743 running a bit hot

[Chris 8603]

Its been pressure washed and steam washed though the access doors. And I checked to make sure I could see though ever inch of it. I don't get it !!!! I'm going to go ahead and pull the radiator and have it checked. I know it's not the problem, it's airflow for whatever reason. But at this point I'm grasping at straws. I'll know tomorrow!!

 

[haymaker]

I do not know what pressure it is hot, I never thought about checking that. It does push water back to the overflow tank when hot and pull it back as it cools.
As far as the impeller it was the metal impeller on both the old one and the new one.

Well that's good to know.
I have seen something as simple as a bad cap, not holding pressure cause overheating on a hot day.
I have also seen plastic impellers on fairly new pater pumps degrade and not move enough water to cool properly.
They should have a cap test gauge at your radiator place, have them test it to be sure. It takes 15 seconds.
Good luck, hopefully they find something that explains this.

 

[Chris 8603]

Well that's good to know.
I have seen something as simple as a bad cap, not holding pressure cause overheating on a hot day.
I have also seen plastic impellers on fairly new pater pumps degrade and not move enough water to cool properly.
They should have a cap test gauge at your radiator place, have them test it to be sure. It takes 15 seconds.
Good luck, hopefully they find something that explains this.

I'll just get another one, it's original anyway. Can't hurt to try at this point

 

[haymaker]

I'll just get another one, it's original anyway. Can't hurt to try at this point

Likely not the problem, just trying to cover all the bases.

 

[Chris 8603]

Likely not the problem, just trying to cover all the bases.

I'll try most anything right now

 

[brdgbldr]

I'll try most anything right now

Have you actually tested the coolant?

Not sure if you mix your own or not, but I have seen people that thought they were putting in premixed coolant but it was actually concentrated/unmixed. By the way, there are different testers for the different types of coolants. So make sure you have the correct tester.

 

[Chris 8603]

Have you actually tested the coolant?

Not sure if you mix your own or not, but I have seen people that thought they were putting in premixed coolant but it was actually concentrated/unmixed. By the way, there are different testers for the different types of coolants. So make sure you have the correct tester.

Yeah I don't buy premixed antifreeze. I think it's ridiculous to pay the same amount for half a gallon of antifreeze. I bought a 55 gallon drum one time of take out antifreeze once for $50. That's the closest I've come to buying premixed. Lol!!

 

[mrbb]

OK just food for thought, but what is the air temp your dealing with, and what oil weight are you running? type of oil as well
I have seen some motors run HOTTER in higher temps where running oil made for the temps more, made a noticeable different in how hot things got
and have also seen where running good synthetic oil of right weights, also lowered operating temps
as I did not see any information about how old your oil is(hours on it, or type/weights here)
so, maybe try different oil>?
fresh oil /filter never hurt anything if nothing else?

 

[Chris 8603]

When I have issues with air temp is 90ish up. The weird part is during the day I don't have a issue, yeah it of course runs a bit hotter. Around 3pm when the humidity rises and the air gets still it claims above 190 and up. I shut it down at 195 just to be safe. For motor oil I run Rotella 10w30 in the summer and 10w40 in the winter. What bobcat calls for weight wise, with a small amount of lucas oil stabilizer. I don't use the full amount, just enough for the extra protection. I run lucas in everything I own. I change my oil every 150-200 hrs or 3 months. The oil has 58hrs on it this oil change. That's the only oil I will run because of the amount and type of wear additives in it than any diesel oil.
I agree with your thoughts, the only thing is it would be all the time not just when the radiator cover is on. It runs just fine with the cover is off.

 

[Wayne440]

Its been pressure washed and steam washed though the access doors. And I checked to make sure I could see though ever inch of it. I don't get it !!!! I'm going to go ahead and pull the radiator and have it checked. I know it's not the problem, it's airflow for whatever reason. But at this point I'm grasping at straws. I'll know tomorrow!!

When you figure it out, let us know. I have a 742 that runs hotter than I like, and has a similar radiator, cooler assembly.

 

[Chris 8603]

When you figure it out, let us know. I have a 742 that runs hotter than I like, and has a similar radiator, cooler assembly.

I will sir. What is yours doing

 

[Tazza]

You saying coolant is going to the over flow and being sucked back when cool, your head and gasket is fine.

Your radiator should not be the same temperature all round, the inlet side should be hotter than the outlet, if it's the same, you simply are not moving heat from your cooling system.

 

[Chris 8603]

Your right, I miss spoke that. I should have said from top to bottom and side to side. Still there's not enough temp change from left to right. Once it starts to get hot, there's only like 10 degrees or less difference. There's not enough airflow to make enough temp change from left to right.
I figured that if it was pulling coolant back the head gasket was fine. And the cap also, but I'm going to replace it after someone else mentioned it just to eliminate a potential problem

 

[Chris 8603]

Ok so radiator was good, nothing in it. The cap he said was a couple lbs to low. No biggie!! But I have a new one. I'm going to put back together and go from there.
Thank y'all for all the thoughts!!!
I'll fiqure something out somehow

 

[thwerench]

Just a few thoughts here. Fan turning the right way ? Has it been off and installed backwards? Does it have a fan shroud that's not installed?

 

[Chris 8603]

The 743's fan is flywheel mounted and can be turned around backwards. Yes the shroud is in place.
Have seen that before though!!!

 

[dfb]

Just to add a few thoughts. This may seem counter intuitive but the Temperature drop across a good radiator core is only 15-20 degrees at full load. A more significant temperature difference would indicate a restriction in the core. It does sound like you have an airflow problem across the radiator. Radiator cap raises the boiling point 3 degrees for every pound of pressure it adds, so if the coolant is not even reaching 212 it is not contributing to running hot. Pressure does help the pump run more efficiently with less chance of cavitation.

 

[oiu789]

If everything in the cooling system checks out ok rad, pump,thermostat, gaskets, fan and alike. Check eng timing. A to far advanced eng will run warmer.

 

[Chris 8603]

Thanks haven't thought about that. I'll have to get into the book on that one. Since those are gear to gear driven, If I remember right you shim the pump to change timing. I don't think there's any thing to loosen and adjust.

 

[Wayne440]

I will sir. What is yours doing

My 742 (same machine as yours-but with a Ford gasoline engine) has the same symptoms, runs hot sometimes, seems like not much air comes out the radiator discharge, but will blow your hat off if you remove the access panel. I'm going to remove the radiator and hydraulic cooler and give both a good cleaning, I think the hydraulic cooler is blocking airflow in my case.