Hitachi EX270LC Overheating

[Adam1965]

Happy New Year everyone. I have a Hitachi EX270LC with the Hino engine. To be as short as possible, the engine is overheating. If I block the two hoses going from the inner cooler to the water pump I get excellent flow through the main radiator but if I unblock them the waterflow in the main radiator stops leading to the overheating. What would cause this? I have had the radiator, oil cooler and inner cooler gone through by a respected radiator shop with no issues. The water pump and thermostat are new. The belts are in good shape with proper deflection. The o-rings and crush washers on the end of the inner cooler have been replaced. I'm desperate for help!! Thank you.

 

[Tones]

Check the hydraulic oil temperature.

 

[Delmer]

who put their grubby little fingers on this? what's the history of the machine, has it always overheated, or a new problem, or a new machine for you?

 

[Adam1965]

who put their grubby little fingers on this? what's the history of the machine, has it always overheated, or a new problem, or a new machine for you?

I have been fighting this problem for the past year. It's a strong runner but I can only run it for about a half hour before it hits 220 and I shut it down. I first noticed there was no flow in the radiator so I took it and the oil cooler off and sent them both to a radiator shop to rule out any blockages. They both came back in good shape with nothing remarkable found. Put it back together, still overheating. Replaced the thermostat. Still overheating. The old and new thermostats both tested ok in boiling water. Decided to replace the water pump. I noticed the old one had a dirt crusted grease zerk and thought that might be the problem. Installed new. With the old one in my hands, it turned smoothly. Still overheating. Noticed a petcock on the intercooler box. Hmmm. That's how I realized it had an intercooler. Opened it slightly and started to get good flow back in the radiator...for a few seconds. There are two lines running from the intercooler to the waterpump. I blocked those lines and got excellent flow through the radiator. So I thought maybe there is an ai rleak causing a problem. Removed the intercooler and sent it to the radiator shop. It was clean enough to eat off of when I sent it off but still hoped it might be the problem. I replaced the o-rings and crush washers on the end of the intercooler and put it all back together. Still overheating!! There isn't a component left that I haven't had my hands on. Not sure what the procedure is to use the bleeder valve on the intercooler box. Frustrated.

 

[Adam1965]

Check the hydraulic oil temperature.

I'll check this first opportunity. The oil cooler has been cleaned by a radiator shop but I can't say for sure what the oil temp might be.

 

[Delmer]

But who had it before a year ago? It sounds like something is hooked up wrong, or an orifice or valve is missing, or something along those lines. So you need specific knowledge of this model to see what is wrong, it's obviously not a plugged radiator, or failed water or other standard overheating issue.

No matter how many times I've heard or read special radiator filling or air bleeding instructions, I've never seen an engine that you couldn't fill the radiator, run it a bit, check the level again, check the level a few times over a few days, and it would bleed itself and keep that level. Are you losing coolant? or is the level staying the same if you shut it off at 220?

 

[Tones]

Shutting down an engine at that temperature is a big no no. Cracked or warped heads is usually the result. It's far better to idle the engine until it's cool enough to shut down.
I've seen others chase engine over heating problems only to find a leaking 0 ring or another case weak springs in the hydraulic relief valves. Because the oil cooler is outside the radiator in these cases the hydraulic oil was heating the engine coolant.

 

[Adam1965]

But who had it before a year ago? It sounds like something is hooked up wrong, or an orifice or valve is missing, or something along those lines. So you need specific knowledge of this model to see what is wrong, it's obviously not a plugged radiator, or failed water or other standard overheating issue.

No matter how many times I've heard or read special radiator filling or air bleeding instructions, I've never seen an engine that you couldn't fill the radiator, run it a bit, check the level again, check the level a few times over a few days, and it would bleed itself and keep that level. Are you losing coolant? or is the level staying the same if you shut it off at 220?

I have spoken with the previous owner but he denied any heating problems with this unit. It is not loosing any coolant while running. Thanks for the info on the bleeder. It has overflowed out of the cap a time or two after shutdown when hot.

 

[Adam1965]

Shutting down an engine at that temperature is a big no no. Cracked or warped heads is usually the result. It's far better to idle the engine until it's cool enough to shut down.
I've seen others chase engine over heating problems only to find a leaking 0 ring or another case weak springs in the hydraulic relief valves. Because the oil cooler is outside the radiator in these cases the hydraulic oil was heating the engine coolant.

I can't understand why I get good flow in the radiator when I block the two lines from the turbo intercooler going to the water pump but get nothing with them unblocked.