Coolant getting in oil / Cracked Cylinder

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Aug 3, 2008
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2007 ST1300
Took my 07 (30k miles) in to have valves inspected and generally gone through - fork oil, clutch fluid, tires, etc.

Mechanic just called me to tell me that when all the work was done, he was warming it up to test ride before delivery, and noticed coolant dripping from the exhaust weep holes (from mufflers) and sight glass shows emulsified oil. He estimates the bike lost a quart of coolant into the oil system in a matter of 10 minutes of idling.

He is now stripping it back down and is saying it's either a blown water pump seal, blown head gaskets, or a cracked head.

Bike has never left any coolant on the ground, and oil level has always been rock stable, though there was some dirt/grime around water pump weep hole (as is fairly normal).


Thoughts?
 
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Re: Coolant getting in oil

Something not right here. If coolant was dripping out the exhaust, that would also mean tons of white smoke should be coming out the exhaust as well, since the only way it could get into the exhaust is through the combustion process, which would indicate a blown head gasket. Did he mention white smoke? I can't imagine the engine would run very well at all with the amount of coolant going through a cylinder(s) that would see it dripping from the exhaust either. Did he change the oil and not notice a milky white mixture come out when drained? If the water pump seal vents to the engine exterior, as it does on the 1100, then that leak would not get into the crankcase. That's all I got.

Playing devil's advocate - is this dealer particularly busy, or maybe looking to drum up some work? You should definitely be in there to witness all he has to say about the issue.

One more thing - you DID have proper coolant in the engine suitable to withstand the sub freezing temperatures needed to prevent a cracked block?
 
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Re: Coolant getting in oil

You said he checked the valves, did he check them only or did he replace some shims. Maybe he didn't get the timing right and the valve contacted the piston.
These are zero clearance engines, so if the timing is not correct you'd have contact.
Just a possibility.
 
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naustin
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Re: Coolant getting in oil

No mention of white smoke.

He said it was especially strange to him too, because it was running fine.

He sent me pictures of the bike with valve covers off during valve inspection, no milky substance evident.

Coolant was last replaced by dealer 4 years ago, with no need to top off or add at any time leading up to this.

It's an independent guy - not a dealer. But yeah - I get the drift that he's busy.
 
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naustin
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Re: Coolant getting in oil

He said he adjusted a number of them to center of range, even if they weren't totally out of spec....
 
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Re: Coolant getting in oil

wow, what a nightmare. What's the chance that you'd randomly blow a head gasket, or crack a head while he had it in his shop? Coolant mixed in with the oil would have been visible if the problem were there when you brought the bike in, so the big question is did he do anything to the bike that could explain the cause of the problem, like changing the coolant?

I also second Bush's question regarding the ability of your coolant to withstand a Minnesota winter. I rarely see temps below 40F, so I'm no expert on that topic.
 
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naustin
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Re: Coolant getting in oil

He said he had the radiator off and changed the coolant as part of all the work.

Shop is heated - and it really hasn't been that cold...

Yes. Nightmare is the right word.
 
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Re: Coolant getting in oil

You said he checked the valves, did he check them only or did he replace some shims. Maybe he didn't get the timing right and the valve contacted the piston.
These are zero clearance engines, so if the timing is not correct you'd have contact.
Just a possibility.
I'd say little possibility of that scenario, as a bent valve(s) would not permit smooth idling for 10 minutes.
 
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Re: Coolant getting in oil

He said he had the radiator off
WHY would he have the rad off??? This just gets stranger and stranger. Do you have a friend knowledgeable in engine mechanicals that could go to the shop with you to verify some of these supposed issues?
 
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Re: Coolant getting in oil

No mention of white smoke.

He said it was especially strange to him too, because it was running fine.
I'm wondering if he has mistaken coolant out the mufflers for water condensation, which will ALWAYS happen when an engine is warming up. I can't imagine a trained mechanic making this mistake, but I have often heard people with no clue whatsoever wondering what that was coming out their exhaust on cars and bikes. Easy test is to dab your finger tip in it, touch it ever so slightly to your tongue tip. If it has a distinctly sweet taste, it is coolant. Wipe it off the tongue right away of course, you will taste it instantaneously. It won't hurt you.
 
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Blrfl

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Re: Coolant getting in oil

He is now stripping it back down and is saying it's either a blown water pump seal, blown head gaskets, or a cracked head.
Thinking aloud here on that and some other things that have been said:

A failed water pump seal would result in oil or coolant coming from the weep hole on the right side of the engine. For oil and coolant to mix there and get back into the rest of the engine, both seals would have to fail.

A blown head gasket or cracked head near a cylinder would show up as a lack of compression, which should be checked before tearing the engine down. A gap in the head or gasket between coolant and oil passages is possible and would result in coolant in the oil sump. Pressurizing the cooling system (again, before teardown) would help detect a leak there.

A bent valve shouldn't cause oil and coolant to mix unless it did damage to the head beyond the valve seat.

On Bush's comments: It's pretty hard to find coolant that will freeze up during winter anywhere in the U.S., and since the bike has been through four years on the same coolant, I'd think it would have frozen up earlier. The condensate angle is possible. No need to taste it, BTW, coolant's pretty slippery, too.

Could post the pictures you were sent?

--Mark
 
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naustin
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Re: Coolant getting in oil

This guy is no novice and comes highly recommend from experienced riders and local track day coaches. His Facebook page for the business is loaded with pics of customers bikes and showing the scope of repairs and the quality and detail he puts into his work.

I'm not ready to call the guy a liar. But, I'm definitely concerned. His shop is about 100 miles from me, so its tough to just drop in. Maybe next week.
 
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naustin
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Re: Coolant getting in oil

I can post pics Monday. I'm on my mobile at the moment...
 
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Re: Coolant getting in oil

WHY would he have the rad off??? This just gets stranger and stranger. Do you have a friend knowledgeable in engine mechanicals that could go to the shop with you to verify some of these supposed issues?
I know you say he is a well respected mechanic, but as Mr Bush says....getting stranger and stranger.
 

wjbertrand

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Coolant getting in oil

I wonder if over torquing one of the cam holder bolts could crack a cylinder head? I'd expect the head threads to strip first, but who knows. It's really hard to imagine what he could have done to cause this, even if he was a total numpty.


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Mellow

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Re: Coolant getting in oil

Removing the radiator is odd... hopefully the pics will help more.
 
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Re: Coolant getting in oil

Way back when I had a new 78 CX500, I had the right head gasket leak. I noticed a different smell to the exhaust and some small glass bead like deposits at the muffler outlet. First step is to do a compression check or leak down compression check.
 

Blrfl

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Re: Coolant getting in oil

This guy is no novice and comes highly recommend from experienced riders and local track day coaches. His Facebook page for the business is loaded with pics of customers bikes and showing the scope of repairs and the quality and detail he puts into his work.
Even the well-seasoned make mistakes. I'm no novice at what I do and will be the first to admit that I goof up once in awhile.

I wonder if over torquing one of the cam holder bolts could crack a cylinder head? I'd expect the head threads to strip first, but who knows.
That's an interesting question. Offhand, I'm inclined to think not since the cam retainers aren't particularly beefy and the service manual warns that they'll break if not torqued in a crisscross pattern in several stages. Making them weaker than the head seems like an intentional design choice; I know I'd much rather replace a couple of cam retainers than the entire cylinder head.

Removing the radiator is odd... hopefully the pics will help more.
I figured changing the coolant fell under "etc." in the first post.

--Mark
 
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naustin
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Re: Coolant getting in oil

More pics. What is the round thing in the 4th picture that looks damaged?
 
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