Is this oil on my intake and where does it come from?

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dibbons

dibbons

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My '72 318 two-barrel is always moist/wet/damp on the intake manifold in front of the carburetor. There is something there like an unused bolt hole on the passenger side where I find a little puddle of liquid, I assume it is oil (unless it's gasoline). Anyone else observe this phenomenon? What exactly is it? Thank you.

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Dunno what the little hole is next to the bolt, but i have seen puddles of oil on the intake caused by oil migrating up the bolt threads and coming to rest under the bolt heads.

When i do an intake gasket i put some rtv on the intake bolt threads. That seems to do the trick.

Best

CE
 
I go along with the intake bolt idea. If it was the valve cover gaskets, it would be wet above the puddle. It doesn't appear to be.
 
Put sealer on the bolt threads, it's wicking through the threads as the hole goes through to the crankcase....
 
Mr Gorsky said:
Leaking valve cover gasket. Guaranteed.
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I have to agree with you 100%, because the clue is right there in the picture.
You can see how it is even soaked out over the intake runner at the very top of the pic.
It ran down that edge and then went into the gasket and coming out that little hole where it spread clear up to the heater hose on the intake.

DSC00062.JPG
 
TrailBeast said:
I have to agree with you 100%, because the clue is right there in the picture.
You can see how it is even soaked out over the intake runner at the very top of the pic.
It ran down that edge and then went into the gasket and coming out that little hole where it spread clear up to the heater hose on the intake.

View attachment 1714941332
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The puddle would have formed between the edge of the manifold and cylinder head then as well rather then only spilling over. OP should put some good teflon tape on his bolts; my car did the exact same thing before I did.
 
Most LA small block owners will be familiar with this problem. It doesn't seem to matter what gasket material you use, it's often a crapshoot whether they leak or not.

Overtightening the valve cover bolts can exacerbate the issue.

This drama is pretty much non-existent on the later Magnum small blocks. More bolts.



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fnaramore said:
The puddle would have formed between the edge of the manifold and cylinder head then as well rather then only spilling over. Put some good teflon tape on your bolts; my car did the exact same thing before I did.
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Look how wet it is right in that corner right above the hole.
It would just stop there suddenly without puddling in that corner and that little hole wouldn't have that much puddled at all if it came from the bolt, so that was my reasoning on that.
Of course do the bolt threads, but the cover is obviously leaking also.
 
Mr Gorsky said:
Most LA small block owners will be familiar with this problem. It doesn't seem to matter what gasket material you use, it's often a crapshoot whether they leak or not.

Overtightening the valve cover bolts can exacerbate the issue.

This drama is pretty much non-existent on the later Magnum small blocks. More bolts.
Click to expand...

And more importantly flat surfaces instead of porous cast, and using the magnum gasket.
I have the magnum pattern heads but using LA style valve covers with 5 bolts.
Dry as a bone all around.
First step would be to throw those cork gaskets away and never use them again, as I hate seeps, and cork always ends up doing it eventually.
With OE cast heads a rubber gasket from Felpro and a small bead of RTV on both sides of the gasket and no more leaks at all (dry as a bone for years)
Oh then cut the tabs off the next day. :D
 
TrailBeast said:
Look how wet it is right in that corner right above the hole.
It would just stop there suddenly without puddling in that corner and that little hole wouldn't have that much puddled at all if it came from the bolt, so that was my reasoning on that.
Of course do the bolt threads, but the cover is obviously leaking also.
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It's quite possible we are both right. You are 100% correct its moist there, I just would have expected it to leave at least some residue, unless of course its just burning off. I just know I had a pretty substantial amount build up when I uh.. forgot to teflon my bolts lol
 
Clean off all the gunk and then observe the area. You can guess at this all day long but it is impossible to tell without cleaning the area first.

Teflon tape is not for regular bolts. First of all, you'll never get the bolts torqued properly (too slippery). Actually it shouldn't be used on anything but pipe threads. Not even really good for that (on engines) because if strands of it get into the oiling system you can ruin bearings and clog up small passageways. Use liquid pipe dope if you must use anything at all.
 
I had a similar problem - but it turned out to be a small leak in my carburetor gasket. Which turned out to be a crease in the gasket. Some amount of oil will come out of the breather and other dirt materials will help color the gas
What does it smell like?

