They've been there for as long as I’ve owned the car but a few years ago I began to get frustrated with the various drips under my car. I’ve fixed the drips coming from the differential and the transmission, but I still have a few drips coming from my engine. Once the suspension and chassis restoration work was finished, I gladly took the advice of driving it more frequently to see if the seals were just dried out and allowing the drips. After driving the car quite a bit this summer I still have the same engine oil leaks, and the most likely culprits are: valve cover gaskets, intake manifold seas, rear main seal(s), and oil pan gasket.
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Back in September I added some UV dye to the engine oil and wow that was interesting. The UV dye showed up at the passenger side valve cover gasket, it showed oil coming up through one of the valve cover bolts, and the dye was visible in other places on the bottom of the engine! It was at this point that I decided to divide the engine in half (top and bottom) and first replace the gaskets and/or seals in the top half of the engine (valve cover gaskets and intake manifold gaskets/seals) and see what affect the new seals/gaskets have on the oil drips that have frustrated me for so long, but some of you know that I’m not mechanically gifted and have been hesitant to start this project because it intimidates me (mechanically).
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For a recent snow, the city put down road salt and I used that as my reason / timing to begin some “winter” projects and the second task on my list (the first was to replace all the fan belts) is to replace the valve cover gaskets and the intake manifold gaskets/seals. With the fan blades and the alternator already off the car (fan belt project), yesterday I started the disassembly – to remove the valve covers and the intake manifold.
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I’ll share my progress, lessons, and mistakes with the forum and along the way ask you guys to provide suggestions, advice, warnings, tips/tricks, etc. I already made one mistake… yesterday when pulling this metal vacuum line off the passenger side of the carburetor… When it finally broke free the metal line scratched the top of the valve cover . So there’s mission creep #1 (repaint the valve covers). Tip to myself and for others: protect any / all surfaces that you don’t want to repaint BEFORE they get damaged.
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I plan to remove the valve covers before removing the intake manifold but there are still some things that I need to remove before I can pull off the valve covers; for instance: the power steering and alternator bracketry, the metal fuel line coming up from the fuel pump, the throttle linkage rod, the spark plug ground leads. I sure wish that power brake booster and master cylinder weren’t there. What else should I remove before pulling the valve covers?

UV dye coming up under a valve cover bolt

UV dye drip on the bottom of the starter

UV dye drip on the bottom of the inspection cover

These are the valve cover gaskets I plan to install

Pulling this vacuum line out I scratched my valve cover (uurrgghh)

I scratched my valve cover (uurrgghh)

Still have some things to get out of the way before I can remove the valve covers

Still have some things to get out of the way before I can remove the valve covers

This is what my engine bay looks like right now

This is what my engine bay looks like right now

 

Corvettes do not leak oil, they’re merely marking their territory. It’s their garage space and no other car can park there.

 

You might want to try this stuff first. It has worked for me.

 

Brian,
I'm probably wasting my time here and speaking to "deaf" ears BUT...you may be opening a can of worms that you wish you hadn't. There is nothing "wrong" with your car as it is. The machining tolerances on these 60 year old cars was nothing like it is on modern cars...they leak...that's just what they do. You can minimize some of the leaks with proper torquing of fasteners, some chemical additives and simple wiping down of the areas that will, inevitably, seep fluids. You'll drive yourself nuts trying to "seal up" one of these old classics. The more you drive her the better she'll operate.
Certainly your car and your choice but....

 

I'm with Leif on this one Brian. Put a piece of cardboard under the car & wipe off the little bit of oil every once in a while. That is an awful lot of hassle for not much reward & you will probably never stop all of the little drips.
Darin

 

Check your oil pressure connection on the engine or if you have a oil pressure sending unit check it..... Can;'t say on corvettes but they are know to leak on other vehicles

 

I completely agree.

Compared to my car, OP's is tight as a drum and I am fine with mine. It's old, it leaks, so what. And the can of worms you mentioned has already been cracked open as he's having to repaint valve covers. What's next.

 

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Thanks for the good tip/suggestion!

