John Deere 430 Overheats

[Suburban Plowboy]

My old John Deere 430 overheated twice yesterday. Steam came out of the overflow hose. The first time it overheated, I looked on the web for answers, and then I cleaned the grass out of the radiator. I would say it was somewhere around 25% obstructed. I ran the mower again, and it heated up pretty fast.

There is no black stuff in the coolant. It seems normal. I haven't seen any leaks.

I am thinking it may be the thermostat. I can't get a new one right away. I was thinking I should pull the old one anyway, since the manual recommends replacing them after a certain amount of time. Can I get away with running the tractor with no thermostat until a new one arrives? Should be several days, or one mowing job. I want to go out of town, and I don't want my grass to make my house look abandoned and tempting.

I figured it was better to try the thermostat before inviting a local dealer to charge me $3000 to replace the head gasket and do whatever else he feels like doing. It ought to be replaced even if it's not the immediate problem.

 

[Kish318420]

Besides replacing the the T-sat also go with new anit-freeze (50/50 mix) according to the manual. Also check the radiator fins with a brite light source to make sure air can flow through and remove the heat like it suppose too.

 

[Suburban Plowboy]

I must be the happiest man in North America right now.

I removed the thermostat, and the tractor overheated again. I figured I was looking at a new head gasket or water pump. Then it occurred to me that while I had checked the belts, I didn't really know for sure that the belts up front had anything to do with the water pump. I took a look in the dark crevice behind the engine, and I saw that there was a pulley there with no belt.

Now I know why the battery light came on at the same time.

I have to find a belt that fits. I don't know what it's going to be like, trying to get into that hole to install it, but it has to beat paying a mechanic. I also have to reinstall the thermostat. Guess I'll get a new one anyway, if I can get the part number.

Thanks for the tips anyway.

 

[Suburban Plowboy]

I assume this thing is a 3/8" belt, but if anyone wants to correct me, I am ready to listen.

JD price: $24, and that's the cheap Ebay price. Tractor Supply belt: $6.99. Hmm...wonder which one I'll buy.

Now if I can just find a Yanmar thermostat instead of the gold-plated JD version...

 

[beenthere]

Depending on the s/n, one JD belt is $12 and the other $16.

Thermostat is either $33 or $21, also depending on the s/n of your 430.

Didn't see anything about "gold plated".

 

[beenthere]

 

[Suburban Plowboy]

Where are you getting your prices? I'm looking at $34 for a tiny thermostat and gasket right now. If you found the belts that cheap, maybe you know someone who sells thermostats, too.

I got my belt, and I just tried to install it. It looks like you have to remove the driveshaft from the rear of the engine. Someone tell me I'm imagining things. I'm going to look at the service manual, but that hasn't been helpful so far. When I looked for info on the thermostat, the service manual said "see operator manual," and the operator manual doesn't contain the information.

 

[Suburban Plowboy]

I found the instructions for changing the belt. Here they are: "remove fan/alternator belt." The alternator belt is not the fan belt, so that's a little odd.

This tractor is really badly engineered for people who work on it, but surely they don't expect me to remove the driveshaft in order to replace a belt. No one could be that stupid. I mean, okay, they did put the hex for the lever that controls the speed range in a place where it is literally impossible to move it more than 1/8 turn at a time, but surely everything can't be that hard to work on.

 

[beenthere]

Where are you getting your prices?

Through my John Deere dealer, via the jdparts site.
John Deere Parts Catalog

s/n above 5001 shows. Maybe that stands for 50,010 break point at 1989 year.

 

[Suburban Plowboy]

Thanks for the info, but since my dealer isn't your dealer, I guess I'm stuck with $34.

I fixed the tractor. I had a linked belt on my drill press, and I had been meaning to remove it and get a normal belt. The linked belt wasn't particularly helpful for the drill press. Now the linked belt is on the JD, and I didn't have to touch the driveshaft, upper pan, or mower deck. Took me about half an hour, and most of that time was spent wrestling with the links, changing the belt's size to fit.

I want to give a shout-out to whoever installed the thermostat and alternator. Way to go, using the impact wrench on the fasteners. That was totally necessary. Everyone should have to use a breaker bar to loosen an alternator, and I enjoyed the thrill of wondering whether my thermostat bolts would snap inside the housing.

That was a total dealership/manufacturer move. Fasten everything tight so it breaks when the user tries to fix it. That will teach us. They did the same thing to my Softail's oil filter.

I was concerned that the alternator bearings or the water pump might be bad, but the alternator works. I won't know if the water pump is okay until I do some mowing, but it isn't binding. I guess the belt just blew up because it felt like it.

Now I have to find the side cover bolt I dropped on the mower deck.

I hope to visit Tokyo one day and egg the house of the engineer responsible for this atrocious design. I have heard that Ferraris have problems like this, but you expect to be able to work on a lawnmower.