My 350 has always had an exhaust leak, sounds like a lifter tap but I am 100% its the exhaust manifold, driver's side, furthest back. (have new lifters and also can feel the leak). I have heard that several people with 350's are experiencing the same thing... Just curious to see how many of you have an exhaust leak on your 350 with or without headers.. Dan
Dan, I suspect my "tapping" noise is also the exhaust, with stock manifolds, on the driver side. Haven't taken the time to find out for sure, or re-torque the bolts. Engine was rebuilt 6-7 yrs ago, a couple owners ago.
I purchased my 69 350 only in Jan and it came with an exhaust leak. I havent fixed it yet but will probably take it to muffler shop instead of hassling with that myself.
My 350 has stock manifolds, and they leak on both sides. I don't have time to mess with it so will take it to the muffler shop. The leaks have been a recurring problem since I got the car in 86.
Before we put headers on my brothers GS he had a pretty bad leak on the drivers side manifold. When we took it off it had quite a bit of high temp rtv behind it and it looked as though the ports on the head were no longer flat. I guess all the years of heat started to take its toll on the exhaust port face. Anyway we installed the headers with TA's best gaskets and so far so good. By the way, is it possible to machine this surface back to square? I know you can pretty much mill everything else, I just never heard of doing it to a cylinder head exhaust surface.
My experiance has taught me that the flanges need to be lined up PERFECT and need to be tightened evenly. I have a leak on one side after putting on the dual exhust at the manifold. I had to line up the flange so they mate perfectly and no problem.
i'm pretty sure my stock mainfolds didn't leak, they were stuck on like glue...if i did have a leak, i wouldn't have heard it over the tick from the rusty exhaust pipes. my headers now have a leak at the back of the drivers side, i've hand-tightened it as much as i can to no avail. when i rebuild my engine, i plan on getting new gaskets and using locking header bolts, tightened very carefully.
Todd, Most any decent machine shop should be able to shave the exhaust side of the heads for you.:TU: It does depend on the machinery they use - some styles of resurfacers can't do certain heads. Some shops have only belt sanders.o No: It's not a bad idea to have your manifolds or headers resurfaced either!:TU:
exhaust leak guys: i too had to replace the exhaust manifold gaskets on both sides of my 350 gs . driver's side was replace in spring of 2001 . cost me over $400 cdn . 6 hrs to remove the manifold bolts . later last year the passenger side started to leak . i decided to let it leak until last winter when i did some restoration work & pulled the engine & tranny . a few good smacks on the exhaust manifold bolts with a large hammer, and no problem removing the bolts ! since the motor was out, i replaced the gasket on the drivers side again . cost $40 cdn to resurface the manifolds . a lot machine shops do not like resurfacing these manifolds because the iron is very hard and thus affects the cutters . before re-installing, i ran a tap through the holes on the manifold to clean them out. also remember to re-torque the manifold bolts occasionally as the torque only to 18 foot-lbs . that's my experience. gerry 72 gs 350
Heres my issue Its not so much that the manifolds leak at the cylinder head, as a matter of fact I havent ever had that problem on any of my motors, but I bet if you hold your hand near the back side of the heat riser you will feel all that hot air coming right out of it. It sounds like a manifold leaking, but its that stupid heat riser not mating. Just get a small flat gasket piece to make up the difference and retorque the pipes. -Jon
! mine were on like glue, put after covering them in penetrating oil, we were able to get them loose with a lot of force and a couple wrenches (strung together like a makeshift breaker bar).
