Coolant heating Cat D6T

S# LAY704

I was out on this today. I was hoping someone could give me the coolant system schematic........mainly how it flows through the radiator since both the inlet and outlet are on the bottom. Its doing some strange things, even my IR gun readings are strange. I want to make sure I'm hitting the right areas of this radiator before I go any further. This is the typical 10 lbs of crap in a 5 lbs box........you cant really get to anything with ease.
I did figure out that the customer was filling the surge tank completely, which was why it is spewing out the cap line, and the surge tank neck was bent so the cap wouldn't seal.

I'm going back out in the morning. I'll post more info once I troubleshoot t a bit more!

WOW! That was perfect Mark...Thank you so much! Exactly what I was looking for!

This started off as a call about this dozer overheating and spewing coolant from the overflow line. When the customer called they were convinced they had a head gasket/ cracked head. I get there yesterday morning to find that they had been filling the system at the surge tank all the way to the top and doing so for over a year. They told me when they would run it that it would lose 4 gallons a day, and lose it out the overflow tube. I opened the engine enclosure door and showed them the sight glass on the surge tank...........they never knew it was there. I then explained that he proper level was when the sight glass was full, that's it.....nothing more.

I then asked if the gauge in the dash or the temp alarm ever went off. 1 operator says it did, the other said no it didn't. I can tell in the first 3 minutes that there isn't a cracked head or a gasket problem, no combustion gases or bubbles showing up, no coolant in the oil, nothing. So I ran the machine up to temp, exactly halfway on the dash gauge.....shot the thermostat housing with the IR gun.......its at 194 degrees, shoot the top of the radiator....its at 188 degrees. Now here is what was confusing me..........the top of the outer core was at 178 degrees. What I didn't know until Mark posted that info was that the flow went back down through an inner core that I wasn't able to see at all. No way I could reach the IR gun inside and down anywhere inside the engine compartment, just too dam much crap in the way to even get your hand in there......so all I could do is shoot the water pump housing at the top.........173 degrees. Not what I would call ideal for what I wanted to see. The machine didn't heat up until the highest rpm while under full load.

I had already looked at the radiator core yesterday and asked if they had pressure washed it.......yeah, with a 2 inch firehose run off a Honda portable water pump. Yeah, that's not going to work. I had them bring their pressure washer to the dozer and me with 2 other guys spent 2 hours washing the radiator until the water ran clean throughout. Topped off the cooling system just above the sight glass and had the operator put it to work for a test. I told them that their firehose routine isn't going to go through that thickness of the double row of cores. When using the pressure washer instead they both saw how much was still plugging the core.

The machine did a perfect run. .....customer is happy which is what counts.

The moral here............I decided, like I always do, to do my own troubleshooting. If I would have listened to what they did and took it for granted, I would have pulled that head, had it checked for cracks.......spent several thousand dollars, and wouldn't have got a dam thing fixed and been back to square one. This site and knowledgeable members has been fantastic........KEEP UP THE GOOD WORK!!