BX25 smoking white

2012BX25

New member

Equipment
Kubota bx25
Jul 5, 2021
4
0
1
Wheeling, WV
2012 Bx25 smoking white and has a knock.
While cutting grass tractor started to smoke white, knock and has a loss of power. Tractor i notice was running hot. took it to the garage and started to look into the problem. drained the oil didnt find any metal shavings in the oil. Pulled the head and found that the #3 piston was white and so was the valves. so i replaced the head gasket thinking it might have blown the head gasket. and adjust the valves and still smoking with and knocking.
 

BigG

Well-known member

Equipment
l2501, FEL, BB, Rotary cutter, rake,spreader, roller, etc. New Holland TL80 A
Sep 14, 2018
1,951
769
113
West Central,FL
Maybe the injector is bad. My diesel truck has done this 2 different times with a bad injector.
 

BigG

Well-known member

Equipment
l2501, FEL, BB, Rotary cutter, rake,spreader, roller, etc. New Holland TL80 A
Sep 14, 2018
1,951
769
113
West Central,FL
Wolfman says not to use the aftermarket replacements but he did have a source for rebuilt ones. I will see if I can fine the info for you.
 

BigG

Well-known member

Equipment
l2501, FEL, BB, Rotary cutter, rake,spreader, roller, etc. New Holland TL80 A
Sep 14, 2018
1,951
769
113
West Central,FL


This thread might help you.
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex., Beer fridge
May 24, 2019
5,721
2,916
113
North of Pittsburgh PA
2012 Bx25 smoking white and has a knock.
While cutting grass tractor started to smoke white, knock and has a loss of power. Tractor i notice was running hot. took it to the garage and started to look into the problem. drained the oil didnt find any metal shavings in the oil. Pulled the head and found that the #3 piston was white and so was the valves. so i replaced the head gasket thinking it might have blown the head gasket. and adjust the valves and still smoking with and knocking.
Is coolant level changing? If you start it cold and look in the radiator, do you see any bubbles? Possible you could have a cracked head that you did not notice when you changed the head gasket...

Just a couple thoughts from a NON mechanic...
 

2012BX25

New member

Equipment
Kubota bx25
Jul 5, 2021
4
0
1
Wheeling, WV
Maybe the injector is bad. My diesel truck has done this 2 different times with a bad injector.
All the injectors are good. I had the tractor idling and cracked each injector line and it would start losing power until I tightened the line back up. I was reading and found that the most common place for the head to crack is between the valves. Before i re-installed the head i die check the head for cracks and didnt see anything.
 

Whatscooking

Active member

Equipment
Grand L 3130. BX2360. RTV900. GRASSHOPPER 721D
May 19, 2021
124
64
28
Indiana
I am retired as a fleet mechanic, which means nothing.
Strike one, you said mowing along and started knocking lost power and ran hot, water/ coolant doesnt like to be compressed. Strike two you said took the head off and found a white piston, sure sign of trying to burn coolant, if it was overfueling it would be sooty black. I hope you prove me wrong but you got a crack letting coolant in where you cannot see.
 
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2012BX25

New member

Equipment
Kubota bx25
Jul 5, 2021
4
0
1
Wheeling, WV
I am retired as a fleet mechanic, which means nothing.
Strike one, you said mowing along and started knocking lost power and ran hot, water/ coolant doesnt like to be compressed. Strike two you said took the head off and found a white piston, sure sign of trying to burn coolant, if it was overfueling it would be sooty black. I hope you prove me wrong but you got a crack letting coolant in where you cannot see.
So, i took off the exhaust manifold to see which cylinder is smoking. I found that its the front cylinder #3 that smoking. I went and asked a diesel mechanic about it and he told me to try and drain all the coolant out of the engine and start it. If it quits smoking you have a coolant leak if it still smokes theres another problem. So i drained the coolant and it still smokes out of cylinder #3. i only let it run for about 20 seconds.
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex., Beer fridge
May 24, 2019
5,721
2,916
113
North of Pittsburgh PA
So, i took off the exhaust manifold to see which cylinder is smoking. I found that its the front cylinder #3 that smoking. I went and asked a diesel mechanic about it and he told me to try and drain all the coolant out of the engine and start it. If it quits smoking you have a coolant leak if it still smokes theres another problem. So i drained the coolant and it still smokes out of cylinder #3. i only let it run for about 20 seconds.
That is interesting.

Perhaps try again a couple times over the next couple days(for the same short time) to make sure the coolant is all gone from inside the engine?
 

eserv

Well-known member

Equipment
BX24, A1000 Kubota Generator
May 27, 2009
2,140
139
63
Hardisty, Alberta
Either it is burning coolant or you have raw fuel from the exhaust. It is time for a compression test and a cylinder leakdown test.
 
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lmichael

Well-known member

Equipment
Kubota G2160
Apr 23, 2021
600
253
63
Rockford IL area
If there is/was coolant getting into the cylinder a 20 second run will likely not burn it off enough to see evidence of it stopping the smoke