Author Topic: Leak (Read 1350 times)

RustyRed · « **on:** March, 30, 2010, 08:09:30 PM »

I've noticed a spot of oil once or twice and I've been trying to chase it down.

Think I know where it's coming from now. It seems to be coming from around the transmission inspection plate. If I wiggle the inspection plate it's "wet" for lack of a better way to put it.

It's oil for certain and not tranny fluid.

I think I know the answer but any chance it could be anything other than a rear main seal? I checked where the heads meet the block and no signs of leaks there. Didn't think to check the back of the intake though.

Motor only has 200 or so miles on it so I am a bit po'd that it's leaking oil from anywhere. It's not a massive leak but still pretty annoying.

apollard · « **Reply #1 on:** March, 31, 2010, 03:36:09 AM »

There are plugs for the oil galleries and a larger plug for the back of the cam there also. Possibilities, but all of them require removing the trans or motor to be able to see which one is leaking

AzPete · « **Reply #2 on:** March, 31, 2010, 04:24:01 AM »

By chance....the rear pan gasket?

RustyRed · « **Reply #3 on:** March, 31, 2010, 05:28:30 AM »

Quote from: AzPete on March, 31, 2010, 04:24:01 AM

By chance....the rear pan gasket?

From what I could see it's not leaking. But that is just what I can see when climbing under there.

I am going to check with a buddy of mine. He had a customer with a '69 that just pulled out a perfectly good tranny to put in a larger AOD one. He had asked if I wanted to buy the one they pulled out. Apparently it was in really good shape with low miles and my bud that runs the shop made a comment about spending money "just because" suggesting to me he didn't mind getting paid to swap them out but seemed to think it was totally unnecessary. Might be a good time / excuse to pull my trans :vic

66gt350 · « **Reply #4 on:** March, 31, 2010, 07:02:30 AM »

There's only a couple places that it could be coming from.

What about from the top end...could the rear seal on the intake be oozing? Or the rear main seal?

RustyRed · « **Reply #5 on:** March, 31, 2010, 07:42:35 AM »

with it coming out of the back of the inspection plate I am guessing it's not the intake and then running down but that is just a wild guess.

My hunch is it's the rear main or maybe the oil pan gasket on the back part of it but not sure how you could tell short of pulling either the motor or the transmission.

AzPete · « **Reply #6 on:** March, 31, 2010, 07:51:00 AM »

Remove the inspection plate. Clean the area real good. Drive the car (yes, you can without the plate) and then use a mirror to see where the leak is from. Depending on how bad it is will make a difference on how long you need to drive the car. Real bad and running in the garage will show it. Remember, the wind from driving will move the oil in many places...

buening · « **Reply #7 on:** March, 31, 2010, 08:58:14 AM »

Or just let it run in your driveway and rev it up a bit to get the juices flowing. Turn motor off and inspect. With my transmission currently being removed I noticed a little bit of oil leaking around the rear main. It's definitely easier to find the leak with the flywheel/flexplate removed :craz Mine only has a few thousand miles on rebuild and used the rubber rear main with the RTV. I'm not happy either :rp

RustyRed · « **Reply #8 on:** March, 31, 2010, 09:53:53 AM »

I did a little investigation at lunch.

It only leaks with the motor running. I drove it Monday to work and back. Tuesday it had a small (nickle or quarter sized) puddle under it. Last night I rolled it back about six inches and let it sit.

Hasn't run = no new puddle.

When I have time tonight and I am not in my work clothes I should have time to get the mirror out and investigate some more.

Any chance the seals have to seat good? I've only got about 175 miles on it now...should I drive it another 100 miles or so and see what happens?

AzPete · « **Reply #9 on:** March, 31, 2010, 10:38:30 AM »

I have always believed if it leaks now, it will leak later. Only if there is crap in the oil that might plug the leak.....but then you have crap in your oil...

