Anything else to do when changing a head gasket?

[buickanddeere]

Has anybody hit this engine with ether ?

 

[Lobanz]

Nope. No ether. Never had any trouble starting. Just noticed some growing overheating problems and then bubbles in radiator.

From my understanding ether is very bad -- especially on diesels.

 

[Baby Grand]

Have you run a compression check ?

 

[Lobanz]

So, we will be tearing into it tomorrow. Have been soaking rusty nuts and bolts in case I have to remove them.

Will try not to remove intake or exhaust manifolds so i don't risk breaking rusty bolts. Will probably just check flatness with best straight edge I can muster and probably look at it with several just to see if they all say the same thing.

Kinda want to clean off valves and such. Replace seals. Maybe lap valves. Not sure if this is really necessary or not. Has about 2400 hrs on it. I guess maybe it depends on what they look like? All black and gunked up with carbon => remove valves and clean. Otherwise leave them alone.

If I do remove the valves, how important is lapping them and installing new seals?

I have another engine to do this on too: head gasket on my Yanmar 1610d tractor also went (overheated and bubbles in radiator). Got to do mower first so grass won't get away from me.

 

[Lobanz]

Nope. Don't have a compressions tester but HF has one with a glow plug adapter for Kubota. Been thinking about it. You thinking about rings?

 

[Coyote machine]

Yup ... that's exactly what R & R Engine and Machine did when I had them do the cylinder head off my OM647 engine ... and it is overhead cam (dual) ...

BTW ... I reused the head bolts ... they were all well within spec (within the tolerance range for stretching) ... that was about 60K miles ago (at least 1000 hours ago, roughly) ... no problems yet

What's exactly what they/you did? Sink the valves or grind the stems down? :confused2:

 

[Coyote machine]

From your description of having this same breakdown happen on multiple motors, do you ever drain and change the coolant, flush the cooling system on any of these engines? A compression test can tell a lot about what is happening, blown gasket, bad valve(s), low compression per/cylinder, broken ring(s), etc. It's a good baseline to use before tear-down. Thermostat, general condition of radiator inside and out are crucial too. Just doing a head job without knowing cause of failure of whatever components can result in having to do it all over again and/or more later down the road.
Example: if marginal cooling system caused whatever the current problem is and you don't fix it too, then you will likely have to fix it sooner than later, and may have to then also replace the head.

 

[Lobanz]

From your description of having this same breakdown happen on multiple motors, do you ever drain and change the coolant, flush the cooling system on any of these engines?

Yes. I have flushed both of them. And had the Kubota radiator boiled out by a radiator shop. Didn't help much.

A compression test can tell a lot about what is happening, blown gasket, bad valve(s), low compression per/cylinder, broken ring(s), etc. It's a good baseline to use before tear-down. Thermostat, general condition of radiator inside and out are crucial too. Just doing a head job without knowing cause of failure of whatever components can result in having to do it all over again and/or more later down the road.
Example: if marginal cooling system caused whatever the current problem is and you don't fix it too, then you will likely have to fix it sooner than later, and may have to then also replace the head.

The mower has had some overheating issues for quite a while. We have found that spraying off the radiator and screen before use, making sure radiator is full (no overflow tank), and keeping sharp blades helps a lot. But under a lot of load it still gets too hot, so we have to stop and let it cool down. Usually running it full throttle (which we pretty much always do) with no load will let it cool down, so cooling system IS working some. After a while of this, it doesn't want to cool back down so we have to let it sit for an hour or so. We shut it down before the needle gets into the red. It's just gotten worse lately and I saw bubbles in the radiator.

The Yanmar hasn't really had an overheating problem, except for a couple of times when it was under a lot of load for a long time. But it did overheat when I was bush hogging real tall grass recently. I let it cool and afterward I saw the bubbles in the radiator.

But yeah. Have to wonder if there is something I'm doing that causes the problem. Possible, but I kinda doubt it. I do want to get to the bottom of it though. Fix the real problem. Only thing I know to do now is fix what's broke.

Maybe I will get the HF diesel compression tester kit. It has a Kubota glow plug adapter. It would tell me before and after compression on each cylinder and help me know if I fixed anything. Doesn't have adapters for Yanmar though, but Hoye Tractor has an injector adapter. But from what I read, injectors can be hard to remove.

Does anyone know of a good online guide to troubleshooting with a compression tester?

 

[rsallen]

There is only so much info one can get with a compression gauge. Don't get me wrong, it is valuable information, but limited. What makes compression more valuable is putting it together with pressurizing the cyl.'s. and leak down tests. Put them all together with some experience and one can come very close to knowing exactly what is going on where.
The compression test is the first thing to acquire because it gives the means to run compressed air to the cyl's.

 

[Coyote machine]

There is only so much info one can get with a compression gauge. Don't get me wrong, it is valuable information, but limited. What makes compression more valuable is putting it together with pressurizing the cyl.'s. and leak down tests. Put them all together with some experience and one can come very close to knowing exactly what is going on where.
The compression test is the first thing to acquire because it gives the means to run compressed air to the cyl's.

Agreed, especially to it's limitations, and the need to use it in conjunction with other tests/tools to determine the 'before' tear-down stats.
And tear-down without some stats to go by as a base line can be an exercise in wasted time/$$$.

Were you, the OP doing something wrong is difficult to say, but if I had to guess I'd say not too likely. I would ask what you are using any of the machines to do that is creating high load conditions for long periods; and suggest that you might consider hogging more frequently, when the grass is less tall and/or cutting when it's cooler out, late afternoon/evening or earlier morning- if possible, and take some breaks to let the equipment cool down...
An overflow tank might actually help because it could allow pressure and very hot coolant to be able to be released to the tank rather than the current situation where you experience overheating. You could also add, if there is room, a thermostatically controlled auxiliary fan to cool the radiator.
Make sure your coolant mix is correct viscosity, and don't run just water; coolant includes chemicals to prevent water pump destruction from minerals in the water. Try not to overfill the radiator either, especially since you don't currently have a overflow tank.
You might have a failing water pump on any of the motors you describe, considering the age of each, # of hours used in high heat conditions, and the tendency of water pumps impellers, (fins)to be destroyed be harsh hard water minerals, assuming you have hard water....
Something to consider since the most frequent thing I hear about your equipment is overheat conditions and radiator bubbles....

BTW, where are you located that you are experiencing so many heat related issues? And have these issues started happening on your machines just recently?
What has you looking for bubbles in your radiators- are your temp gauge needles redlining?