I finally had the chance to take the car out on the road for the first time with the 383 and 6 speed swap and i was impressed BUT i have oil leaking from my sending unit. I have a brass T adaptor so i can run the sending unit and switch off the same T and i cannot get the threads to seal. I tried the white teflon tape and the yellow tape which is for oils, gas ect. and it's still leaking bad. Seams all three of the threads are leaking what can i use to seal it up? Black RTV on the threads work?

 

Liquid teflon.

 

liquid teflon, teflon paste, teflon tape, red loctite, whatever..
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oh ya, you musta put the tape on wrong because whenever i use it, i get a good seal.. do you "tighten" it on?? in other words, you turn the bolt closkwise(tightening motion) and roll the tape on?? if you go the other way, it will bunch up and rip when trying to screw the piece on..

 

I put the tape on counterclock wise and i pull it tight on the threads. After i screw it in so far it seems like the tape kind of gets pushed out of the threads and it all bunches up, maybe im putting too much on? I have some paste stuff but i didnt have good results with it on my fuel lines. How far do they have to be screwed in? I put them snug but there are still threads showing, maybe im not getting them tight enough. Ill go out tomorrow and redo it once again.

 

so i redid all the threads today, twice. After 3 hours of messing around its still leaking just as bad. Seems to not leak when car is ideling but after i take it for a 5 minute spin the block has a puddle of oilon it and the brass fitting is covered in oil. How good does that liquid teflon work? Im not having any luck with the tape.

 

4 words for you: Indian Head Gasket Shellac. I swear by this stuff and it's been around for a dog's age. Seals up oil, gas, water or anything you're likely to find in a car.

It's my go-to-goo. Haven't found the fitting it wouldn't seal up yet- I use it on all my pipe-thread fittings.

You can buy it most good automotive stores. Looks like this (click for picture):

 

do you have the right matching male and female threads?? i'm thinking one could be metric and the other SAE.. try screw it on without anything.. is there ANY play in the threads?? or how far in does it screw in??? i'm not gonna ask if you cleaned the threads cause it should still work if you didnt clean it..


also, any chance we could get a pic of what we are working with?? if not thats fine.. is the sending unit near the back of the intake manifold, by the distributor?? or elsewhere??

 

He is talking about where the sending unit screws into the top of the block, back by the distributor and right directly behind the intake. I honestly have no idea why he is having such a hard time with the thing sealing. I actually gave him that fitting from my engine as I now have a two-in-one (sending unit and switch) so I didn't need the T adapter. Anyhow, I thought that it was NPT (not NPS). I'll bet I didn't even have any teflon tape on it when it was in my block and it never leaked a drop. We had the thing run in pretty well on his engine, so like I said I don't know why it is leaking.

Adam, are the threads damaged? Is it only leaking at the block, or also at the two sensors at the T?

 

No the threads are not damaged, it seems to be leaking at all three locations. I wipe my finger under the sensors where they mate with the T and my finger is coated in oil. Right behind that hole the block flares outward and a puddle of oil fills up in 5 min and it just runs down the back of the block and sprays on my clutch and i think its causing it to slip. Im not sure if having high oil pressure would cause it but my gauge is reading around 55 psi at idle. Ill try to get a pic up asap.

Damon ill have to try that stuff you are talkng about

 

jeez.. just braze that sucker on.. that way, no possible leaks.. lol..

too bad i wasnt back at my house and you lived on maui, of course.. with all the crap i have, i could make that sucker seal better than a zip-loc double zipper bag.. lol

ok i just about ran out of ideas.. the only thing that comes to mind is wrong threads.. it has to be wrong threads.. cause wrong threads will leave gaps in the grooves not being used and allow oil to escape through there..

how do the threads fit when screwing them together?? they should go on square and smoothly.. k, last question.. is it leaking from all openings of the t-fitting??

 

Before we break out the torch, here's one more idea: Maybe it's the sending unit itself leaking or an oil blowby leak from the nearby valve cover blowing oil onto the sending unit. You can reseal the threads till the cows come home and the sender will still be wet.

 

could very well be a crapped out sending unit. They should be fairly cheap, you might want to just toss a new one in there and see what happens. If it still leaks, oh well, the old one was probably on its way out anyways


BTW, i see you said you wraped the teflon tape counterclockwise...

If your holding the sednding unit in your hand and looking at the threads, you should be wraping it clockwise...

 

Sending unit is new.