You might pull the starter to get a better view with the mirror and flashlight.

sigtauenus · « **Reply #10 on:** March, 31, 2010, 10:39:38 AM »

I don't know about seals having to seat good. They should be holding from day one, no leaks.

I'm hoping I don't have these problems either. Its happened to me more than once now putting an engine together on the stand, everything looks nice and tight, fire it up and get a water or oil leak. Can't stand that. And you never get it as pretty again either after you booger up the bolts taking stuff apart again.

monkeystash · « **Reply #11 on:** March, 31, 2010, 10:41:12 AM »

I've always assumed if the rear main seal doesn't leak, there isn't oil in the engine.

RustyRed · « **Reply #12 on:** March, 31, 2010, 10:42:27 AM »

What I was wondering is a rear main only going to leak when it's running or all the time?

Thinking of checking the valve cover gaskets, back of the intake, etc, etc before I do anything else.

sigtauenus · « **Reply #13 on:** March, 31, 2010, 10:48:01 AM »

With the car parked level all the oil is in the bottom of the pan. You can't even verify if the pan gasket is leaking with the car sitting still, let alone the rear main.

Also, its amazing how far oil from the intake can travel.

AzPete · « **Reply #14 on:** March, 31, 2010, 10:49:30 AM »

Yes, check all locations.

Leaks are going to be under running conditions with pressure to the leaking area. Static leaks are from areas that have oil standing sunc as the drain bolt.

RustyRed · « **Reply #15 on:** March, 31, 2010, 03:58:02 PM »

I started it up and let it run on the drive for a while and did some looking around with a mirror at the same time.

The back of the valve covers and intake look bone dry and clean as can be minus some dust.

It has been sitting for a while now after I shut it off and no leak.

The lip of the oil pan has some oil on it.

Any chance it is the pan seal on the back? Wondering if going down the road sloshes the oil around causing the drip verse when it is just sitting and running it doesn't seem to leak a drop.

MarkStang · « **Reply #16 on:** March, 31, 2010, 04:12:41 PM »

I thought I remembered learning as a kid fro guys talking cars long before the internet that a rear bearing may only leak under load. Just a thought , but hey I was just a kid.

AzPete · « **Reply #17 on:** March, 31, 2010, 05:01:24 PM »

Oil does get splashed around when running. That could show a rear pan gasket leak.

Did you also check the rear seal of the intake? Those are good for a leak.....

Oil can blow from the front of the engine and drip off things that don't even have oil in them. Check all over.....

RustyRed · « **Reply #18 on:** March, 31, 2010, 06:51:56 PM »

Quote from: AzPete on March, 31, 2010, 05:01:24 PM

Did you also check the rear seal of the intake? Those are good for a leak.....

Yep, checked it with a mirror from both sides. Can't really see back there otherwise.

lethal289 · « **Reply #19 on:** March, 31, 2010, 07:29:41 PM »

heres a tip, sprinkle some baby powder around the back of the intake. Not too much, and be careful not to get it everywhere. Start it up, drive it around the block, let it run for a few minutes, check it again with a mirror. Sometimes its not visible, but with the powder you can see a trail. When your done, the powder just washes away with a cup of water or a wet rag.

RustyRed · « **Reply #20 on:** March, 31, 2010, 07:34:00 PM »

Thanks Lethal.

Naturally I just changed the oil so it is really clear being a very low miles motor...makes it hard to see the oil / leak.

Might double check it with the powder though I don' think I have any. I am going to Wally World tomorrow so I might pick some up.

RustyRed · « **Reply #21 on:** April, 01, 2010, 06:03:37 AM »

I was just thinking about something....there is one spot where I have seen evidence of a leak.

On the driver's side of my block is a plug (kind you screw in with an allen wrench) and it looks like it has had a very slight leak. I am running a 302 that required a dipstick relocation.

Any chance that could be leaking and then running back due to wind / motion of the vehicle and so forth?

I think tomorrow I am going to clean the area around the plug, maybe even put baby powder on it then go for a 15 minute drive and see what I get.

Sound like a plan?