Torn down engine.. take a look at what you see

[~TABASCO~]

This customers bike has about 45k miles... I've never seen a piston this clean.... This orange ring at the top looks and feels like rust... What are your thoughts ? When I removed the TB's I found green liquid sitting on one side of the intake valves. Not full, but like half a Tsp. Also the intake valves are extremely clean. Like I've never seen a Tenere with such clean valves. Where they normally carbon up a bit on the intake side, these things are clean as a whistle..

 

[Eville Rich]

Head gasket issues? Internal headgasket leak lets coolant into the cylinder/s which steam cleans the carbon.

If I'm right, do I win a prize? ;D

Eville Rich
2016 S10
2015 WR250R

 

[Sierra1]

So, don't leave us hanging. Why the tear down? What was the green liquid? Why so clean? Inquiring minds want to know.

 

[Dogdaze]

Head gasket issues? Internal headgasket leak lets coolant into the cylinder/s which steam cleans the carbon.

If I'm right, do I win a prize? ;D

Eville Rich
2016 S10
2015 WR250R

I'm with you on this one, based on old water mist into the airfilter to clean the carbon on pistons

 

[Sierra1]

I also tend to agree. But, he did say green liquid. I figured he knows what anti-freeze is, and this may be something different. (of course I don't know of any other green liquid that would be in a water cooled engine )

 

[~TABASCO~]

Head gasket issues? Internal headgasket leak lets coolant into the cylinder/s which steam cleans the carbon.

If I'm right, do I win a prize? ;D

Eville Rich
2016 S10
2015 WR250R

I agree... Maybe a head gasket leak... Ive never read about ANYONE ever having any issues with a head gasket, but this might be the case for this bike....

 

[~TABASCO~]

So, don't leave us hanging. Why the tear down? What was the green liquid? Why so clean? Inquiring minds want to know.

Its a customers bike... He went to install a new CCT, the chain skipped and he didn't know if that was 'normal'... Then he turned the engine over to start it... It wouldn't start.... So I'm checking the head and valves for valve damage.......

The green liquid: I don't know, looked like antifreeze to me...

Normally when you see valves and pistons clean, that's because of ingestion of some type of water and it steams the water off pretty fast. I'm going to take a GOOD guess this customer did fall in water or cross a river.... I'm thinking maybe there was an issue with the head gasket, but don't truly know..

 

[~TABASCO~]

I also tend to agree. But, he did say green liquid. I figured he knows what anti-freeze is, and this may be something different. (of course I don't know of any other green liquid that would be in a water cooled engine )

to me; that would make the most sense.... I've never seen liquid sitting on a closed valve before.... strange

 

[Eville Rich]

So assuming the liquid is antifreeze and if it didn't come in through a head gasket leak, I see two ways coolant would get on top of the valves (in the head and not the combustion chamber):
1) A coolant source coming in from the air side - is there any sign or potential for a coolant hose to get coolant into the intake? I don't know enough about the S10 to know if this is remotely possible.
2) A cracked head - a coolant passage in the head had a crack that allowed coolant to seep into the valve train.

Not sure if any of these are reasonable. A question I wonder - what triggered the interest on the part of your customer to deal with the CCT? Poor running? Just generally a good idea? If it was poor running, then that might provide a series of clues. If water did get into the intake due to a water crossing, that could stress on the engine, lead to a crack and subsequent coolant leak, and would also relate to poor running.

A fun little mystery here.

Eville Rich
2016 S10
2015 WR250R

 

[BWC]

An interesting one. It's a 12 model?
From the pics the top of the piston shown doesn't quite show normal carbon buildup. Any sign of valve contact? I've seen that hard brown looking carbon at the top of cylinders before look like rust when it's not. Both cylinders/pistons look the same?
The head on the other hand looks pretty good. Exhaust valves are a nice even tan-grey on both cylinders. With coolant found on the back side of the intake valves on the one cylinder, and the head looking nice and even for carbon it couldn't have run much, if any with coolant getting into the one cylinder.
Other than that a few more questions to the owner might help solve the mystery. ::017::

 

[BaldKnob]

Was the owner experiencing any overheating or having to add coolant? It does appear to be a leaking head gasket.
2nd question would be, was his timing off causing the no-run issue? I know it's a PITA but taking the valve cover off to zip-tie the chain to the cam gears is the only way to know you've done the CCT correctly.

