URGENT- help needed for newbie

[molsongoldon]

Please excuse my lack of understanding, but need you guys to help.

I have a 4 year old Sears DYT-4000 yard tractor with a Kohler 20hp engine. Never had a problem until today.

The engine runs great, but is now making a strange tapping noise. It is getting louder. All I have done in the last year is replace the oil with OEM filter and recommended oil.

I first thought it was a loose exhaust- no, maybe a blown plug- no. My neighbor thinks it is a blown head gasket?

Any ideas? i can give more information as we get wquestions. i am going to contact kohler and am reading about a known head gasket issue with older models.

[Wineslob]

Depending on the speed of the tap as compared to the engine speed, it could be a rod bearing or a sticky valve.

If it sounds roughly like it's at the same speed as the engine, rod, if it sounds slower (about the same as the exhaust "pop" at the muffler at idle) it's a valve.
Check the oil for metal. Get some of the oil on a plate, or anything non absorbent, and look at it in strong light. You don't want to see anything "sparkle", or have it be very black in color.
You can also rub some of the oil between your fingers and see if it feels rough.

[molsongoldon]

Wineslob,

engine oil is brand new and "clear". no abrasive feeling to it. I have read that the sticky valve was a problem and addressed by synthetic oil use?

Just not sure why all of a sudden this would creap up.

Thanks

[Treemonkey1000]

Are you sure it is coming from the engine? Nothing that the engine is connected to like a pulley and belt? Does it make a difference if you engage the clutch or not? All hardware on the engine tightened down like cowlings and filters and engine mounts? Start with the easy things first.

[powerstroke444e]

If you put the wrong oil in it the lifters may not be pumping up??? Lots of issues if you put the wrong oil in it.

[Tex5String]

Hi Mr Molson!

Try the shade-tree mechanic's stethoscope: a piece of broomstick or a long screwdriver. Put one end of the broomstick (or the screwdriver handle) against your jaw joint, pressing the little flap of flesh back to close your ear canal, then move the other end to various locations on the engine, frame, etc. You will be hearing the internal engine sounds by bone conduction and shutting out exhaust noise, etc. You may want to put a finger in your other ear also, just to shut out external noise. I learned this trick from a mechanic.

Good luck!

Tex

[Soundguy]

when my 15ys old 700$ murray started doing that this year I though it was getting ready to throw a rod.. turned out that the 4 lag screws ( YES! ) that pass thru the frame into the base of the engine block to mount the engine to the tractor were ALL loos and the engine actually hammered in a rotational manner as the cyl fired.. tightened it up.. all fine now.. worth a look..

soundguy

[Wineslob]

Originally Posted by Treemonkey1000

Are you sure it is coming from the engine? Nothing that the engine is connected to like a pulley and belt? Does it make a difference if you engage the clutch or not? All hardware on the engine tightened down like cowlings and filters and engine mounts? Start with the easy things first.

+1

Doubtful that it's lifters, they are "solid" (not hydraulic) in these kinds of engines.

[Treemonkey1000]

So did you figure out where the noise was coming from?

[banjodunn]

G'day kohler had a prob with blowing head gaskets on some of their engines their fix was a new style head gasket and new head tensions as well as a modified flywheel/ flywheel key to adjust the timing. They were doing this mod over here as a warranty job on select engines that were well and truly out of warranty can't say wether yours would be covered but may be worth a try at the local agent. They also had a prob with flywheel ring gears breaking and making a **** of a racket also been known to take out coils when they go and i know that this is an indefinite warranty fix on these engines over here at the moment. Good luck with yours though


Jon