L185DT - Overheating - Think I've tried everything

[jkevans]

Hello,

New to posting to the forums. I'd consider my skill level as beginner as far as technical skill(s) go. I do regular maintenance myself as far as fluids and filters though. I've had the tractor about 12 years now. I bought it used, and am the third owner. Tractor has 2000 hrs on it. No major problems up to this point. She's been a real champ. I use it mostly for mowing brush and prairie meadow grass and general land maintenance on recreational property in SE Kansas. I only use the tractor on the weekends for a few hours at a time, and don't even use it some weekends. It's keept in a barn and out of the elements. Anyway, hope you all can help, as I feel like I've tried about everything...

I have an L185DT that's overheating whenever the engine is put under a load. Whistle blows when I start to mow (4' brush hog) only after about 5 mins., or if I pull a heavy trailer, ect. Been dealing with it now for a few months now. I only get to work on it on the weekends. I've read all the treads on the site dealing with overheating, and tried all the suggested advice (I think). Here is what all I've done over the last couple of months (that I'm capable of doing).
1. Oil & filter change.
2. Gear oil change in the gear box of the mower.
3. New air filter.
4. New radiator cap.
5. Ran tractor without rad cap and looked for bubbles (to check for bad seal or cracked heads) -- no bubbles.
6. Drained and pulled radiator (last weekend 2/13/15). Blew out fins (not that dirty), soaked it in vinegar overnight, flushed it with distilled water, reinstalled and filled with new coolant (Premix 50/50).
7. Top rad hose gets hot, bottom hose is cold/cool.

Now, one thing I found odd, and may be a clue. When I refilled the system with coolant, it only took about half the amount that the manual said it would take. It is supposed to take roughly 1 and a half gallons. It only took about 3/4 a gallon. So, I redrained it and filled it again to be sure. And again, only 3/4 a gallon of coolant. I did run it after it was refilled to make sure everything got circulated. I also tried mowing again, and same result...after 5 minutes, the whistle blew.

Now, I did notice on the side of the tractor down by the oil dip stick, there are 2 open threaded holes that I'm not sure should be open or not (see photo attached, red arrows pointing to open holes). Could dirt and debris be entering there, and over the years have filled up space to the point that I can only add half the amount of coolant? Tractor didn't always overheat, just started the last year or so of the 12 years that I've owned it.

Any ideas?

P.S. Forum has been a big help in troubleshooting!!!

 

[sburns502000]

Try a new thermostat.

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[windzer]

I wonder if your thermostat is sticking closed andhave you tried flushing the whole system

 

[jkevans]

From what I understand, this model (L185DT) doesn't have a thermostat, or a water pump. It uses thermo-siphioning to cool. Am I wrong?

 

[sburns502000]

I'm not sure now that you mention it.

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[jkevans]

What do you mean by draining the whole system? I opened the drain on the front of the radiator, and the other on the right side (drains the engine block I would guess). Plus, after that, I pulled off the whole radiator and soaked it overnight in vinegar to try and clean the inside of it.

Don't know a lot about tractors, so I'm not sure if there was something else I should have done to drain the "whole system."

 

[D2Cat]

Jkevans, good to have you here.

It sounds to me like you may have some air in your cooling system. There may be a bleeder screw where the upper rad. hose goes to the block. If not park so the front end is uphill some. Run the engine with the cap off. See if it will burp itself.

Another thought is to check your cooling system with a infrared temp. sensor like this.

http://www.amazon.com/Etekcity-Lase...&sr=8-1&keywords=Infrared+Temperature+Sensors

You can pick one up at WalMart also.

With it check the temp at the top tank on your radiator, at the top radiator hose, at the engine block. This will tell you exactly what the temp is.

 

[L3010HST]

No thermo or water pump How could it ever get to and/or maintain normal op temp

When you filled your system and it didn't take the full capacity amount was because, there's still quite a bit of coolant still in the engine block even after draining from lower radiator hose.

Once I was running real hot while mowing pastures/under a load. Did a lot of trouble shooting then noticed my debris screen in front of radiator was packed with dried grass and dirt from many previous seasons of mowing. Cleaned that screen off and she ran at normal op temp again. I felt dumb doing all that trouble shooting on cooling system prior to seeing that plugged debris screen Live and learn I say lol.

 

[85Hokie]

D2Cat has a great answer with the probe.

another thing to try is a vinegar IN the radiator, add a quart of good ol vinegar to the straight water, run it for a good while - use your infrared gun and record the temps:
at head, at upper neck and then at lower neck of radiator.

Run it till it gets hot......empty - flush with water, run it , flush again with water......each time record the temps - the vinegar as you know is an "acid" and will eat away at some bad stuff, the water behind it will get it all out.

ON your tractor - there is no water pump, so the hot water will rise and cool and then fall, the circulation is key......too much water and it will kick it out !!!! AND 50-50 antifreeze is fine IF it is gonna freeze ....both otherwise 70% water and 30% antifreeze will do a better job of cooling - straight water is the BEST coolant , but you need some antifreeze to keep from freezing and raise the boiling point and lube the inside.

report back with your temps......curious to see if there is a difference after a good flush

 

[D2Cat]

85Hokie, He's done that.

