Overheating problem

[Rich Waugh]

A couple weeks ago, I was mowing the orchards and the tractor overheated and blew steam all over. The **** regulator fuse had blown fifteen minutes earlier so I had no gauges and took a chance dumb, I know. Okay, I shut it down and cooled it off and added water to get back to the shop where refilled with fresh coolant. Started and ran fine. Then a major oil leak cropped up and I put the water thing out of my mind again, dumb.

I was mowing a few days back and thought it was running a hair warm. Stopped and cleaned the chaff screen and it cooled back to 80-85C and was fine. When I got back to the shop it was a gallon low on coolant and I could see where it had been peeing out the overflow. Topped it up and watched for oil, bubbles, etc. Looked okay. Developed a burst of delayed conscientiousness and torqued the head bolts - all seemed to take very little additional movement to get up to the recommended 125 #/ft.

Mowed again a day or two later and it got warm again. I was done so I just brought it in and put off the checking until the next day. It was down a half gallon. This time I topped it up and brought it up to heat until the 'stat opened and I could see flow. Flow was good. I could also see, when I first took the cap off, foamy coolant in the radiator neck. Blew the suds off like a fresh beer and watched a while - good flow, but it looked like the water is lightly "carbonated." Capped it off with my palm but couldn't feel any pressure building. Still, it shouldn't look carbonated, should it? I don't beans from barleycorn about diesel coolant or cooling systems, obviously.

No prominent signs of water burning, other than a slight bluish-white exhaust vapor during acceleration, particularly when cold. I do feel like the engine has somewhat less power than it did last month. Had to run some hills one gear lower than before, but that could be grass density, too. Still, seemed a mite wimpy to me for an engine purported to be 30 hp, but once again I have no real experience to draw on here. I did the injector checking thing and all produced the same drop when cracked, FWIW.

I'm coming to the conclusion that I may have a leaking head gasket. The initial overheating incident happened at about 80 hours, before the head was ever re-torqued and maybe that could have damaged the gasket? I could use some inspiration here from those who are rless ignorant than I am (that would be almost everyone).

I'm not intimidated by pulling the head and replacing the gasket after splitting the whole blasted thing in two a week ago. I'd take the head to my machinist buddy and have him check it for flat too, if I should. The "spare parts" kit has a new head gasket. I don't want to do it, of course, but if I should I will.

There it is, to the best of my ability to describe it. What do you guys have to offer in the way of guidance? I need this thing running right and dependably. Anything else I should check or look at? I'm limited on diagnostic equipment - no compression tester for diesels, no leak-down tester for the radiator or combustion chambers, no combustion gas detector, etc; just wrenches and stubbornness.

I picked up a new Delco 12Si alternator for it that I'll get around to soon, I hope. Still need to get a new fuse block first - I ain't impressed with the Chinese one at all. That problem with the regulator fuse has caused me too many headaches and I gotta fix all that crap right and be done with it so I can believe my gauges and not screw something else up.

Thanks in advance for your input! That痴 if you're still actually awake after trying to read this magnum opus.

Rich

 

[greg_g]

I'm coming to the conclusion that I may have a leaking head gasket. The initial overheating incident happened at about 80 hours, before the head was ever re-torqued and maybe that could have damaged the gasket?

Fair conclusion, especially considering that conventional wisdom recommends retorquing the head gasket and setting valve lash at 50 hours. After all that overheating, just hope all you find is a bad gasket.

The bubbles you're observing through the filler neck by the way, are most typically caused by exhaust gases leaking into the cooling system. And the blue-white observation suggests oil (blue) and water (white) getting into the exhaust manifold.

//greg//

 

[Grommit]

I understand what you are saying regarding the water loss. My 30hp Siromer went fine for the first 2 years then started to overheat regularly, the electrical gauges being totally crap were my first thought (they have since broken and been replaced with mechanicals) but I also suffered water loss out the overflow. I changed the radiator cap, no change. Removed the thermostat, no change. I had been regularly blowing seeds and stuff out of the radiator and thought it was OK but removed it anyway and washed all the fins though and flushed it out, finally it stopped over heating (except when flail mowing in 30 degrees C which I forgive it)

Before pulling the head etc. remove the rad, clean inside and out with a low pressure hose and refit. Its worth a try as it's simple to do and there is no parts expense!!

