle of gauge) while driving, its only when I completely let off that it drops to zero. It doesn't do this all the time, just most of the time. The rest of the time the gauge reads normally even at idle.
Again, the engine runs and idles like new, no unusual noises, knocking, pinging, rough idling, etc... this is why I am hoping that despite the high mileage, it could be something relatively minor like a bad oil pressure sensor... or at least I want to try that before just assuming that the engine is worn out.
However, despite being a reasonably intelligent person who is capable of doing his own routine maintenance, I have no idea what the oil pressure sensor looks like, where it is, or what would be involved in replacing it (I am not someone who works on cars as a hobby). Is this something that a "reasonably intelligent" person can do himself? Where is the sensor located? What does it look like? I've seen other posts describe it as being "near the distributor", and buying a replacement sensor would solve the mystery of what it looks like, but I still don't know exactly where to look for it, how much a new one costs, and whether replacing it is within my ability.
Any help would be greatly appreciated!
Meniscus
* * * *
Anyway, I just wanted to come in here and tell you that you aren't alone and that it is a very common thing to happen to the 305's with 180k or more miles. I'm pretty sure in your case it is the sensor since you've stated that it is maintained regularly. I'll be watching this topic to see if/when you get a resolution.
#3
01-08-2008, 05:29 PM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
RE: Oil Pressure problem
I have had that happen to me too, scared the crap out of me to watch the pressure slowly drop to zero. Luckily a new sending unit took care of it. Yours is located on the driver's side of the block, in front of the oil filter, and looks like the attached pic. Just be careful not to break it off. Maybe you'll be lucky and that's all it is.
Now, if your pressure still drops the same after a new sending unit, then the other suspect would be from worn rod and main bearings, especially considering the miles on the engine. With a cold engine, the bearing tolerances are tighter and oil pressure is at it's highest. As the engine gets hot, bearing tolerances loosen up a touch, plus the hot oil flows easier as well. That's why the oil pressure will drop a little on a hot engine, and that's normal. Dropping to zero however, is neither normal nor a good sign.
To compare the importance of proper bearing tolerances, think about a garden hose. Turn the water on and let it run open without a nozzle and the water just runs out (bad bearings). Now hold your thumb over most of the opening of the hose to make a high pressure spray (good bearings).
[IMG]local://upfiles/10318/D501D362C64C442F9F8F04F69867DE47.jpg[/IMG]
Now, if your pressure still drops the same after a new sending unit, then the other suspect would be from worn rod and main bearings, especially considering the miles on the engine. With a cold engine, the bearing tolerances are tighter and oil pressure is at it's highest. As the engine gets hot, bearing tolerances loosen up a touch, plus the hot oil flows easier as well. That's why the oil pressure will drop a little on a hot engine, and that's normal. Dropping to zero however, is neither normal nor a good sign.
To compare the importance of proper bearing tolerances, think about a garden hose. Turn the water on and let it run open without a nozzle and the water just runs out (bad bearings). Now hold your thumb over most of the opening of the hose to make a high pressure spray (good bearings).
[IMG]local://upfiles/10318/D501D362C64C442F9F8F04F69867DE47.jpg[/IMG]
#4
01-08-2008, 10:52 PM
RE: Oil Pressure problem
The part looks like it just screws in, right? Will I need a deep socket wrench or anything like that to get to it, or will I be able to reach it with a standard socket or my fingers? Any other pitfalls that I might run into?
Thanks for the replies, I will definitely follow up with how this turns out.
Thanks for the replies, I will definitely follow up with how this turns out.
#5
01-09-2008, 12:13 AM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
RE: Oil Pressure problem
The portion that screws into the block is metal, the black portion is plastic. The only real pitfall would be if the thing is frozen (corroded) into the block. From under the car, first try to use a box end wrench to loosen it. If your reach or swing is limited, then go to a deep well socket, work it slowly and don't force it. If it's all rusted in place, soak it with penetrating oil. You can also heat it up with a torch if it's still being stubborn. Or you might get lucky and the block could be allcaked with oil, preventing rust. Be sure to use a thread sealant like teflon tape on the new one before reinstalling.
