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D6h series 2

4730

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Oct 8, 2017
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89
Location
Canada
Have a 1990 d6h series ii the darn engine is heating after an hour of working it. Was working perfect last week but all of a sudden getting to warm. Goes to 210 on gauge. was always at 180 before. Transmission is staying at 170. Can water pump be going? It will cool off in 2 minutes is let stand and high idle. Rad is clean outside. Belts tight on fan.
 

JD955SC

Senior Member
Joined
Mar 13, 2011
Messages
1,349
Location
The South
Have a 1990 d6h series ii the darn engine is heating after an hour of working it. Was working perfect last week but all of a sudden getting to warm. Goes to 210 on gauge. was always at 180 before. Transmission is staying at 170. Can water pump be going? It will cool off in 2 minutes is let stand and high idle. Rad is clean outside. Belts tight on fan.

could very well be

shoot top and bottom of radiator with IR temp gun and if more than 10 degree temperature difference there is an issue…and will likely be. Can be water pump, or internal clogging, or a combo of both especially talking about a 30 year old machine.

Also check your radiator cap and replace if necessary. if it doesn’t hold pressure it can cause overheating. It’s the $15 part that gets overlooked a lot but can make a real difference.
 

4730

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Oct 8, 2017
Messages
89
Location
Canada
We put thermostat in Pot of hot water brought temp up to 200 never opened. Took a screw driver and pushed open. Now it seems to work once water hits 180. Wonder if that is the problem will be putting new one in.
 

JD955SC

Senior Member
Joined
Mar 13, 2011
Messages
1,349
Location
The South
We put thermostat in Pot of hot water brought temp up to 200 never opened. Took a screw driver and pushed open. Now it seems to work once water hits 180. Wonder if that is the problem will be putting new one in.

toss it and install new, sounds like it’s probably the issue. Another part that can cause headache far out of proportion to its cost.
 

catman13

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Aug 22, 2011
Messages
435
Location
oregon usa
Occupation
refrigeration engineer/excavation contractor
check and see if you have bubbles in the radiator , you may be losing a head gasket.
my d5h did the same thing , head gasket
 

catman13

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Aug 22, 2011
Messages
435
Location
oregon usa
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refrigeration engineer/excavation contractor
i sent it to my cat dealer , did not have time to do it , had them go thru the head while it was off,
if you are good at wrenching not to bad , if you have a shed to nose it into to keep it out of the weather while you do it
 

4730

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Joined
Oct 8, 2017
Messages
89
Location
Canada
Well I guess the head is Going to have to come off. Hopefully just a gasket. After 10 min warm up air bubbles in rad.
 

catman13

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Aug 22, 2011
Messages
435
Location
oregon usa
Occupation
refrigeration engineer/excavation contractor
mine was just a gasket , sounds like that is all you have to to do also, have the head gone thru while you are at it
 

Bluox

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Jun 19, 2010
Messages
1,960
Location
WA state
What does the head look like?
Pull the spacer plate and gasket.
Bob
 
Last edited:

4730

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Oct 8, 2017
Messages
89
Location
Canada
Wonder if just old age machine 1990. The thermostat was sticking to
 

Bluox

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WA state
That is what I thought I saw, you have a problem with that liner or the block.
Lets see the head and pull the spacer plate.
Bob
 

4730

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Oct 8, 2017
Messages
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Location
Canada
Sorry not sure what the spacer plate is? Not sure why it looks like three groves to top of cyl. When you use fingernail you don't feel them.
 

Bluox

Senior Member
Joined
Jun 19, 2010
Messages
1,960
Location
WA state
You see the damage on top of liner above the scratches?
Spacer plate is between block and head gasket ,pull off gasket and plate will come off block.
Bob
 

4730

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Oct 8, 2017
Messages
89
Location
Canada
Haven't had a chance to pull spacer plate off yet. Is there a gasket for that spacer plate to? What seals it?
 
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