Deere overheating

Guys,

Didn't have muc luck on the tractor forum - would appreciate your help - if better place to post, pls advise.

Have a 6x4 Gator/gas, 97 model

Changed the oil/filter [Pennz 10W-30] 1.4Qtz w/ about 1oz of M-Mystery Oil. While letting her drain, I pulled the battery, cleaned and 12v trickled-charged.

Oil stick is reading pefectly in the center, but now the temp gauge light is coming on after running her for about 5-10 minutes. Fan has not kicked on...ambient temp here is from 35 - 59. I checked the radiator and [greenish] mixture is nicely coming to the top, resevoir is filled with a-freeze. Fins inside look perfect.

I have checked all the wiring to insure I did not disconnect something [fan-line, etc]. I remember reading something about a fan-sensor switch? Way to test this?

Anyway, I hope I can get this wrapped-up...thank in advance for any and all advice.

Thanks again,
tstex

Is 97 the year, what's the model? Knowing the model it would be possible to look up the thermal switch at jdparts.com and see where it's located.

I'm NOT familiar with Gators but, FWIW, my son has a Yamaha 4 wheeler and head fan trouble a while back.

We found the thermal sensor screwed into the lower radiator tank. A little more looking found a rubber-encased fuseholder in the wire to the fan and the fuse inside was blown. Son figured fan blew the fuse when he "forded" some deep water and the fan was trying to sling water instead of air.

Have you found the fuse for your's... might be in-line like the one I mentioned, or in a fuseblock up on the chassis or maybe even a breaker. Look for a switch screwed into the radiator tank with two wires coming out of it. Who knows... may be on the engine instead.

Bob,

I am the orig owner and the orig OP's Manual states:

"GATOR 6X4 Utility Vehicle", it is a 1997 Gas

The OP's man # is OMM128780, Issue G6, [Replaces OMM126591 A6].

I will have to pull the seats off and other to get to the radiator...I will try your suggestion on locating the model and parts...

Thank you very much,
tstex

Looks like the fan thermal switch is in the upper radiator tank, and there's a serial # break before or after 068204.

Product ID # is WOO6X4X031724
Engine Ser# is FD620D148412

If the sensor is "in the radiator", does it even possibly state how to get to it? Maybe I can take the line that goes to it and install a new sensor that both works and is more accessible.

Bob, would you be so kind to send the link to where you are looking?

thanks,
tstex

Looks like the sensor screws into the top radiator tank from the back. Shouldn't be too hard to see. You can view or print out the parts manual for free at jdparts.com. (To check availability or price you DO need to sign up with a dealer, but OT to look at the parts books.)

At the middle LH side of the page, click on "John Deere Parts Catalog. A new page will open. Then, enter "gator" and drill down through the menu 'til you find the 6X4 version. (It looks to me like the parts book you want to look at is #2387.)

Bob,

Got it - thanks a million...I can really use this site..I just now have to go through the trouble-shooting process to discern what is working and what is not?

Thx again,
tstex

In case you're not aware, you can get a shop manual direct from DEERE Techpubs buy calling them @ 1-800-522-7448 with credit card in had. NOT cheap, though!

the fan thermal switch is just a long metal probe stuck in between the fins of the radiator and held with a metal clip. Has 2 wires on it, is in the upper corner.

this has a bleed screw on the engine, near the carburetor, you have to fill the engine with coolant and let the air out through this hole, as well as filling through the radiator. if this isn't done, the engine becomes air locked and will overheat. the overheat sensor is located in the engine block, its not the same one foudn in the radiator.

If all is well, if you run the engine at full throtle (trans in nuetral, and your foot to the floor), the thermostat should open after about 10 minutes, and after another 5 to 10, the fan should come on.


I have the service manual, explains all this with pictures, but its about 60 MB, too big to email.

tl,

Thank you immensely - great information.

While waiting for the oil to drain, this is where I took the radiator cap off and looked into the radiator to check fluid level, color and fins...I noticed the cap to the anti-freeze resevoir was screwed on a bit crooked. At this point, the Gator ran fine and did not overheat.

I unscrewd the cap and pulled the line out of the antifreeze and checked the bottom of the line. The bottom of the line looked like it was narrowing, but ok i guess...i then put the line back in and tried screwing the cap on evenly, but it still kind of skews a bit. Could pulling this line out and/or unscrewing the cap cause the cooling system to air-lock?

Based on the info above, what steps would you perform to determine/ensure the cooling system checks out or is corrected?

Finally, she was running normal before I performed the maintenance items and afterwards [in 2 different weekends], the heat-light came on both times within 8-10 minutes while the fan never came on..

Thanks again,
tstex

Thx Bob. I bought the tech ser manuals for the 1951 JD MT tractor that I restored: $120 bucks...i know they are $$$$ and trying to avoid at this time - thx, again.

