Oil Leak
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Joined: Jan 2005
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From: Denton Texas
Oil Leak
What is the best way to find an oil leak?
I have a 95 LT1 with 76,0000 on it. Slight oil leak. It hasn't even used a quart of oil between changes (yet). For the most part the oil seems to be dripping from the the oil filter side down to the bell housing.
I'm hoping its not the rear main seal. I gather this would require pulling the engine. What about the oil pressure sensor? Where is this at & could this be the culprit?
I guess it could be 1 of several things, so what I really need to know is what is the best way to find out where an oil leak is originating from.
I have a 95 LT1 with 76,0000 on it. Slight oil leak. It hasn't even used a quart of oil between changes (yet). For the most part the oil seems to be dripping from the the oil filter side down to the bell housing.
I'm hoping its not the rear main seal. I gather this would require pulling the engine. What about the oil pressure sensor? Where is this at & could this be the culprit?
I guess it could be 1 of several things, so what I really need to know is what is the best way to find out where an oil leak is originating from.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
The rear main seal would simply leak oil down the bottom and out the inspection shield. It's not that hard to tell.
Your leak is more than likely coming from the intake manifold. It's a common problem. Check the back of the engine (by the firewall) for moisture.
Another good source is the valve covers... check them, too.
How to test for it, you need a dye kit. It has a liquid dye that you add to the engine oil, and a special ultra-violet light, with glasses. Run the car for a few days, checking for the leak with the light and glasses. The dye will turn like bright blue or something. Then you can ID the source.
I think Autozone and places like that are now selling these kits. The glasses and light are sold as a pair, and the dye is in a little bottle.
The dye is also good for coolant leaks, too. There is a special dye used for AC systems.
Your leak is more than likely coming from the intake manifold. It's a common problem. Check the back of the engine (by the firewall) for moisture.
Another good source is the valve covers... check them, too.
How to test for it, you need a dye kit. It has a liquid dye that you add to the engine oil, and a special ultra-violet light, with glasses. Run the car for a few days, checking for the leak with the light and glasses. The dye will turn like bright blue or something. Then you can ID the source.
I think Autozone and places like that are now selling these kits. The glasses and light are sold as a pair, and the dye is in a little bottle.
The dye is also good for coolant leaks, too. There is a special dye used for AC systems.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
I like to wipe off the oily areas clean and start fresh. Then I keep a close eye on it with a flashlight. They also sell a dye that you can add to the motor oil. The leak will then clearly show under a black light I beleive.
Le Mans Master
Joined: Jan 2006
Posts: 6,564
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From: Woodstock Georgia
No secrets on this one. Clean it up best you can and then after running for a while get it up in the air and go underneath with a flashlight. An inspection mirror can help for the tight or hard to see spots. There are also dyes available from auto parts stores to help locate an oil leak. It is very unlikely to be a rear main seal, that would be leaking out from the bellhousing only. For what it is worth I had front crank seal seeping and put 1 pint Lucas Oil stabilizer in with Mobile One on last oil change and no more seepage (so far).
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From: Denton Texas
This is probabaly a stupid question but I need to ask.
If it turns out to be the intake, will I have to remove the fuel rails from the intake?
I hate dealing with the fuel lines. I just got down replacing the fuel pressure regulator. It was quick, but I just hate dealing with the fuel.
If it turns out to be the intake, will I have to remove the fuel rails from the intake?
I hate dealing with the fuel lines. I just got down replacing the fuel pressure regulator. It was quick, but I just hate dealing with the fuel.
Advanced
Joined: Oct 2004
Posts: 81
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From: Loveland CO
Another source for an oil leak is the seal between the oil filter adapter and the engine block. I fixed this recently on my '96 LT4. I believe you have the same adapter on your LT1.
If you see a drop hanging from your bell housing AND from your oil filter, this could be the source.
Good luck!
If you see a drop hanging from your bell housing AND from your oil filter, this could be the source.
Good luck!
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Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
Originally Posted by MilehighZ51
Another source for an oil leak is the seal between the oil filter adapter and the engine block. I fixed this recently on my '96 LT4. I believe you have the same adapter on your LT1.
If you see a drop hanging from your bell housing AND from your oil filter, this could be the source.
Good luck!
If you see a drop hanging from your bell housing AND from your oil filter, this could be the source.
Good luck!
I have had issue with that one over the years. The heat is great there, and between the oil and the heat, the paper gasket turns to stone. It's a real bitch to get off.
I coated my replacement with high tack, hoping it will make it easier to replace down the road. I will report back when that time comes.
