Farm Equipment - blowing out coolant on my 185

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blowing out coolant on my 185

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=49583
Printed Date: 21 Aug 2025 at 7:07am
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Topic: blowing out coolant on my 185

Posted By: brian-MO
Subject: blowing out coolant on my 185
Date Posted: 25 Apr 2012 at 10:57am

After I have been running my 185 hard enough for long enough that it's good and hot (but the temp gauge is still at the bottom of the green), as soon as I pull back on the throttle and drop the RPMs noticeably it starts blowing coolant out of the overflow tube. It doesn't leak coolant, and it doesn't happen with moderate use of the tractor...only when it's hot because I've been brush-hogging a field or something like that. Any ideas as to what would cause this? The only thing I can think of is that the water pump impeller is going, and when it's at higher RPMs it's able to circulate the coolant fast enough but when I throttle back it doesn't have enough circulation and the coolant starts to boil. I did check the radiator to make sure the airflow was not restricted because of dirt/weeds & it was OK. If it was a radiator that was clogged inside or a stuck thermostat then I would expect the temp gauge to show it's running hot, but it rarely gets above the bottom of the green area. I have no indication that a belt is slipping either. Thanks, everyone.

Replies:

Posted By: Gary in da UP
Date Posted: 25 Apr 2012 at 11:29am

The only way to know for sure is to drain it, See what comes out when drained, Take a light , inspect inside the top tank If it looks clean , verify it, remove the hoses from the rad and flush first top to bottom with a garden hose at full force, see what comes out. If is partly plugged, and the water pump is weak, the bottom hose it collapsing a bit, All these things add up. You may have one problem or three. The fan belt is tight , eh? If you have been replacing coolant as it spews, you may be overfull, every system has a sweet spot where it works best, tops of the tubes need 1 1/2" of coolant above them. Good Luck

Posted By: Flint23
Date Posted: 26 Apr 2012 at 4:04pm

My 45 would do the same thing so I put a catch can on it, ran the tractor for a few days then checked the can, it only had a bit of coolant in it so I figured that I had over filled it by that amount. guess it needed room to expand...

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been there done that, not doing it again...

Posted By: DrAllis
Date Posted: 26 Apr 2012 at 6:31pm

You are most likely overfilling it to begin with and/or have a bad radiator cap. Level must be down probably 4 inches when cold.

Posted By: scott in tenn
Date Posted: 26 Apr 2012 at 9:42pm

I had same problem on my 185 and replacing the water pump solved the problem. HTH. Scott

Posted By: MACK
Date Posted: 26 Apr 2012 at 9:43pm

Let it run at about 1500 RPMs untill it cools for a while. MACK

Posted By: SteveM C/IL
Date Posted: 26 Apr 2012 at 11:09pm

Sounds like a weak cap.Easy enough to change and try.

Posted By: brian-MO
Date Posted: 27 Apr 2012 at 7:09pm

I forgot to mention that the first thing I did was to replace the cap. It's really supposed to be down about 4 inches when it's cold? If that's the case then I am quite certain that I'm overfilling it because I usually fill it right to the top. The thing I still find odd is that it doesn't blow out the coolant when it's real hot and the RPMs are high, and it should have the same expansion when it's hot regardless of the RPMs. It's only when I throttle back that it blows the coolant.

Posted By: DrAllis
Date Posted: 27 Apr 2012 at 9:35pm

You're carrying it too full.....4 inches down from where the rad cap rubber seal is.......best I can tell you and not be looking into a radiator.

Posted By: Stan IL&TN
Date Posted: 27 Apr 2012 at 9:48pm

When I replaced the radiator, water pump and hoses on the Ferguson I thought I had no leaks until it got it good and warm and coolant started to drip from somewhere. The fan blew the leaking coolant around where I couldn't see where it was coming from. I could see steam rising up and then I was convinced that the water pump wasn't circulating the way it should and it was getting too hot but the temp guage showed normal operating temps. It was about then that the light bulb in my brain came on and that I had overfilled the radiator. Sure enough as I let it run the dripping stopped and all was right with the world again. LOL

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1957 WD45 dad's first AC

1968 one-seventy

1956 F40 Ferguson

Posted By: Flint23
Date Posted: 28 Apr 2012 at 1:18pm

It's a presure thing, When you rev. up the tractor it causes the pump to suck the water through which sucks water out of the rad. when you throttle back the water goes back into the rad. now that the water is hot, it expands and leaks out of the rad cap. I'm not much at explaining things but this might put some light to it.. that's why you have a hot and cold level on your catch can in your trucks and cars.

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been there done that, not doing it again...