Methods for finding oil leak
Thread Starter
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
Methods for finding oil leak
Hey all,
Not surprisingly, I am having some trouble with my first engine rebuild. I built a 383 with vortec heads and put it in my '80. It fired right up and ran well but I had a couple of leaks. I had run the car several times at low speed and in the garage while looking for oil, coolant, etc. Not a drop. Now after having it out on the road for a real drive I came home and popped the hood to find oil all over the underside of the hood. I cleaned everything and started it and watched and watched and no leak... until I took it out for a road-speed drive.
I can't get the thing to leak oil when I am in the garage but when I have it out on the road it blows the oil all over the engine compartment and I can't tell where it is coming from.
Can you guys give me some tricks on finding an oil leak without pulling the engine?
Not surprisingly, I am having some trouble with my first engine rebuild. I built a 383 with vortec heads and put it in my '80. It fired right up and ran well but I had a couple of leaks. I had run the car several times at low speed and in the garage while looking for oil, coolant, etc. Not a drop. Now after having it out on the road for a real drive I came home and popped the hood to find oil all over the underside of the hood. I cleaned everything and started it and watched and watched and no leak... until I took it out for a road-speed drive.
I can't get the thing to leak oil when I am in the garage but when I have it out on the road it blows the oil all over the engine compartment and I can't tell where it is coming from.
Can you guys give me some tricks on finding an oil leak without pulling the engine?
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
There is no indication of heavier oil on one side? Could mean the leak is centrally located. Do you use an engine driven cooling fan with a shroud? The air flow from it is probably blowing the oil all over the place, could point to a leak at the top of the engine. If you were to remove the fan and take it for a short spin, you might get a better idea where the leak is. Be careful not to over heat it, if you keep the speed up over 25-35 mph, you should stay cool. Clean all oil very carefully, and spray some spray can foot powder all over the engine, a nice thick layer. An oil leak will show up extremely well against the contrast of the white foot powder. If someone held a gun to my head and said "Take a guess!!", I'd have to say maybe the front intake manifold seal to the block is leaking? Good luck, let us know how it goes,
Scott
Scott
Le Mans Master
Joined: Sep 2004
Posts: 5,116
Likes: 5
From: Livonia MI
Easiest way I know of, is to put some UV trace dye in the oil, then later after a drive, scan around with a UV light. These UV flashlights have really come down in price. May help doing this inside a dark garage.
Thread Starter
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
Two great ideas. I was worried about putting any powder on the engine (flour, baking powder) as it would be a horrible mess to clean but the I never though of Tinactin! If this doesn't work I will look for some of the UV dye and a light. The garage is pitch black at night so that should work well too.
I am worried about that front valley under the manifold too, Scotty. I didn't use a gasket here and I remember how thick the bead of RTV was to get it to seal. But to guess the side, I would say it seems to be heavier on right. And it seems as if the it is blowing from low on the motor up to the underside of the hood as the manifold and valve covers are relatively clean compared to the hoses and frame on the underside. Almost like it is carried by an updraft rather than being blown back by the fan. I would love to see a wind tunnel experiment of the flow of air through the engine compartment on a C3 with a glass hood!
I am worried about that front valley under the manifold too, Scotty. I didn't use a gasket here and I remember how thick the bead of RTV was to get it to seal. But to guess the side, I would say it seems to be heavier on right. And it seems as if the it is blowing from low on the motor up to the underside of the hood as the manifold and valve covers are relatively clean compared to the hoses and frame on the underside. Almost like it is carried by an updraft rather than being blown back by the fan. I would love to see a wind tunnel experiment of the flow of air through the engine compartment on a C3 with a glass hood!
Drifting
Joined: Jun 2010
Posts: 1,781
Likes: 15
From: Oxford Ohio
My guess is the front of the intake where the sealant is. You may have a head gasket leak causing pressure in the intake. I suspect oil under pressure to come out in that amount from an area that shouldn't have pressure.Tape a scott towel over the front of the intake and take a short drive.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
When all else fails, this is the method of choice for me!
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Two great ideas. I was worried about putting any powder on the engine (flour, baking powder) as it would be a horrible mess to clean but the I never though of Tinactin! If this doesn't work I will look for some of the UV dye and a light. The garage is pitch black at night so that should work well too.
I am worried about that front valley under the manifold too, Scotty. I didn't use a gasket here and I remember how thick the bead of RTV was to get it to seal. But to guess the side, I would say it seems to be heavier on right. And it seems as if the it is blowing from low on the motor up to the underside of the hood as the manifold and valve covers are relatively clean compared to the hoses and frame on the underside. Almost like it is carried by an updraft rather than being blown back by the fan. I would love to see a wind tunnel experiment of the flow of air through the engine compartment on a C3 with a glass hood!
