140 OverHeat?

bustab

Seaman Apprentice
Joined
Mar 16, 2008
Messages
48
A J140PL4ST is overheating. The top half of the cylinder head is getting well above 160 degrees while the bottom half is staying cool. Ive replaced the thermostat as well as impeller. Ive plugged the water pressure releif valve hole on the oil pan to see see if the spring was week and not building the pressure to reach the top half of the motor with no luck. still getting hot up top.

what is my next step in diagnosing this problem?

there is a black plate with what i assume is the voltage regulator as well as what looks like two thermostat covers attached on the side of the motor. if i pull this plate will i be able to get a peak at whats going on in the water passages?

or do i have to pull the powerhead and timing chain to get the valve train off to have a look?

i guess i'm just looking for ideas on what to do next.

absolutely any insight would be greatly appreciated,
thanks
 
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