| Author | Message | ||
     Etennuly |
I have seen many times that J-B Weld has been mentioned here, and I mostly use Epoxy Putty for these kind of repairs. I have a cast aluminum oil pan on a GMC S15 Jimmy. It has a small impact crack on the vertical surface behind the front axle. I used the Epoxy Putty first. I cleaned and sanded the surface very well, then let it set overnight before applying putty so that no oil would run onto the repair, then let that set overnight before putting oil back in. It started to leak within hours. I re-did it using the same methods and used J-B Weld with the same results. The oil leaks right through the stuff. I can weld it, but that will require removing the pan to really clean the inside. This is one of the 4x4 PITA ones with the crank sensor and it bolts to the transmission housing. The front axle will also have to come all of the way out to make it happen. Not that I am lazy or anything, it is irritating that I can see it, I can touch it, but I'm having trouble fixing it. Anyone use anything that can permanently hold back oil on a cast aluminum piece?  | ||
| Simple |
http://www.rockymountainatvmc.com/productDetail.do ?navType=type&navTitle=Chemicals&webTypeId=400&web CatId=23&prodFamilyId=1879 that stuff is suppose to work pretty good for minor repairs. its cheap enuf to not be a huge waste to try out. they also make it for steel. i have no personal experience, only read testimonials on an ATV message forum i use to frequent. edit: N/M, looks like it might be the same type stuff you tried. (Message edited by simple on January 04, 2009) | ||
| Rpm4x4 |
It may sound crazy but try bondo. I repaired a rusty gas tank with bondo on a bomber truck I had. Everything was so rusty that I was afraid of the can of worms I might open. It held for over 2 years when I sold it. BTW the guy I sold it to rolled it and I bought it back. The bondo even survived the rollover. I drove it onto the trailer. | ||
| Swampy |
Also try spraying things down with Brake Clean and scuff the pan up a bit. Then use the Kwik-set JB Weld. I have used it on a gas tank before with great results. I tried using the regular JB Weld but it did not hold. | ||
| Etennuly |
Simple, that is the stuff I use for a lot of things. I think the only difference between the alum and steel is the color. RPM, being a bodyman myself, I just don't see bondo being oil proof.....not really even duraglass. But if I get desperate who knows? Swampy, I didn't know they had a quick set one, but the oil comes right through the product, I didn't expect that. | ||
| Just_ziptab |
I would like to think that you could drain the oil and heat up the crack with a hand torch to burn off the oil,clean and dry it and then wire weld it from the out side. You wouldn't have to have much penetration to seal it, just a light surface weld.(no,I don't have huge experience with welding Aluminum) | ||
| Etennuly |
I do a lot of alum mig welding. Problem there is even if burning it off, the inside oil will present a contamination issue. The pan is thin cast, vertical position, nozzle won't reach with any kind of a decent angle. I have done a lot of vertical and upside down alum welding, it requires extremely clean on all sides. I can easily weld it, if it is removed. I feel that if I try to weld it in there, the oil, or burned oil, on the inside will contaminate the weld and make me burn a large hole in it. If it were thicker I would drill and tap a 3/4" hole, seal and screw in a very short bolt. | ||
| Tom_b |
the problem is it is aluminum, It contracts and expands at a different rate than steel especially cast aluminum versus stamped steel. when the engine oil gets hot, it leaks. the problem is more heat expansion and contraction than the material your using.ie jb weld, which is not pliable once it hardens. fuel tanks usually remain a fairly constant tenperature in relation to the atmosphere. that is why jb weld works great on fuel tanks and such.try something a little more pliable | ||
| Etennuly |
Tom, it isn't leaking around the product, it comes right through it like it was a porous rock. No cracks or looseness around the edges. Wipe it clean with thinner and it wets up and weeps right through it in about five minutes. Just for the heck of it I wiped it clean and smeared a coat of black RTV over it. I doubt that will do anything, but it was there. | ||
| Tom_b |
I understand now. That sucks. sound like a welding job is in order. I would try some serious rtv first with maybe a duct tape patch on top of the rtv. good luck. | ||
| Etennuly |
Man, you guys are great! I appreciate the help and ideas. Keep them coming if you think of anymore! Thanks!  | ||
| Ceejay |
I've used JB weld on a gas tank before. worked well but I had taken the tank off first. Another trick is to drill the crack into a hole and plug it with a 3/8" bolt/washer/rubber washer/pan/rubber washer/washer/lock washer/nut. Of course you have to pull the pan for that too...Good luck. | ||
| Xbduck |
Being a body and finder man could you use body solder? Or what about those wonder rods Eastwood sells that they claim will repair aluminum or pot metal with just a propane torch or Jeweler's Torch. I've never used those rods however I have seen them used with good results, just not for what your doing. | ||
