[AT] no exhaust gasket?

[John Hall]

Not tractor but old combine. My Deere 3300 with a 219 gas engine has an 
exhaust leak. It is where the exhaust pipe attaches to the manifold. 
This is accomplished by means of a very heavy cast elbow bolted directly 
to the manifold with 3 bolts. There was no sign of any gasket. Me nor 
the parts guys at Deere can find a gasket in either the engine or the 
combine parts books. There best parts guy at the local store (I highly 
respect his ability) suggested there wasn't a gasket used. I cleaned and 
checked the surfaces and they are relatively flat, within .005" or so. 
What do you guys think about the no gasket used possibilty? I have a 
friend that used to do heavy truck repairs. He says NAPA has an exhaust 
sealer that is very tar like. He said they were able to seal some 
exhaust leaks with it--used it where the flare of the pipe clamped to 
the manifold. He also said some Chevrolets were put together with no 
exhaust manifold gasket--I think this was figured out by mechanics, not 
the factory. This is all new to me, Every exhaust I dealt with had a 
gasket. What do you guys think?

John Hall