743 cooling system

[misplacedplowboy]

I have been running my 743B at 3/4 throttle for the first couple of weeks that I have had it and no problems. This weekend I needed to run it wide open for digging matted horse manure and twenty minutes after doing so I strarted to boil the antifreeze, and it was shooting out of the fill bottle cap like a squirt gun. When I had it stopped I could hear the air gurgling through the system but took off the radiator cap(after it cooled) and it was full. I first dumped the antifreeze and that came out green and clean. I then removed the thermostat and tested it and right on cue at 190 degrees farenheit it opened up. Then I stuck my finger in the radiator and found what I didn't want white chunky slime. Is there any thing else that could be causing this skidder to overheat? I found a new oem replacement at Dillon Radiator in Rochester,MN for $316 and I will have that tomorrow. but to make matters worse the service manual says to pull out the muffler in order to get the radiator out and that is rusted solid to the muffler extension flex pipe. Bobcat wants over $500 for a muffler and $125 for a new flex pipe, any cost saving ideas? I found an extension pipe on ebay for $30 for a s130 that looks idetical to the one I need but does anybody know if it will fit?

 

[Tazza]

Some times giving it a little heat and tapping with a hammer can free the rust up. As for the pipe, the 743 and S130 have different engine directions, i would seriously doubt they would be the same angle and lengths, sorry.

 

[mrfixitpaul]

Have you checked that the underside of the radiator isn't plugged? You have to remove the cover(s) above the engine to clean out. Also could be a stuck thermostat causing overheating. Since you've been running it a while, I figure you can rule out the possibility of gasoline being in the fuel.

 

[misplacedplowboy]

Have you checked that the underside of the radiator isn't plugged? You have to remove the cover(s) above the engine to clean out. Also could be a stuck thermostat causing overheating. Since you've been running it a while, I figure you can rule out the possibility of gasoline being in the fuel.

mrfixitpaul i have only put 20 hours on it so far and the tank was topped off when i bought it but the day before this happened i bought 2 new cans only to be used for diesel for the skidder and dumped one of them in. i will double check that they didnt screw up at the station and mix gas in the diesel pump. As far as the radiator goes it is dirty but not built up. I went to napa to get a new thermostat on saturday but they did not carry one for it and of course bobcat was not open past noon. They told me to put it in a pan of water and heat it up until it gets to 190 degrees and it opened up on cue. then i took it out and blew on it and it closed. did this again and it was working perfectly. I am confused about the fuel gauge though when i topped off the tank it was reading 3/4 full after 1/2 hour of use it was down to 1/4 tank this is what auctually got me to stop and check things out.

 

[Tazza]

mrfixitpaul i have only put 20 hours on it so far and the tank was topped off when i bought it but the day before this happened i bought 2 new cans only to be used for diesel for the skidder and dumped one of them in. i will double check that they didnt screw up at the station and mix gas in the diesel pump. As far as the radiator goes it is dirty but not built up. I went to napa to get a new thermostat on saturday but they did not carry one for it and of course bobcat was not open past noon. They told me to put it in a pan of water and heat it up until it gets to 190 degrees and it opened up on cue. then i took it out and blew on it and it closed. did this again and it was working perfectly. I am confused about the fuel gauge though when i topped off the tank it was reading 3/4 full after 1/2 hour of use it was down to 1/4 tank this is what auctually got me to stop and check things out.

The fuel gauge is NEVER rite, i bought a new one and a full tank showed as being 3/4 full, even with a new gauge and sender. If you are happy the thermostat was opening and closing correctly it should be ok. The only other thing it could be is your water pump impeller. If the fins have rusted off you won't be pushing coolant around.

 

[misplacedplowboy]

The fuel gauge is NEVER rite, i bought a new one and a full tank showed as being 3/4 full, even with a new gauge and sender. If you are happy the thermostat was opening and closing correctly it should be ok. The only other thing it could be is your water pump impeller. If the fins have rusted off you won't be pushing coolant around.

Sounds like the fuel gauge on all three of my semi's. I had to go by the miles not what it showed me. I have this much ripped apart why not open up the pump too. Its cheaper to fix it than the motor! with as much build up as I saw in the radiator it wouldnt surprise me to see the fins rusted on the pump. Thats one thing that I have checked every time I have the oil changed in the truck is the acidity of the coolant and too many people dont realize what it can do.

 

[Tazza]

Sounds like the fuel gauge on all three of my semi's. I had to go by the miles not what it showed me. I have this much ripped apart why not open up the pump too. Its cheaper to fix it than the motor! with as much build up as I saw in the radiator it wouldnt surprise me to see the fins rusted on the pump. Thats one thing that I have checked every time I have the oil changed in the truck is the acidity of the coolant and too many people dont realize what it can do.

True, it will cost you some silicone when you put it back on, thats all. A new pump is about $120 or so if you need to replace it. Then at least you know your entire cooling system is spot on.

 

[misplacedplowboy]

True, it will cost you some silicone when you put it back on, thats all. A new pump is about $120 or so if you need to replace it. Then at least you know your entire cooling system is spot on.

What type of silocone do you have the best luck with? I have always used gaskets.

 

[Tazza]

What type of silocone do you have the best luck with? I have always used gaskets.

I got a pile of high temp silicone that some times come with gasket kits for car engines. My dad used to work in that industry and got heaps of them. If you buy a new pump it should have a gasket. This silicone can handle higher temperatures, in the order of 200C, has yet to fail on me.

 

[Garauld]

JC Whitney has a decent selection of SST flexible pipes for $30 or so. A local auto parts store may also have what you need.

 

[misplacedplowboy]

JC Whitney has a decent selection of SST flexible pipes for $30 or so. A local auto parts store may also have what you need.

Anybody have a good idea for the muffler? $500 plus is a joke for it! I understand paying top dollar for quality parts but come on does bobcat think were made of money!

 

[Tazza]

Anybody have a good idea for the muffler? $500 plus is a joke for it! I understand paying top dollar for quality parts but come on does bobcat think were made of money!

Give Mark from IM bobcat in Utah a call, hopefully he can help you out a bit there. That price sounds like what they charge from my local dealer in Australia!
Now, defending my dealer a bit here.... I got a price on the muffler from my local dealer and from a muffler shop for the exact same item. The dealer was actually a bit cheaper then the muffler shop, and that was him really looking after me!. It was a Donaldson muffler for a later model machine though, the 743 runs a Nelson.

 

[skidsteer.ca]

Give Mark from IM bobcat in Utah a call, hopefully he can help you out a bit there. That price sounds like what they charge from my local dealer in Australia!
Now, defending my dealer a bit here.... I got a price on the muffler from my local dealer and from a muffler shop for the exact same item. The dealer was actually a bit cheaper then the muffler shop, and that was him really looking after me!. It was a Donaldson muffler for a later model machine though, the 743 runs a Nelson.

I don't like the spiral wound flex pipe for exhaust, unless you can get stainless, the steel variety rust out to quick and leaks severely.
I have never done it for a skid but on our larger equipment we have had pipe bent up or bought elbows and cut them to the correct angle to fab up exhaust for the float truck (ford was 2200.00, we made ours for 600 worth of parts and a days welding. and for the skidders.
I also did one for the 16 hp onan in our miller welder, 300.00 for a new muffler, I just cut it open and built one from a couple different diameters of pipe with the same design. I had to drill alot of hole in the inner pipe to make a baffle, but 10 years later its still going.
Do call a few different dealers as prices on oem parts do vary alot. I have had good luck with www.BarronSupplyco.com in Barron Wi
Ken