DK35 Coolant issue

[Roscoe294]

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]

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]

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]

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]

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]

...
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]

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]

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]

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]

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