TM 5-3895-359-14&P
TROUBLE SHOOTING
SUGGESTED REMEDY
7.
Black carbon deposits extending from the valve
1.
Check for carbon deposits, a bent valve guide,
seats to the guides indicates cold operation due to light
defective spring or antifreeze (glycol) in the lubricating
loads or to the use of too heavy a fuel. Rusty brown
oil. Replace a bent guide. Clean-up and reface the
valve heads with carbon deposits forming narrow collars
valve. Replace the valve if necessary.
near the guides indicate hot operation due to overloads,
inadequate cooling or improper timing which results in
2.
Check for excessive valve-to-guide clearance,
carbonization of the lubricating oil. Clean-up the valves,
bent valve guide or carbon deposits. Replace a bent or
guides and inserts. Reface the valves and inserts or
worn guide. Clean the carbon from the valve. Reface
replace them if they are warped, pitted or scored.
or replace the valve, if necessary.
8.
Check for a worn valve guide or excessive
3.
Check the operating conditions of the engine for
exhaust back pressure. Replace a worn guide. Check
overload, inadequate cooling or improper timing.
the valve seat for improper seating. Reface the valve
Reface the valve and insert. Replace the valve if it is
and insert or, if necessary, replace.
warped or too badly pitted. Use a harder-face valve if
the operating conditions warrant.
9.
Check for a bent valve stem or guide, metal chips
or dirt, or for lack of lubrication. Clean up the valve
4.
Check for contact between the valve head and the
stem with crocus cloth wet with fuel oil or replace the
piston as a result of incorrect valve clearance, or a
valve. Replace the guide. When installing a valve, use
defective spring. Check the valve guide, insert, cylinder
care in depressing the spring so that the spring cap
head and piston for damage. Replace damaged parts.
DOES NOT scrape the valve stem.
5.
Check for excessive valve-to-guide clearance, a
10. Check for a gear train failure or for improper gear
defective valve spring or etching of the valve stem at
train timing.
the weld. Improper valve clearance is also a cause of
this type of failure. Check the guide, insert, cylinder
11. Check the operation of the engine for excessive
head and piston for damage. Replace damaged parts.
idling and resultant low engine exhaust back pressure.
Install valve guide oil seals.
6.
Replace a worn valve guide. Check and replace
the valve, if necessary.
10-2-132
