Kubota glow plugs

[Welder Dave]

I have an indirect injection V1902B that the glow plug indicator has stopped working which I think also means not all the glow plugs are working. It took forever to start today. Are they easy to test and/or easy to change? Also are they real expensive? Have about 4500 hours on the machine.

 

[Coaldust]

It’s not scientific. Many other, safer and complicated ways to do it with test equipment. But, a sure-fire, simple method:

Use a hefty jumper wire and go from the battery + to the individual glow plug terminal. The wire should spark at the glow plug. Because the glow plug is drawing amps. No spark means the glow plug is open. But, you gotta take the glow plug buss bar harness apart and test them individually.

Don’t burn down your tractor, please.

 

[Welder Dave]

Would it be good to just change all 4 of them? How. Many hours is good for Kubota glow plugs?

 

[Coaldust]

It’s cheap and easy enough. If you can even find them in stock. 500 hours or so or three winters is about the life span.

 

[Welder Dave]

They're original from 1994. Needed all the time on a cold engine even in summer. Newer direct injection Kubota's don't need them in the summer. Sounds like I should just replace them all.

 

[mekanik]

Use a test light and make sure the glow plugs are getting power when they are activated.
There is a solenoid that supplies power to them, it may have failed. The power for the glow plug
light may come from the glow plug solenoid.
Glow plugs should be replaced periodically as having a tip fall off one into the cylinder is not unheard of.

Terry

 

[Birken Vogt]

I've seen many engines of this type that go their whole life w/o changing a glow plug. I would spend the time to diagnose and only replace what is necessary. Could save the work if one breaks and it was not necessary to be changing it anyway.

Two methods I can think of off the top of my head:

1. Hefty jumper as mentioned above with an amp clamp on the wire, if you have one, to each plug. Each one should take a few amps. One that is open will take no amps. One that is shorted will set the wire on fire, take way too many amps. I had a shorted one once that burned out the glow indicator.

2. If you have no amp clamp, maybe you can rig a remote start setup or have someone help you. Apply power to one plug at a time for the correct duration and then attempt to start the engine. If the plug is working correctly you will hear one cylinder firing off when attempting to start. Open circuit will be obvious and shorted you will be able to figure it out.

 

[MarshallPowerGen]

With leads removed, glow plugs should be around 0.9 ohms from post to body. Easy way to test for open is a test light clipped to battery positive and then touch the probe to the GP post; if it lights it has continuity, if it doesn't it's open.

 

[Simon C]

Have seen one old glow plug that burnt off a cat 3412 engine. Hit piston and destoyed head also. Does not happen often but when it does it is 10000 dollars plus. Most of the time they just stop working.
Simon C

 

[Welder Dave]

I'll see if I can get some help to check them or the solenoid. I have the parts manual for the engine so will see where the solenoid is located. Some of the glow plugs must be working because it did start. Really good engine but very cold blooded.

 

[Midnightmoon]

9 times out of 10 it's the power going to the glow plugs that's the issue. I've seen original glow plugs in light towers with kubota engines with 18000 hours and still working. What is the engine in?

 

[Birken Vogt]

He said a V1902 in the skid steer forum so I was assuming it was a Bobcat. Extremely easy to get at.

 

[Welder Dave]

V1902B in a skid steer but not a Bobcat. Really good access as there's nothing over top of the engine, Back door opens and then a panel flips up over the engine for even more access. I'll look in the parts book and see if there's a relay that maybe is or has gone bad.

 

[tractormech]

Whatever you find out be very careful if you wind up having to remove the glow plugs. Sometimes they come right out. Sometimes the end will swell up and not want to come out of the hole. If this happens spray a little penetrating oil around the glow plug and get some vise grips on the hex part of the glow plug. Stick a small pry bar or screwdriver under the vise grips so you can GENTLY pry up and GENTLY work the glow plug back and forth. TAKE YOUR TIME! It's NOT a race! It will work the electrode tip down in size and it will come out. GO SLOW! Don't break the electrode off and don't break the hex off of the glow plug- either way and you have problems. If it takes 30 minutes each you're money ahead. This isn't the time for brute force and awkwardness. Again, don't be in a hurry. Finesse it out. Easy does it. You'll get it. Reinstall with a little Nevr-Seez on the threads. Good luck with it!

 

[Bootheal]

My nephew has a smaller, newer tractor. While it was at the dealer, he wanted them to install a block heater. Salesman talked him out of it. “These tractors don’t need anything to start in cold weather!”

Several years later, after having difficulties starting every winter, he found the glow plug fuse - missing! Never installed. New fuse and he’s been a happy camper ever since.

 

[Welder Dave]

Must not be where it can get to -25C and colder. I have dual batteries and below about -15C I wouldn't trust it start without being plugged in. Below -20C it needs the block heater and hyd. oil heater. -30C and it's questionable if it will start even plugged in. Newer direction injection engines start much easier.