Low Oil Pressure After Sending Unit Fix and Filter Adapter fix
05-23-2015, 12:28 AM
#1
Drifting
Thread Starter
Low Oil Pressure After Sending Unit Fix and Filter Adapter fix
Hey CF
Long time no see
It is funny I haven't posted in a year or more but the good news is I've still got the 1985 that my dad gave to me almost 6 years ago now
Anyway here's whats up. A while back I busted a major oil leak. The car was dumping oil maybe a quart a minute. I was pulling out onto one of those texas highway access roads
and gave the vette a little juice. Well maybe a lotta juice. Anyway, motor starts smoking and I pull over to see dripping oil. My dad and I tow it back home where I begin searching for the massive leak (on the way back we tore off the custom exhaust I made a several years back. The headers are fine but the H pipe and mufflers as well as the muffler hanger brackets are pretty rough).
My first thought was the oil filter adapter that goes between the cooler ("warmer") and the block. My family mechanic recommended that I remove the adapter and inspect the check valve for proper functioning. He also recommended reinstalling the adapter without the inner adapter to block gasket. I reinstalled the adapter by just bolting it to the block without the gasket. I reinstalled the cooler with O-Ring and a new oil filter as per FSM.
That didn't fix the oil leak so then I hunted some more and ended up pulling the plenum and redoing the entire oil pressure sender and switch assembly. At the back of the plenum behind the distributor there is a T fitting and a little plumbing leading to an oil pressure sender and an oil pressure switch. I replaced both with new parts store units and reinstalled everything with teflon tape. The leak was fixed
Just a heads up I had to remove the wiper motor to complete that job.
Anyway all is well the massive oil leak is gone BUT my oil pressure is reading significantly lower than it used to. Right now after being warmed up the car idles at 15-20 PSI
Under hard acceleration after being warmed up I can barely build 45 PSI.
Before when the car was warmed up it would idle around 30-40 PSI and under acceleration would go to 50. That's what I can remember before the leak sprang.
The motor has got 130,000 miles on it. These days it is feeling pretty damn slow on the highway but I can certainly get the tires loose if needed.
The basic gist is this: Had normal oil pressure. Sprang an oil leak around the pressure sending unit during a hard acceleration. Removed oil cooler adapter to block gasket during trouble shooting. Fixed leak by installing new pressure sender and switch. Oil pressure now dismally low.
Would love to hear some advice from the Gurus!
As always thanks guys.
Long time no see
It is funny I haven't posted in a year or more but the good news is I've still got the 1985 that my dad gave to me almost 6 years ago now
Anyway here's whats up. A while back I busted a major oil leak. The car was dumping oil maybe a quart a minute. I was pulling out onto one of those texas highway access roads
and gave the vette a little juice. Well maybe a lotta juice. Anyway, motor starts smoking and I pull over to see dripping oil. My dad and I tow it back home where I begin searching for the massive leak (on the way back we tore off the custom exhaust I made a several years back. The headers are fine but the H pipe and mufflers as well as the muffler hanger brackets are pretty rough).My first thought was the oil filter adapter that goes between the cooler ("warmer") and the block. My family mechanic recommended that I remove the adapter and inspect the check valve for proper functioning. He also recommended reinstalling the adapter without the inner adapter to block gasket. I reinstalled the adapter by just bolting it to the block without the gasket. I reinstalled the cooler with O-Ring and a new oil filter as per FSM.
That didn't fix the oil leak so then I hunted some more and ended up pulling the plenum and redoing the entire oil pressure sender and switch assembly. At the back of the plenum behind the distributor there is a T fitting and a little plumbing leading to an oil pressure sender and an oil pressure switch. I replaced both with new parts store units and reinstalled everything with teflon tape. The leak was fixed
Just a heads up I had to remove the wiper motor to complete that job.
Anyway all is well the massive oil leak is gone BUT my oil pressure is reading significantly lower than it used to. Right now after being warmed up the car idles at 15-20 PSI
Under hard acceleration after being warmed up I can barely build 45 PSI.
Before when the car was warmed up it would idle around 30-40 PSI and under acceleration would go to 50. That's what I can remember before the leak sprang.
The motor has got 130,000 miles on it. These days it is feeling pretty damn slow on the highway but I can certainly get the tires loose if needed.
The basic gist is this: Had normal oil pressure. Sprang an oil leak around the pressure sending unit during a hard acceleration. Removed oil cooler adapter to block gasket during trouble shooting. Fixed leak by installing new pressure sender and switch. Oil pressure now dismally low.
Would love to hear some advice from the Gurus!
As always thanks guys.
05-23-2015, 05:02 AM
#2
Le Mans Master
These Chinese oil senders we get now are known to be all over the place as far as oil pressure readings..I removed my 25 year old sender which was reading close to 30 pounds at hot idle, and installed a new china made A/C Delco sender, and my oil pressure showed 12 pounds hot idle. 
..The only way to know for sure what your pressure is, would be to hook up a hand held oil pressure gauge...
...WW
..The only way to know for sure what your pressure is, would be to hook up a hand held oil pressure gauge......WW
Last edited by WW7; 05-23-2015 at 05:05 AM.
05-23-2015, 11:26 AM
#3
Drifting
Thread Starter
These Chinese oil senders we get now are known to be all over the place as far as oil pressure readings..I removed my 25 year old sender which was reading close to 30 pounds at hot idle, and installed a new china made A/C Delco sender, and my oil pressure showed 12 pounds hot idle. ..The only way to know for sure what your pressure is, would be to hook up a hand held oil pressure gauge......WW
..The only way to know for sure what your pressure is, would be to hook up a hand held oil pressure gauge......WWThat was my dad's theory, that the new parts store senders were not calibrated correctly for the application. I was hoping that wasn't the case, installing them was a PITA on account of the wiper motor.
05-23-2015, 01:17 PM
#4
Le Mans Master
It could be the unit you installed.
OR.....quick question.....did you use Teflon tape on the threads before screwing it in. I had a issue few years back where I used the tape and a small piece came off while screwing it into place. This partially blocked the hole to the pressure unit restricting the oil flow to the unit. Removed the tape from the hole and all was well again.
OR.....quick question.....did you use Teflon tape on the threads before screwing it in. I had a issue few years back where I used the tape and a small piece came off while screwing it into place. This partially blocked the hole to the pressure unit restricting the oil flow to the unit. Removed the tape from the hole and all was well again.
05-23-2015, 11:28 PM
#7
Drifting
Thread Starter
It could be the unit you installed.
OR.....quick question.....did you use Teflon tape on the threads before screwing it in. I had a issue few years back where I used the tape and a small piece came off while screwing it into place. This partially blocked the hole to the pressure unit restricting the oil flow to the unit. Removed the tape from the hole and all was well again.
OR.....quick question.....did you use Teflon tape on the threads before screwing it in. I had a issue few years back where I used the tape and a small piece came off while screwing it into place. This partially blocked the hole to the pressure unit restricting the oil flow to the unit. Removed the tape from the hole and all was well again.
I hear what you're saying and that is definitely a possibility. I'd like to think I started the tape far enough back on the threads to avoid any issue like that. Thanks though!
If I go back in there to check the teflon tape I'll probably replace the sender and switch with OEM parts if possible.