 

you know...there are 2 styles of pipe threads, taper and parallel. taper threads obivously have a taper style to them, and rely on the taper to seal the threads (approx 3-5full turns to get it finger tight, then you use a wrench to finish the job). parallel threads dont taper, so they have to rely on either a gasket or an O-ring to stop the leakage. both styles have the same pitch (amount of threads per inch) so they will go together, but not easily and it wont be healthy. this "T" piece that you got...it may not be taper threads which would cause a leak.

try troubleshooting...take away the "T" from the equation...just bolt the sending unit straight to the block and look for leaks, if there are no leaks then you found your problem.

heres a tip about teflon tape btw...always put it on CLOCKWISE with the threads facing you. go around 4 times and make sure to run your fingers over it before inserting it into the hole to reduce the chances of the ends fraying or unravelling.

 

I put the tape on correct i turn the threads clockwise i was just thinking of holding it different thats why i said counterclockwise. I didnt have time to mess with it today but i will spend time on it tomorrow. They all thread together nicely and they go far in so they must not be tappered. Im 100% sure it not the valve covers i just got them to seal a few weeks ago and they are leaking no oil. Ill post up a pic tomorrow and what i find out.

 

No pic today i forgot probably because ive been so agrevated. I worked on this thing all day and havent figured it out. Im actually thinking, is it possable to come out of the back of the intake if i didnt get it sealed correctly? Its leaking quite a bit of oil but it doesnt leak a drop while it sitting there ideling. I take it up the road come back and there is a puddle laying in there and its leaking down the back of the block and dripping on the ground. I bought a new T adaptor, tried the indian gasket sealer with no luck. Im starting to think its the intake.

 

please tell me you didnt use the cork gasket across the intake.

 

The gaskets were not cork. Even if it wasn't sealed totally in the back, why would oil leak that badly from there, there is not pressurized passageways through the intake. I just don't see how it is possible to leak from there, especially that bad.

 

well like i said before...TROUBLESHOOT...take away the T, put the stock sending unit on there WITHOUT THE "T" and try it, if its still leaking then youve got other problems.

do you think it could be a crack in the block?

 

I was talking about leaking from the intake/block seal, not repeating what I said earlier about leaking from the threads.

Unfortunately I live nowhere even close to his car, I'm just answering your guys' questions and helping what I can from what I know of his car from when I do help him (when I go there sometimes).

I don't think that it is possible to directly screw in the sensor or switch to the block as the intake is prohibiting doing that, there's barely room to screw in the pipe nipple (the T adapter). Anything wider than the nipple will not fit, including anything you could put a wrench around, that's how close the intake is to the hole. I guess that's what is making it so hard to tell what is trully going on here.

 

well i bought a new T fitting and tried that with the same results and they are the same threads as the sending unit. I used black rtv on the china wall and around the ports on the gaskets. I dont believe it has a crack in the block (knock on wood) because oil is coming from that flange where the intake and sending unit are. There is also a bit of oil on the other side where the intake meets the block but this could be from oil blowing around back there. The weird thing is, it doesnt leak a drop until i drive the car. I watched it while it was ideling and i reved it a few times and it didnt leak at all.

This is unrelated to my oil leak but i noticed on the gaskets around all the ports it looks wet what would cause this? I was thinking the rtv soaked into the gasket maybe?

 

Another thing you might want to check as a troubleshooting/elimination step is the distributor. Make sure you have the round gasket underneath it where it rests on the intake manifold. Also, you might want to remove the cap and see if there's any oil inside the distributor housing. I've seen distributors go bad before where engine oil gets pumped up into the distributor housing. In fact, it was the same small cap HEI style that our 86-92 cars use that I saw this problem on once. Can't hurt to check.

 

the round gasket on the distibuter is wet from oil but it doesnt appear to be leaking from it, it would run down the other side of the block. A mechanic mentioned it could be crankcase pressure from my rings not being seated yet. He said he doubts it is leaking from the intake.

 

i'd hate to suggest this but you could try again and literally watch the motor for how ever long it takes to start leaking.. then you will know where the problem is.. remember, this is just a thought.. i'm not telling you to do it or not..

 

i already did that. I started up the car and sat there for 15 min. watching and it did not drip a hint of oil, took it up the road 100 yards come back and there it was the puddle of oil and it was running down the block. I have elimated the threads on the T adaptor and the sending unit because it would be leaking all the time not just when i drive. Im really thinking it is the intake. Anybody else have any ideas?

 

sit and watch it and then pull on the throttle cable.

 

doesnt leak a drop when i do that, only when i drive the car. Took the intake off today and resealed it, we'll see how that works tomorrow if the weather is decent.