JD 650 Overheating - 521 hours - thermostat replace?

[Capricious]

"...would it potentially help if I started by flushing the radiator..."


Wouldn't hurt. How long as the old coolant been in there? Catch it as it drains out and see what comes out with it.

Get some flushing stuff from the auto parts store and follow the directions.

 

[Capricious]

"...On the latter, Jerry/MT, how would I know this? Fan is running, fins are clean, etc. I'm not probably familiar enough to understand what you mean..."



He means make sure the element in the air cleaner is not all plugged-up. If it is old, wouldn't hurt to replace it anyway.

 

[Edensgardener]

Roger on both Capricious - thanks. I'll look up where the air cleaner is - I think I know - it's the round barrel shaped thing with the air filter in it, right?

And honestly, I can't recall if the radiator has been flushed in the 200 hours since I've had it.

 

[Capricious]

"..I can't recall if the radiator has been flushed in the 200 hours since I've had it..."


How many years have you had it?





"...air cleaner is - I think I know - it's the round barrel shaped thing with the air filter in it, right?..."


Sounds right.

 

[arrow]

First simple job is to make sure you have a good seat on the thermostat housing so as to not be leaking out of there. Second simple job is too have the radiator professionally cleaned. Taking it out is not as nightmarish and is rather a straight forward job. These small Yanmars had a rather annoying idiosyncrasy. When they overheat, they tend to blow head gaskets. How do you know if you've done that? 1. steam coming out of your stack or 2. Mysterious disappearance of coolant with no visible leak. After the radiator, the second culprit could be the water pump is shot. Fortunately radiators, head gaskets and water pumps are still available for this model. These engines also blow oil pumps but that as well is a simple job. You need to make sure your oil pressure idiot light bulb is still functional when you turn your key on just before "start" position or else you'll have nothing else to tell you of an oiling problem.

 

[Capricious]

"...they tend to blow head gaskets. How do you know if you've done that? 1. steam coming out of your stack or 2. Mysterious disappearance of coolant with no visible leak..."





With the engine cold, you might also look for bubbles/gasses in the radiator, with the cap off.

 

[Rock knocker]

Time to bite the bullet. Pull and have the radiator boiled and cleaned, and price a new water pump. The impellers could be worn. Also pressure test the system to make sure the head is OK

 

[Capricious]

My inclination would be to go ahead and try the do-it-yourself flush, before pulling the radiator.

It MIGHT cure the problem. And if it doesn't, it will at least clean some of the crud out of the water jackets.

If you just pull the radiator and have it cleaned, crud remaining in the engine might flow right back into the
radiator and plug it again.

While flushing, i would drain by removing hoses, not just opening petcocks.

 

[Rock knocker]

I don't know the 650, and have never pulled the radiator on my 950, but it certainly looks simple.

 

[Edensgardener]

Well, this was not how I had planned to spend the afternoon - but so be it. Just got back from auto store with flush and 50/50 coolant. I've had it a few years, only put 200 hours on it since I've had it. Used to have a tractor shop in town and they serviced it once for me, I think oil change/flush. But yes, that's been 2 years ago. I don't use it a lot - so that's my excuse for not doing all of this stuff to it annually. That, and I just didn't really realize it needed it so much with such little use.

I hope it's all just needing a flush - no, no signs yet of a blown head gasket - thankfully. It has run like a champ up till last week so I'm hoping it's just over due for what should have been some rainy day preventative stuff.

You all are awesome for chiming in! Thanks a bunch! I'll let you know how it goes.