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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 87swb on August 21, 2006, 06:36:00 pm

Title: oil sending unit ?
Post by: 87swb on August 21, 2006, 06:36:00 pm
assuming that was this is right above the oil filter on my 87 305 TBI. how do you get it off and clean it? and will any oil leak out of the block?

Title: Re: oil sending unit ?
Post by: Stewart G Griffin on August 22, 2006, 12:43:00 pm
Being that yours if fuel injected?  I'm not sure what function this serves on yours, but on mine (83) i think it has to do with the choke.  Does yours have two prongs or one?

Its not nessesarily easy, but i took some channelocks and loosened it.  Oil should not come out if the truck has been sitting for a while.

As far as cleaning?  If you're referring to the threads, a wire brush i rekon.   As far as the outside, degreaser, i guess.  I didn't have time to clean mine.

2) Make sure you take notes and plug the wiring in exactly the way you took it out.  I might be having problems with mine because i plugged it in upside down, but i'll get back to you on this.

Title: oil sending unit ?
Post by: 87swb on August 22, 2006, 02:39:00 pm
whatever this is it has 1 prong and its just above the oil filter no hoses or lines go to it but 1 wire plugs on to the prong on top of it. i'm thinkin this is the oil sending unit and all i want to do is take it off and clean it(if you can) in hopes of the oil pressure raising back up.

Title: Re: oil sending unit ?
Post by: Stewart G Griffin on August 23, 2006, 12:17:00 am
What i want you to do also is check near the distributor and see if there is also a sensor.

If so, then the sensor near the oil filter might be (and don't quote me on this cause i don't know what the heck i'm talking about but i read) for your fuel pump.  What happens is, yes this sensor is also for oil pressure but if the oil pressure drops too low, this tells the fuel pump to shut off.  Whereas the one near the distributor goes to your gauge/or warning light.

When you think about it, it makes sense.  You've got fuel injection so you've got an electric fuel pump.  If the oil press ever gets too low then shutting down the fuel pump should save the engine.  

But yeah, you should be able to unscrew it out with channellocks.  I use Sears "robogrips."   And no oil should leak out if the truck has been sitting for a while.  I.e., at least 2 hours.

Edited by: Stewart G Griffin at: 8/22/06 11:24 pm
Title: oil sending unit ?
Post by: 87swb on August 23, 2006, 12:31:00 am
i just got done taking off the unit above the oil filter. i looked at it, wasn't dirty or anything. theres only two things by the distributor and they plug into the side of it(the distributor). i unplugged the wire that goes to that unit above the oil filter and then turned the key in my truck and the o.p. gage wouldn't do anything so the wire that goes to it has something to do with the gage. i'm thinkin the unit may just be bad or worse i need another oil pump. hope not. thanks for your help by the way.