One hot 301.5!!!

Hey guys....could use a lil advice on my 2002 CAT 301.5. My friend and I bought a used 301.5 this winter to do a few odd jobs that both of us had. I finally got around to using it the other day and noticed after about 30 minutes of use it would run hot. I took a digital thermal gun and shot the engine (210f) and then the neck of the radiator (175f) the core of the radiator (150f) and the bottom tank (165f). I could tell the water pump had recently been replaced so I assumed it was good. You can bring the engine temp down immediately by turning on the heat in the cab....it was 91 degrees out so I really didn't need the heat on too bad..lol! The way the heater core for the cab is plumbed directly into the water pump that tells me that the water pump was doing its job. Today I pulled the thermostat and put it in a pan of water and brought it to 190 degrees, the thermostat opened as it should. This basically leaves the radiator as the culprit correct? I washed out the fins with hot soapy water before removing the thermostat and it was clean. I can see in the top tank and there is no corrosion or calcium built up inside. Would it be beneficial to remove the radiator and have it boiled? It looks like a TOTAL PITA to get the radiator out!

What am I missing? The only thing I thought about after disassembly was wether or not the fan blade was installed properly?

HELP!

Junkman


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You might also want to check the hoses to and from the radiator. One of them may have a flap inside blocking the flow. Checking the fan is a good thought too.

Good luck,

Rick

boaterri said:

You might also want to check the hoses to and from the radiator. One of them may have a flap inside blocking the flow. Checking the fan is a good thought too.

Good luck,

Rick

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That's the only thing that makes any sense to me. It sounds like blocked water flow with those temps, and the fact that the heater will cool it off. I agree that the water pump is working if the heater will cool it off like that.

Maybe take the hoses off and check for delamination, and blow out the radiator at the same time with a garden hose and a blow gun stuffed into the bottom outlet with a rag. Wait for the water to run out the top, then give it a little blast of air, repeat.

Fan belt condition and tension maybe..?
Have you taken a good look at the air flow through the radiator..? If it's clean inside my suspicions would lie with the outside. It's almost impossible to check the external condition without removing it TBH.

Thanks guys, the fan belt looks new, it was banjo tight. The radiator has the oil cooler partially blocking the front of it but from the inside it looks good. I am going to inspect the hoses tomorrow and have a look at the fan blade to determine by paint wear if the PO could have put it on backwards while replacing the water pump. I am not looking forward to pulling the radiator as it looks like the cab may need to come off


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If the top tank is 175 and the bottom tank is reading 165, why would that be hot? Sounds more like the problem is internal to the engine to me, or as suggested reduced flow to the radiator. I would think that if the radiator were plugged that the top tank would be way hot with the bottom tank much cooler?

Nige said:

It's almost impossible to check the external condition without removing it TBH.

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Second that. Unless you can see light through it to tell, then you have to assume that it's plugged up pretty good.

Would it be easier to take the oil cooler out to get access to inspect/clean the radiator than removing the radiator. Can you put a shop light next to the fan, and get close enough to the other side to see through it?

I think I can move the cooler out of the way, I also have a little more real estate to work with now that the fan shroud, blade and water pump have been removed. I washed the radiator out pretty good prior to today's tear down. As long as it took for it to actually exceed "normal" operating temperature the problem has to be something simple......it is just being a booger to find!


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Sounds like pretty normal temps to me.
The disparity in your temp readings could likely result from the different materials you scanned (cast iron-aluminum-brass-copper etc.).
The digital thermometers are sensitive to the different emissivities of the various materials.Meaning a CI engine block will show a higher temp than an aluminum or brass radiator.
Also even a slight change in distance results in averaging a larger area.
190deg. , 210 deg. . Sounds completely normal from here.
HTH
Jay
:usa

AirBornOne said:

Sounds like pretty normal temps to me.
The disparity in your temp readings could likely result from the different materials you scanned (cast iron-aluminum-brass-copper etc.).
The digital thermometers are sensitive to the different emissivities of the various materials.Meaning a CI engine block will show a higher temp than an aluminum or brass radiator.
Also even a slight change in distance results in averaging a larger area.
190deg. , 210 deg. . Sounds completely normal from here.
HTH
Jay
:usa

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I was thinking the same thing...just takes a little longer for me to reach those temps up north.

melli said:

I was thinking the same thing...just takes a little longer for me to reach those temps up north.

