Caterpillar MS 70 Excavator

Tracy Brown · Jun 25, 2016

I just bought this machine for home use. It has a couple of issues I need to address before use. It had been setting a few years and would not
start. The PO had the injector pump rebuilt and now it starts and runs good. I have not run it very long at a time but noticed it starts to overheat.
There is no water/oil mixing anywhere. I removed the thermostat. No change. My next thoughts were water pump and or radiator, but if the
timing on the injector pump was not done exactly right, can that effect operating temp? I know it can on a gas engine. It has a Mitsubishi 4D30
engine. I believe this entire machine is Mitsubishi. Some of you experts, where would you look next. Thanks

markct · Jun 25, 2016

Did you replace it with an oem thermostat or one that fits from auto parts store? I ask because I know the one on my Isuzu looks simular but has a bottom button that covers a second passage and if that wasn't present it wouldn't circulate properly.

Tracy Brown · Jun 25, 2016

I did not replace it, just removed it to see if any change occurred.

jm. · Jun 25, 2016

Yes Tacy engine timing can be a source of overheating . Most common thing is someone took the water hose to the radiator . When that happens all that dust and weed seed in the fins becomes swelled and air just will not go thru the radiator. Look close at the radiator, you may have to take a small flat piece of shipping strap and work ever opening. Time consuming but got to get that stuff our. Air hose and work will same the radiator core if that is the problem.

markct · Jun 27, 2016

That can cause water to circulate too fast and not cool, if anything snip the center out to leave some restriction.

shinnery · Jun 28, 2016

You may want to be sure water is flowing around the system. I bought a Kubota UTV that had all the fins rusted off the impeller in the water pump. NO flow.

Janicholson · Jun 28, 2016

Circulating water through the radiator (with the air channels open, and a fan blowing) will not over heat due to fast circulation. The higher the difference in temperature the greater the transfer of heat. Jim

dpendzic · Jun 28, 2016

i would make sure the fins are clean for air flow and then make sure its not clogged internally--disconnect a lower radiator hose and put a hose in the top and check the flow

jm. · Jun 28, 2016

Jan School is really out on this one. I tend to agree with you BUT ever catapillar school I have attended they show a video of REMOVING the thermostat and claim that the increase flow actually caused the unit to run hot. They used a 513 skidder for the demonstration. There claim is the water goes thru the block too fast to absorb the heat. Me I am kind of with you looks like more flow and more water equals cooling but there are schooled folks that sure will argue to NEVER remove a thermostat. My experience with overheating is fully 80% of the time it is AIR flow whether slipping fan belt or clogged radiator fins.

Winchester1 · Jun 29, 2016

You should have a 10-15F water temp drop in the radiator. Anything greater indicated an internal blockage.

Check all of the basics, could be as simple as a hose sucking shut or the fan on backwards.

Caterpillar MS 70 Excavator

Tracy Brown

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markct

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Tracy Brown

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jm.

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markct

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shinnery

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Janicholson

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dpendzic

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jm.

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Winchester1

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