ZR-1 Net Registry Forums - View Single Post - Passenger Side Header Stud

WB9MCW · 08-11-2014

It has been well documented that the LT5 commonly leaks oil out of the header studs side, and leaks down on the cat. If it sits around a couple of weeks, it would smoke badly after about 5 minutes of warm up. On each header side is a stud located in the middle of the header, where it mates to the manifold. The stud is about a 1 1/4" long and has a nut welded on. The stud screws into the block and into one of the oil galleries. With all of the heat generated here, the stud will fail to seal and an oil leak is the result.

CORRECTION - To fix the problem, use the following procedure. 1. Remove the front tire from the side to be fixed. 2. Remove the rear inner wheel well. It has an assortment of Torx and hex head bolts. 3. You will now be able to look at the headers and see the stud, situated between the first 2 and last 2 cylinders. 4. Use a 15mm socket to remove the stud. The nut is welded on to the stud.

NOTE: IT MAY NOT BE WELDED AND JERRY'S TWO NUT METHOD USING A GOOD BOX WRENCH MAY BE THE ONLY WAY TO GET IT OFF. SOME HAVE NOT BEEN ABLE TO EVEN GET IT OFF AT ALL AND TOLD ME THEY JUST COATED THE ENTIRE CIRCUMFERENCE OF THE STUD AND NUT WITH HI-TEMP RTV AND IT WORKED WELL ENOUGH TO STOP THE LEAK - IT IS A VERY TIGHT AREA WITH THE MANIFOLD ON FOR SURE. I STILL NEED TO DO MINE SOMEDAY AS WELL SEE NOTE DETAILS BELOW

5. Clean up the stud, and apply a liberal amount of high temp Red RTV to the threads. 6. Very carefully thread the stud back into the manifold. This is the hardest part, as it is very close quarters. Don't drop the stud, or it will fall into the deep crevices of the exhaust tubes. 7. Let the RTV set up overnight, and enjoy a leak free LT5.

8. As long as you have the wheel well out, you might as well clean the air bag crash sensor, located on the frame rail. The right side one gets a lot of AC runoff, which corrodes the grounding. Disconnect the battery ground before removing the sensor. The sensor has 2 different bolts securing it. (13mm and 10mm I think). Once removed, you can clean up the surface and apply some dielectric grease to the surface to keep the water out. The main grounding comes from the bolts, so make sure they're clean.

NOTE DETAILS
Hi Bryan, the nut (at least from the factory) is not welded to the stud. Many times the stud will come out when loosening the nut, but if it doesn't you can get another M10 nut and lock against the 1st one then turning the lower nut back the stud and both nuts out. Reverse process is the best way I know of to re-install the stud, with out a stud driver. Hope this helps...Greg Van Deventer

Bryan, These instructions are correct except for one thing. The nut is not welded to the stud (at least it wasn't on mine). When you loosen the nut, the stud may stay in place. You need to put two nuts on the stud and lock them together to remove the stud. This is easier said than done, because there isn't a lot of room to work. I never did get my stud out. I ended up cleaning it while it was still installed with brake cleaner and coating both the stud and nut with high temp sealer. No leaks for the past two years.

THNX TO ALL WHO HAVE PM'ed AND EMAILED ME ON THIS ISSUE OVER THE YEARS - SOMEDAY I WILL FIX MY LEAK -- LOL

08-11-2014	#4
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,584	Re: Passenger Side Header Stud - Replacing Bolt It has been well documented that the LT5 commonly leaks oil out of the header studs side, and leaks down on the cat. If it sits around a couple of weeks, it would smoke badly after about 5 minutes of warm up. On each header side is a stud located in the middle of the header, where it mates to the manifold. The stud is about a 1 1/4" long and has a nut welded on. The stud screws into the block and into one of the oil galleries. With all of the heat generated here, the stud will fail to seal and an oil leak is the result. CORRECTION - To fix the problem, use the following procedure. 1. Remove the front tire from the side to be fixed. 2. Remove the rear inner wheel well. It has an assortment of Torx and hex head bolts. 3. You will now be able to look at the headers and see the stud, situated between the first 2 and last 2 cylinders. 4. Use a 15mm socket to remove the stud. The nut is welded on to the stud. NOTE: IT MAY NOT BE WELDED AND JERRY'S TWO NUT METHOD USING A GOOD BOX WRENCH MAY BE THE ONLY WAY TO GET IT OFF. SOME HAVE NOT BEEN ABLE TO EVEN GET IT OFF AT ALL AND TOLD ME THEY JUST COATED THE ENTIRE CIRCUMFERENCE OF THE STUD AND NUT WITH HI-TEMP RTV AND IT WORKED WELL ENOUGH TO STOP THE LEAK - IT IS A VERY TIGHT AREA WITH THE MANIFOLD ON FOR SURE. I STILL NEED TO DO MINE SOMEDAY AS WELL SEE NOTE DETAILS BELOW 5. Clean up the stud, and apply a liberal amount of high temp Red RTV to the threads. 6. Very carefully thread the stud back into the manifold. This is the hardest part, as it is very close quarters. Don't drop the stud, or it will fall into the deep crevices of the exhaust tubes. 7. Let the RTV set up overnight, and enjoy a leak free LT5. 8. As long as you have the wheel well out, you might as well clean the air bag crash sensor, located on the frame rail. The right side one gets a lot of AC runoff, which corrodes the grounding. Disconnect the battery ground before removing the sensor. The sensor has 2 different bolts securing it. (13mm and 10mm I think). Once removed, you can clean up the surface and apply some dielectric grease to the surface to keep the water out. The main grounding comes from the bolts, so make sure they're clean. NOTE DETAILS Hi Bryan, the nut (at least from the factory) is not welded to the stud. Many times the stud will come out when loosening the nut, but if it doesn't you can get another M10 nut and lock against the 1st one then turning the lower nut back the stud and both nuts out. Reverse process is the best way I know of to re-install the stud, with out a stud driver. Hope this helps...Greg Van Deventer Bryan, These instructions are correct except for one thing. The nut is not welded to the stud (at least it wasn't on mine). When you loosen the nut, the stud may stay in place. You need to put two nuts on the stud and lock them together to remove the stud. This is easier said than done, because there isn't a lot of room to work. I never did get my stud out. I ended up cleaning it while it was still installed with brake cleaner and coating both the stud and nut with high temp sealer. No leaks for the past two years. THNX TO ALL WHO HAVE PM'ed AND EMAILED ME ON THIS ISSUE OVER THE YEARS - SOMEDAY I WILL FIX MY LEAK -- LOL Last edited by WB9MCW; 08-11-2014 at 12:38 PM.