How is the bottom of the compartment that holds the fan and radiator? you probably have to take both seats and that plastic cover off to really see in there, but over time, the area around the fan gets dirt and debris in there, and can prevent the fan from turning.

that cap and line is the overflow bottle from the radiator, the radiator cap itself is under the passenger seat. removing that with engine cold shouldn't cause any problems, but if you removed the line from the coolant in the reservir while the engine was hot, it couldhave sucked in air as the engine cooled, instead of coolant (as the engine gets warm, the coolant expands and the excess goes in that bottle, when the engine cools, the excess coolant is pulled back into the engine from the bottle.

Because there aree so many high and low spots for an air buble to get trapped in that system, anything is possible.

make sure the radiator itself is full to the neck when the engine is cold.

with the engien runnig, and the radiator cap off, I'd run it until it warms and you see the coolant actually moving in the top of the radiator, this means the thermostat opened. put a bucked under it, as the coolant may expand and leak out, but only a small amount. Don't remove the cap after the engine is hot, or the pressurized system will spray hot coolant all over you, resulting in burns. just run it with it off. another way to check with the radiator cap on, is to feel the incoming and outgoing radiator hose near the radiator. they will gradually warm up a bit as the engine runs, but when the thermostat opens, they will change tmperature noiceably. that will tell you for sure the thermostat is opening and the coolant is moving. if the hoses continue getting hotter and the fan doesn't come on before the overheat light, then maybe a wire came off the fan switch, or the fan itself, or fan has something caugh in the blades and can't turn...

tl,

You have been most gracious with both your time and feedback...time for me to start testing. I do want to answer your questions:

"How is the bottom of the compartment that holds the fan and radiator?" I do keep the screens and area around very clean. However, anything can happen and I have not visually inspected it, but will. I had to take the gas tank out 6+ yrs ago when an old german dropped his pen in the tank...very time-consuming.

My orig goals were to change both the oil and transaxle fluids...so I did drive her a bit to get the fluids warmed & moving. There is a good chance when pulling the cap off & line out of the resevoir, the engine was cooling and the line sucked-in air...makes sense since everything else was fine prior and I did pull the line...

I'll remove the rad-cap before starting, fill to top, then turn her on...I will also watch both inside the radiator and keep an eye on the radiator in/out lines to the block.

Finally, I remember a JD tech opening the bolt/valve near the carb and adding some a-freeze, but it was yrs ago. I am not sure of the entire process. If it is air-locked, doesn't this allow for the air to escape at the top while sucking in the appropriate amt of a-freeze to flush the bubbles into the resevoir?

Thanks again and I will post back when I do my testing this weekend at the ranch.

Much appreciation to both you and Bob.

Regards,
tstex

yes, that bolt the JD guy removed is the bleed screw, and is part of the bleed procedure in the manual. Its been a few years since I've done one, but I remember having to pour a cup or 2 of coolant down that hole.

Here is the best I can do with copy and paste of the fill and bleed procedure from the manual.
maybe it will help you if you think you have air in the cooling system. you might be able to work your air bubble out (if you do have one) by loosening that bleed screw a couple turns and running the engine long enough to get the thermostat open, and monitor the coolant level at the radiator, filling as necessary.
stesps 1-3 jsut say to check hoses and clamps, remove the shrouds, and radiator cap.

Don't rule out the possibility of a loose wire or connection to the fan motor, or to that temperature probe.

4. Fill cooling system as follows:
• Remove the black bleed screw (B) from bleed screw
hole (C).
• Add coolant to radiator until it comes out of radiator
cap hole. Install radiator cap.
• Add coolant at bleed screw hole (C) until coolant runs
out.
• Install bleed screw (B) halfway.
• Run engine at MEDIUM speed for approximately five
minutes. Check that upper radiator hose is warm
indicating thermostat has opened and coolant is
circulating.

• Add coolant to radiator until only coolant is coming
out of bleed screw hole (air bubbles no longer visible).
Tighten bleed screw.
• Run engine for approximately five more minutes
Check that lower radiator hose is warm indicating
coolant is circulating through entire system.
• Run until cooling fan starts, approximately five more
minutes (15 minutes total), indicating coolant and
engine have reached operating temperature and system
is functioning properly.
M55758
5. Remove cap (E) and fill expansion bottle with coolant to
approximate level shown (D).

tl,

You have certainly gone beyond the call of duty...i am indebted - thank you.

I will remove all the parts needed to thoroughly examine both the radiator and fan to ensure all wires and parts are intact.

If so, I will then bleed the cooling system and follow your steps...I am going to keep this post for both future personal reference and post the next time someone else has an issue.

Again, thank you very much and I will post-back the results this weekend.

Regards,
tstex