 

[EricV]

Another thought is that the air box breather hose was off for some indefinite period of time and external, non-metered air/water was being sucked in. I've seen similar, and the valve train can be pretty clean, but you also get accelerated ring wear from 'dusting'. A funky water crossing might be enough to get contaminated water in there that might account for the green. Do we have bronze valve guides? That could also account for the green color.

Any evidence of head gasket leaking at the gasket? It's usually pretty self evident.

 

[holligl]

Maybe a lot of green algae in that water crossing!

 

[~TABASCO~]

Another thought is that the air box breather hose was off for some indefinite period of time and external, non-metered air/water was being sucked in. I've seen similar, and the valve train can be pretty clean, but you also get accelerated ring wear from 'dusting'. A funky water crossing might be enough to get contaminated water in there that might account for the green. Do we have bronze valve guides? That could also account for the green color.

Any evidence of head gasket leaking at the gasket? It's usually pretty self evident.

The bike is in good condition and all the parts are installed properly. He has ridden in heavy rain like all of us but nothing else. Everything looks normal. The head gasket appears to be in ' normal ' condition. After vacuuming out the cylinders the pistons look like almost new with not many miles on the engine.

Someone asked why he installed a new CCT. The bike is a 2013 and he had just a little timing chain noise, so he tried to install a 2014 unit. The chain skipped on the cams.

 

[Don in Lodi]

Any sign of milkshake in the crank case? That could be an indicator of how long water was being digested.

 

[~TABASCO~]

Any sign of milkshake in the crank case? That could be an indicator of how long water was being digested.

Oil looks 'clean'....

The situation is kinda strange... All indications of a head gasket issue... But, some of the other known issues that come along with a real head gasket problem are not found in this case..

 

[~TABASCO~]

An interesting one. It's a 12 model?
From the pics the top of the piston shown doesn't quite show normal carbon buildup. Any sign of valve contact? I've seen that hard brown looking carbon at the top of cylinders before look like rust when it's not. Both cylinders/pistons look the same?
The head on the other hand looks pretty good. Exhaust valves are a nice even tan-grey on both cylinders. With coolant found on the back side of the intake valves on the one cylinder, and the head looking nice and even for carbon it couldn't have run much, if any with coolant getting into the one cylinder.
Other than that a few more questions to the owner might help solve the mystery. ::017::

Its a 2013..

Ive seen many Tenere's.. This engine is really clean for 45K miles. Ive spoken to him, he is a "totally normal rider"... Looks like a head gasket issue, but other things normally associated with head gasket issue are not found in this situation..... kinda strange... We were not even looking for this situation. I was looking for possible valve damage due to a CCT install that someone else did. Found no valve damage but stumbled across these strange pictures...

 

[greg the pole]

I'm at a loss.
Those valves are spotless for 45k. There is an o-ring on the pump (#21) but no way would that get coolant to the top of the pistons. It would just mix with the oil below the pistons.
http://www.cheapcycleparts.com/oemparts/a/yam/53306f36f870024560f03e16/water-pump

I made sure to replace that one when I was rebuilding my motor.
My head at 79k km/49k miles
https://flic.kr/p/QVvGth

Quite a bit of carbon due to valve seal leaks.
Piston and rings well in spec. Bores needed a hone

 

[~TABASCO~]

I'm at a loss.
Those valves are spotless for 45k. There is an o-ring on the pump (#21) but no way would that get coolant to the top of the pistons. It would just mix with the oil below the pistons.
http://www.cheapcycleparts.com/oemparts/a/yam/53306f36f870024560f03e16/water-pump

I made sure to replace that one when I was rebuilding my motor.
My head at 79k km/49k miles
https://flic.kr/p/QVvGth

Quite a bit of carbon due to valve seal leaks.
Piston and rings well in spec. Bores needed a hone

Yep,

Valves (top and bottom), and pistons are super clean... Everything is super clean.... really strange....

 

[WJBertrand]

Even without the valve timing slipping, engines will sometimes spit back through the intake tract, so it should not be too surprising to find coolant on top of an intake valve in the case of a failed head gasket. The deposits on the piston crown seem to indicate it was at one time pretty wet and then dried up, leaving that strange pattern of deposits.