Weird issue with coolant system on Allis Chalmers WD. Help!

So I flushed the coolant system in the old WD and refilled it with water (am going to put antifreeze 50/50 mix this weekend). However, I ran the tractor with the cap off for about 5 minutes to let it bleed off and get the air pockets out... Then put the cap on and drove it around for about 15 minutes. I noticed something strange...

If you go from wide open throttle down to idle, water will spit out of the overflow. Now, I did have the radiator full up to the overflow hole to start with (and filled it back up that high as it bled off air, as well).

So I ran it some more with the cap off, and noticed that at idle the water would shimmer a bit with turbulence, but it would come up almost to the overflow hole. However, if I would pull the tractor into mid-throttle or more, the level of coolant in the radiator would drop almost an inch and stay that way for most of the time (sometimes it'd come back up a little, then drop back down again).

Then you'd drop the tractor back down to idle and it'd fluctuate back up to the overflow hole again. Other than the fact that it would look weird and dribble water from time to time, the tractor was running great and sounded just like it always has for the past 10 years or so.

I was mostly doing this to watch for air bubbles to see if I had a head gasket leak, but I am mostly just puzzled... Do I have a bad thermostat? Blown head gasket? Just some gunk in my coolant system that I need to work on flushing out before I put antifreeze 50/50 mix in it? Or is this normal and I just overfilled the system? I am at a loss here.

Are you sure it has a thermostat in it??? Sounds like it does not have one and when at idle it is only moving the coolant slowly but when you have the RPMs up the coolant moves a good bit faster so then it seems to drop down. Or maybe the thermostat is stuck wide open

Smell it and see if it smells a little like exhaust..... I've had a couple cars and my last little tractor act like that and it was the head gasket....

(quoted from post at 17:01:43 09/28/12) Are you sure it has a thermostat in it??? Sounds like it does not have one and when at idle it is only moving the coolant slowly but when you have the RPMs up the coolant moves a good bit faster so then it seems to drop down. Or maybe the thermostat is stuck wide open

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Well it didn't exhibit this problem until late last year/early this year... So I was doing a coolant flush to see what was up, and I think my thermostat may have gotten stuck (at least, I think it has one). When it is running at mid or fast throttle, it's hard to watch for bubbles or anything in the radiator since there's so much turbulence and vibration there's always a ripple on the water because of that. I'm picking up a new one this weekend so I can install it after I drain the coolant again before I put antifreeze in it.

(quoted from post at 17:18:12 09/28/12) Smell it and see if it smells a little like exhaust..... I've had a couple cars and my last little tractor act like that and it was the head gasket....

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It's hard to get any type of smell out of it, except that lingering antifreeze smell... But it's still on my list of concerns.

Just run it and keep an eye on things..... mine took almost 3 years of daily chores before it got bad enough to replace.......

Beep it filled to the top and watch for bubble while running
hard. If so it the head gasket and will cause over heating when
working hard.
Walt

(quoted from post at 17:43:11 09/28/12)
Just run it and keep an eye on things..... mine took almost 3 years of daily chores before it got bad enough to replace.......

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Well this one only gets out about a dozen times a year, and never runs over mid-throttle. Mostly just moving equipment around. Haven't put it on a mower in years, and only use it to disc up the garden for an hour or so.

(quoted from post at 18:00:37 09/28/12) Beep it filled to the top and watch for bubble while running
hard. If so it the head gasket and will cause over heating when
working hard.
Walt

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Yeah, I'm going to run it, throttle it up, and keep filling it to try and see if it bubbles when going full tilt. It's just hard to tell though because there's so much turbulence in the radiator.

It doesn't seem to bubble at all when at idle though, as far as I could tell, but it does ripple a bit from the vibration.

Just a little precaution.............. If it IS a HG and your rad cap is not vented, you may wanna run it with the cap on the loose notch to avoid coolant filling a cylinder when you shut it off... Water don't compress real well :roll:

(quoted from post at 18:11:46 09/28/12) Just a little precaution.............. If it IS a HG and your rad cap is not vented, you may wanna run it with the cap on the loose notch to avoid coolant filling a cylinder when you shut it off... Water don't compress real well :roll:

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Oh dear, you do raise a good point. :shock:

Okay, got a new thermostat and temp gauge... So my current plan of attack is:

1. Flush the coolant system again.
2. Install a new temp gauge/thermostat pair while the system is empty.
3. Fill the system with water again.
4. Run it with the cap off for awhile
5. Put the cap on and see how the temp holds and if I get bursting out the overflow still
6. Drain the system again for one final flush
7. Put my 50/50 antifreeze mix in and run it for about 10-20 minutes to mix it through good before parking her

I started this endeavor because I had foaming antifreeze, which a mechanic buddy of my suggested may be indicative of bad antifreeze (since it was at least 10+ years old) and to check that before I went and checked the head gasket.

Put the thermostat back in.

Dean

I have seen this a lot of times: the water pump is pushing and sucking at a high speed and then you slow it down. Probably can t suck as fast as it pushes i guess. But normal in my book.
MARK

Keep an eye on the oil, crack the drain plug, and see if some
water/AF runs out. It is possible that you have an o-ring leaking at
the bottom of a cyl liner. There is a test kit, to see if there is
exhaust leaking into the radiator.

(quoted from post at 22:09:22 09/28/12) Keep an eye on the oil, crack the drain plug, and see if some
water/AF runs out. It is possible that you have an o-ring leaking at
the bottom of a cyl liner. There is a test kit, to see if there is
exhaust leaking into the radiator.

Click to expand...

I believe I am okay on this front -- oil level is proper and shows good color, got no discernible water when cracking the drain plug until fluid comes out.

I agree with mark,and see if the radiator eventually finds its own level. Bill

Well I went out tonight and flushed the coolant system for a second time. Check out what my coolant looked like (keep in mind that I flushed the system a week ago and put water back in). Take a look at the bucket of yellow crap that came out (the bucket wasn't clean, so nevermind the floaters):



So I am going to flush this out tomorrow, put on my new temp gauge and thermostat, and then put in my 50/50 antifreeze mix.

But she started right off on the first click, no choke required, and she burped and spat water a bit early on but once the radiator found it's level (which was a bit lower than anticipated, but those dang air pockets), it didn't throw any fits while I was out moving some equipment.

Figure I'll run her for about 20 minutes tomorrow after putting the new parts on and filling her with the antifreeze mix just to make sure it is mixed well and all throughout the coolant system.