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From: Denton Texas
Originally Posted by MilehighZ51
Another source for an oil leak is the seal between the oil filter adapter and the engine block. I fixed this recently on my '96 LT4. I believe you have the same adapter on your LT1.
If you see a drop hanging from your bell housing AND from your oil filter, this could be the source.
Good luck!
If you see a drop hanging from your bell housing AND from your oil filter, this could be the source.
Good luck!
I'll have to check this one. This sounds close to what I'm seeing.
Did you just have to replace the seal or was there more to it?
Advanced
Joined: Oct 2004
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From: Loveland CO
There is a gasket and a large O-ring between the adapter and the block. The dealer offers a kit which contains both pieces.
There are two bolts which hold the adapter to the block. The adapter may require a little persuading to remove, because the inner gasket has hardened pretty well over time and has done a fine job of adhering the two surfaces together. The toughest part of the job is scraping off the old gasket material from the block. As Bogus described, it's a bitch...you need to be creative in your tool selection, because there isn't a lot access to that surface under there. Be sure to wear safety glasses- gasket material will be falling down onto your face!
Good luck!
There are two bolts which hold the adapter to the block. The adapter may require a little persuading to remove, because the inner gasket has hardened pretty well over time and has done a fine job of adhering the two surfaces together. The toughest part of the job is scraping off the old gasket material from the block. As Bogus described, it's a bitch...you need to be creative in your tool selection, because there isn't a lot access to that surface under there. Be sure to wear safety glasses- gasket material will be falling down onto your face!
Good luck!
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I used a pneumatic die grinder with a steel brush on the end... THAT worked... 
Over time...
There is a chemical gasket removal spray that did help to soften it a bit... everything helps... you just dont' want to gouge the soft aluminum.
Over time... There is a chemical gasket removal spray that did help to soften it a bit... everything helps... you just dont' want to gouge the soft aluminum.
Team Owner
Joined: May 2006
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From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
I take a small mag light and an extention mirror(like the ones plummers use for lookin' around pipes for leaks)! You can direct it to an area and use the flash light to highlight the initial spot. I also look for the highest sign of oil(or wet spot on the motor).This usually works and suits me good, and the mirror should extend at intervals to about two feet(round mirror on the end). Can get one at Home Depot(in AC section or plumming and the tool crib possibly even at the Auto store)
I hope this helps!
Thanks, Matt
I hope this helps!
Thanks, Matt
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Originally Posted by DG'sVette
What is the best way to find an oil leak?
I have a 95 LT1 with 76,0000 on it. Slight oil leak. It hasn't even used a quart of oil between changes (yet). For the most part the oil seems to be dripping from the the oil filter side down to the bell housing.
I'm hoping its not the rear main seal. I gather this would require pulling the engine. What about the oil pressure sensor? Where is this at & could this be the culprit?
I guess it could be 1 of several things, so what I really need to know is what is the best way to find out where an oil leak is originating from.
I have a 95 LT1 with 76,0000 on it. Slight oil leak. It hasn't even used a quart of oil between changes (yet). For the most part the oil seems to be dripping from the the oil filter side down to the bell housing.
I'm hoping its not the rear main seal. I gather this would require pulling the engine. What about the oil pressure sensor? Where is this at & could this be the culprit?
I guess it could be 1 of several things, so what I really need to know is what is the best way to find out where an oil leak is originating from.
Last edited by MikeC4; Jun 25, 2006 at 05:18 PM.
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From: Denton Texas
Update:
I'm planning on putting the car up on stands this weekend to look into this deeper.
However I took a little look from the top down this evening.
On the drivers side I'm not able to see any wet spots.
On the passengers side I'm able to see some wet spots pretty far down buts its below the EGR pipe. (A little tight so its hard to see) I can not see exactly where the leak seams to be starting from.
This is the highest location that I can see of any possible oil leak.
I'll know more this weekend.
In the mean time. Any more ideas?
I'm planning on putting the car up on stands this weekend to look into this deeper.
However I took a little look from the top down this evening.
On the drivers side I'm not able to see any wet spots.
On the passengers side I'm able to see some wet spots pretty far down buts its below the EGR pipe. (A little tight so its hard to see) I can not see exactly where the leak seams to be starting from.
This is the highest location that I can see of any possible oil leak.
I'll know more this weekend.
In the mean time. Any more ideas?
Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
Use a mirror when you do the inspection's it helps out tremendously. The kind Plummer's use for looking around pipes after they are soldiered up, It has an extention on it and usually round and can extend to about 18"'s.(Use your flash light too!)It can also twist to get different angles(About a 2" mirror)
Thanks,Matt
Thanks,Matt