"another thing to try is a vinegar IN the radiator, add a quart of good ol vinegar to the straight water, run it for a good while - use your infrared gun and record the temps:
at head, at upper neck and then at lower neck of radiator."

 

[Daren Todd]

No thermo or water pump How could it ever get to and/or maintain normal op temp Live and learn I say lol.

It's a common set up on the older kubotas. L175, l185, l1500, and l1501. My l1501 has always run good, and haven't had any issues overheating. And yes, there isn't a thermostat or water pump anywhere on it Here's an article on how it works


https://en.wikipedia.org/wiki/Thermosiphon

 

[jkevans]

I will try bleeding the air out of the system, then take some temps.

Now, I did put straight vinegar IN the radiator when I pulled it off the tractor. I plugged the bottom hole where the bottom hose fits on with a rag, and let it sit overnight, then flushed it all out with distilled water.

Are you saying to run vinegar through it mixed with water after start it up and run the tractor after I've got it all put back together?

 

[Daren Todd]

Sometimes blowing the fins out on a radiator doesn't really cut it. I prefer to spray the radiator down with a degreaser, or some dawn dish detergent. Let it sit for a bit, then gently flush the fins with a garden hose. Just be careful with the stream so the fins aren't damaged.

On my l1501, the fins looked good and clean. After hitting with some dish soap and started washing it, I was getting mud!!!!

Bleeding the air out on your system is easy. Just disconnect the upper radiator hose from the top of the motor, and dump coolant down the pipe till it's full. Then hook your line up and finish filling the radiator

 

[jkevans]

By "dump coolant down the pipe" do you mean the opening on the top of the motor that the top radiator hose was hooked to? Sorry, just want to make sure that I understand 100%. I'd hate to create another problem for myself

I did spray it off with water from the garden hose after I blew it out with air, but I didn't degrease the fins. I'll try that as well as bleeding the air out of the system.

 

[rbargeron]

I'd take the radiator to a repair shop. They can boil it out and test it for flow resistance. With age the tubes plug up. That could explain the reduced capacity too. The top and bottom tanks can be un-soldered to rod out the tubes if needed. Without a pump in the sytem any leak stopper material that's ever been added can collect in the tubes.

 

[85Hokie]

85Hokie, He's done that.

"another thing to try is a vinegar IN the radiator, add a quart of good ol vinegar to the straight water, run it for a good while - use your infrared gun and record the temps:
at head, at upper neck and then at lower neck of radiator."

D2Cat - notice he flushed the radiator OUT of the system - no block/engine

("6. Drained and pulled radiator (last weekend 2/13/15). Blew out fins (not that dirty), soaked it in vinegar overnight, flushed it with distilled water, reinstalled and filled with new coolant (Premix 50/50)")

- NOTICE that I said RUN it with IT in it , huge difference.......trying to get gunk out of engine, and I want him to understand that after 3 tries with filling and flushing and filling again.....to see if there is anything different INSIDE the block and heads.

the temps should go down a hair ifn the engine and block get a little stuff out of them, and placing vinegar in the radiator aint the same as heating it up to 220 and cooking through the system - I read his question and read it again, trying to work outside the box and rule out anything else........

shoot it could be that the radiator is shot and gunked up on the inside and aint nuttin gonna fix that but a good coring !

 

[Daren Todd]

By "dump coolant down the pipe" do you mean the opening on the top of the motor that the top radiator hose was hooked to? Sorry, just want to make sure that I understand 100%. I'd hate to create another problem for myself

I did spray it off with water from the garden hose after I blew it out with air, but I didn't degrease the fins. I'll try that as well as bleeding the air out of the system.

Yes, where the coolant line attaches to the motor.

Most people don't realize where the water travels on your tractor. Coolant goes out the bottom of your radiator. Up through the crank case cover (timing cover for those in the south), then enters the engine block about 2/3 of the way up the block. There is an o'ring on the back side of the crankcase cover that seals for the water jacket.

You could very well have a blockage inside of the crank case cover. Draining the radiator and disconnecting the bottom hose. Pour water, coolant, or vinegar into the upper radiator hose to fill the engine block. Once the block gets full, it should start running out the bottom radiator hose. If it doesnt, then you could have a blockage inside the crank case cover.

There is an inspection cover for the water passage up near the top of the crank case cover.

 

[windzer]

I was meaning they have a cleaner you can buy called radiator flush u can get at any auto parts store you can dump it in with water then run the machine then drain the radiator and block again and see what kind of crap comes out of it but these other guys are suggesting using vinegar and that may work to I've never done that myself I may have to try that.

 

[North Idaho Wolfman]

I'm betting on a bad head gasket, get a water system pressure tester.

 

[Tooljunkie]

I have to agree, machine sitting running wide open wont simulate a working engine. Have seen cars where they will idle all day without issue, put on highway and instant overheat. Cylinder pressure under load will do exactly as you describe.