so i have been having a slow leak coming from my oil pressure sender, the one above the oil filter. i went to replace it tonight with the new version that is shorter and has the smaller "nut" on it. when i removed the old one i saw this...



so i think it is safe to say that the threads in the block are also stripped out. is there anyway to fix this? i am thinking maybe tapping it but i dont know how i would get a tap in that are with the motor installed. and i dont think that it is standard threads.

any ideas?

 

Your right. That dose not look good. How ever its pipe thread. Pipe threads are tapered.That's how they seal and get tight.The more you screw it in is like driving a wadge with a hammer.

I would try teflon tape. Wrap it around the threads of your new sending unit four to six times and thread it in. Do not over tighten.

If it leaks,tighten some more.

If it strips it is going to need taped deeper or bigger. This is going to need to be done right. Try the tape first as the threads in the block could hold even if they don't look ideal. I'd Like to know how this works for you. I or some else could have tips on thread repair if it comes to that.

 

ok, the only problem with that is with the the sender in the pic. the "nut" part hits the block where it comes out above the filter. here is a pic of what i am talking about...


as you can see, the nut part is physically hitting the block. the new one i got is the same design but the nut part is smaller (1-1/16 new vs 1-3/16 old) and it is also a little shorter. the connections are the same though.

so my next question would be, should i wrap tape around the old one and grind down where it is hitting so i can turn it in more. or should i take the new one, that has the teflon paste on it, and jam it in there? if i use the new one i know i will mess up the threads on it but the nut is smaller so i should be able to thread it in farther without grinding the block.

 

You might be able to use a short nipple in the block with a coupling on the end. Then thread the sending unit into the coupling, moving the sending unit a little further from the block.

 

do you have an cast iron block or aluminum? if iron your threads may be fine because the steel is weaker than the iron. try and tread the old one in before you start altering the sending units pressure.

 

Nothing to worry about as far as the block.

The block is cast iron; that little POS is basically chinesium. Doesn't stand a chance when some knuckle-dragger cross-threads it and just reefs it all the way in ANYWAY.

Look at the threads in the hole. If they look OK, they are. Clean all the remains of the OPSU out with a dental pick or something, before drawing your final conclusion.

If the threads look damaged, chase em with a pipe tap, JUST ENOUGH to clean em up. We're not talking, run the tap in as far as it will go; all ya gotta do, is enable the new one to screw in. If you decide to do that, put A WHOLE BUNCH of REAL THICK grease on the tap, to grab and hold the chips; since that's an oil passage, any "foreign matter" that gets in there, has EXACTLY ONE place to go, and that place is, RIGHT STRAIGHT INTO your bearings. This is widely considered bad.

Then when you put it in, use about 4-5 wraps of Teflon tape, start it BY HAND rather than gorilla-ing it in there from the get-go like that last mouth-breather did, and tighten it to around 15 ft-lbs.

 

So clean the threads in the block then wrap the new one with the Teflon Tape and install?

I tried putting the new one in last night but it wouldn't even start.

 

make sure the thread is the same as the one you pulled out if its a different thread pitch or different thread size it wont go in just try and put the old threads (whats left of them) on the new sending units threads. the threads should fit into each other to be the same. if not get the right part

 

Threads are the same

 

is it too big diameter wise?

 

It's fine. He just needs to chase the threads in his block. Or maybe, just remove the remains of the old threads that the Neanderthal munged into there.

 

Yeah the diameter is the same. I will have to find a npt tap to chase the threads. Where would the best place to find that at?

 

Hardware store

¼" NPT if memory serves

Take the sender along and match it up, won't be too hard to figure it out

 

Little update, tried installing the new sensor but the threads started to get messed up. Took the old one and wrapped about 5 layers of Teflon tape around it. Installed it and started the engine. It doesn't leak when the engine is running but when you turn it off it will start leaking. I guess the next step is to get the tap and chase the threads.

 

so quick update. i tapped the threads last night and put the new sensor in. got it finger tight then turned it about another 2 turns. it still does the same thing. it wont leak while running but after i shut it off it will start to leak. should i try and tighten it some more? i know the tap made good threads i could feel it and when i took the tap out every couple turns there where shavings. any ideas

 

i would look into something like this http://578e7a9bafc08e847f59-b21544d4.../lrs-9278c.jpg if it is hitting the block, it can not be going in right

 

Should have mentioned that the new one is the version with the smaller nut. So hitting the block is no longer an issue.

 

Yup, just tighten it.

A normal-ish torque for that size of thing would be in the 15 - 18 ft-lb kind of range.

4 - 5 wraps of Teflon tape; being EXTREMELY CAREFUL that when tightened, NONE of it will stretch across the opening. Or, glop it with the Permatex "automotive pipe thread sealer w Teflon".