Valve cover gasket on 4500z

zmountaineer · Sep 24, 2018

I’ve got a leak on my valve cover, anyone else have this happen on their kubota gas? I have the dealer ordering me a a new gasket. Any chance someone on here knows the torque specs for it?

wrenchit · Sep 28, 2018

zmountaineer said:
Iè‡´e got a leak on my valve cover, anyone else have this happen on their kubota gas? I have the dealer ordering me a a new gasket. Any chance someone on here knows the torque specs for it?
View attachment 572173

You will find on the Kabota 4500z that the valve cover will not come off due to the coil bracket. To remove the coil bracket the muffler shield has to come off (hood included).
To easily remove the valve cover , unbolt the coil plate and remove the coils, the bracket can then be gently bent up around 1/4/ 3/8 inch and the valve cover will come right off after its unscrewed. The gasket is a large "o" ring. the only reason they fail is from excess heat. Look and see if you have any missing manifold nuts, or bolts as they are common to come loose and fall off allowing the manifold to move enough to blow exhaust up and overheat the valve cover and cause the o ring to harden and leak.. Also check the heat shield bolts. Do not bend the bracket anymore then needed or the coils can arc off the hood with the hood closed. Make sure you scrape any hardened o ring off the head surface. the torque specs are 2.9 to 4.3 Ft Lb. I just snug them good and tight, because the o ring is the seal, not the bolt torque. I do mobile service on Ventracs and have seen it all over the years.

zmountaineer · Sep 28, 2018

wrenchit said:
You will find on the Kabota 4500z that the valve cover will not come off due to the coil bracket. To remove the coil bracket the muffler shield has to come off (hood included).
To easily remove the valve cover , unbolt the coil plate and remove the coils, the bracket can then be gently bent up around 1/4/ 3/8 inch and the valve cover will come right off after its unscrewed. The gasket is a large "o" ring. the only reason they fail is from excess heat. Look and see if you have any missing manifold nuts, or bolts as they are common to come loose and fall off allowing the manifold to move enough to blow exhaust up and overheat the valve cover and cause the o ring to harden and leak.. Also check the heat shield bolts. Do not bend the bracket anymore then needed or the coils can arc off the hood with the hood closed. Make sure you scrape any hardened o ring off the head surface. the torque specs are 2.9 to 4.3 Ft Lb. I just snug them good and tight, because the o ring is the seal, not the bolt torque. I do mobile service on Ventracs and have seen it all over the years.

I changed it out today. I have yet to start it up yet. As you stated, that coil bracket needed to be moved. I took off the shield then the bolt for the bracket next to the manifold. I was then able to loosen the bolt on the other side and just swing it out of the way. Took a dead blow hammer and nudged it a couple times. Came right off other than the side next to the manifold. There was a section that was stuck on there real good. It took me literally hours to scrape off the old rubber taking great care to not get the shaving in the engine. When I installed the new gasket I used some gasgacinch and only time will tell if that was a smart move or not. My torque wrench is a torsion style and I measured what it was when I took the bolts off. It was around 150 inch pounds to break loose. I righted to 75 inch pounds as I contacted someone and was told 60-96 inch pounds. I went for the middle.

Thanks for the tip of looking for the manifold bolts. I’ll look in the morning. But the manifold side was absolutely the side that was leaking. Here is the only picture I took.

zmountaineer · Sep 28, 2018

Oh if anyone wants to know the part number from kubota

prs · Sep 29, 2018

I will make sure to check mine in the morning before firing up.

Wrench it, if the manifold nuts loosen, will the involved manifold gaskets be ruined? Are they metal crush rings or flat gasket?

prs