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catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 2242
Experience:  Field service technician for CAT 19 years.
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Have a cat 312 7dko68#### runs hot after 20 mins, hydrulics

Customer Question

have a cat 312 7dko68#### ***** hot after 20 mins, hydrulics squeel on any type of load. have changed the hyd filter, water pump, thermostate, belts tight, blown out radiator, I was told there is a pressure spring on fuel return line that is causeing it to run lean?? is there and where is it. tks Bud
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  catmastertech replied 1 year ago.

Hello,

If all the hydraulics are squealing, the main relief would be the issue. All hydraulics would be weak too. Pressure testing would quickly show the main system pressure is below the 4500 psi normal setting.

The engine has a hidden SCREEN in the suction line to the fuel transfer pump and this is the cause of most low fuel pressure problems.

Remove the banjo bolt from the bottom of the transfer pump, (the part on the side of the injection pump with the hand priming pump) and inside the banjo bolt is the screen. Remove the screen and clean it out. See if fuel will flow freely from this line, if not, your tank needs cleaning and the line should be blown out.

If you need more help with this, please post the full machine serial number. The number you posted is only part of the engine serial number and does not help me find information on this machine.

Customer: replied 1 year ago.
full # ***** ***** tks bud
Expert:  catmastertech replied 1 year ago.

Sorry, but there are no equipment configurations that match serial number '7DK06825'

This appears to be an engine serial number. I will need the machine serial number to find the correct information to help you.

The number will be the last 8 digits of a long number on newer machines. Older machines will be just 8 digits anyway and the 8 digits will begin with one of these three digits shown below.

EXCAVATOR
Model Prefix
312 EXCAVATOR 6BL
312 EXCAVATOR 6GK
312B EXCAVATOR 2NS
312B EXCAVATOR 3ES
312B EXCAVATOR 6SW
312B EXCAVATOR 9GR
312B EXCAVATOR 9HR
312B EXCAVATOR 9NW
312B L EXCAVATOR 2KW
312B L EXCAVATOR 3FS
312B L EXCAVATOR 8JR
312B L EXCAVATOR 9FS
312C EXCAVATOR BNN
312C EXCAVATOR BWH
312C EXCAVATOR CAE
312C EXCAVATOR DBN
312C EXCAVATOR FDS
312C L EXCAVATOR CBA
312C L EXCAVATOR CBT
312D EXCAVATOR DLP
312D EXCAVATOR FBJ
312D EXCAVATOR HCW
312D EXCAVATOR HJX
312D EXCAVATOR KCD
312D EXCAVATOR LRK
312D EXCAVATOR PHH
312D EXCAVATOR RHL
312D L EXCAVATOR JBC
312D L EXCAVATOR KES
312D L EXCAVATOR L44
312D L EXCAVATOR L5W
312D L EXCAVATOR RKF
312D L EXCAVATOR SKA
312D L EXCAVATOR TGY
312D L EXCAVATOR XGK
312D2 EXCAVATOR DGF
312D2 EXCAVATOR GWN
312D2 EXCAVATOR KLE
312D2 EXCAVATOR TJY
312D2 GC EXCAVATOR BRW
312D2 GC EXCAVATOR F4F
312D2 GC EXCAVATOR RXZ
312D2 L EXCAVATOR EAB
312D2 L EXCAVATOR FAB
312D2 L EXCAVATOR HBF
312D2 L EXCAVATOR MGJ
312D2 L EXCAVATOR MPP
312D2 L EXCAVATOR WHJ
312E EXCAVATOR GAC
312E EXCAVATOR PZL
312E L EXCAVATOR MJD
312E L EXCAVATOR WEY
312F GC EXCAVATOR FKE

What can I help you with?

Did you find the screen and clean it?

Did it help your power problem?

Did you test the pressures?

Did you replace the main relief?

Customer: replied 1 year ago.
I call my local Cat dealer nd he said it is a gray market machine and that is the correct number and I have ordered parts with that # ***** The # ***** ***** seat level after the control panel., key switch, below on plate, this plate also has the engine configuration #. I still don't have the cause of the over heating and now the water temp gauge is splitting apart while in the green??????? and jump to red with spaces between.
Expert:  catmastertech replied 1 year ago.

Are you sure the temperature gauge is reading correctly? Sounds like your dash is failing. Try reading the thermostat housing temperature and compare it to the water pump inlet to see how much heat loss the radiator is giving. Infrared heat guns are fairly cheap now and can be within 10 degrees of the actual temperature.

Place the lens about an inch away from the surface for an accurate reading. Use it on painted dull surface, rubber and shiny parts will give a bad reading.

The most common issue I find for overheating is missing baffles. If the seals in the hood or around the radiator are missing, they must be replaced. Too much air flow will be sent from the engine into the radiator and it will overheat. Next verify the cores are absolutely clean. Never wash the radiator with a water hose. You need a pressure wash and compressed air to dry it out. If air is used regularly, wash should not be needed. Clean grass lands or house demolition cause the most trouble with plugged radiators.

Overloading is a common problem for these machines too. Often I find the operator try to replace a 320 size machine with this small one and it just cannot do the same work. Oversized buckets and extra attachments just add to the problem. If engine power is not correct, this too can cause overheating. Lugging the engine is often too much for the cooling system to recover. Engine speed must be keep at high idle and fan cannot slip. Fan belts must be maintained and pulleys replaced when worn. If machine came with the high ambient cooling package, the correct parts must be installed or it will not cool correctly. Water pump, pulley, fan belt and sometimes the fan itself can be different.

Did you find the screen and clean it?

Did it help your power problem?

Did you test the pressures?

Did you replace the main relief?

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