Replacement Cooling System Orfice Plate

Gaowlpoop · Apr 10, 2017

Over the past while, there has been much discussion about the cooling system on some of the Mahindra tractors. Some have said that the problem is in the temperature gage, others that the cooling system is oversized, and still others that coolant bypass hose is to big.

This is the email that I sent to the Mahindra dealer I bought my tractor from.

I have been using my new tractor, got a whole 20 hours on it. I have also been reading about it. It seems that there is a problem with the cooling system. I have noticed and have read about the 45-40's not coming up to operating temperature. This is due to an oversized thermostat bypass hose. It simply allowed so much cooler past that the thermostat never activates.

It is my understanding that Mahindra has a fix, which involves a restrictor in the coolant bypass hose.

I was wondering If you knew anything about this, and if so how I can get one.

This is the email I received back.

I have talked with the territory service rep. There is a replacement orifice that goes in the top of the radiator on the small hose to the left of the radiator fill neck. It allows less water to return back to the radiator to allow the temperature gauge to get on up. I have a few of these orifices on order. Once we receive them, I'll contact you.

I shall wait and see what happens.

Gaowlpoop · Apr 18, 2017

I received this today from my sales rep.

I hope all is well. Please see the attached photos. This is the fix for your issue. It is a replacement orifice that goes in the top of the radiator to the left of the fill neck / radiator cap. It is a matter of remove the hose clamp; pull off the 3/8 hose; unscrew the original orifice out of the top of the radiator; screw in the new orifice (be sure not to over-tighten); reattach the hose and tighten the hose clamp. The territory service manager said you would lose approximately a table spoonful of coolant from the hose removal. I can send the orifice to you and you can do it or I will be glad to send my father up there to do it. Just let me know. I hope you and your family had a great Easter weekend!

When ever the fitting arrives, I shall put it in and see what happens. To tell the truth, I am not very confident in this fix.

mcfarmall · Apr 19, 2017

Please post the orifice diameter of the old fitting vs. the new one. Use a drill bit to measure or calipers if you can get them in there.

Gaowlpoop · Apr 19, 2017

Will be glad to.

rockarosa · Apr 20, 2017

Called my dealer yesterday regarding my 4550 temp gauge not working. He told me that I'm the first one that has called him with this. Said there was no info from the factory about problems. The tractor has 38 hours on it and I told him that when I come up for my filters and oil we can discuss this more. Seems like a decent guy and has been selling tractors at the same location for close to 30 years.

Gaowlpoop · Apr 21, 2017

I received the new orfice fitting today and I was very surprised.

Here are some pictures of the old one and the new one.

As you can see, the new one is way smaller then the old one.

Here are the numbers:

Original orfice: 0.225 inches a #2 drill

New orfice: 0.041 inches a #59 drill

You need a 17mm wrench to remove the fitting.

PLEASE NOTE: There is a small washer under the fitting, be careful or you will loose it.

Only time will tell if this will fix the problem. I do not exactly get a warm (no pun intended) fuzzy feeling about this fix. Only time and running the tractor will tell.

jb1390 · Apr 22, 2017

Gaowlpoop said:
I received the new orfice fitting today and I was very surprised.

Here are some pictures of the old one and the new one.

View attachment 506804

View attachment 506805

As you can see, the new one is way smaller then the old one.

Here are the numbers:

Original orfice: 0.225 inches a #2 drill

New orfice: 0.041 inches a #59 drill

You need a 17mm wrench to remove the fitting.

PLEASE NOTE: There is a small washer under the fitting, be careful or you will loose it.

Only time will tell if this will fix the problem. I do not exactly get a warm (no pun intended) fuzzy feeling about this fix. Only time and running the tractor will tell.

It'll work. Very similar to the original prototype restrictor that I have in my 3550 machine. That top hose is just a vent hose for air in the egr cooler, not ever supposed to flow coolant, just bleed air. It's amazing how much cooling capability that little hose actually has. Unless the engine is really working, it's not actually putting out much heat and that little hose without a restrictor is enough to drop the temp.

Gaowlpoop · Apr 26, 2017

I received the fitting last Friday I believe and installed it with no problem. I was amazed at the size of the hole in the new one. I was truly doughtful about this "fix", I just couldn't believe that a 1/4 inch hose could carry enough coolant to prevent that big engine coming up to operating temperature. Anyway, I had a chance to do some things with the tractor today. I ran it and kept an eye on the temperature gage. It took a while but the temperature came right up into the operating range. Learn something new every day.