Need help... blown head gasket on my ST1100?

paulcb

paulcb

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Location
Celina, TX
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'97/'01 ST1100 ABSII
Well, the title says what I'm thinking but really hoping I'm wrong.

A few weeks ago, it was running a little warm, so I added some coolant but there were no visible leaks. I took a look at the oil sight glass and saw this...

IMG_0592.JPG

The bubbles gave me a little heartache, so today I drained the oil and this is what came out. My heart dropped when I saw it.

IMG_0702.JPGIMG_0704.JPG

The bike is a 2001 ST1100 ABSII. I bought it in Feb 2016 with 16k miles and it has about 86K on it now. It's always run perfect, 40-45 mpg, 42 on last fill-up a few days ago. The last oil change was about 6k miles ago and it was nice and black, no foam. It's never over heated since I've had it.

So, what does the collective think?
 
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Blown head gaskets generally cause coolant to be introduced into the oil and when that occurs the oil turns into a chocolate shake color and consistency. Unscrew your oil fill cap and check underneath it. If you have any coolant in the oil you'll see condensation on the under side of the cap.

What that looks like to me is leak in the suction side of oil pickup system where the oil is getting aerated causing it to foam
 
When mine was running a little hot last year that's what I thought happened to mine. Take the Tupperware off and take off the radiator cap. Start it and see if you see any bubbles in the radiator as it warms up. Also see if it smells like exhaust in your radiator filler neck. When I dumped my oil before I put it away for the season my oil was all good no bubbles in the oil........p.s. Be sure to put some oil in it before you check it. Good luck.
 
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It doesn't look like a coolant leak to me. Perhaps you overfilled the oil causing the oil to get frothed up in the crank etc. Look like a lot of air in the oil not coolant. Let the oil sit for a while and see if it returns to a more normal state. If it stays frothy it probably is coolant mixed up in it. If it clears up it is just frothed up oil with air in it.
 
Thank you for the comments, please keep them coming. A few more clues...
  • when I changed the oil this time, I only let it warm up for about 3-4 minutes, just long enough to heat the oil but not long enough to burn off any condensation. My bad.
  • I don't see any condensation on the underside of the oil cap.
  • It wasn't overfilled on the last oil change, i.e. it the level was below the top line 10 minutes or so after shutdown. The sight glass image above was taken a couple minutes after shutdown.
  • I plan to send a sample to Blackstone for analysis, but that could take a few weeks.
  • I've not checked the coolant level, but will do that today (done - see below).
 
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Instead of editing my posts above, I'll update as I go along.
  • Just checked coolant level, it was 3/4 cup low. I filled it a few weeks ago, but did that cold and did not check again after running, so there was probably some air in there.
  • Overflow bottle coolant level was at the top line, right where I set it a few weeks ago. No change.
  • Overflow line from thermostat housing to bottle is clear... blew through it and could hear bubbling in the bottle.
  • I don't think there are any leaks in the overflow line.
I sampled some oil from under the foam. Pic colors are pretty realistic. FWIW, it's pretty black and feels, smells like oil.
IMG_0705.JPG IMG_0708.JPG
 
To me that oil in the glass don't look bad. Looks like used oil. Before I sent in an oil sample I would do some more checking like I suggested earlier. Pay attention to the radiator filler neck and see if you have bubbles and gas blow by. If you filled it full it should stay full.Unless you got a leak. These kinds of problems are a bear to trouble shoot but keep on it you'll find it. Just thought of another clue check your exhaust is there more water coming out that smells like antifreeze?
 
Hey Paul, the foam does look a little concerning, but doesn't look like anti-freeze in the mix, it would be more frothy than that, and your oil level would be high by the amount of coolant mixed in with the oil. Also, depending on how a gasket blows you can get different symptoms. Because the oil pressure is higher than the coolant pressure you'll often get oil in the coolant instead of the other way around. Or you could have a breach from a coolant passage to open air inside the engine, and the coolant will leak out and fall from gravity down into the oilpan and mix with the oil. Either way it will be a very foamy mix.

Check the radiator cap, that could explain your coolant loss. Also check hoses, especially the overflow hose off the radiator nipple, look closely for cracks. I'd also try to figure out what caused the surface foaming on the drained oil, I've never seen that before, that's not normal. Could be due to overfilling, but if its not overfilled then I have no other explanation.

Also, blown head gaskets are more common on engines with steel block and aluminum heads, because the metals expand at different rates when overheated. All aluminum engines like the ST are more homogeneous in their expansion rates, plus the fact that blown head gaskets are pretty rare on the ST.
 
Thanks for the insight Doug. The overflow hose is good (see post 7) and it wasn't overfilled (post 5). I've not seen any oil in the coolant, although I need to run it and check it again since I just added a little. After draining this oil, I've not put oil back in yet, pending the outcome here. I'm comforted that the prevailing wisdom so far is that it's just oil foam and not coolant. I tend to agree after seeing the sample in the glass, just curious as to why it's so foamy. When it happened, I jumped to the worst case conclusion and started this thread.

