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94 ZX6E Blown Gasket - Bottom end full of coolant

5K views 19 replies 3 participants last post by  Eddiezx600e 
#1 ·
When I pulled up to my house from a 2minute ride around the neighborhood the bike decided to stall out as I stopped (I think it stalled due to lack of fuel). I got off and put my helmet down. When I walked back over to the bike I saw a milky coolant/oil mixture dripping onto the ground from the carb area:

My dad and I pushed the bike into the garage. Looking at the oil level window on the side of the motor showed a milky oil and a very full lower end (with the bike on the kickstand the window was still almost full). So full that I some of the oil/coolant mixture was pulled up into the intake VIA the oil breather tube. Luckily it looks like not much if any made its way into the actual carbs as most of it just leaked out of the air box. I immediately used an evacuator and emptied the out all of the oil. Filled the lower end with oil and again as I disassembled the bike. I drained the oil again and dropped the oil pan. I sprayed as much as I could with carb cleaner. I also drained all of the coolant lines, and removed the radiators, ect. I put the pan back on and filled the bike back up with some oil and sea foam so it could sit over night.

I looked into the each cylinder with my snake camera and didn't see any cylinder damage or water/oil. I believe the pistons and top end are fine. The lower end also seems like it will be okay as long as nothing rusts. I think I acted quick enough to stop any damage. I also think it happened very close to when I pulled into my house as I only went around the block 2 times.

My question is what would cause so much coolant to enter the bottem end in such a short amount of time? I am thinking it must be the coolant pump gasket or something because the bottem end filled up extremely fast. This is my first bike so I don't know too much about the layout. Considering the top end looks okay I am assuming it is not a head gasket?

What gasket do you guys think leaked? I am just not sure what would allow that much coolant to enter in under 2 minutes.
 
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#2 ·
I pulled the water pump today. The impeller wiggles a bit but it isn't anything crazy. I pressure tested the water pump to check for leaks but the thing didn't leak. I also used a drill to pump coolant through it and it didn't leak either. I believe the water pump is still good and isn't the issue.

I am thinking either a bottom end or top end gasket is causing the problem now..

Is there an easy way to check whether it is the head gasket or bottom end gasket leaking? What else could cause so much coolant to enter the bottom end in under 2 minutes?

Thanks, guys!
 
#3 ·
Most likely the head gasket suddenly failed.

Hopefully you stopped the engine quick enough to save the connecting rod bearings, rings and valves from excessive wear and overheating.
 
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#4 ·
None of the cylinders had any liquid in them at all so I can't see it being the head gasket.

Yes this all happened within 2 minutes as I just went around my neighborhood once.

I am considering the base gasket failed suddenly, or the water pump is bad and I just am thinking it is okay. It was leaking coolant next to the kickstand and a little from the carbs so I have a feeling some was coming from the weep hole, which apparently means the pump failed?

Thank you for the reply!
 
#5 ·
Most likely (you will need to do a visual inspection) a head gasket section between a cooling passage and an oil passage failed, not a head gasket section between a cooling passage and the inside of a cylinder. See if all of the cylinders are clean inside, on top of the pistons and on top of the rings, and deep inside the spark plugs.

Base gaskets very rarely fail- they are under less pressure and cooler, but it is possible.

It is also possible that a head wall or cylinder wall cracked.

A leaky water (coolant) pump would less likely put coolant in the oil, but it is possible.
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#6 ·
I pulled the spark plugs and checked the pistons with a snake cam and they showed no sign of liquid. That is why I thought I could rule the head gasket out.

I took off the oil pan today and filled the block with coolant and exposed it to about 10psi of pressure. No coolant dripped down from the bottom end.

I also took out the water pump and inspected it. There is a small amount of play with the impeller but it doesn't seem to leak. I sealed it off and pressure tested it with about 15psi in a bucket of water and it didn't leak. I also filled it with coolant and spun it with an electric drill and it didn't leak.

I really cannot seem to figure out what the issue is.

Do you have any ideas or tests I could perform?
 
#7 ·
I would hire a mechanic to do a compression test and probably take the head off and replace the head gasket, while inspecting everything for cracks and leaks and other problems, and to adjust the engine valves while they are there. It is probably a good idea to add a new cam chain tensioner while this work is being done, to help prevent future problems.

