AZhitman Posted December 9, 2016 Share Posted December 9, 2016 As posted on the big forum (http://www.corvetteforum.com/forums/c5-tech/3915786-bizarre-low-mileage-z06-oil-leak-weird.html) My 38k-mile '03 C5Z recently developed an oil leak that presented all of a sudden. Further investigation on a lift revealed "blown-back" oil all over the lower pan, transverse leaf, and bottom of the upper pan (just behind the balancer). A full scrubbing and cleaning ensued, followed by application of UV dye to track the source. Here's the weird part:ALL the "usual suspects" are fine. No oil from the sending unit, filter, filler plug, balancer, or rear main - all mating surfaces are clean, dry, and revealed no dye. The UV dye revealed (very clearly) that oil is seeping out of the center of the upper pan, immediately above the transverse leaf spring. Is there a possibility that a rock or road debris somehow got on TOP of the spring and made hard contact with the center of the aluminum pan (maybe over a bump or decompression of the front suspension)? Has anyone ever heard of this?I'm so damn bummed. NOT looking forward to the expense of R&R on the upper pan. Thanks in advance for any guidance, guys - and if anyone has a line on an upper pan, or can weld aluminum, I'm in the market. Link to comment Share on other sites More sharing options...
Desertdawg Posted December 11, 2016 Share Posted December 11, 2016 Anything is possible. But before you buy a new pan make sure it's not the gasket. Link to comment Share on other sites More sharing options...
AZhitman Posted December 11, 2016 Author Share Posted December 11, 2016 Not the gasket - edges are clear. It's clearly coming from the very center of the pan, above the spring. Link to comment Share on other sites More sharing options...
HOXXOH Posted December 11, 2016 Share Posted December 11, 2016 What's an upper pan? I only see pans, not upper and lower pans. BTW, if it's cracked and seeping, you're better doing a replacement than welding. It's real difficult to clean it enough that remaining oil in the crack won't cause a poor weld. Link to comment Share on other sites More sharing options...
AZhitman Posted December 11, 2016 Author Share Posted December 11, 2016 A C5 has an upper and a lower pan. Yeah, welding is a bad idea, as porous as that casting is. Link to comment Share on other sites More sharing options...
Final Effort Posted December 13, 2016 Share Posted December 13, 2016 Devcon is your friend. Link to comment Share on other sites More sharing options...
Azmotorhead Posted December 13, 2016 Share Posted December 13, 2016 Could be just a porous casting. Yes it happens. If you need someone to do it for you I can get you in after the 1st Link to comment Share on other sites More sharing options...
corvettech Posted December 17, 2016 Share Posted December 17, 2016 sounds like aluminum porosity, gm had issued a tsb on porosity on aluminum wheels a while back. seems like an oil pan with porosity bad enough to cause a leak would be rare although definitely plausible. most likely its going to be a bad casting, a void inside the oil pan wall that was missed on the production line. either way though your best bet is to get another oil pan, cast aluminum doesn't take to welding all that well Link to comment Share on other sites More sharing options...
AZhitman Posted December 17, 2016 Author Share Posted December 17, 2016 Yep, new pan acquired, ready to go in. Now I just gotta muster up the cajones to tackle it. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now