ZD326 running in the red

Gouverneur

Forum Newbie
Joined
May 31, 2018
Threads
1
Messages
3
I bought a 2014 Kubota ZD326P late last season with approximately 160 hours on it. It has the factory-installed mulch deck. The temperature gauge is hitting the low to mid part of the red area when under load. I don't know if the two problems are related or not, but the machine just doesn't seem like it has any power. It bogs down quite a bit under load even when I'm just cutting about five days' growth (I'm in Ohio) and removing about 1/3 of the blade of grass. I've verified that the grass is not building up underneath the deck when this is happening. I know you have to slow down a bit when mulching, but this is grass that my JD 636M QuikTrak would have no problem with. I find it hard to believe that a diesel machine with so few hours on it would have this little power. When I accelerate rapidly up a hill to verify that I'm losing power, it hesitates quite a bit but then catches up and will run at top speed.

I have meticulously cleaned the intake grilles, radiator screen, and radiator cooling fins. I've hit all the grease points on the machine and am running new blades. I've adjusted the fan belt tension so that there is about half an inch of deflection as per the manual. As far as I can tell, the water pump is circulating the coolant. I've replaced the thermostat, flushed the coolant, and verified the new antifreeze mix ratio. I just changed both fuel filters as well. I cut open the old ones and they didn't look too bad. The one toward the front of the machine (I believe this is the one that the fuel passes through right after leaving the tank) looked a bit dirtier than the one toward the back. I do have access to a fuel pressure tester. What should the PSI be at idle?

Where does the needle on the temperature gauge on these engines normally run? Any help would be greatly appreciated! Thanks.

Marc
 

jekjr

Lawn Addict
Joined
Jan 3, 2013
Threads
271
Messages
1,968
I bought a 2014 Kubota ZD326P late last season with approximately 160 hours on it. It has the factory-installed mulch deck. The temperature gauge is hitting the low to mid part of the red area when under load. I don't know if the two problems are related or not, but the machine just doesn't seem like it has any power. It bogs down quite a bit under load even when I'm just cutting about five days' growth (I'm in Ohio) and removing about 1/3 of the blade of grass. I've verified that the grass is not building up underneath the deck when this is happening. I know you have to slow down a bit when mulching, but this is grass that my JD 636M QuikTrak would have no problem with. I find it hard to believe that a diesel machine with so few hours on it would have this little power. When I accelerate rapidly up a hill to verify that I'm losing power, it hesitates quite a bit but then catches up and will run at top speed.

I have meticulously cleaned the intake grilles, radiator screen, and radiator cooling fins. I've hit all the grease points on the machine and am running new blades. I've adjusted the fan belt tension so that there is about half an inch of deflection as per the manual. As far as I can tell, the water pump is circulating the coolant. I've replaced the thermostat, flushed the coolant, and verified the new antifreeze mix ratio. I just changed both fuel filters as well. I cut open the old ones and they didn't look too bad. The one toward the front of the machine (I believe this is the one that the fuel passes through right after leaving the tank) looked a bit dirtier than the one toward the back. I do have access to a fuel pressure tester. What should the PSI be at idle?

Where does the needle on the temperature gauge on these engines normally run? Any help would be greatly appreciated! Thanks.

Marc
I had a 2013 326. I traded it on in 2015 with 800 hours on it. I forget exactly where it ran but it by no means ran in the red. I am to sure that your issue is but something is definitely not right there. Wish you were closer to me I would like to look at it.
 

cpurvis

Lawn Addict
Joined
Aug 25, 2015
Threads
21
Messages
2,256
Several possibilities:

1st question is, "Has it been this way ever since you got it, or is this a condition that recently developed?" Maybe now we're finding out why it was sold with so few hours on it.

High Temperature:
1. Gage reading incorrectly? My Kubota L3000 barely registers on the temp gage.
2. Defective water pump?
3. Low coolant level; i.e. air in system?

Low Power:
1. Deck too big for engine and grass load. This is not a problem that crops up overnight. It would have been evident from Day 1.
2. Torque required to turn blades excessive, (spindle bearings, idler pulley bearings), something sapping engine horsepower. Usually results in something getting HOT.
3. Engine not making rated power due to not getting enough (fuel restriction, injection timing, governor)
4. Insufficient intake air. Diesel engines run with a huge surplus of combustion air. If they can't get that air, I don't know what effect that has on engine temperature. SMOKE.

That's all I have for right now.
 

Gouverneur

Forum Newbie
Joined
May 31, 2018
Threads
1
Messages
3
Several possibilities:

1st question is, "Has it been this way ever since you got it, or is this a condition that recently developed?" Maybe now we're finding out why it was sold with so few hours on it.

High Temperature:
1. Gage reading incorrectly? My Kubota L3000 barely registers on the temp gage.
2. Defective water pump?
3. Low coolant level; i.e. air in system?

Low Power:
1. Deck too big for engine and grass load. This is not a problem that crops up overnight. It would have been evident from Day 1.
2. Torque required to turn blades excessive, (spindle bearings, idler pulley bearings), something sapping engine horsepower. Usually results in something getting HOT.
3. Engine not making rated power due to not getting enough (fuel restriction, injection timing, governor)
4. Insufficient intake air. Diesel engines run with a huge surplus of combustion air. If they can't get that air, I don't know what effect that has on engine temperature. SMOKE.

That's all I have for right now.

Thanks for your reply. I mowed with it several times last fall. It ran just about as hot as it is now, but I don't recall it having the loss of power issues. It could be because of the thinner, drier grass in the fall, but as I said, it is bogging down even in just several days' worth of growth. I'm wondering if there is a way to test the resistance on the gauge to see if it is simply inaccurate, but I really do think the engine is running much hotter than it should. The coolant level is where it should be. Other than letting it run with the radiator cap off to "burp" out the air when you add coolant, is there a separate procedure for bleeding the cooling system? I am leaning toward a defective water pump. If I run the engine with the radiator cap off, I see the coolant vibrating from the vibrations of the engine. Should I be able to look down the radiator neck (from a distance of course!) and see the coolant moving through?
 

EngineMan

Lawn Addict
Joined
Jun 12, 2012
Threads
9
Messages
2,275
Had this on a local a few years back he couldn't work out what it was (Kubota engine) so he ask me to take a look at it, it turn out to be a loose fan belt...!

You could also check the the exhaust ports are not restricted, ( have you seen a lot of black smoke) remove manifold and take a look, also check for restriction of the muffler, (leave muffler off) see if temperature drops, check also air flow in, timing/water pump has already been posted above.
 

delawnman

Forum Newbie
Joined
May 19, 2018
Threads
3
Messages
6
check your radiator for blockage in the fins, you can wash out the areas between the fins with a garden hose. How does the engine run when not under load? Does it throttle up like it should at idle with the pumps in neutral? does it bellow black smoke? a short video of this would really help.
 

Gouverneur

Forum Newbie
Joined
May 31, 2018
Threads
1
Messages
3
check your radiator for blockage in the fins, you can wash out the areas between the fins with a garden hose. How does the engine run when not under load? Does it throttle up like it should at idle with the pumps in neutral? does it bellow black smoke? a short video of this would really help.

I have washed out the radiator fins. You can see see right through them if you shine a light. The engine runs fine when not under load. It throttles up and down responsively. I'll work on getting a video up.
 
Top