: Engine oil level sensor leaking



Dadillac
04-21-08, 12:04 PM
I just performed an oil change on my '02 Seville SLS and noticed my oil pan and surrounding areas covered in oil. I have never had a leaking issue so far. My N* has 105K miles on it. Upon close inspection I noticed that the oil level sensor, and the torque plate bolts that is between the oil pan and trans, had oil build-up on them. The rest of the area just had a coating. I checked as best I could, and could not see that it was coming from the pan bolts, main seal area, or higher up. It appears as it is coming from the sensor, and blowing upward and backward. I cleaned the sensor, oil pan, and torque plate bolts, and will check it again next week. If it should be the sensor that is leaking, does the sensor need replacing? Or is there a serviceable o-ring that can be replaced?

Don

Ranger
04-21-08, 12:54 PM
Don,
I checked my '02 FSM and it makes no mention of an "O" ring. The seal must be integral.

Submariner409
04-21-08, 01:34 PM
If the N* oil pressure switch/sending unit is built like most others, the phenolic/bakelite body is crimp sealed to the metal nut/ threaded portion with an internal O-ring which loses strength over time and causes a weep around the joint. Easy replacement fix. Should be several options in gmotors, gmpartsdirect, or rockauto. Not expensive, do it at your next oil change while the filter is off. (The actual "seal" into the filter adapter is by tapered pipe thread.)

Ur7x
04-21-08, 02:35 PM
Good to know... Mine leaks there too...

There is a certain irony that the oil level sensor is causing the leak which the oil level sensor is there to detect :helpless:

Submariner409
04-21-08, 04:37 PM
Yeah that, but a telltale leak is a damsight better than having the whole sending unit blow apart on Rt.41 in the dead of night in the SC swamps. (1967 Cougar 289, 1978)

tateos
04-21-08, 06:29 PM
Are we talking about the oil level sensor or the oil pressure sensor??

Submariner409
04-21-08, 06:42 PM
Oil level sensor. I can't read writin'.........but the same assembly technique applies.

Tommy Deville
04-21-08, 06:54 PM
From what I understand this is a common prolbem in the N*

Dadillac
04-21-08, 06:59 PM
I am uncertain if the sensor is leaking from where it goes into the oil pan, or from the unit itself. Just wondering if I find it is leaking from between the sensor and pan, is it sealed with an o-ring, that can just be bought new. I really do not want to remove it to find out, without having the o-ring, or new sensor, to install.

Don

Tommy Deville
04-21-08, 07:05 PM
I am uncertain if the sensor is leaking from where it goes into the oil pan, or from the unit itself. Just wondering if I find it is leaking from between the sensor and pan, is it sealed with an o-ring, that can just be bought new. I really do not want to remove it to find out, without having the o-ring, or new sensor, to install.

Don

All I can say for sure is that replacing the sensor WILL stop the leak, a new sensor should come with an O ring

Dadillac
04-21-08, 07:05 PM
Yeah that, but a telltale leak is a damsight better than having the whole sending unit blow apart on Rt.41 in the dead of night in the SC swamps. (1967 Cougar 289, 1978)

I had a '67 Cougar back in '86. It also had a 289 with a 4 speed. the previous owner had boosted compression and installed a flat lifer cam. That car hauled the mail. One time I was driving to work and was about 3-4 miles from my destination. the oil pressure went to zero. I was running late, so I just continued to drive. Once I got to work, I spoke to a few of the mechanics (I worked for a trucking company) and they had an oil pump brought to me. I was able to drop the oil pan, without raising the engine, or removing any steering linkage. The pump was still good, but had a small piece of bearing material lodged in it, that caused the oil drive to snap. Got a new part in the morning, buttoned it up, and started it up. No engine damage due to running with no oil pressure. I guess that the straight 50w that I was running was the reason for that.

That is the only car that I have owned that I really wish I didn't sell.

Don

tateos
04-21-08, 07:22 PM
The sensor has an o-ring. I think I read there is a problem with replacing it with the engine in place - I think it hits the cradle on the way out. I think maybe you have to jack up the engine off the cradle a little to get the clearance you need. I changed mine when I did my HG project - I got it from Rock Auto. for a '97 ETC it was Airtex #5S3008 $25.79 a few months ago. It looked like maybe mine was leaking; I'm not sure, but I think it was not from the o-ring but from the sensor itself - it's hard to tell - I had a lot of leak points: rear main seal, oil cooler line, oil pan gasket for starters, so I changed it while the block was out of the cradle and it was easy to do

Dadillac
04-21-08, 11:51 PM
The sensor has an o-ring. I think I read there is a problem with replacing it with the engine in place - I think it hits the cradle on the way out. I think maybe you have to jack up the engine off the cradle a little to get the clearance you need. I changed mine when I did my HG project - I got it from Rock Auto. for a '97 ETC it was Airtex #5S3008 $25.79 a few months ago. It looked like maybe mine was leaking; I'm not sure, but I think it was not from the o-ring but from the sensor itself - it's hard to tell - I had a lot of leak points: rear main seal, oil cooler line, oil pan gasket for starters, so I changed it while the block was out of the cradle and it was easy to do

Just how far does the sensor go into the pan? There seems to be a lot of room on my '02. That would be unless the sensor is 6" long.

Don

Ur7x
04-22-08, 01:20 AM
According to my Online GM eSi tool.... There is no need to remove any braces, mounts, or brackets... Unscrew old one, screw in new one... tighten to 15 ft lbs... and that's it... Oh ya, drain the oil first ;)

Ranger
04-22-08, 12:36 PM
I recall removing the sensor on my wifes '96 Bonneville (3800). Probably the same sensor. I seem to remember it being longer than I had expected, but less than 6".

tateos
04-22-08, 09:38 PM
I think it was at least 6" long

Dadillac
04-23-08, 08:28 PM
UPDATE:
I checked the leak today, and it definitely isn't leaking at the level sensor. It seems as though it is the pan gasket, and in two places, maybe the half case. So I did a thorough cleaning and checked the torque on the pan bolts. Most of them were at 89 lb/in. I broke them free, and re-torqued them. Most took at least a full extra turn to reach torque spec. I tightened every bolt I could get my socket on. Hopefully this will help, but I am not optimistic. In my FSM, it states that to change the pan gasket, the crossover only needs to be removed. While under the car I didn't check on this. But is this so? Obviously the level sensor needs to be unplugged, and the torque plate needs to be removed. But after that, is it easily removed from there?

Don

Ur7x
05-01-08, 12:11 AM
did you manage to re&re the pan with the engine in the car??
I think the exhaust crossover is in the way too.

Dadillac
05-01-08, 07:44 PM
Another update. The oil leak is still broken :D. I may try one of the high mileage oils the next oil change. It isn't dripping onto my driveway yet. But we all know that it will eventually. I hate that to all hell. I also took a look at the crossover pipe. I cannot for the life of me see how that thing could snake out of the car with the engine and trans still married together. But it definitely seems that if the crossover pipe can be removed, the pan can be dropped while still in the car.

Don