#6
01-09-2008, 05:25 AM
RE: Oil Pressure problem
ORIGINAL: Camaro 69
Now, if your pressure still drops the same after a new sending unit, then the other suspect would be from worn rod and main bearings, especially considering the miles on the engine.
Now, if your pressure still drops the same after a new sending unit, then the other suspect would be from worn rod and main bearings, especially considering the miles on the engine.
Oh, and thanks for the info on how to change the sending unit. I was about to go looking for it.
#7
01-09-2008, 10:53 AM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
RE: Oil Pressure problem
If you replace your sending unit and the pressure is still down just the same, another thing you can look at is your gauge. You can rule out a possible bad gauge issue by installing a "T" fitting at the sending unit and also hook upan aftermarket oil pressure gauge. If it's no better, then you have internal engine issues. Even though the gauge is dropping down to read zero, there is still a small amount of pressure, just not enough for the gauge to read. If there wasn't anything, you would be hearing a lot of loud clanking right before the engine locks up. So, if it is an engine issue, you're driving on borrowed time. If the bearings are the cause of your near-zero oil pressure, keep a close ear on the engine, because a spun bearing could be in the engines future. If you had low pressure across the board, another possibility could be the oil pump. But a drastic drop from cold to hot is generally caused by extremely worn bearings.
#8
01-09-2008, 07:21 PM
RE: Oil Pressure problem
ORIGINAL: Camaro 69
If you replace your sending unit and the pressure is still down just the same, another thing you can look at is your gauge. You can rule out a possible bad gauge issue by installing a "T" fitting at the sending unit and also hook up an aftermarket oil pressure gauge. If it's no better, then you have internal engine issues. Even though the gauge is dropping down to read zero, there is still a small amount of pressure, just not enough for the gauge to read. If there wasn't anything, you would be hearing a lot of loud clanking right before the engine locks up. So, if it is an engine issue, you're driving on borrowed time. If the bearings are the cause of your near-zero oil pressure, keep a close ear on the engine, because a spun bearing could be in the engines future. If you had low pressure across the board, another possibility could be the oil pump. But a drastic drop from cold to hot is generally caused by extremely worn bearings.
If you replace your sending unit and the pressure is still down just the same, another thing you can look at is your gauge. You can rule out a possible bad gauge issue by installing a "T" fitting at the sending unit and also hook up an aftermarket oil pressure gauge. If it's no better, then you have internal engine issues. Even though the gauge is dropping down to read zero, there is still a small amount of pressure, just not enough for the gauge to read. If there wasn't anything, you would be hearing a lot of loud clanking right before the engine locks up. So, if it is an engine issue, you're driving on borrowed time. If the bearings are the cause of your near-zero oil pressure, keep a close ear on the engine, because a spun bearing could be in the engines future. If you had low pressure across the board, another possibility could be the oil pump. But a drastic drop from cold to hot is generally caused by extremely worn bearings.
#9
01-09-2008, 11:10 PM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
RE: Oil Pressure problem
Blitz, I would first rule out any possibility of a gauge/sending unitmalfunction, could be that's all it is, for both you guys. Frankly though, I wouldn't have driven it so many miles with the pressure registering near zero without checking into it. Itcertainly would have concerned the hell out of me.
#10
01-10-2008, 07:13 AM
RE: Oil Pressure problem
ORIGINAL: Camaro 69
Blitz, I would first rule out any possibility of a gauge/sending unit malfunction, could be that's all it is, for both you guys. Frankly though, I wouldn't have driven it so many miles with the pressure registering near zero without checking into it. It certainly would have concerned the hell out of me.
Blitz, I would first rule out any possibility of a gauge/sending unit malfunction, could be that's all it is, for both you guys. Frankly though, I wouldn't have driven it so many miles with the pressure registering near zero without checking into it. It certainly would have concerned the hell out of me.