[racerboy]

I got my pulley alignment worked out. When I went to start the car, I had a major oil leak that was collecting on the top of the filter. I thought that the filter might be bad or that there was a leftover rubber oil gasket. I replaced the filter and the same thing happened.

Thinking the oil filter housing might be cracked, I replaced that but I still was getting a leak. I took a video but can’t seem to upload it. The leak starts at the back on the left and then just pools on the top and runs down the filter.

Any idea on what to try next? I ran this 428 for about 10 yr and it never leaked oil before. The oil filter housing gasket is new. I am running 20W50 oil. My oil pressure does seem a little high at start up (65 psi) but I can’t remember what pump is in this engine. It is definitely a Canton pump that came with the pan.


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[leeklm]

First guess is a leak where the sending unit or oil pressure line connect to the housing. I also had a leaky valve cover gasket seeping down to the filter housing.

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[racerboy]

I thought it was the sending unit as well but that’s not leaking. I’ll check to see if is somehow running down the back of the block to oil filter.

Is there a way to load a video here, or only photos?


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[64speed]

I had this exact same thing happen to me last go around. Valve cover gasket was pinched in the back and half was draining back and half was pouring out. Between it and a cracked housing I lost 6 quarts in about a minutes run time. Because it was clean oil I couldn’t find it either.

[Verdoro 68]

I chased a leak down there for years and it ended up being a hairline crack in the boss for the sending unit on the adapter. Should have been a clue that my sending unit wouldn’t fully tighten.

Otherwise check your gaskets. Could be the distributor, valve cover gasket or vent tube gasket dripping down the valve cover.

[racerboy]

I checked all the other gaskets from the distributor and the valve cover. Everything is dry. A friend recommended I try a different oil filter. Both PF24 filters I tried leaked, and while they were both new, they have both been stored in my shop for at least 5 years. Maybe as long as 10. I can’t recall when I bought them, but I bought a.case of them a while ago not realizing that the rubber could dry out. There is a hint of rust on the bare metal, so maybe it’s as simple as needing a more recently manufactured filter. I’ll let you know how that goes.

I don’t think it’s the filter housing because the one off the 400 never leaked before, and while I had the second one laying around for some time, it would seem odd that both were cracked. Will update later once I try the new filter.

Even if the rubber wasn’t dry-rotted, could the higher pressure be an issue? Could that force oil past the gasket? When I first fire it up, it doesn’t leak immediately. It takes about 10-15 seconds before you see the oil start to run down the oil filter lip.


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[JSchmitz]

You could try some fluorescent oil dye and a UV light. Something like this: https://www.amazon.com/ACDelco-10-50...0976453&sr=8-4

[Don 79 TA]

Originally Posted by JSchmitz

You could try some fluorescent oil dye and a UV light. Something like this: https://www.amazon.com/ACDelco-10-50...0976453&sr=8-4

OMG i remember doing this...
I chased an oil leak after a cam swap, and my gawd i cant tell you how many times i thought it was the lower corner of the timing cover oil pan area
i mean i can't even count
turned out to be an oil breather i used, leaked at the bottom and the way it trickled around and down things was just stunning, you wanna talk about feeling SO stupid. NEVER able to see it until i did the dye trick. worked totally amazing and so baffeling how that was SO hard to see
i swore it was from the timing cover area, because sometimes the oil drips got in that area, again, so baffling. took that breather off, and wallah, NO leaks/drips

[JSchmitz]

Originally Posted by Don 79 TA

OMG i remember doing this...
I chased an oil leak after a cam swap, and my gawd i cant tell you how many times i thought it was the lower corner of the timing cover oil pan area
i mean i can't even count
turned out to be an oil breather i used, leaked at the bottom and the way it trickled around and down things was just stunning, you wanna talk about feeling SO stupid. NEVER able to see it until i did the dye trick. worked totally amazing and so baffeling how that was SO hard to see
i swore it was from the timing cover area, because sometimes the oil drips got in that area, again, so baffling. took that breather off, and wallah, NO leaks/drips

LOL! I can relate.

