formariz 11,849 #1 Posted August 1, 2017 So I noticed that the last couple times I used it my Swamp Rat was sounding a little different like it had an exhaust leak somewhere, and it also had a couple of strange backfires out of the stack. Today confirmed that there definitely there is an exhaust leak somewhere by plugging muffler. Keeps running and there is exhaust coming from under shrouds somewhere. There is also a little oil on some of the engine fins.I am thinking a blown head gasket. Its going to take me a while to get to it since there is a ton of stuff to remove to get to it. The oil is concerning me a little bit. Is it possible that it may have developed a crack in block? It does not use oil at all and never had any leaks. Any input is greatly appreciated as always. Share this post Link to post Share on other sites
rmaynard 14,864 #2 Posted August 1, 2017 The oil is a little disconcerting. A blown head gasket should not normally produce an oil leak. However, if oil is getting past bad rings, it could exit via the bad gasket. Also, a blocked breather could be causing oil to be pushed past the oil control ring as well. 3 Share this post Link to post Share on other sites
squonk 38,844 #3 Posted August 1, 2017 Many of my well worn Kohlers have seeped from the gasket. Like Bob said. Rings and breather. 2 Share this post Link to post Share on other sites
R. L. Addison 299 #4 Posted August 1, 2017 I've also scrapped several Kohlers because of cracks between the cooling fins. I currently have a K321AS on my engine stand that started showing oil between fins and I swapped out pulled the head on & found no signs of a crack or other reason for a leak, and am ready to run it for a couple hours to see what happens. Another thing to be done on my long list. Share this post Link to post Share on other sites
formariz 11,849 #5 Posted August 1, 2017 Yes I agree that the oil is a little disconcerting. Its is between the cooling fins and isolated to one particular small spot with everything else around it bone dry. It is also on the opposite side from where the exhaust leak is coming from. Head gasket on the oil side is dry. This is a NOS engine that I put in service 9 years ago so I don't think it has worn rings since it does not use any oil whatsoever and does not have many hours on it. I know also that the breather is not blocked. I will have to remove tins and check head gasket for leaks first. 2 Share this post Link to post Share on other sites
AMC RULES 36,941 #6 Posted August 2, 2017 Good luck Cas... let us know what you find. Share this post Link to post Share on other sites