Replaced the gasket and problem went away
 
I first I thought the carb was to blame because there indeed was a wet spot directly underneath the float bowl, but after putting a NOS carb on, no more wetness under the carb, but the the mini-oil puddle showed up again. I will have to clean it up and start over. I had thought that maybe it was a common problem and forum members would have known right away where the oil was coming from, but evidently I must have overestimated the commonality of the problem/symptoms.
 
dibbons said:
....I had thought that maybe it was a common problem and forum members would have known right away where the oil was coming from, but evidently I must have overestimated the commonality of the problem/symptoms.
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Which part of the word guaranteed don't you understand? The evidence of the source is in your own pictures (as has already been spelled out).

I've been down that path. Traveled this road. Crossed that bridge. Run this race. F#cked this cat.

OEM LA valve covers buckle, get bent, are distorted over time. No-one torques them correctly. They go too far, then tighten them a little more. If a leak occurs, they get tightened again!!

You have form for ignoring advice and whoring up forums with thread after thread. I'm done here.
 
my bet is on the intake bolt....
and cork is fine with regular use...like a wine bottle,if the cork stays wet it will
expand and seal.Occasional use...not so good.
 
Mr Gorsky said:
Most LA small block owners will be familiar with this problem. It doesn't seem to matter what gasket material you use, it's often a crapshoot whether they leak or not.

Overtightening the valve cover bolts can exacerbate the issue.

This drama is pretty much non-existent on the later Magnum small blocks. More bolts.



MN1037.JPG


MN2029.JPG
Click to expand...
so here is a thought, with those five extra holes in there, and the oulines cast into them to reach the bolts, the magnum covers look to be a whole lot more flex resistant then the LA units
would magnum covers on LA heads have less chance to leak?
 
That last comment regarding the cork gaskets makes a lot of sense. I always wondered why they were always packed in the gaskets sets for the valve covers. Keeping them "wet" probably keeps things buttoned up. But with multiple classic cars at the house, it is difficult to give each one a fair share on the road when a daily driver takes precedence.
 
Probably an excellent idea to perform both repairs. The gaskets and the bolt sealing. Woundn't hurt not one thing.
 
Torque the valve cover bolts in sequence and they'll never leak. Unless you already pooched the covers by over torquing.
Then you need to straighten the rails out.

And yah you can see exactly where the oils coming from.
 
diymirage said:
so here is a thought, with those five extra holes in there, and the oulines cast into them to reach the bolts, the magnum covers look to be a whole lot more flex resistant then the LA units
would magnum covers on LA heads have less chance to leak?
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I doubt it, because mag heads are flat on the sealing surface of the heads both ways.
If you put a straight edge on a OE head you notice a rise in the center of the head on both rails of the head.
This is what people that use fabbed or cast valve covers on cast surface OE rails run into and then wonder why they leak or bust corners off.
I literally had to add 1/8 more gasket on each end to get mine to seal.

I started with the original rubber type Felpro gasket and then got another set and cut about 6 inches of the ends off .
I laminated those together and then mototooled a gradual taper from the ends down to the center of the gaskets and the aluminum fabbed covers fit like a glove and sealed perfectly.
I ran this motor for a few years afterwards and this is how the motor looked. (Dry as a bone)
The magnum heads were/are flat and straight, so I didn't have that problem.

The ribs in the magnum covers might help a little for structural strength, but the fact that they are literally flat front to rear would probably cause the same problem on an LA motor as I had putting flat fabbed covers on the LA heads.

motor.jpg
 
interesting point trail

I seem to remember reading about those homemade gaskets of yours a while ago
 
I think Trailbeast hit the nail on the head. Don't know if the op has cast valve covers.
But I'd had trouble getting my covers to seal and not leak. I've put a straight edge along the sealing surface of my heads and they are not flat, my cast covers are very flat. I made a double thick set of cork gaskets gluing them together with silicone, and then installing. Worked a little better.
I have my heads off now, and i'm thinking of taking them to a machine shop and having them "flatten" the gasket area around the top of the head.
 
RustyRatRod said:
Probably an excellent idea to perform both repairs. The gaskets and the bolt sealing. Woundn't hurt not one thing.
Click to expand...

Funny thing is my little 273 was doing the exact same thing.
Just a little puddle. Nothing at idle, just after a freeway trip.
I just "snugged" the valve cover bolts as they did not appear to be loose but
to my surprise when I put a wrench on the intake bolt it was way loose.
So I re-torqued all the intake bolts and like I said earlier re-checked the valve cover bolts and that seems to have cleared it up.

I agree with Rusty here, I'd go ahead and do both, it won't take long.
 
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