 

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I've got to try, and just think of all the learning I'll accomplish along the way! <<< that's my positive attitude haha

 

You shouldn’t have to remove any accessories to remove the valve covers. Once the bolts are out and the VC freed from the gasket, you can slide them around a bit and they should lift right off. There is no reason for an intake manifold to leak. Using the proper intake to head gaskets and RTV on the end rails is pretty bulletproof. VCs, oil pressure sender, oil pan, and rear main seal are another issue. VCs and oil pans usually leak due to being overtightened and the flanges warp, there are also much improved gasket materials today. You are smart to start at the top as many leaks that seem to come from lower on the engine are often VC leaks. Good luck and share your findings and progress.

 

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Yep, it is very possible that I'll never stop all the drips but I'm going to try.

 

if you like chasing your tail you going down the right path

 

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I've checked this location and it's dry. Thanks for the idea.

 

Understood.
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I agree. The engine was balanced and blueprinted back in 2008 and who knows what kind of materials they used when they put it all back together. I'll figure that out when I take it apart. And when I put it back together I'll make sure it gets done right and follow up over time with checking the intake manifold bolts' torque values.
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Yah, I know it's too soon to tell but I think I'm going to find that the VC's are the primary source of the oil drip(s) from ABOVE. I'm no mechanic but presuming I am somewhat successful with reducing the oil drips from the VC's and/or the intake manifold (what I'm calling the seals and gaskets on the "top" of the engine) I think I'll still see drips on the bottom because I'd be surprised if the rear main seal wasn't dripping too.

 

the 327 in my '32 Ford leaks just like the one in the '66. I think it's a universal Chevy thing.......lol!

 

While it may be ultimately futile, there's nothing wrong with the attempt.

No man can tell another how to engage in a pleasure activity. You do you, Brian

 

I've never seen a C2 that was bone dry underneath. Maybe in the first few decades but not now. I'm sure somebody's gonna chime in that they have no leaks, not even a drip. Hey! hats off to you brother. My car gets driven every week rain or shine.

I think it's good for the car... engine etc. I keep it on a lift and probably once a month wipe down the underneath just to keep the dirt off. Usually find a drip or two.... maybe the size of quarter every 6-months. They leak fellas!

 

As mentioned by @Factoid, one of the biggest causes of leaks on sheet metal valve covers and oil pans is overtightening. Folks tend to put too much muscle into these bolts and it deforms the flange and ruins the gasket. When you get the valve covers and pan off of the engine, check the flanges and straighten any deformation. When replacing them, I always use an inch-pound torque wrench, tighten in the recommended sequence and tighten in steps until reaching the minimum recommended torque. Then run the engine or drive the car to get it up to operating temperature. Check for leaks. If you find a leak, tighten the bolts again in sequence. You will find that the bolts will turn some more without increasing the torque. If you still have a leak after tightening again, increase the torque setting another 5 in. lb. and do it again. Repeat as necessary but don't exceed the maximum recommended torque. I've had very good results using this method.

Ted

 

If you want the valve covers to stop leaking do this. Remove covers remove old gasket clean thoroughly. Check the straightness of the rails. Now use the gaskets you bought they are fine but now get some RTV. I prefer black put on some rubber gloves and smear the RTV over the entire gasket. Now I don't mean thick but like painting it. The whole gasket must be black sides and all. now let it skin for a few minutes. now put it on and snug down the bolts inside ones first in sequence a little at a time and not to tight but snug. Now walk away for a day. Come back check the bolts give them maybe a eighth of a turn. It should not leak again.Let me know when you want to attempted the intakeOh and by the way my car does not leak

 

I would have guessed a 327 until half est through the pictures

with a survivor 427 those leaks kept a lot of stuff from rusting all the way back to the dif

valve covers
use the technique above
Non acidic rtv
solvent like brake cleaner
not mineral spirits to clean metal surfaces
you are going to coat the ridge in the head and mating side of the gasket

thats making you seal with barely tightened bolts

same process on the oil pan

intake can be a real bugger you have coolant passages as well, are you sure you had oil leaks from the intake???