H1502 Bolens Iseki still overheating

   / H1502 Bolens Iseki still overheating #1  

amanda11270

Silver Member
Joined
Nov 18, 2010
Messages
111
Location
Pennsylvania
Tractor
Bolens Iseki H1502
I flushed my radiator real good over the summer, and I haven't used the tractor much, as my smaller tractor cuts a little better. But my smaller tractor cant move the snow like my Bolens, im prepping it for the winter, and decided to investigate this oveheating further (It overheats after I run it for a long while and the temp light comes on). I had the thermostat out, and put it in some hot water, and it opens not too long before boiling like 190 F which seems normal to me. However, I ran the tractor for 1 1/2 hrs and drove the tractor around my yard up and down hills, and I can still pull the radiator cap off and no antifreeze seems to be circulating. If im not mistaking, with the radiator cap off, shouldn't the water pump push coolant overflowing out of the radiator once the thermostat opens? Im guessing my impeller may be rusted away or something at this point.
 
   / H1502 Bolens Iseki still overheating #2  
My Yanmars hot light comes on everytime I use it. Serviced the radiator and all that and the light still came on. Later I learned on TBN that Yanmar temp sensors over time start coming on prematurely as they wear.

Whats your anti-freeze mixture? Too much anti-freeze in the mix could cause over-heating.

A leaky old radiator cap can depressurize the cooling system and cause lower boiling points.

Maybe use a thermometer next time the light comes on and check the radiator temp.
 
   / H1502 Bolens Iseki still overheating #3  
From my experience ,the only time I had high temp was when it was 90 degrees outside or the radiator was being restricted from clippings or just weeds getting in the screen in the front that protects the radiator . Cooler weather should be good enough to keep it from overheating . If possible take a high pressure air hose and blow all debris from the radiator from the front after you remove the screen .The light has never come on while I was plowing snow ,if you still experience this after you cleaned the radiator then start looking elsewhere for a cause . How many hours are on the hourmeter . Mine has 675 hours and as long as you treat it right it will last longer than your desire to plow snow.
 
   / H1502 Bolens Iseki still overheating
  • Thread Starter
#4  
Mine overheats or at least the temp light comes on when I use it to mow grass, and also the temp light has been coming on towards the end of my plowing the end of last season.

I used to fix restaurant equipment, and I have a really good digital liquid thermometer. Correct me if im wrong, but if the water pump was not circulating coolant the radiator wouldn't get hot real fast would it? I was trying to determine when the tstat opened, and the radiator seemed to get hot so that would mean its circulating right? The temp never went above 178 at the top of the radiator in the cap. Maybe the temp light is wearing out?
 
   / H1502 Bolens Iseki still overheating #5  
If the engine is not hot the stat won`t allow for much movement in rad . .
These small tractors seem to overheat , but as long as you don`t abuse them they cool down without damage
from what I have experienced But a good diesel needs heat for good combustion , so a high operating temperature is necessary ,to operate efficiently .Though the light should not be on during operation normally . And yes to your question ,the temp of coolant from tstat to rad would be hot as soon as it was released slowly to be cooled by rad. Eventually the whole system would be hot ,but still be within the temp zone that would be contolled by the tsat and radiator .You will start to have movement in radiator ,but will see much more when operating temp is reached..
 
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   / H1502 Bolens Iseki still overheating #6  
:2cents:I just got an idea ,try this out to see if it provides any results. Use a lower gear ,or increase the rpm`s , or both . Which in turn would make the engine build less heat ,. Which may be the reason for your overheating. I know from driving trucks in high outside temperatures , over hills/mountains , we used a lower gear to keep rpm`s up to make the engines work easier ,which in turn made it less prone to overheating . I believe this is the factor you might need to pursue . I know it does work. I believe you are working the engine too hard for the cooling capacity ,this could solve your problem .Increase rpm`s , or use lower gear with high rpm , not over red dot on tack though.
 
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   / H1502 Bolens Iseki still overheating #7  
A couple things to keep in mind:

1.) The water pump pulls from the bottom of the radiator and discharges out to the top of the radiator from the cylinder head. Use a temp gun to compare the bottom and top hose temps. If you're not getting circulation, the bottom hose will be close to ambient air temp.

2.) Your temp switch in the cylinder head is designed to close around 230°F. This can be tested by imersing in oil (vegetable, motor, etc.) and using a candy thermometer (or equivalent) to monitor the oil temp as it's heated on your stove or other heat source. Connect a continuity tester to switch, one lead to anywhere on the case, and the other lead to the wire connection. Watch the thermometer temp and note it when the switch closes indicated by the continuity tester. If the switch doesn't close after 250°F then stop heating the oil and replace the switch (not the problem for this thread obviously).

3.) Remember that the water pump and fan are on the same pulley. It's possible your belt can be loose, causing both the fan and pump to turn slower than they should, reducing cooling.

External radiator plugging, as mentioned, is the most prevalent cause from my experience.
 
   / H1502 Bolens Iseki still overheating #8  
I flushed my radiator real good over the summer, and I haven't used the tractor much, as my smaller tractor cuts a little better. But my smaller tractor cant move the snow like my Bolens, im prepping it for the winter, and decided to investigate this oveheating further (It overheats after I run it for a long while and the temp light comes on). I had the thermostat out, and put it in some hot water, and it opens not too long before boiling like 190 F which seems normal to me. However, I ran the tractor for 1 1/2 hrs and drove the tractor around my yard up and down hills, and I can still pull the radiator cap off and no antifreeze seems to be circulating. If im not mistaking, with the radiator cap off, shouldn't the water pump push coolant overflowing out of the radiator once the thermostat opens? Im guessing my impeller may be rusted away or something at this point.

My Bolens G174 tried a similar tactic last spring with the overheat light coming on intermittently. A new sender was unavailable in North America, but a vendor in California sent me a Yanmar sensor which he thought would do. it wouldn't. Different threads. So I put the old one back in and it hasn't complained since.

As interim steps I also replaced the coolant and fan belt. That didn't help the overheat light, but the tractor now has a new fan belt and good coolant. BTW there is a space to wiggle a new fan belt in under the radiator. The fan belt job wasn't bad.

I also bought a laser thermometer. The surprise was that most parts of the engine ran fairly cool, but there was a hot spot right at the temp sensor in the front, left hand corner of the engine. I speculated about a foreign object blocking water flow. My son suggested an air bubble, so I eased the temp gauge out while the engine was warm and then re-tightened it.

I don't know it there was any air trapped, but the engine's run fine ever since.
 
   / H1502 Bolens Iseki still overheating #9  
My Bolens G174 tried a similar tactic last spring with the overheat light coming on intermittently.

I bought a laser thermometer. The surprise was that most parts of the engine ran fairly cool, but there was a hot spot right at the temp sensor in the front, left hand corner of the engine. I speculated about a foreign object blocking water flow. My son suggested an air bubble, so I eased the temp sender out while the engine was warm and then re-tightened it.

I don't know if there was any air trapped, but the engine's run fine ever since.

Today the Bolens was well warmed up and I tried the laser thermometer on various parts of the engine again. After releasing any potential air bubbles by loosening the temp sender, the hot spot has largely disappeared. Before I was reading 235 F around the sensor. Now it's more like 200 to 205 F. Other temps range from 99 F to 185, but I think checking for an air bubble was a good idea in this case.
 
   / H1502 Bolens Iseki still overheating #10  
Interesting share, I'm glad you found it. I wonder if just driving up a steep hill would also let it travel out of the head and to the radiator to be expelled (?)
 
 
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