Oil & Fuel YM2500 Pushing Coolant Out the Radiator

[Travis_R]

What could be wrong with my YM[emoji6][emoji[emoji6][emoji6]][emoji[emoji6][emoji6]]?

At high engine idle, I’m guessing around [emoji6][emoji[emoji6][emoji6]][emoji[emoji6][emoji6]]-[emoji[emoji6][emoji6]][emoji[emoji6][emoji6]][emoji[emoji6][emoji6]] RPMs, it’s boiling coolant out the radiator’s filler neck with the cap on. There is no load on the engine.
Does this tractor have a thermostat? It has the T[emoji[emoji6]][emoji[emoji6][emoji6]] Yanmar diesel engine.

Thank You,

Travis

 

[bmaverick]

Have no idea what you posted. You will need to use a different browser to post. Those strange things took over.

 

[careyo63]

Head gasket! or Hopefully dirty Radiator. Have your Mechanic Pressure Check the radiator and see if it is getting pressured up!. Should be around 15 PSI.

 

[Travis_R]

Head gasket! or Hopefully dirty Radiator. Have your Mechanic Pressure Check the radiator and see if it is getting pressured up!. Should be around 15 PSI.

What should the correct radiator cap PSI be? It has “0.5 PSI” stamped on the cap.

 

[Travis_R]

Have no idea what you posted. You will need to use a different browser to post. Those strange things took over.

I was using the TractorByNet app on my phone. I deleted it and was going to download it again, but can’t find it in the App Store. Apparently there is no TractorByNet app anymore.

 

[Travis_R]

Have no idea what you posted. You will need to use a different browser to post. Those strange things took over.

At high idle, 1200-1800 RPMs, my YM2500 is boiling coolant out the radiator’s filler neck, past the cap. It has a 0.5 PSI radiator cap.

What do you recommend?

 

[careyo63]

I thought 15
0.5 ? Sure about that.
The Yanmar radiator cap pressure is rated at 13 psi1. It is a small size cap used by Yanmar, with a rating of 0.9 kpa2.
A earlier thread. Radiator cap on (most?) Yanmars is 13 psi. 7psi also works well. Head Gasket is my guess.

 

[Travis_R]

Let’s see if this video will post…

 

[Travis_R]

Here is the YouTube link of the coolant in the radiator with the tractor running…

 

[careyo63]

You can get pressure tester at any local auto store. Some will loan you it. You just need the correct size cap to check the Radiator pressure. Many sizes of caps are in the test kit. It has a gauge that attaches to them so you can see how high the pressure is on the Gauge.
The big Bubble and the water level rises is a good sign of a pressure problem. Also The Rusty / Dirty anti freeze reflects that also. You can flush the Radiator and see if that helps but with the Big pressure rise is the problem. Bad gasket,Warped or crack in the head is why that usually happens.

 

[RayIN]

Let’s see if this video will post…

Yup, that's the sign of a blown/leaking head gasket.
Fix it right away, anti-freeze can seize an engine if ran that way.
My first action would be to remove the valve cover and re-torque the head bolts, then run a compression test.
That likely will not fix the problem, but its a shot.

 

[aba4430]

Try and replace the radiator cap with a properly specced one. See if it stops. Cheap enough check.

 

[George2615]

I don't have a Yanmar. I watched the video and it looks to me to be full of brown water. Is there antifreeze coolant in there?

I'd drain and flush the radiator, replace the thermostat, refill with 50/50 AF and replace the cap.

 

[careyo63]

No Thermostat on a YM2500
Warning light switch # TS-44901 which is like my YM2000.
Radiator cap # RC-28
Overflow Tank/Bottle # OFT-4450

 

[Travis_R]

Try and replace the radiator cap with a properly specced one. See if it stops. Cheap enough check.

New radiator cap will be here Tuesday morning from Napa. Sparex #S.68401.

 

[Travis_R]

13 PSI Cap.

 

[careyo63]

You have massive air in the Radiator. Pressure build up! The video shows a problem. Does a radiator cap go bad?. Sure it can but when they do It leaks Anti freeze around the top. A dry Residue will appear and you will see it on the top of the Radiator and shroud. A cap Rated 0.5 PSI? Should be 13-15 PSI so that is a problem. Did it get used to keep the PSI in the Radiator pressure down and release pressure could be very possible. Until you Pressure Check the Radiator PSI you are guessing and just Throwing parts at it!!. NAPA has quality Auto parts but mine local Doesn't even stock a Ford fuel filter. Having problems with one now! They used a NAPA filter that's sucking air at the fuel line connection. Which is going to Ford and get replaced this week. Told them to use Org. Ford parts. So it's Going to the dealer. They told me they see a problem with them often. I looked at the receipt and sure enough 13$ Napa filter and 59$ from Ford. Go figure! Cut the motor off and it won't start back up! Let it sit for a few minutes and the Gas pushes the air out and it fires right up!
0.5 pressure cap is going to be a problem if that is true! I would call Hoye or Fredricks and get the correct Yanmar cap for sure!

 

[Travis_R]

The radiator cap coming from Napa is actually a Sparex part. It’s Sparex part # S.68401 and is Napa part # BK S68401. The specs state that it’s a 13 PSI cap. I believe the cap will be just fine, although it may not be the problem.
The day I bought the tractor at Fredricks, on 11/22/2024, I remember checking the coolant in the radiator and one of their mechanics had to add some water to it because it was low.
I agree with you, I’m not gonna throw parts at it. I shouldn’t have to. I’m calling Fredricks again tomorrow morning. The tractor came with a 1 year warranty and I paid very good money for the tractor. I believe Fredricks will take care of whatever’s wrong. They have treated me good so far.

 

[careyo63]

Fredrick's is Top Notch! Refurb. Tractor and parts. I actually have been there! Drove from ATL. Ga. for a Yanmar Tiller. Many Yrs. ago though! My church Purchased the Refurbished YM2500. Retired Catholic Priests retirement home. I cut the property with my YM2000 until I no longer could. The YM2500 and my all Org. YM2000 came from Spalding in Ga.. Who was Fredrick supplied. What the 2000 looked like in 2008 when I bought it. I still have and use it to the day!

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[ruffdog]

If you are getting bubbling in the radiator like that, you have a bad head gasket. Combustion chamber pressure is being forced into the coolant passages.