Another possibility is adding a used engine from another bike, if you trust it is a good one. You might get your engine taken apart and find a big crack or warp, usually in the hotter top areas with ignition adding a lot of pressure.
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#8 · (Edited)
I would hire a mechanic to do a compression test and probably take the head off and replace the head gasket
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I just did a compression test. The results are with a cold block and the measurement is the pressure at which the needle stopped moving:
Cylinder: 1 2 3 4
Dry Test: 65psi 65 60 50
Wet Test: 70psi 70 60 60
From these results it is obvious that the cylinder 4 rings are on their way out. But all of these numbers seem very low to me, I am used to 150psi+ with my other toys.

At this point since they are all so low and the bike was running perfectly fine before the incident I think it is safe to skip the leak down test and assume it is a blown head gasket. What do you think? (Also note the bike was bored out so there is a possibility of the water jacket being thin and cracking or leaking)

I also have a new water pump on its way. So if it isn't the head gasket and it was the pump I have that covered too.

I will be dropping the motor this week and changing the head gasket out. I am assuming the zx6e motor comes out the same as the zx6r?


On a side note: I find it weird that I have a loss of compression but no coolant or oil leaked into the cylinder..
 
#9 ·
Especially if you are doing it yourself, I would try a new head gasket first, and do a full inspection for the top end while you have the head off. There is a good chance a new head gasket will fix it enough to ride, even though the rings seem somewhat worn for the one cylinder since they got better wet- a 10 to 15 psi difference from the other cylinders is not huge.

If the engine was not knocking and the overheat light was not on long before you shut it off, there is a good chance (not 100% though) that the rod and crank bearings are fine.
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#10 ·
No the bike was barely even warmed up when it happened. I was just going around the neighborhood warming up the bike and the tires since I had just put on new tires.

I have the engine out and so far have made it up to pulling the cams out. My airgun wasn't strong enough to remove the allen bolts holding on the top end so I need to borrow a friends gun or figure out a way to hold the engine still while using the breaker bar.

I will post updates as I go.
 
#12 ·
If you are lucky it will be an inexpensive fix.

I am wondering if the head surfaces were properly cleaned and if the head bolts were tightened properly (check the threads for damage), or if the new head gasket was a cheaper Chinese-made gasket.

I would ask an expert (not me) about maybe adding a head gasket sealer and maybe a bolt thread locker made for high heat and high pressure. Another possibility is one or more of the older head bolts stretched and got weaker when tightened a second time for the new gasket.
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#15 · (Edited)
It sounds like the cam chain is scraping something, but I am not that familiar with your engine.

Hopefully someone who knows more than me will answer. According to the far (from) right here, that is almost everyone on earth <grin>.
 
#16 ·
It sounds like the cam chain is scraping something, but I am not that familiar with your engine.
I thought that too, I reset the chain tensioner and it didn't make a difference. I also tried pushing one more click on of it like some people said but it was taking too much pressure to do it so I decided against it. I also thought maybe I wasn't getting spark on a cylinder but they all checked out and have spark.

I also took off the oil line that the oil gets pumped through to get to the cams and it shot oil out so I think the top end is getting oil.

One thing I did notice was I had one of the baffle plates on 180 degrees and so the cover wasn't sealing properly. I fixed that and it helped with the sound.

If anyone has any ideas let me know. Also the idle seems a bit low. Timing seems fine to me!
 
#17 ·
The idle can be adjusted faster, either with a hand turned knob on the shifter side of the engine, or with the pull throttle cable adjustment at the bottom of the pull throttle cable- the top of this cable also adjusts for the amount of cable slack- it is best to have a little slack before the engine starts to speed up above idle, after turning the throttle.


The push throttle cable is for safety, if the pull cable ever breaks this cable makes the engine go to idle, and also so the throttle takes a lot longer to start to get stuck in one place when the oil inside the throttle cables starts to get dirty or missing.


I am a believer in using a spray oil specially made for inside throttle cables, such as the Cable Life or PJ1 brands. You can buy a special applicator that attaches to the top of each throttle and clutch cable, to spray the oil inside the cables.
 
#18 ·
I repacked the exhaust, upped the idle to about 1.5k, and threw on the plastics. Bike runs and sounds great now, I think there was a lack of back pressure along with a low idle making it sound rough. It starts right up and runs perfect just like it had before the head gasket went!

I have used WD40 on the throttle cables because they have gotten hard to move before.

Thanks for all the help Jeff!
 
#19 ·
I am glad I was of some help, especially since it turned out to be the head gasket and not something worse.

I guessed wrong for someone with an engine rattle that tried a new cam chain tensioner first, and it turned out to be bad lower end bearings. They can hopefully use the new CCT later or return it.
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