DK35 Coolant issue

Roscoe294 · Apr 6, 2017

Hello, need some help.....

2004 DK35
2000 hrs

The issue I'm having is that recently I've notice coolant leaking from the coolant reservoir while the tractor is running. It doesn't matter if the engine is cold or hot. Seems when running the coolant is pushed to the reservoir where it eventually fills the reservoir to the point it leaks out the overflow hose or bubbles out the plastic lid. When the engine is shut off, the coolant is then drawn back into the radiator and the reservoir sits full between the minimum and full lines.

No other leaks, no overheating and when I just topped the radiator off it took about 3/4 of a gallon.

What are your thoughts?

Thank You

jabelding · Apr 7, 2017

You probably have a leak in your head gasket if you fill the radiator up and let the engine run do you see bubbles constantly?

adventure bob · Apr 7, 2017

2 things that are cheap before you do something drastic like pull the head. 1 pressure test your cooling system. 2 leak check the cylinders. you can get both testers at auto zone on their loaner pgm. I wouldn't call it a head gasket leak till I did both of those.

ritcheyvs · Apr 7, 2017

I agree with jabelding but also with Bob. Measure twice, cut once. Before you disassemble anything be sure you are fixing the right thing. The good news is that a head gasket in a non-overhead cam engine isn't so bad but must be done right, including new bolts if so specified.

Roscoe294 · Apr 10, 2017

This issue has been in progress for weeks maybe even months. What made me finally check it and pull the engine covers was the moisture from the reservoir leaking and the gurgling of the coolant reentering the system after shutting the motor off. All in all it leaked about a half gallon. Seems after the system purged the said half gallon, I wasn't loosing anymore.

There is no water in my oil and I don't have smoke during operation (other than start up as always). Motor has never been overheated or tampered with.

As far as pressure testing the coolant system, what should the proper pressure be? I see the radiator cap has a number on it (cant remember what it is). Does that # indicate the psi?

Thanks

ritcheyvs · Apr 10, 2017

Roscoe294 said:
...
As far as pressure testing the coolant system, what should the proper pressure be? I see the radiator cap has a number on it (cant remember what it is). Does that # indicate the psi?...

The purpose of the pressure test is to see if the cooling system holds pressure or if it leaks. So any pressure up to (and even a little above) the radiator (reservoir) cap limit is OK.

That cap is designed to release at a specified pressure (usually around 15 psi) to prevent damage to the cooling system.

If there is little to no coolant in the system, leaks are obvious fast. If the system is full, a leak below the water line can take a long time to read decreased pressure. This test is best done on a cold engine because a hot engine will be changing pressure constantly as it cools and small leaks evaporate, making them hard to see.

The test is very simple: pump it up and wait to see if the pressure leaks off.

jabelding · Apr 10, 2017

First thing I would check is for bubbles in the radiator with the cap off and engine running. If you pressure test the radiator and the gasket is mildly bad you could force enough coolant into the cylinder and hydro lock it and have a much worse problem. If you don't see bubbles then I would change your radiator cap and see if that fixes it. Remember the pressures in the cylinder are over 300psi so sometimes when there is a weak spot in the gasket it only lets pressure from the cylinder into the coolant but there is not enough pressure in the coolant to force it the other direction, unless you test it, but sometimes not even then since you don't go above 10-15psi. The only other thing I would try is a compression test but only to confirm that the gasket is bad.

ritcheyvs · Apr 10, 2017

If you do see a constant stream of bubbles in the coolant reservoir with the engine running, give it the smell test. Does it smell like Diesel exhaust?

jabelding is right saying a cooling system pressure test is likely to be inconclusive (false negative) and potentially damaging if it drives coolant into a cylinder. I think a leakdown or compression test would be more reliable. But if you get exhaust bubbles in the coolant reservoir, that's pretty conclusive of a head gasket leak.

Gittyup · Apr 10, 2017

Mine is in the shop now for a head gasket. Still waiting on the estimate to repair. At least the OP got 2000 hours before it gave out. Mine is less than 700 hours.

Roscoe294 · Apr 11, 2017

Coolant does not smell of diesel.

With the radiator cap off and filled to capacity, there is no problem with bubbling over in the reservoir.

With the radiator cap off and engine running, the radiator builds bubbles.

As soon as I cap the radiator, the problem starts again.

The breather that comes off the top of the engine? What is that for? There seems to be a bit of what looks like steam blowing out of the hose but the engine is not warm. Same goes for the radiator.

After reading about doing a pressure test I'm leary and don't want to create a problem that isn't there.

For a compression test I will have to find a mechanic

Thoughts?
Thanks

Roscoe294 · Apr 11, 2017

Update...I put the radiator pressure tester on the radiator and started the engine. Within 20 seconds pressure climbed to 20+ psi and was still climbing until I killed the motor.

jabelding · Apr 11, 2017

Sounds like you need a head gasket. It is fairly involved to do it correctly I would take it to a dealer or a trusted independent that knows kubota or Kioti engines they are almost the same.

Coyote machine · Apr 11, 2017

Sounds like gasses of combustion are passing from the cylinder(s) past your head gasket into the coolant system, causing the rapid rise in pressure shown on the radiator pressure testing gauge.
Once you have removed the head and it's gasket, make sure the gasket is the failure point, and not the head itself from a crack or warp, etc.

adventure bob · Apr 11, 2017

Sad to say that it does indeed sound like a head gasket leak. Not sure of your tractor, but most combustion engines run about 15PSI. Check your radiator cap though because some run as high as 30PSI. Your cap relief pressure gives you the high end of where you should be because your cap should vent at that pressure.

ritcheyvs · Apr 11, 2017

Looking at the MIE online parts catalog, you may have one of two different engines. Engines up to s/n E614-00284 had the external stop solenoid on the right side of the engine (as an easy way to ID that engine). From s/n E614-00685 on, the stop solenoid is bolted to the front of the engine block. These two versions use a different head gasket AND there are at least two versions of the newer version head gasket and four versions of the older style, where newer versions superseded older versions.

It looks like improved versions of the head gasket were developed during production. Discuss this with your dealer/mechanic to endure you get the best replacement gasket. Also, be sure tour dealer/mechanic checks the head and block for flatness before reassembly and checks/replaces the head bolts as required.

I have a 2006 DK45s with the newer (front stop solenoid) engine however the only service manual for the DK45s only addresses only the older type engine. I believe the newer engine is the same as a DK40se, but that's a guess. So it may take some communication with Kioti to determine the correct head bolt specs and torquing procedures, which tend to depend on gasket type. Head bolt replacement (if so specified) and proper torquing tend to be critical in head gasket longevity.

Roscoe294 · Apr 11, 2017

I graded the driveway tonight and noticed after I lost my top off coolant my temp gauge was all over the place.
At one point it was showing near overheat. I felt the radiator cap along with both top and bottom hoses. They were cool to the point where I could hold onto them.
Shortly there after the temp showed operating range and they were hot to the touch.
Could this simply be a fault t-stat? Although that doesn't explain the building pressure.
I'm just trying to start at the easiest, simplest thing first before I haul it off to the Desiel mechanic.

Thanks

ritcheyvs · Apr 11, 2017

You could certainly try a t-stat; easy to do. More likely you had air pockets in the engine that prevented coolant from reaching all the hot spots. Typical water pumps just move water around and will not "lift" it any significant distance. So air pockets probably prevented coolant from circulating until it sloshed just the right way.

jabelding · Apr 11, 2017

I wouldn't run it much until you get it fixed you can do a lot more damage to the engine like warping the heads or hydro locking a cylinder it is definitely a head gasket and not a thermostat.