| Nik |
To repair an aluminum casting that contained oil for an engineering fire test I used 7356A32 (pg 3315) from McMasterCarr. It's like JB weld but specifically for cast aluminum and it was able to handle being blasted from a direct flame so an oil pan should be fine. | ||
| Cyclonemduece |
what is the motor by the way LS-X??? | ||
| Jramsey |
"I can easily weld it, if it were removed" A plumbers faucet always leaks. Pull it off and weld it or replace it. When customers bring me stuff that they gooped J-B or epoxy on I tell them right up front the price would have been half as much if they wouldn't have tried the hardware store fix in the first place. | ||
| Etennuly |
Jramsey, yeah, I know, I do the same thing. It is my son's truck, a 4.3L V6, and the job doesn't pay too well. Doing it as a spend ten minutes to try something and set it aside. Although it leaks it is still drivable, just pesky. They had to mount the bellhousing and the crank sensor in the pan, that makes everything a critical fit that I don't want to disturb if I can help it. XBD, I will look into that. Nik, I will google that now. Thanks. | ||
| Etennuly |
Nik, I has dun learnded sumpin on that site! The alum epoxy putty is totally different in composition than the steel putty.  I wrongly assumed it was for the color variation. My local guys have the alum putty, I will give that a shot. Thanks again. | ||
| Bill0351 |
I worked pretty extensively with epoxy when I used to sail. You can build diesel tanks out of epoxy and glass, so there should be no problem with it being porous if it's the right formula. Try this site. It can be confusing, but there is a ton of information in there. If you get in touch with them directly, they are extremely helpful. http://www.epoxyproducts.com/ Bill (Message edited by bill0351 on January 05, 2009) | ||
| Bandm |
I use RTV Silicone to seal rusted through steel oil pans. Clean area with brake cleaner until no oil weeps from hole(s). Spread RTV 1/8 to 1/4 inch thick with a rubber spatula, 1 inch past edge of hole, 2 inch diameter for a pin hole. Allow at least 24 hours to cure. A customers truck that I covered 80% of the oil pan to seal multiple leaks (like frosting a cake) is still leak free after 5 years. Clean, oil free surface, and allowing RTV to fully cure is key. | ||
| Skinstains |
The six most important things you need to keep in mind for all automotive/mechanical repairs: CLEAN, CLEAN, CLEAN, DRY, DRY, DRY. The fact that the piece being repaired is subject to sizable changes in temperature may be playing a big part in the failures of these magic fixes. Make your kid take the pan off and then weld it and hand it back to him so he can put it back on. | ||
| Bill0351 |
If you are going to go through the trouble to take it off, you could just replace it. I doubt a salvage yard would get more than $30.00 to $40.00 for that part. | ||
| Sleez |
not a true weld, may be easier; http://www.aluminumrepair.com/ http://www.alumiweld.com/ http://www.muggyweld.com/super5.html | ||
| Reepicheep |
That alumaweld is a little awkward to use, especially upside down, but I have had some good luck with it before. I rebuilt a KLR-250 mirror perch from nearly completely gone to better then new (including tapping it out and putting a Buell mirror in it). | ||
| Sokota |
Marinetex.com , Have done all types of block repairs , sometimes will add drywall fibreglass mesh tape to repaired area. | ||
| 99savage |
Not aware of any miracle stick-um, epoxy, plastic-aluminum, whatever that will stick to an oily surface. I like the 2 part Devcon If you were to drain the oil & wait long enough to assure that NONE remains - then clean the surfaces w/ a strong solvent (MEK a personal favorite but will try brake cleaner next time – thanks for the hint) – then rough the surfaces w/ coarse emery & wipe down again – you should have a chance. If you could stop drill the ends of the crack you have a much better chance. Question for experienced welders – why not scab a patch on?? | ||
| Jramsey |
Most auto oil pans are die cast and have a tendency to stress crack depending on the location of the repair when cooling down. Welding a patch larger than the original crack makes for a larger hole to repair after it stress cracks. Stamped or cast Aluminum pans generally weld with no problems. I myself would remove the pan and stitch weld it inside and out. | ||
| Etennuly |
It seems to have stopped leaking for now. I can assure you everything about it was clean and dry and sanded and blown off. There was no oil film to go over. As far as welding a patch over it, the same issue applies to welding a thin cast aluminum piece that is in a too tight position to move the nozzle around. To weld at all it needs to be removed and cleaned on the back side, as alum weld will penetrate through and pull contamination from the back side into the weld. Having an eighteen year old son, who doesn't pay close enough attention when disassembling things is not one to be taking this pan off with it's sensitive crank sensor location and all. Oh well, thanks again for all of the ideas and suggestions. We have in hand, some specialized aluminum epoxy putty that is guaranteed to hold out oil and gas. So if the J-B Weld with RTV over it starts to leak again we will go this route. |