 

[Bob Rooks]

Carry on Rich, your literary competency is very refreshing. :thumbsup:
You should also consider installing a coolant recovery cannister. This will assist you in determining if you are loosing coolant through expansion only (they are also a great aid in de-aerating the cooling system). The "carbonation" you are witnessing could also be from cavitation around cylinder liners or air entrapment from plugged or restricted coolant passages.
When you capped off the radiator with your hand did you remember to plug the overflow also? (just checking ).

 

[Rich Waugh]

Thanks, Bob. Uhhhhhh...no. I didn't think to close off the overflow tube, blast it. That was dumb. Have to try that again the right way, huh?

The coolant recovery canister is on the way. I'll get it put on if I can find a spot for it. It may be a mite too big to fit comfortably, though. Won't know until it gets here. For a temporary check of the concept I could just use a 20 oz Dasani water bottle and a hose clamp, I suppose. Nice and clear, too. I have an inexhaustible supply of them, too - should have thought of that before I bought one. Too quickly I get older, too slowly I get smarter.

I doubt that I have any blocked coolant passages, but it is possible. Only 100 hrs on the thing and I did flush it all out when new and again when it overheated. Doesn't cost anything but time to do it again, though. Might be core sand or someone's stale won ton in there somewhere.

What causes cavitation around cylinder liners? Is that something I can affect, or is it one of those shrug your shoulders and hope things? Over my pay grade, I think, but it never hurts to learn something new.

Thanks for keeping me straight here.

Rich

 

[Bob Rooks]

For a temporary check of the concept I could just use a 20 oz Dasani water bottle and a hose clamp, I suppose.
That will work just fine for a test.

I doubt that I have any blocked coolant passages, but it is possible.
Yes. I have had to do re-works and found gasket fragments, rags, tools, etc. left in engines.

Only 100 hrs on the thing and I did flush it all out when new and again when it overheated. Doesn't cost anything but time to do it again, though. Might be core sand or someone's stale won ton in there somewhere.
:laughing: If you haven't had the engine apart, then another shouldn't be necessary at this time.

What causes cavitation around cylinder liners? Is that something I can affect, or is it one of those shrug your shoulders and hope things? Over my pay grade, I think, but it never hurts to learn something new.
Turbulent liquid over rough surfaces at velocity, hot spots on liners due to casting sand impingement (which creates the rough surfaces), casting sand or debris build up creating eddy currents and voids around liners (strong arguments for coolant filters and coolant with SCA's), and the list goes on...

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[2rex2]

yes, I went nuts and did all that stuff too. alot of time and money replacing with new parts. One fellow on this site said " if you do a lot of mowing, the dust (read pollen) will coat the fins off the rad. ". Well you could shine a light right through, so I ignored the advice. Wrong!! those fins remind me of an air conditioners, light and closely spaced. long story short (to late) brought it steaming back to the shop and used the water hose to flush both front and rear, and yes it quit overheating. so ever time it overheats back for a douche. so as my dad used to say, start with the simple and work back towards the expensive.

 

[Rich Waugh]

Thanks Terry, that's a good point to keep in mind about most issues.

Rich

 

[Mgrove]

You know for a buck or two, you can buy thin room air conditioner filters, They may not stop all of the dirt, but they will catch a good majority of it. You can either replace them or just clean them once in a while. You can hold them in place with cheap plastic clips from Harbor Freight. ITs easier than blowing out the Radiator.:thumbsup:
Mgrove

 

[greg_g]

FWIW, I use washable furnace filter material. Inexpensive, easily cut to fit with a scissors, available at most WalMarts. Stands up will to either water hose or air compressor. It's a full inch thick, so I don't even need to fasten it. And is big enough that I can cut two tractor filters from one furnace filter.The air cleaner housing bracket holds it in place nicely. Pulls right out for cleaning, and it's tough stuff. Have had the same pieces on both my tractors for several years now, neither show signs of needing replacement yet.

//greg//