Chasing An Oil Leak!!!

[toofun]

Well,
I got a leak detector. It was for an A/C and radiator leak but came with the Black light and yellow glasses.I bought some dye that is to be used for OIL. I put a half an ounce in and ran the car for a good 20 minute spirited drive. Pulled it back into the garage and within a couple of minutes I could see the oil dripping off the scattershield onto the floor. I grabbed the glasses and the light and shined it on the oil spot on the floor. It showed up as a dark mustard color. Visible but not really like a bright light set. I traced it up the oil pan up the oil filter under the back part of the head and it looks like from what I can see it is pooling on the back of the motor on the part that the bell housing connects to on the block. I tried to get behind the motor but as many of you know that is near impossible to do without ripping the motor out. I see the same trail on the back of the motor on the other side as well. But there are a couple of things I noticed for sure.
1. It definately is NOT coming from the distributor or the valve covers.
2. I think it may be coming from the back of the manifold but cannot confirm this 100% since I cannot get behind it from any angle to see if it is coming from there.
3. I see the stains on the back part of the heads just underneath it between the head and the block but am not sure if this is wicking from trailing from the back of the block or if it is coming from that area also.
4. The dye is visible but not super bright. I tried making the garage as dark as possible to try and give it more light but it still doesnt show anything super clear. Kind of like there may be a leak behind the manifold but cannot say definately.
Anyways sorry for the long post but this is driving me crazy. Can oil leak from between the heads and the block?? If it is pooling on the back of the motor up near the top end of the ^ shape on back of the motor does this mean that the leak is definately coming from the manifold? The oil sender unit is there as well but like I said before there is not enough of a brightness to make a definitive answer. Is there a better brand name dye to use that will show up SUPER BRIGHT? I also am using synthetic oil. ANY HELP AT ALL WOULD BE GREATLY APPRECIATED..
Mark

[streetk14]

Mark, oil leaks can be a real pain to track down. First, what motor are we talking about here? I was assuming it's just a gen 1 small block.

I used to have problems with valve cover leaks until I bought a set of rubber-coated steel shim valve cover gaskets. Never had a problem since many years later. You seem pretty confident that it is not the valve covers, so let's move on

I have seen oil leak from the intake manifold (from between the block and manifold). You did use a nice bead of RTV to seal those parts of the manifold, not the cork crap they give you in the gasket kits?

This is what I would do if I were you.
1) clean all the oil from the engine as best as you can
2)run the engine in the shop or driveway at 3000 rpm or so for 10-15 minutes

Driving the car is ok, but then you get a lot of air moving under the car causing the oil to move in directions that don't make sense. I've seen oil leaks that you could swear were coming from one place, but it was just airflow under the car playing tricks on me.

By running the engine while the car is stopped, I think you have a better chance of finding where it is coming from. Just my 2 cents, hope this helps.

Andy

[HILROD]

Oil can come from the rear of the manifold, from under the heads or under the drivers head right near the back there is an oil plug. I had a car leaking from that plug. It seeped ever so slightly. After I pulled the head and resealed the plug it was all gone. FRANK

[zbugger]

I've seen a cool little tool at the parts store before. It's called a mirror. It's small, and round, and it will help you look behind the manifold. Use that and a flash light and you may find the leak.

[Steve68]

A what????? mirror

[MrQuick]

Hey Mark,
thats a high leak so concentrate there.
Another cool trick I like to use is baby powder and take for a spin or a romp on a dyno. Sounds like its seeping intake rear seal area...how is your PCV system and blow by?
Yeah Frank, another common spot is that galley plug, i've seen that one or twice. That one is a PIA to diag.when it is leaking.

[streetk14]

A what????? mirror


Sorry, I was going to say something about using a mirror but it slipped my mind in my earlier post. Very useful tool in tight spaces.

[toofun]

Hey guys thanks alot. I didnt even think of using a mirror. That is the great thing about sites like this. Sometimes the logical, common sense answer is right in front of you and you just dont see it. I used a thick bead of silicone instead of the cork crap they supply you with. Originally I thought it was coming from the head since there seemed to be alot of oil concentrated on the drivers side under the back side of the head in the rear but couldnt figure out how it could leak oil there.But there also is some oil on the passenger side too but NOT UNDER THE HEAD. Seemed to drip down from the back of the block and down the side. I dont know if this was from a leak on the drivers side blowing over to the other side so I guess I will try the non moving test as well to eliminate that. One question about that oil galley plug. Where EXACTLY is it located and is their another one on the other side as well?? I have a chevy 383 stroker motor (350 block)

Thanks
Mark

[HILROD]

The plug is about an inch or so down from the top flat block surface and might be just peeking out from the head gasket. FRANK

[Matt@RFR]

Man you guys like to do things the hard way sometimes.

Stuff a paper towel in one breather. Wrap your air gun with a paper towel and stuff that into the other breather. Push air gun lever. Spray all possible leak sites with soapy water. Find bubbles. Done.

[kamaroman68]

Got the same problem with a 97 dodge Grand caravan 3.0 liter. This pig is leaking so bad (but still cant find it) that when we stop driving and open the hood smoke pours out. Common problem with these motors is the V/C gaskets replaced so it must be somewhere else. Did i mention that working on this vehicle is a P.I.T.A. Chris

[toofun]

Funny thing is the leak got worse when I switched to synthetic oil. I think running it on the highway may have blown oil all over the place as I cannot get a definative reading on the leak as well. I know it is definately coming from the back of the motor, but am not 100% sure whether it is coming from the back of the manifold or the oil galley plug that is half way showing under the cylinder head or BOTH. Obviously I am hopeing that it is just the manifold since the latter is ALOT more involved. I think what I will do just to safeguard myself is clean the entire engine all over again and then make sure I cannot see any of the dye on the block. Then I will run the motor while it is sitting on the jack stands in the garage. Hopefully this will give me a true reading of where it is coming from without it blowing all over the place from riding it around. What is the best cleaning spray to use to clean all the oil/dye out of all the crevices and surfaces??

[streetk14]

I like Simple Green degreaser. It is non-toxic and easy on paint, but does a very good job. An added plus is that it kind of smells like root beer, that is if you like root beer :)

Andy

[Charley Lillard]

Wipe off the back of the intake with either lacquer thinner on a rag or even brake kleen. Don't get it on the paint. Get the little mirror and a light and look back there. If you think it might be the back of the intake you can smear some silicone sealant back there with your fingertip, forcing it in the gap where the crappy cork gasket goes. Just make sure it is clean.

[rocketman]

I would say it's leaking between the intake and the block,if it's coming down the bellhousing,sounds like the intake valley didnt seal or the silcone is seeping.

[tumper93]

The first thing before saying it is the intake is check and make sure your fitting to your oil pressure gauge is not leaking or sending unit if you are using an electric gauge. Intake gaskets can leak oil that fast but I have only seen one in 13 years at the dealership and the sealer had a pin hole in it where an air bubble burst while drying. The fix for that was just a small dab of sealer over top of it since it was just a small pin hole. The plug on top of the engine by the intake could also leak but can be repaired the same way.

[toofun]

"The plug on top of the engine by the intake could also leak but can be repaired the same way".

Which plug are you referring to?? I would be curious in knowing where this plug is located so I can check it as well.

Thanks
Mark
TOOFUN

[Norwoodx55]

I might have missed this (too lazy to read all the posts) but are you using a gasket between the distributor and the intake?