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Oil leak

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Old Nov 11, 2021 | 08:11 PM
  #1  
2names's Avatar
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Car: 88' Iroc convertible
Engine: 305
Transmission: 5spd
Oil leak

Hello, I'm working on my 305 which has a substantial oil leak. The oil pan is leaking bad enough there is oil all the way back to the tank. I pulled the tranny as I figured the rear main was also leaking so was going to do the whole deal. Inside the bellhousing was covered in oil but the rear main is dry. There appears to be oil coming from the frost plug right above the main.

My understanding is that coolant runs behind frost plugs so I'm at a loss as to what's going on here. Any help would be appreciated!



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Old Nov 11, 2021 | 08:39 PM
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Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: Oil leak

That center plug is is the rear camshaft expansion plug. Coolant shouldn't be behind it, so the oil makes sense.
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Old Nov 11, 2021 | 08:56 PM
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From: Edmonton
Car: 88' Iroc convertible
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Transmission: 5spd
Re: Oil leak

Originally Posted by aliceempire
That center plug is is the rear camshaft expansion plug. Coolant shouldn't be behind it, so the oil makes sense.
Thanks for sorting that out for me. Now what is the repair for a leaking rear camshaft expansion plug?

Last edited by 2names; Nov 11, 2021 at 09:05 PM.
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Old Nov 11, 2021 | 09:43 PM
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From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: Oil leak

Come to think of it, I've never dealt with one while the cam is in place. Best GUESS is drill a hole center where the camshaft has a divot. Use a screwdriver to pry it out with that. Make note the depth of the old plug and make sure the new one seats in the same depth. I heavily suggest you search the webs for people's experiences.
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Old Nov 12, 2021 | 07:43 AM
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Re: Oil leak

Ditto aliceempire's repair description.

You'll find it difficult to come up with just that one plug, in all likelihood. I suggest getting a whole engine kit, which of course will include it; get a kit of this sort, with BRASS core plugs (they really have nothing at all to do with frost or freezing, except to the extent that they often fail under those conditions); and replace as many of them as you can get to, ESPECIALLY the 2 in the back of the block of course, while you have it in this condition.

I see what I would compare to a dripping faucet at the cam tunnel plug, but A GUSHING FIRE HOSE at the valve covers. That whole motor is DRENCHED SOAKED IMMERSED from the leeeeeeks at BOTH valve covers. You won't even NOTICE the one leak being repaired as long as the other is allowed to remain.

I also suggest you look at this hole right here.



If there is not a bolt in that hole, put a SHORT one in there, with a drop of sealer on the threads. 3/8"-16 x ½".
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Old Nov 12, 2021 | 10:22 AM
  #6  
2names's Avatar
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From: Edmonton
Car: 88' Iroc convertible
Engine: 305
Transmission: 5spd
Re: Oil leak

Originally Posted by sofakingdom
Ditto aliceempire's repair description.

You'll find it difficult to come up with just that one plug, in all likelihood. I suggest getting a whole engine kit, which of course will include it; get a kit of this sort, with BRASS core plugs (they really have nothing at all to do with frost or freezing, except to the extent that they often fail under those conditions); and replace as many of them as you can get to, ESPECIALLY the 2 in the back of the block of course, while you have it in this condition.

I see what I would compare to a dripping faucet at the cam tunnel plug, but A GUSHING FIRE HOSE at the valve covers. That whole motor is DRENCHED SOAKED IMMERSED from the leeeeeeks at BOTH valve covers. You won't even NOTICE the one leak being repaired as long as the other is allowed to remain.

I also suggest you look at this hole right here.



If there is not a bolt in that hole, put a SHORT one in there, with a drop of sealer on the threads. 3/8"-16 x ½".
The whole plan is to do all the seals/gaskets so started with the bottom working my way up. Thanks for the info as I will take all the advice I can get for this project!
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