One thing I did notice is that the radiator cap spun off pretty easily. It's a new one I put on a few weeks ago, the one that fits a Honda Accord and is supposed to fit our ST1100s. I think I'll inspect that a little closer. I'm leaning towards adding oil, checking the coolant as it warms up and checking/replacing (again) the radiator cap. If all is good, ride it for a few hundred miles, keeping a close eye on the oil sight glass. Wish the radiator cap was accessible without pulling all that plastic!

Appreciate everyone's comments, more are welcome.
 
My first thought would be you have condensation whipped up by the crankshaft rotation not being boiled off. Based on you said no apparent coolant loss.

It doesn't look very bad to me. It has some foam but the oil looks pretty solid and not milky. Your oil could just have a small amount of moisture from humidity and short rides to work which means the bike has some condensation inside that needs boiled off (if possible). The important part of your pictures is the bottom of the glass containers, I don't see any water or coolant. Oil floats on water but might not separate out readily when mixed good and it's cold. Drain the engine while it's real warm next time and check for water on bottom of the oil (or milk chocolate color).

First I would be sure the problem persists. I think you have already changed the oil so now you need to ride! Try to ride to where the engine warms up good. Idling bikes with radiators don't get all that warm. I don't think it will ever get hot enough to boil water off the insides. At your altitudes (450'?) boiling temp is probably real close to 211'. You need those fans kicking on real steady to be close to that magic steamy boiling temp.

If you have a leaking gasket you will definitely see a quick drop in the coolant level. Then start thinking bad things like head gaskets.

I suggest you ride when you can and watch both the oil sight glass and the coolant level and I'd check the coolant when its dead cold. You will likely leak coolant out the cap if you take it off warm. It doesn't look foamy enough at this point to be hurting the engine much if any, it looks like oil so should be lubing your engine still unless it gets worse. The foam is on top, the oil pump is located down below what little foam you have and is still pumping pressurized oil if the oil pressure light is not coming on.
 
See any bubble at the radiator cap neck with the radiator cap off with the bike running ? Remove some antifreeze fluid before starting the bike to prevent overflow / spilling.

Also, you could do a compression check to rule out a leaky head gasket.
 
Thanks again for the insights and comments. The oil in all the pics has 6k miles on it and is Delo400 15W-40. I've been using it since I bought the bike.

As I mentioned before, I'm leaning towards adding oil, checking the coolant as it warms up and checking/replacing (again) the radiator cap. If all is good, ride it for a few hundred miles, keeping a close eye on the oil sight glass.

FWIW, the foam has completely disappeared and the oil in the glass tumbler has not separated at all... just looks like dark used oil.

1548001528092.png
 
paulcb said:
Thanks again for the insights and comments. The oil in all the pics has 6k miles on it and is Delo400 15W-40. I've been using it since I bought the bike.

As I mentioned before, I'm leaning towards adding oil, checking the coolant as it warms up and checking/replacing (again) the radiator cap. If all is good, ride it for a few hundred miles, keeping a close eye on the oil sight glass.

FWIW, the foam has completely disappeared and the oil in the glass tumbler has not separated at all... just looks like dark used oil.

1548001528092.png
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I've watched this thread with interest. At first, that 'oil' looked terrible.
But upon further info/consideration I think Raymond has it right.
Take it for a long ride keeping an eye on watching the oil sight glass and coolant level.
Glad to hear the foam has disappeared.
 
I'm just going to throw this out there for the debate: Delo is an oil made for diesel engines. Diesel transmission gears are not lubricated by the engine oil. Our bike's transmission gears are lubricated by the engine oil. Motorcycle specific oils have additives that help to prevent oil foaming caused by the gnashing it gets in the gear train. Diesel oil does not require such additive and may be why you see that foaming in your oil.

Other than being "cheap", I have never seen any good reason to use it, or literature that says diesel oil is recommended for use in a 4 stroke m/c engine.
 
Paul, one other thing I thought about a few minutes after my last post, have you changed out the coolant hoses and elbows under the carbs? Your bike is 18 years old now so if that hasn't been done its something that needs to be done. If you're slowly losing coolant that could be one possible location for a leak that isn't easily visible.
 
dwalby said:
Paul, one other thing I thought about a few minutes after my last post, have you changed out the coolant hoses and elbows under the carbs? Your bike is 18 years old now so if that hasn't been done its something that needs to be done. If you're slowly losing coolant that could be one possible location for a leak that isn't easily visible.
Click to expand...

I had the carbs rebuilt about a year ago and replaced everything under there... elbows, o-rings, 3 hoses, etc, along with new coolant and new thermostat.
 
Well, I think I have the most definitive answer I can get without an oil analysis... I heated up some oil to ~300°F, and saw no boiling. Googling tells me that 50/50 coolant boils at around 225°F when not pressurized. So that tells me there's no coolant in my oil. :)
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