Head gasket replacement on a digger

[Mick4271]

I know, strange question but I'm no mechanic. I have a 20 year old Kubota digger that needs a new head gasket, which I'm doing now and have got everything off, cleaned and ready to go back on. Now do I just fit the head gasket to the head or should I be using some sort of sealant? Any help greatly appreciated

[Badgerboy]

You'd need to be a bit more specific on the type of engine, but for cars you do not apply any sealant to the headgasket.

Are you changing it for any particular reason? If its blown and your not sure why, make sure you check that the head has not warped at all with a straight edge before putting it back together. It may need a skim.

And just to note typically head bolts are stetch bolts, so don't reuse them!

[stoocake]

Pictures?

[forks]

You can reuse the head bolts, as long as they are still within the tolerances allowed. For instance, the manual for the 4G63 derivative for Mitsubishi forklifts allows for 11mm!

[Mick4271]

I've fitted the new gasket without any sealant and filled up both oil and water, I've checked the dipstick and sump full of water . The head appears to be Ok, not warped, am I right to think the only other possible explanation is the water pump?

[roscozs]

Mick4271 said:

I've fitted the new gasket without any sealant and filled up both oil and water, I've checked the dipstick and sump full of water . The head appears to be Ok, not warped, am I right to think the only other possible explanation is the water pump?

Did you get the head checked professionaly becuase the slightest distortion at anypoint on the head can lead to problems? the other possibility could be a cracked cylinder liner? If it has them.

[lescombes]

is it one of the 3 cylinder Kubota engines?

[john_p]

Cracked head?

[Mick4271]

It is a 3 cylinder Kubota engine, is there normally a problem with these ?. I have owned the digger for 2 years but not used it much, but its been generally reliable

[eldar]

Mick4271 said:

I've fitted the new gasket without any sealant and filled up both oil and water, I've checked the dipstick and sump full of water . The head appears to be Ok, not warped, am I right to think the only other possible explanation is the water pump?

Obvious questions. Was the oil OK before the job. Has the water level gone down as the sump level went up?

[Mick4271]

The sump was full of water before trying my repair, so I assumed it to be the head gasket?

[eldar]

Mick4271 said:

The sump was full of water before trying my repair, so I assumed it to be the head gasket?

You did change the oil after the repair?

Could be the head gasket, but that normally pressurises the coolant and blows water out the rad, or makes it smell of exhaust.
Has it got an oil cooler in the rad?

[Mick4271]

The radiator does not appear to have a cooler. I put in new oil and replaced the oil filter, wrongly assuming that the problem was the head gasket and that I had completed my repair. I'm not sure whether to replace the water pump or replace the head, I think my best course of action is to take the head off again and take it somewhere to have it checked?

[HellDiver]

Did it have antifreeze in it over winter? Could have frosted the block, splitting the water jacket which may let water in to the oil.

When you've the head off again, fill the water jacket and see if the water drains through. I suspect it may.

Edited by HellDiver on Monday 26th April 09:36

[Mick4271]

Whats a water Jacket ?

[bazking69]

I suspect Mick is in too deep already...

[TheRoadWarrior]

bazking69 said:

I suspect Mick is in too deep already...

LOL

[eldar]

Mick4271 said:

Whats a water Jacket ?

The holes and passages in the block that carry the cooling water. You can see these holes with the head off.

I'd suggest getting someone who understands engine basics to have a look.

[Mick4271]

u may have a point