Northstar Engines and System Technical Discussion Discussion, Cracked oil pan... in Cadillac Engine Discussion; A fun thing happened today coming home from work...with all the new pothole repairs going on around here, I can ...
A fun thing happened today coming home from work...with all the new pothole repairs going on around here, I can usually avoid them. However, today I hit some major road debris which were essentially unavoidable, and it looks like one of the pieces of asphalt hit my oil pan pretty hard and cracked it. The car (98 STS) is now leaking directly from this crack at a pretty good pace, and I don't know what to do. I know that it's pretty much impossible to change out the oil pan without removing the transmission, etc. and that will likely turn into a major job. Should I try some heavy duty epoxy, or fasten a piece of aluminum over the crack and try to fix it on there as best I can? Are there any other paths I could take here, since the car is now pretty much undriveable? Thanks for any help you can give
The idea of patching it with epoxy is not as crazy as it sounds. Time for the JB Weld....seriously. That is the toughest stuff that I know of. The hardest part will be getting the area prepped and clean as oil will likely continue to seep thru the crack contaminating the repair. I would drain the oil and flush some solvent (such as mineral spirits) into the pan thru the drain plug port to try and flush out as much residual oil in the pan as possible. Use brakeclean spray to clean the outside of the pan thoroughly and spray thru the crack to get as much oil out of the crack and away from the area as possible. Sand the surface around the area with course sand paper to rough it up and clean it as much as possible. Mix up the JB Weld and smear away.
My neighbor had the same thing happen to his Saab and patched it this way with JB Weld and it held fine for several months until he removed the pan for a more permanent repair.
I prefer the idea of reinforcing the area with a patch of aluminum pressed into the JBWeld after you cover the area thoroughly. Put way more JBWeld on than the patch will cover and press it into the wet epoxy so that the edges of the aluminum are sealed thoroughly. Heat the epoxy with a hair dryer or heat gun on low heat to speed up the epoxy cure to try and beat the oil seeping thru the crack.
You might look around for a good welding shop that can handle heliarc welding and that has a hoist. You could get the car in the air, drain the oil and flush the pan out with mineral spirits and have the crack heliarced if it is accessible for welding. Most places would probably not want to deal with it but a good shop should be able to do that.
A friend of mine holed the case of his dirt bike on a sharp rock out in the woods years ago while trail riding miles from nowhere. The trans oil immediately drained out.... We turned the bike on it's back, scoured the area of the crack with gas to clean it and scratched it up with a rock to "prep" it. Mixed up a pack of "instant epoxy" that I carried in my tool kit (this was not the first time for something like this....LOL) and patched the hole up with the epoxy and a piece of pop can that someone had conveniently discarded nearby that we cut out with a pocket knife. Filled the trans with two stroke oil and rode off.... THREE YEARS later I was riding with the same guy, same bike and asked him how he had "fixed" the hole in the case. He looked at me kind of funny and said "we fixed it in the woods, remember...??" It was still running fine with that temporary patch we made. Probably still is somewhere...LOL LOL
hahah that's a good story, and thanks for your expertise. I was thinking JB weld epoxy could work, but your idea about a welding shop was actually reinforced by a call I made to a shop owner I know. He quoted me 1200 for the whole repair, but said that I "might as well have it welded instead." If they are willing to do it, this could help me avoid a major headache. The pan is aluminum, correct? I'm assuming aluminum is a bit more difficult to weld? Thanks again!
If you can get an idea of how thick the oil pan is in the area of the crack you can go to your local general aviation airport and pick up a product called Cherry Max Rivets. They are a very hi-tech pop rivet that captures the shank when they are pulled with a conventional pop rivet gun and will not leak. I have seen and done some amazing repairs by roughing up the fractured surface, applying J-B Weld or even better DevCon metal filled epoxy , covering it with a fitted piece of .060 aluminum sheet, drilling the appropriate holes, and using Cherry Max rivets. Some of the repaired items lasted 15 years or more. I would suggest 1/8 in. diameter rivets that are long enough to grip all the material in the sandwich.
I would only ever consider the JB Weld to be a temporary repair even though it MAY last a long time. The key to success here of course, is immaculate surface preparation as bbob described. Although the JB Weld is pretty amazing stuff, on trips hundreds of miles away, you don't want to be thinking about whether the JB weld is holding or not.....and with the price of a Northstar replacement what it is, I would weld it and forget about it. Another consideration, if you plan on having it welded (which is what I would do without a doubt) you may not want to be smearing JB Weld all over the crack, since every bit of it will have to be removed before it is welded.
Speaking with about 30 years experience TIG welding cast aluminum aircraft cylinders, the problem you're going to have welding the pan is that it is going to warp unless you can get it off the engine, bolt it to a flat steel plate, pre-heat it, weld it, and let it cool slowly. If you weld it in place you are going to burn up the existing sealant. Can you get a picture of the crack?
If someone was going to take the time and effort to drop the front suspension and cradle and remove the pan, I would suggest replacing the pan rather than welding it. If he doesn't want to spend the bucks for a new one, most junkyards have more than a few dead Northstars (mostly headgasket failures) that they'll sell the pan from. However, I'd at least try welding it first on the vehicle, with the oil drained and flushed, especially if the crack isn't too large.
I've used JB weld on more than a few occasions to fix radiators, carbs, blocks and oil pans. As Bbob pointed out...get the oil out and flush the pan good with solvent, clean the outside good and your ready to go.