D2Cat,
lets look at the big picture once again brother, in his original opening - he said,
"1. Oil & filter change.
2. Gear oil change in the gear box of the mower.
3. New air filter.
4. New radiator cap.
5. Ran tractor without rad cap and looked for bubbles (to check for bad seal or cracked heads) -- no bubbles.
6.
Drained and pulled radiator (last weekend 2/13/15). Blew out fins (not that dirty), soaked it in vinegar overnight, flushed it with distilled water, reinstalled and filled with new coolant (Premix 50/50).
7. Top rad hose gets hot, bottom hose is cold/cool.
And it ran hot........ok - he states the "Whistle blows when I start to mow " this happens quickly - as if a head gasket is doing it.
so - throughout the process, we are under the assumption that it is being pressurized (HG) or water flow is restricted - or.....a bad cap.
New cap.......did not do the job, so either it is bad and the other problem is still there - or the cap is fine.
Now - we are moving into the radiator, hell - this would be the most obvious to me to be the culprit, (my B7100 gets pissy if the grill is clogged) and a new piece of info - this is a thermosyphon system, no pump to push the water through, it has to do slowly at first and then pick up as the heat starts to change.
SO - he took the radiator to the shop and had it cored, and said : "The radiator shop said that it looked pretty good and they didn't see anything wrong."
Now...........
all things back together with
100% water..........
he says.....
Set 2 (after 15 mins of bush hog):
Top hose: 152 deg
Btm hose: 108 deg
Block: 175 deg
so the machine has gone from at least 212 (steaming whistle blowing) to 152 at top of radiator..........
and NO - a diesel should NOT run cool like that - IT IS VEEEEERY bad for it! Now Dave mentioned placing a piece of cardboard over the air flow, this or something similar is done on big rigs that are running at 60 mph it 12 degree weather, so that it will STAY hot. The people who pay for that rig - want it running hot on purpose. Now remember - my idea of hot would be water at 200+ degrees going in top hose.
Now, somewhere - either the cap and NEW radiator and a cleaned out system has improved the situation - dramatically!!!!
Now remember - this is a thermosyphon system, unlike your L305, which has a good ol' thermostat and pump, this type of system the water is
still at idle, the movement - other than the engine shaking the hell out of it, is stationary! Once heat is absorbed, and this happens somewhat slowly, but unlike a forced system, this water starts a slowwwww process to move. In a thermostat system, water sits still UNTIL is gets hot enough to open the stat, and once open, all the water is now flowing freely. This system only moves as fast as convection moves it, so that fact that the radiator is doing a great job - seems to be the answer, or all the pieces of the puzzle have helped.
BUT after 15 minutes - the water still has not reached temps - it needs to get HOT, ok - not 212 - but up there as said before, hot enough so the engine oil burns off the bad stuff. That little 2 banger is gonna need a work load placed on it and roll with the punches!!!
Now - glad as I am that it is cool - the engine should be getting hotter than that - and I think it will, like NIW said - RUN IT!
Run the hell out of it.....but...
stop in the middle of the field, after 30-45 minutes, and write down the temps.
Once you get to your mixture of antifreeze - I think you will see the system get and stay hotter.....and once you see it get there - let it idle back for 10 minutes, and you'll see it come back down to numbers that you got before.
Personally - I'd cut the top hose, insert a temp gauge and then you can have your cake and eat it too! About a $40 peace of mind!
