Common Leak Points?
Frustratingly I am still fighting a fairly substantial oil leak at the back of the engine after resealing the top end last year.
After 2-3 days there will be a puddle of oil about the size of a Folgers can directly below the rear of the engine at the crank housing. While I was having some transmission work done last year I had the techs check to see if the rear main was leaking. I was advised that it was dry. However, oil pools on to the starter and flows to the bottom of the crank housing, between the block and torque converter where it drips. I've tried a fluorescent oil dye, but have not been able to verify where the oil is coming from visually. The top of the block around the distributor housing is dry to the touch, so I know I'm not weeping oil out of the distributor housing or from the back of the valley pan. I do have a known oil leak at the fuel pump block-off. I believe I need to seal the threads on that. I've not been able to see that leak flowing rearward to the back of the engine however. At this point I'm looking for any ideas, but I think I'm going to end up having to deal with it for this driving season, then yank the engine in the fall for a complete refresh if I can't find the source of this thing. Thanks in advance! |
cam plug? oil galley plug?
|
My moneys on the rear pan seal, or the rear main seal
|
Did you feel the back of the heads for oil? I had a valve cover leaking on the back of the drivers side. It coated the starter with oil and the rear of the pan.
|
I will check there this evening. I'm running Butler's fabbed valve covers with Edelbrock's steel core reusable gaskets. Those are new as of a year ago.
|
If oil is pooling onto the armature section of the starter, or if the top of the stater solenoid is getting wet I would have to conclude that it’s not a leak source from within the bell housing.
I would say it’s a valve cover leak from at the rear of that drivers side head. |
what year oil pan? if its the older ones with the 3 holes in the rear U section they are known to leak there due to the rubber U seal, it can roll or get squished out of place & cause a leak that will look like a rear main leak. inspect that area real good after wiping it dry with a good solvent or brake cleaner. it could be leaking anywhere in the U area & where the ends meet the side rail gaskets.
|
Smoke it, you can even make your own smoker pretty cheap. All good shops will smoke the rebuilds so they don't get come backs. Not new or high tech engineering here, but WILL find your leak.
|
Quote:
Are you talking about what's pictured here? https://i.imgur.com/GQCGX0vh.jpg This is precisely where my drip is coming from. |
Quote:
Quote:
Quote:
I'm wondering if I can clean that area of the rear pan up and RTV it. Anyone have success with sealing that up with the engine in the car? |
Try an aerosol can of Right Stuff. Clean the area in the gap with brake clean and compressed air, then fill with right stuff. I have done a few hack jobs similar to this and it might just get you by until the next time you have the pan off.
Sent from my SM-G965U using Tapatalk |
Yes I have done such on a neighbor’s Buick, but with the conveter backed off and the flex plate off for good access.
A sprayed down that whole area with carb cleaner and also right into the pan to main cap gap , let that all evaporate off for 2 hours and then layed on blue gasket maker and packed it in. Then let that all set up for 2 full days due to no motor heat. Last step was touching up the paint due to the carb cleaner removing it. Just to reiterate, the key here is good access and total oil film removal! |
Quote:
|
Quote:
i just went through this with a milodon 7qt pan that uses that same seal, didnt leak quite as bad as yours but i thought it was a rear main. after replacing the the pan gasket & rear main (BOP) it still leaked, after talking with a couple pontiac guys, the fix was to use the 1/4" thick cork gasket in place of the rubber U seal with a good gasket sealer/RTV. been 6+ years on a 500+hp stroker motor & its still dry. i'd start there if you confirm no other source up higher that could cause that big of a puddle. sounds like you verified it was coming directly from that area, after wiping it dry & running for a few minutes then let sit overnight, you should be able to see fresh oil, if its dry above that U seal its not from higher up on the block. also be sure you have the metal load spreaders for the corner pan bolts. another gasket option is the one piece BOP that gets great reviews. good luck finding the leak, i hated dealing with mine for a couple weaks... i pulled the engine each time to replace the pan gasket, but when its that fresh of an install, it came out quick & easy. |
Quote:
|
Your oil pan does not seem to follow the rear main cap at 2:00 and 10:00 very well.
A thick cork gasket sometimes does a much better job. Tom V. |
Quote:
Quote:
|
Quote:
|
Quote:
I had these fabbed valve covers on both of my E-Headed cars with the thin, steel reinforced Viton VC gaskets. They look fantastic. But, at least on my cars, the bolts that drop through the holes in the valve covers were just barely bottoming out in the holes in the heads before getting a decent compression on that Viton gasket. It all ‘felt’ snug - but they leaked like crazy - especially at the rear of the head by the firewall. My starter was coated with oil. I ended up using a band saw to carefully lop the last 1-1/2 threads off the bolts then cleaned them with a die. That gave me just enough clearance to compress the Viton gaskets. All was good after that. |
General post concerning Pontiac oil leaks. Little background. I was in charge of repairing ALL the oil leaks at my Pontiac dealership when I worked there. actually all leaks period including water leaks and wind noise. The #1 Pontiac oil leak is the rear main seal. (at least it was when rope seals were all I worked with). #2 was the rear of the oil pan #3 was valve covers. Both the oil pan and valve covers had the same problem. Thin, crappy sheet metal parts and not enough fasteners, and spaced too far apart. #4 was the valley cover. (again, huge thin, cheap piece of sheet metal, 2 fasteners, #5 Timing case to block and front pan. I replaced 13 rear main seals in Pontiac V-8's in one week at the dealer. Took 2-2.5 hours in the car once you had all your proper wood blocks for each body style. Moving on: Oil plugs, freeze plugs, cam plugs, casting porosity, pretty rare leak sources. Occasional fuel pump pad and oil filter pad leaks.
My best fix methods and procedures/products. Rear main seal: Rope: the "Best" brand seal, packed hard into the groove and cut with a NEW razor only, Dot of RTV on seal ends. Rubber seal: BOP 2 piece or 1 piece seal following their instructions and lube the lip. MUST have a second person to install the 1 piece seal. Rear of pan: cork seal if cap has a groove, I do not use the 3 or 5 tab rubber seal. That is a leak source. If cork, a light film of RTV on pan side of the cork and small blob in corners. If no cork, thick bead of RTV only. Valve covers: I do not use any type of rubber gaskets. Cork only, glued to cover lightly with a tack agent, like high tack or weather strip adhesive, nothing on cylinder head side. Do not over tighten. Valley cover: Preferred method Cork gasket. I test fit cover first, no gasket, adjust with shot filled hammer as needed to get consistent gap. Then lightly tack cork to cover with high tack or weatherstrip adhesive. Then I apply a light film of RTV to the cork, cylinder head side and install. I put a small amount of RTV around the bolt heads at the top where they contact the valley cover. Timing case to block: I use the paper gasket and aviation form a gasket liquid on the paper gaskets for timing case, water pump and thermostat housing, very thin coat. If case is badly eroded, sometimes use a small amount of RTV to fill. Use a small blob of RTV at front corners. I hope all this makes sense and helps. I love Pontiacs, but they are very difficult engines to seal, because of a number of compromises in the design. The #1 fault is too much space between fasteners IMO. Then when over tightened, it just makes a bad situation worse. Much like owning a Harley, I guess, we have to live with a little drip sometimes. I have mentioned using a smoke machine to find a specific leak point is by far the best way to pinpoint a leak. IMO, much better than dye. Good luck with your repair and I hope this long post has a few ideas some can use. STAY DRY! |
All times are GMT -4. The time now is 03:53 PM. |