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Same here, those temperatures are well within the normal operating specifications on that machine. I do not see an issue.

Perhaps the gauge or the temperature sensor is bad.

With a 190 degree thermostat I think 210 degrees is excessive, especially no harder than I was working it.


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You can compensate for shiny metal surfaces by using a piece of electrical tape as a target. If the radiator is painted then it should read close enough. Or shoot the radiator hoses and heater hoses and go by those temps.

There is plenty of overcapacity in most cooling systems so that it shouldn't run hot without some major plugging, the heater cooling it down shows that also. I assume you meant that the gauge was reading higher than the normal range when it was running hot.

Depending where you shot the engine temp I'm thinking (after pondering overnight) that you could likely have a flow issue. If the engine is 210 then the hose leaving the thermostat housing to the rad should also be 210 or as near as damnit. A difference of 10 between inlet and outlet of the radiator indicates it is pretty well working to spec, the optimum is 12.

You say it had the water pump replaced. If the old pump had a non-metallic impeller I wonder if it broke and that a passage from the pump could be partially blocked..? Is the replacement pump new or overhauled..? Are you sure it's pumping as it should..? Have you seen what condition it was in internally before installation..?

The possibility of the temp sensor being bad is also one that needs to be investigated.

Update.......today I verified the hoses were good, radiator was SPOTLESS, the coolant passages I could see we're clean and clear from obstruction, the belt was good, the fan blade had been installed properly......Sooooooooo.........I put a new t stat in a pot of 190-200 degree water with the old one and verified that it worked similarly to the old one and it did. I installed the new thermostat and reassembled the engine. I put new coolant in it as the old extended life had reached the end of its life and was NASTY! I ran the machine for 20 minutes in the shop to verify I had the coolant level correct and took it to a dirt pile to "play". I ran it for 30-45 min and it never got over 200f with my thermal gun at the port for the coolant temp sensor. The gauge in the cab read approx 2/3 the way up so I have ordered a new sender as I feel that is higher than maybe it should be at 200f.....thoughts?


You guys have been a ton of help and I really appreciate all of the comments and advice!

junkman


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200 with a 190 thermostat and 90+ ambient sounds fine to me, I would run it but keep an eye on it for changes. With the proper coolant and pressure cap you can theoretically run an engine as high as 240 usually before you start boiling and venting steam. Not recommending, lol, just saying. What's you altitude there?

Skidoojunky said:

With a 190 degree thermostat I think 210 degrees is excessive, especially no harder than I was working it.


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Even if 210 is higher than 'normal' it is certainly not excessive.
BTW the thermostat temp. rating is Not the operating temperature,it is merely the point the thermostat opens.
This is to allow the engine to reach operating temp quickly,getting all the components to expand to their proper fit & clearances,
boiling off undesirable compounds (& water) from the lube oil.
Ambient temps & humidity play a major role in a cooling systems performance as does the coolant so variations of 10-40 degrees could occur normally.
HTH
J
:usa

If your ELC was "Nasty" I hope you gave the cooling system a couple of good flushes with clean water before putting the new ELC in........

Skidoojunky said:

Update.......today I verified the hoses were good, radiator was SPOTLESS, the coolant passages I could see we're clean and clear from obstruction, the belt was good, the fan blade had been installed properly......Sooooooooo.........I put a new t stat in a pot of 190-200 degree water with the old one and verified that it worked similarly to the old one and it did. I installed the new thermostat and reassembled the engine. I put new coolant in it as the old extended life had reached the end of its life and was NASTY! I ran the machine for 20 minutes in the shop to verify I had the coolant level correct and took it to a dirt pile to "play". I ran it for 30-45 min and it never got over 200f with my thermal gun at the port for the coolant temp sensor. The gauge in the cab read approx 2/3 the way up so I have ordered a new sender as I feel that is higher than maybe it should be at 200f.....thoughts?


You guys have been a ton of help and I really appreciate all of the comments and advice!

junkman


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Click to expand...

If I had to bet I would say the new sender wont change anything. Most engines seem to run around 180-190 F and getting up to 230F would be in the red so to have the gauge above the middle at 200 F seem correct to me.