# Kohler CV492 Engine Noise



## geogeiges (Jun 22, 2016)

I recently acquired a Simplicity Broadmoor with an 18HP Kohler CV492S in it. It had a severe oil leak at the PTO side of the crankshaft. After replacing the seal the engine developed a sharp rap in the camshaft area when the engine came up to operating temp. I disassembled the engine paying particular attention to the camshaft and the decompressor mechanism. The piston & bore are fine. The lifters are not collapsed. I need to disassemble the head, but don't expect to find anything there. I called the regional Kohler tech guy. He had no info on that type of noise. I suspect the camshaft, but see no obvious fault. I didn't run the engine long enough before the seal repair to know if the noise was there prior to replacement.


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## BigT (Sep 15, 2014)

Hello geogeiges, welcome to the forum.

I would write to Kohler and explain the problem. In reading on the internet, their 'Command' engines had an oil foaming problem in the lifter area which causes noise. They have a kit to solve this problem. Don't know if this applies to your engine, but it's worth a try.

Another possibility is that the decompression valve is causing the noise.


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## FredM (Nov 18, 2015)

have you removed the rod cap and checked the big end journal for grab from lack of oil ?, if the engine had a severe leak as you describe, the PO may have let the oil get too low, changing the oil seal will not be the cause of the noise, does your engine have the counter balance fitted?, there may be some wear in the bearing area if fitted.


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## geogeiges (Jun 22, 2016)

FredM said:


> have you removed the rod cap and checked the big end journal for grab from lack of oil ?, if the engine had a severe leak as you describe, the PO may have let the oil get too low, changing the oil seal will not be the cause of the noise, does your engine have the counter balance fitted?, there may be some wear in the bearing area if fitted.


All bearing surfaces good. Camshaft end play .005". Valves fine, no scoring on stems, rockers fine. Will reassemble and use Kohler's oil. I suspect the oil foaming is the likely explanation. There is absolutely no sign of extreme wear or damage,


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## FredM (Nov 18, 2015)

thumbs up, a lot of the bigger singles seem to hammer or knock when starting up and running, I have just fitted a 19HP Briggs single to a Cub Cadet zero turn for a mate and this gets a hammer up when starting and running, I have owned a few big singles at times and these always hammered when running, hope the anti foaming oil fixes our problem


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## jhngardner367 (Apr 5, 2011)

Does the knocking change as the speed changes,or does it stay the same ?


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## geogeiges (Jun 22, 2016)

The noise does change with engine speed. To me it sounds like half crankshaft speed-camshaft.


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## geogeiges (Jun 22, 2016)

I've reassembled the engine after honing cylinder, lapping valves, and disassembling lifters then priming on reassembly. I used Kohler oil this time. Other than some minor lifter tap that went away after idling for 5 minutes the noise is gone. My conclusion is oil foaming. I never had a problem using Castrol GTX. I replaced nothing inside the engine.


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## FredM (Nov 18, 2015)

that is great,--- your motor is running like it should.


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## jhngardner367 (Apr 5, 2011)

Some engines can be sensitive to certain oils.
i won't use Pennzoil,in any engine.
I think it has to do with "additves"that some use.


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