Kubota v1505 overheating

[MrFritsch]

It came with a mechanical fan. I put the electric fan on the new radiator because the shroud wouldn’t fit the new radiator

 

[mike holcomb]

It came with a mechanical fan. I put the electric fan on the new radiator because the shroud wouldn’t fit the new radiator

I think u just answered your own question. No shroud.

 

[chidog]

If after the airflow through the radiator is fixed. And it still over heats take that bypass hose off and block the ports.

 

[Simon C]

The engine was broke in with 15-40 oil and let at a high idle for 45 minutes. The head was pressure tested and valve guides replaced at the machine shop. I ended up buying a replacement head because it was still overheating and still have the same issues. What are you asking was plastic or metal? The head gasket was the 2 piece metal

Never put an engine to high idle and leave it there unless heavily loaded. Better to use light load and slowly increase load while varying the engine speed. Up and down on RPM is better and tends to prevent cylinder glazing and subsequent blow-bye. Sometimes it will clear with load afterwards.
Just what I have done too many times to count.
Simon C

 

[MrFritsch]

Never put an engine to high idle and leave it there unless heavily loaded. Better to use light load and slowly increase load while varying the engine speed. Up and down on RPM is better and tends to prevent cylinder glazing and subsequent blow-bye. Sometimes it will clear with load afterwards.
Just what I have done too many times to count.
Simon C

What are your thoughts on break in oil? One I get the overheating fixed I plan on replacing the rings and honing the cylinders then do a proper break in

 

[HarleyHappy]

I still like to use a straight 30w oil for diesels for break in.
I try and use a non-detergent oil, if available.
I have used a 10/30 or 10/40 but notice more oil pressure loss after break in using those oils.
Think that’s a personal opinion but I do watch that oil pressure closely.

 

[Tinkerer]

Did you verify that the new head gasket matched all of the passages in the block and the head ?
Especially the size of the coolant passages.
Fuel injection timing set correctly ?
The blow-by is a cause for concern. Has the head been manga-fluxed for leaks ?
Is there any solder bloom on the radiator tubes ?

 

[MrFritsch]

New head gasket was perfect match. The old head was pressure tested and passed. I got a new head anyhow after I still had problems. Tonight, new rad and thermostat installed. I confirmed the rad is cooling. Thermostat housing 210+, top rad 200, bottom rad 170-175, the same hose going into the water pump is 195 an inch before the thermostat. Had the temp gauge about red lined when tracking 50 feet back and forth a few times after I let it warm up.

 

[MrFritsch]

The timing on this Kubota uses shims under the pump, when I put the pump back in I used the same shims it had previously. I’m not sure how to check timing on these engines

 

[MrFritsch]

When temping near each injector when it’s running, one cylinder is 20-30F hotter then the others. It has new injectors

 

[chidog]

And what is the temp for the thermostat? 180?
And what about the by pass hose? Turn that off for this test.

By pass does just that by passes the themostat/ radiator for warm up.

So try a 160 thermostat, if the radiator is working then?

I say there is just too much bypass volume happening.

Timing what fuel pump?
I thought all the fuel timing, not over fueling etc was all sorted?

 

[MrFritsch]

Thermostat rating is 180. Timing the injection pump I meant. I’ll pinch off the bypass tomorrow and give it a try

 

[davejo]

Drill down on the reason there are multiple water pumps available from which to choose. I see that your 4 cylinder kubota uses the same water pump as a 3 cylinder motor d905. 1000cc motor vs 1500cc

Quite possible you have the wrong pump or pulley diameter so try a different combination. You can't assume the bigger 70mm impeller pump is better in all cases. maybe the pumps are different heights or displacements. maybe your pulley is turning your big impeller too fast or slow for the design of the housing etc etc.


Try oem parts, assuming you are using aftermarket.

Timing pump is matter of turning the engine over by hand to different marks on the flywheel and watch for fuel welling up into the pump outlets. find a manual online or utube etc

 

[MrFritsch]

I’ll do some research tonight on the water pumps. The pulley is OEM. I’ll watch a video on the pump timing as well

 

[MrFritsch]

It’s a v1505ka if that narrows it down with your information

 

[Tinkerer]

Here are the details of your water pump.
It doesn't appear that the impeller could be pressed on backwards or could it ???
When you checked the impeller how tight is it on the shaft ? Could it be slipping at engine operating temperature?
Fan belts can develop a glaze on them and slip. I have seen it happen and they didn't even smoke or stink.
Have you tested the thermostat in hot water to see what temperature it is opening-if it is opening at all.
The fuel injection pump timing isn't set with shims that I can see. Or were you referring to the mechanical lift pump ?
Strangely the camshaft for the fuel injection pump is mounted in the engine block.

 

[chidog]

So its just an old mechanical style multiple jerk pump? If so its a drip timing deal.

Will the machine move okay with very little engine speed and low throttle position?

Seems to heat more and faster with machine movement, are the brakes applied, even if it says they are not? Does if feel like the machine puts undue load on the engine?

 

[MrFritsch]

The impeller appeared to be in the push not scoop orientation and was tight on the shaft. The belt is new and pretty tight, I didn’t notice any slipping. I was referring to the fuel injection pump timing for adjusting with shims. This engine doesn’t have the cam for a mechanical lift pump, so it has an electric lift pump. The machine has good power at all throttle levels. It has a light color smog when full throttle digging but not heavy. It heats up faster when machine moving, there’s no brakes on the machine. Then the muffler is off it seems like it uses a ton of energy to move the machine but put the exhaust back on and it seems to operate normally besides the overheating and blow by

 

[MrFritsch]

Would a 60mm impeller vs a 70mm cause the coolant to back flow or not flow properly? When I had it apart I believe the casting was 80 or so mm and the impeller machined area was about 70, the extra 10 was for water flow by the shape of the casting

 

[MrFritsch]

The motor was bastardized before me, so any part may not be original or was tampered with. It had all this issues prior to any machine shop work