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mike_sdak

Briggs Vanguard 16 - excessive oil leakage

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mike_sdak

Hello.

Kind of off brand, but I thought I would ask to see if anyone has ideas on the topic. It has been a stumper for me so far.

I have a briggs vanguard 16HP horizontal shaft, in a grasshopper mower. It has been leaking a fair amount of oil for about a year. I don't note any smoke, so I suspect it is just leakage.

Last year, I replaced the flywheel end crankshaft seal, which was protruding from its recess. It had leaked around the seal for quite a while, as the shroud was very oily. After replacing the seal, it has still gone thru a lot of oil due to leakage. Oil drips are visible on the fins when running.

Due to the seal protruding, I wonder if I have a crankcase pressure issue? Head gasket? Maybe the breather? I don't recall servicing the breather on it.

I plan to do a cylinder compression and leakdown test to see what I can track down, before tearing into it. I really hate to pull the engine again, as I had it removed just last year for the crankshaft seal. But I am not sure it will be avoidable, unfortunately.

Any thoughts and experiences would be greatly appreciated.

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RayS

More than likely breather related. A non functioning breather will cause the crank case pressure to push the oil out the seals. What does it do if you remove the dipstick while running? Be careful. If breather is not working you may get a bath.

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mike_sdak

I removed the dipstick with the engine at somewhere between idle and WOT - maybe 1500 - 2000 rpms. It didn't give me a bath, but it definitely was positive pressure. When I covered the tube with the palm of my hand, it was coated with oil within a few seconds.

I am looking into servicing the breather,

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mike_sdak

The service manual is pretty brief on the subject - just some test involving inserting a wire feeler gauge underneath the flapper, to check for proper clearance. But what if it is clogged internally? Is there some test involving sucking or blowing through the breather to check for function?

At this point I suspect it is one of 3 things: breather, Worn rings, or a bad head gasket somewhere which would permit combustion chamber pressure to bleed into the crankcase.

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Scott Salmons

Have you checked the grommet seal around the base of the dipstick tube? This will aid in giving positive pressure in your crankcase. Can also contribute to leaking.

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mike_sdak

OK,

So I ran a compression test tonight:

Left cyl = 100#

right cyl - 120 #

Too much variation. I hate to tear into her, as the grass is rapidly growing. What is the most likely cause for something like that? Head gasket leak?

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ka9bxg

Bad head gasket. My sunrunner was doing the same thing friend said that it would be a bad gasket. I had him replace it and no more leak. I know that it does not make sense but it did fix the problem .No I do not know how to tell what head gasket to replace. Bob

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