Komatsu pc 200-5 6d95 engine overheating

[anwat]

Dear professional members,
I recently had an issue relating to engine overheating,the engine had major mechanical component inspection on board but did not find any suspicious error and the hydraulic main pump was also adjusted to lower the engine load,which regarded as the main cause of the overheating but those did not give much difference,as the work operation was urgent,one spare engine was sent to replace it,improvement was,but not much,the previous installed engine was disassembled at the cylinder head to inspect the combustion chamber,all the 6 pistons surface found with white pattern so was the cylinder head part for each piston,does the white pattern mean something,
I hereby attached some photos

 

[GregsHD]

Do you run some type of oil or fuel additive?

How was it verified that the engine was overheating? Mechanical gauge or infrared gun?

I've seen the wiring harness on these engines rub through the clamps and give a false reading on the gauge/ activate the overheat shut down.

Was the radiator cleaned / inspected when the engine was replaced?

Is the hydraulic system running hot also?

If all that is ok and have good airflow/ temp differential from upper to lower rad hoses, and not overloaded but still running hot I'd be testing the fuel supply for possible contamination? Gasoline or alcohol accidentally mixed?

 

[anwat]

The unit did not use any additive in the fuel or the oil
About the white pattern inside the combustion chamber i have just had news that the operator accidentally use a container which previously filled with chemical silicone base liquid and they did not get it cleaned before refilling it with fuel (damn)then they fill into the tank
The white pattern issue cause known
But the installed engine was still overheating,it posed headache to me,all of the related parts had been check and i did not know which part that i miss
What i am curious about is
Will a hot weather in my country lead to engine overheating?

 

[GregsHD]

How hot has the weather been? Are you running with the engine cover open?

 

[John C.]

The most common cause of overheating on those units was debris between the radiator and hydraulic cooler. As I recall there is a plate under the house that can be removed that is right under the coolers. Blowing the radiator / hydraulic oil cooler out with air pressure with that plate removed would let the debris fall out of the machine. You have to clean both sides in order to get the machine to run cool again. There should be some foam between the coolers on the top side as well. If it is not there air will flow around the hydraulic oil cooler.

The white coating on the head is not uncommon on those machines. Injector firing pressures were higher than most other diesel engines for that time period. If you look at the holes on the injector tips you will see they are in line with the patterns seen on the head.

 

[anwat]

Dear gregsHD,the ambient temperature ranged from 35 to 38 degrees.
Yes,we urged the operator to open up the engine compartment hood but still the temperature rose to top after 2 to 3 hours of operation

Dear john c,regarding the white pattern on the cylinder head and pistons
Did you pinpoint the cause at injectors high injection pressure?
Can you tell me the theory behind it?
Also what is it like normal apperance of combustion chamber for common diesel engine,is it blacky carbon coated ,browny or?
Dear friends
Thanks for all your kind help

 

[John C.]

I've seen the white before when the injectors are good. The high injection pressure atomized the fuel better and made for high firing temperatures. High firing temperatures provide a more efficient burn with better starting and fuel economy. Higher firing temps also cause the formation of oxides of nitrogen which the air pollution people targeted as bad for the environment. That is another story though. The head in the photo looks pretty much like what I have dealt with in the past. Since you had overheating problems you should check that head very carefully of cracks. I used to see them around the injectors running toward one of the valves.

 

[anwat]

Dear friends,
many thanks for all your advices and guidance

 

[jujub]

jAnyone has information on the pressure at which injectors on a Kobelco 200LC-6E excavator fires? The engine is a Mitsubishi 6d34-te1?

 

[Leonbachu]

Dear members,I recently acquired a komatsu pc210-7k but I am having problems with the engine overheating.
It works for about 2 hours then the temperature starts to rise until it reaches red.
I checked the radiator and its clean.any advice would highly be appreciated.thanks