Leaking Side Sill?

[DPViper]

I have covered my sills in clearbra and there is a 2" circular spot on the bottom of driver side where the clearbra is holding a milky liquid that appears to have seeped through a small crack/blister in the bottom of the sill. You can't see it now (unless you lay on the ground) but it appears to be growing. I have a Corsa Track exhaust. Anyone else see anything like this? Thanks for your help.

 

[DPViper]

Today I cut out the spot in the clearbra holding the liquid and there are 2 small blisters/cracks in the sill. When I took the sill off of the car there is corrosion between the sill and the foil heat shield that wraps around the exhaust. It appears that something has caused the inside of the aluminum sill to corrode which caused the 2 seeping holes. Mark Jorgensen at Woodhouse said some of the Gen 2 cars had this type of problem if the wrong screw was used and the fix is grinding out the affected area and then repainting the sill. Anyone have this type of problem? Thanks for your help.

 

[gts_2001]

Sounds like a case of "dissimilar metal reaction" (galvanic). Either the heat shield on the exhaust, a screw of "other" metal type (e.g. stainless steel), or the exhaust pipe itself made continuous contact with the aluminum sill. Because of the differences in the metals (electrical charges of the atoms, molecular structure and bonding architecture, etc.), a type of "battery" is formed and ionic flow from one metal to the other begins. As it progresses, the metals begin to break down and corrosion is the net effect. This is similar to hanging a piece of aluminum off the stern of a boat to act as a "sacrificial anode". It breaks down first and the other metal parts on the boat are preserved. I'm sure it's not what you had in mind to try to make your (aluminum) engine block last forever!

You need to find out what the offending part is before replacing the sill, or else the same thing will happen all over again.

Here's more info about it: http://www.corrosion-doctors.org/Corrosion-History/Eight.htm

Good luck!

 

[Phoenix SRT]

I have a question unrelated to the corrosion problem: where on the sill have you applied the clearbra? I haven't installed clearbra or similar on my SRT's sills because I've been told by the suppliers/installers it wouldn't stand up to the heat generated by the exhaust.

I am interested to know if you have the clearbra on the part of the sill that gets hottest and, if so, whether the heat affects it (yellowing? peeling? etc.?) Thanks for any info.

 

[DPViper]

Phoenix: I have clearbra along the entire sill and into the door openings and I have not had any yellowing or peeling problems. I have a Corsa exhaust which does not get as hot as the stock exhaust. I have put 5,000 miles on so far. I think doing the entire sill is probably overkill. Once I have my leaking sill repaired, I will have to decide how much area behind the front wheels needs protection. I'd like to hear from members that HAVE NOT put clearbra on the sill - what size area takes a beating and needs clearbra protection? Would a 12 inch piece behind the front wheels be enough? Thanks for your help.

 

[DavidSB]

I had my Clearbra installer make up triangular shaped pieces (with rounded corners) 13" long x 8" high for the area behind the front wheels and 9"x8" for the rears. Both seem about the right coverage with no dings from 5,000 miles of daily driving and two track days.