I am worried about that front valley under the manifold too, Scotty. I didn't use a gasket here and I remember how thick the bead of RTV was to get it to seal. But to guess the side, I would say it seems to be heavier on right. And it seems as if the it is blowing from low on the motor up to the underside of the hood as the manifold and valve covers are relatively clean compared to the hoses and frame on the underside. Almost like it is carried by an updraft rather than being blown back by the fan. I would love to see a wind tunnel experiment of the flow of air through the engine compartment on a C3 with a glass hood!
I like Indiancreek's idea about the paper towel, too.
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Another suggestion, if you don't want to remove the fan, is to take a short drive. You want to try to catch the leak before it has time to be blown all over the place. Might help diagnose the cause of the leak if we know exactly what conditions make the leak start, too.
Scott
Scott
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Melting Slicks
Joined: Apr 2004
Posts: 2,008
Likes: 38
From: Space Coast Gator Territory
I agree, oil leaks can drive you nuts and the powder can leave you with another mess to clean up. I bought my UV dye kit with light for around $20 some years back and was a smart investment. In retrospect, if I had bought the kit right off, it would have saved me a lot of unnecessary searching and guessing. My UV light is the size of a pen flashlight. Hopefully, your leak will turn out to be an easy fix.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
You can buy a lamp at Bass Pro for seeing the fishing line... 
They have a cheap one around five or six dollars.. but even something like this will work.
http://www.basspro.com/Quarrow-TriEy...0210377/114682 $10.99.
The dye is readily available from your locals parts store too.
They have a cheap one around five or six dollars.. but even something like this will work. http://www.basspro.com/Quarrow-TriEy...0210377/114682 $10.99.
The dye is readily available from your locals parts store too.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
The foot spray technique that I use has always worked well for me, I have never used the UV dye. The foot powder isn't free, it costs a few bucks, and you really need to spend some time getting the suspected leak area nice and clean before spraying. I imagine that is not necessary with the dye, just dump it in, fire it up and shine the UV light on it. Easy-peasy-lemon squeezy. I'll have to give it a try sometime.
A thought: Whether you choose foot spray or UV dye, neither one is going to do you a bit of good if the oil is literally spraying all over the engine compartment. If you shine the UV light on the engine, and everything glows, that's not going to tell you much. So, I guess you should take a short drive and check it frequently. As in, dump in the dye, fire it up, back out of the driveway, hop on it for a few seconds, turn around, pull into the garage, shine the UV light.
Scott
A thought: Whether you choose foot spray or UV dye, neither one is going to do you a bit of good if the oil is literally spraying all over the engine compartment. If you shine the UV light on the engine, and everything glows, that's not going to tell you much. So, I guess you should take a short drive and check it frequently. As in, dump in the dye, fire it up, back out of the driveway, hop on it for a few seconds, turn around, pull into the garage, shine the UV light.
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Something finally clicked in my head!!! There is a chance that this could be a very, very simple fix. Read this article, and see if you are missing the bolt in question. it's pretty common after a rebuild. If so, easy fix.
http://www.rowand.net/Shop/Tech/Myst...evyOilLeak.htm
Scott
http://www.rowand.net/Shop/Tech/Myst...evyOilLeak.htm
Scott
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Flour doesn't hurt a thing.
Least expensive method i know of is use white baking flour. U may have to wipe the block dry first. Wherever the flour shows wet spots u have a leak.
Hope this helps,
cardo0
Hope this helps,
cardo0
Thread Starter
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
Something finally clicked in my head!!! There is a chance that this could be a very, very simple fix. Read this article, and see if you are missing the bolt in question. it's pretty common after a rebuild. If so, easy fix.
http://www.rowand.net/Shop/Tech/Myst...evyOilLeak.htm
Scott
http://www.rowand.net/Shop/Tech/Myst...evyOilLeak.htm
Scott
I will be working on the car over the weekend so I will get you guys some feedback. Thanks for all the great suggestions!
Mike
Last edited by myko; Jan 28, 2012 at 04:29 PM.
Thread Starter
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
That was it! I hope. I can't believe that I put the engine back in and didn't remember to go back and put that bolt in. It would have been a lot easier when in was on the stand, too. I took it out for a short test drive and have it parked with a sheet under the engine to see if there is any leaking overnight.
Thanks,
Mike
Thanks,
Mike
Last edited by myko; Jan 30, 2012 at 09:09 PM.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
That was it! I hope. I can't believe that I put the engine back in and didn't remember to go back and put that bolt in. It would have been a lot easier when in was on the stand, too. I took it out for a short test drive and have it parked with a sheet under the engine to see if there is any leaking overnight.
Thanks,
Mike
Thanks,
Mike
Scott
