Oil & Fuel Oil coming from valve cover breather

[Reddogs]

I finished putting on my backhoe on my John Deere 790 and fixing or replacing the hydraulic hoses that were leaking, and when I cranked it up to test, all of a sudden a rush of oil came out of the hose from the valve cover breather. I always had it vent out and drip a little but never stream out like a faucet, and it left a stream of oil from the barn to the road and back to the driveway where I parked to check it. I checked the breather vent metal screen and reset it and checked the oil level and it seemed fine and the oil is clean, but now its shooting out oil and puddling under the tractor as soon as I crank. Everything sounds and drives normal, and power is fine but dont like it loosing so much oil like that. I'm going to open the engine up, what should I check or look for?

 

[bmaverick]

I finished putting on my backhoe on my John Deere 790 and fixing or replacing the hydraulic hoses that were leaking, and when I cranked it up to test, all of a sudden a rush of oil came out of the hose from the valve cover breather. I always had it vent out and drip a little but never stream out like a faucet, and it left a stream of oil from the barn to the road and back to the driveway where I parked to check it. I checked the breather vent metal screen and reset it and checked the oil level and it seemed fine and the oil is clean, but now its shooting out oil and puddling under the tractor as soon as I crank. Everything sounds and drives normal, and power is fine but dont like it loosing so much oil like that. I'm going to open the engine up, what should I check or look for?

When was the last time the Yanmar engine filter was changed? Ag machines need the tallest possible filter without getting touched by other working hardware on the machine and the filtration micros no lower than 24 microns. The finer the filtration, the faster the filter will clog up.

With that said, IF the oil filter has not a by-pass valve, you could see blow-out just like the JD790 event now.

These Yanmar engines are made to JIS standards and not SAE, best oil to use is 10W30 diesel Rotella T4 or Quaker State or Valvoline equals.
15W40 is too thick and will trap heat in the engine longer. JIS standards for oil passage ways are narrower for engines too. So, 10W30 summer and 5W30 winter.

 

[5030]

Sounds to me like the drain back passages in the head are clogged with sludge. How many hours, what oil are you using and how often to you change it?

 

[Reddogs]

Sounds to me like the drain back passages in the head are clogged with sludge. How many hours, what oil are you using and how often to you change it?

Thats what I am thinking....I had the oil change a few months ago, then changed a few weeks ago with 15w40.

 

[Reddogs]

When was the last time the Yanmar engine filter was changed? Ag machines need the tallest possible filter without getting touched by other working hardware on the machine and the filtration micros no lower than 24 microns. The finer the filtration, the faster the filter will clog up.

With that said, IF the oil filter has not a by-pass valve, you could see blow-out just like the JD790 event now.

These Yanmar engines are made to JIS standards and not SAE, best oil to use is 10W30 diesel Rotella T4 or Quaker State or Valvoline equals.
15W40 is too thick and will trap heat in the engine longer. JIS standards for oil passage ways are narrower for engines too. So, 10W30 summer and 5W30 winter.

Just changed it, but not sure what you mean by ''tallest", got standard one from dealer.

 

[5030]

Not a plug for Archoil but I use their Nano-Borate additive in my engines constantly (it ain't cheap). The interior of all my diesels and gas engines are clean and free from any sludge or build up. No bronze tint on anything either which is typical from using multi grade synthetic oils.

 

[loggin]

Not a plug for Archoil but I use their Nano-Borate additive in my engines constantly (it ain't cheap). The interior of all my diesels and gas engines are clean and free from any sludge or build up. No bronze tint on anything either which is typical from using multi grade synthetic oils.

Hey 5030, what is the "bronze tint" you speak of due to using multigrade synthetic oils? I ask because I was thinking of switching to shell synthetic 5w40.

 

[Gator6x4]

Check your hydraulic fluid level. Sounds like something was changed and hydraulic fluid is being forced into the engine.

 

[bmaverick]

Just changed it, but not sure what you mean by ''tallest", got standard one from dealer.

Short and stubby filter vs tall filter in height. That is all.

Yanmar engines will work better and last longer on 10W30. We've hit this topic so much in both the compact Deere sub-forum and the Yanmar sub-forum over the years here and elsewhere.

 

[Gator6x4]

Hey 5030, what is the "bronze tint" you speak of due to using multigrade synthetic oils? I ask because I was thinking of switching to shell synthetic 5w40.

Not 5030 but, here is more than you ever wanted to know about automotive oil.

Oil color with different brands?

I know oil color doesn't necessarily tell us much, but wondering if anyone knows why it varies with different brands? I used to use PP pretty exclusively, and it would take around 3k miles before the oil darkened. Now for the past 3 changes I've been using Mobil 1 and it darkens within a few...

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