(quoted from post at 18:34:03 09/04/15) what does the temperature gauge usualy run on the mf 35 gas motor with a 5 foot bushhog.mine was at about 230 but never sounded like it was boiling or anything.running that temp sorta scared me.was it way to hot if so where should it run.
As others have already mentioned, thermostat regulates the minimum temp, and the radiator then allows the heated fluid from the motor in the cooling system to exchange heat, and return fluid cooler to enable it to absorb heat once again from the engine.
If the rad is not externally blocked up with mud, dust, and bits of plant material, then its most likely blocked up internally.
First, check through the core externally, with front grill/ screen removed, is the core in sound shape, or has the fins between the tubes (where the water runs) corroded or dissolved away.
If all ok externally, I would suggest the following.
First remove the radiator, and as others have suggested, replace the thermostat whilst you do.
With the hose, back flush from the bottom outlet so the water flows up thru the rad, and out the top outlet.
Watch as best you can via the rad cap top if all or none of the tubes are moving water, this can give you a good indication of how well they are blocked/ unblocked.
Remove hose and observe how quickly the water comes back out the lower outlet.
Try this a few times, and see if the tubes that were not flowing well improve.
Also observe what comes out the top outlet.
Ok
Now, get an inner brake/ gearshift cable from a push bike, and gently put it in each tube whilst the water is flowing up from the bottom outlet, this will move most debrits that are not moved with the back flush of water.
I say gently for a reason.
Rad shops take the top or bottom tank off, and "rod" the tubes with thin steel strips a bit smaller than the tubes, your doing the same thing, but without removing the tank.
With some patience and determination, you should be able to do all the tubes, or nearly all of them this way.
Ok now next step.
I mix up in a bucket about 2 heaped teaspoons of citric acid powder (food isle in the supermarket maybe near the baking soda, bicarb soda, tartaric acid etc), and dissolve it all up in some hot water.
Lay the radiator down flat, put the rad cap in, and fill the rad with this hot solution, try and cap the outlets, ie rubber gloves and rubber bands, and then slosh the solution top to bottom till your arms get tired.
Then rest, have a cup of tea, and try again, and again.
Leave this solution for 30min or so, you may see bubbles as soon as you fill the rad, other times not much, but either way, let the weak acid work on the scale and buildup.
Once your arms are trembling, and you have had enough sloshing the rad gently side to side, empty, and rinse, again with the hose on the lower outlet, and use the inner brake cable wire to "rod" the tubes once more.
By now the inside of the radiator should look much cleaner, and if you had any difficult tubes that would not be rodded with the cable, they may now yeild and allow the blockage to be cleared.
Often this will dislodge large amounts of scale, and at the very least, removes the coating of scale that insulates and reduces heat transfer of the core.
After you have also flushed the block from lower rad hose, and drained the block via the drain cock/ tap, put everything back together and refill with your chosen antifreeze/ boil/ anti corrosion mix, check for leaks, and you should be good to go.
This is often a better solution than having the tanks removed at a rad shop if your a long way from such a place.
Yes, this is exactly how I did my 35, and many other vehicles for that matter with very good results.
If the core is damaged, then just go ahead and replace, but if its sound, this will certainly help with any blocked rad core.
Also make sure the fan is on the correct way, not the first time ive seen one fitted to blow air towards the front hehe.
Let us know how you get on.
Trains