I haven't actually used the oil dye yet. Have used coolant dye several times. Works great! Coolant can be very hard to trace. Clean oil is also.

[mgarblik]

Pontiacs and oil leaks. They seem to be made for each other. One of the most difficult engines to seal 100%, but I won't go into that here. There are three Other areas near the oil filter housing that can be sneaky and cause a collection on the oil filter and a drip in that area other than the housing, filter, and sending unit. Since you replaced the housing. filter. gasket, and sending unit, lets assume those 4 areas are now OK. 1. The right rear corner of the valve cover gasket would be the next suspect. With the flimsy stock valve covers and 4 little fasteners to seal those big covers, Pontiac was begging for them to leak. The only gaskets I can make seal are cork. Make sure the rails are flat and work them with a hammer and dolly as needed. I tack them into the cover with an adhesive like high tack or weatherstrip adhesive. NO RTV of any kind. On the head side, I install clean and dry. Fairly high success rate. To diagnose, clean with brake clean on a rag, run engine and then wipe with clean paper towel. Any oil on towel, you found your leak. 2. Distributor paper gasket. Oil will leak out, wind it's way down the right side of the block and collect on the oil filter. Easy fix of course. 3. Valley cover at rear. A very common leak point that can be hard to detect. Brake clean and rag will find it usually. Obviously, some work involved to reseal.

If you want to find an oil leak 100% of the time, you need to buy, rent or borrow an evaporative smoke machine. I highlighted how effective they are in another thread. You use the machine to fill the engine with harmless white smoke. Wherever you see smoke escaping, that's your leak. Simple as that 100% effective. Use on exhaust system, power steering, transmission, rear end, engine and the emission system, which is what it was designed for. Good luck with it and report back.

[vertigto]

Good information @mgarblik...thx.

[JSchmitz]

Get it clean and dry. Use a mirror to look at the back side of the engine. Run or drive it in short duration until you spot it. If you drive it too much it'll run all over the place.

[grivera]

Originally Posted by mgarblik

If you want to find an oil leak 100% of the time, you need to buy, rent or borrow an evaporative smoke machine. I highlighted how effective they are in another thread. You use the machine to fill the engine with harmless white smoke. Wherever you see smoke escaping, that's your leak. Simple as that 100% effective. Use on exhaust system, power steering, transmission, rear end, engine and the emission system, which is what it was designed for. Good luck with it and report back.

Does the oil pan need to be drained of oil to use the smoke machine?

[mgarblik]

Smoke machine works best with empty oil pan yes. If the leak is up high like a valve cover, it doesn't matter.

[racerboy]

I swapped on a new Purolator filter which fits the filter housing, though the canister is markedly smaller than the PF24. The other think I did was replaced the filter housing bolts. The ones that were on it were 1” long. I did some research and they are supposed to be 1.25”. I fired up the engine and the oil leak was very much reduced, but there was still a bit of oil on the back side of the filter (closest to the block). I cleaned everything up and let it sit over night. You can see in photo below that there is a small drop where bottom of filter housing meets the block. I think it’s also interesting that the paint is missing there, which makes me believe that there may have always been a leak there, even when this 428 was in my GTO, but I never noticed. There really was no oil on the floor the next day, just a bit down the back of filter. Do you think I should double-up this gasket?




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[mgarblik]

Did you put any type of dressing on the paper gasket? I prefer Permatex Aviation Form a gasket on paper gaskets like that. Both sides. It is a brush top non hardening liquid sealer. Since this is giving you so much grief, go ahead and torque the bolts. 30 Ft. Lbs. Hope that does it for you.

[racerboy]

No I just used the gasket by itself. I can put some dressing on it tomorrow and will torque it 30 lb-ft.


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[JSchmitz]

Absolutely have to make sure the bolts are the correct length on this as I recall. 1-1/4" does sound right. Of course in combination with lock and flat washers. The holes are not very deep. Easy to be bottoming out and not tightening the housing properly. Glad you're making progress! HATE LEAKS!