overheating?

[jft]

I have a '87 ('88?) kubota b4200 2 cylinder diesel mini tractor. i noticed some coolant puddling below the radiator a few months back but it only happened once and i couldn't find a leak. regardless, i flushed the radiator and ran sealant through it. there was a lot of sediment in the fluid that came out and i had to poke around in the drain to get anything to come out. it was really brown. it has never leaked since but every now and then i hear what can only be described as a loud "chirp" coming from the engine either while i'm running it or even after i turn it off. sometimes it sounds like escaping pressure (my impression). the coolant level is remaining the same but sometimes i find a strange splatter on the wheel that looks like spraying coolant. i also feel like the engine is running hot but again its only my impression because i don't have a temp. gauge. it is hot here this summer but parts of the tractor get so hot while i'm running that its uncomfortable to touch them and i feel like more heat is coming off the hood than i've noticed before. i'm wondering if the coolant isn't circulating like it should. my question is (1) how can i tell definitively that the tractor is running hot. can i install an aftermarket T gauge? (2) where do i start, to figure out what, if anything, needs replacing? my dad mentioned getting the radiator 'rodded'. should i just replace the whole thing? what about the temp pressure switch? i'm certainly not a mechanic but i like would like to learn more and do as much as i can on my own. does anybody have any suggestions? thanks.

 

[firemanpat2910]

I know a few simple things to check and defer to the experts for more detailed help. Is the water in the radiator getting as hot as the motor? can you see it circulating past the cap hole when the cap is off? can you feel it "pulse" through the water hoses? all these will help tell if water pump is pumping. Is the fan belt tight? is the fan slipping? Is there dirt or grass plugging the radiator? How long since last oil change? Have you mounted any thing (push bar, tool box, weights) in front of the radiator? Is the motor clean?

 

[Highbeam]

One of the simplest ways to check for a plugged radiador is to put your hand right on the core when it is supposed to be hot. Shut your engine off of course and feel for changes in temp. The dead and plugged areas are very noticeable. I had radiator pluggage that wiped out the centers of the cores on both a 1985 toyota pickup and a 1960s ford bronco. If your radiator passes this test and is evenly hot then the next easiest thing to check is airflow through the radiator. Run the engine rpm up to pto speed and the fan should full a very noticeable amount of air into the radiator, at idle the engine fan should still pull plenty of air.

So now you verified hot coolant to the radiator and air flow through the radiator. If you are still unsure, then I would go buy a cheapy infared thermometer. The kind that is like a gun you point at an object and the gun tells you it's temperature. These are not a bad tool to have around since you can check all sorts of things with them.

 

[3RRL]

Another thing to check is the "shroud" around the radiator fan. It is very important that air is sucked through the cooling fins and not from the side or hot engine compartment. Check for cracks or missing pieces. In my case, it is normal for my tractor to run hotter in the Summer too....usually 9°F to 10°F hotter than in the cooler Winter.

 

[firemanpat2910]

great idea on the shroud. Very comon for them to be removed when working on engine and left off cause they're such a pain. You can have the fan running like mad and if it is not encased in the shroud its not doing its job.

 

[normde2001]

I would replace that water pump ASAP and flush the entire cooling system in the process. The mysterious coolant loss, (check the weep hole), and chirping are dead giveaways on the water pump.

 

[Egon]

Is it a thermosiphon model? If so there may be tube comming off the top of the rad and down on front right side that has a whistle on it. If overheating this whistle will sound and vent steam. Also check the rad cap to make sure it is good and has a proper seal. This model probably does not have a water pump.

Having the rad cleaned may also be a good idea after your descrition of draining it. Flushing the coolant system with some of the commercial prducts made for this may help clean up the block a little.

 

[RobJ]

It seems not all models have a fan shroud. At least my L2500 does not. I don't see one in the parts manual either. Mines been running hot lately to. After flushing the system I left plain water in. The temp got up there but no weeping from the overflow tube. An this was while under a heavy load (disking). I'd heard a while back that plain water is best for heat extraction, but antifreeze keeps it from freezing and keeps rust out of the system.

A pic of a sticker L2500.

 

[deerhunterf350]

I'd heard a while back that plain water is best for heat extraction, but antifreeze keeps it from freezing and keeps rust out of the system.

Anti-Freeze also raises the boiling point of Water, water boils at 210 degrees at Sea level, lower than that at higher elivations. Depending on the concentration of Anti-Freeze will determine the increase in the Boiling temp.

If you run plain water at higher elivations, then you can be boiling the water out of the system. And depending on mineral content of the water, you can get some nasty Scale buildup in the cooling system, which will only add to the Overheating Problem.

 

[RobJ]

Didn't know that, I know that being under pressure with the cap raises the boiling point.

It'll sit for another couple weeks before I get the anitfreeze in it. Up at the weekend place the water is soft (slippery) in the shower, so I think that means less minerals. In Spring we have the hard water.