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Front Cylinder Head Gushing Coolant

21K views 135 replies 24 participants last post by  realshelby 
#1 ·
Well, it's finally happened.

At 193500 kilometers, the old Vee has experienced a, shall we say, potentially catastrophic failure.

Arriving home in the dark after a 45-minute highway commute this evening, I pulled up to my gate and thought, "What's that smell?" Then I noticed the cloud of steam rising up around me, illuminated by the cold glow of my LED headlights.

I opened up the gate and rode it into the shop and it's leaving a trail of coolant all the way in.

I'm thinking, "I hope it's just a hose worked loose," but no such luck. It's the front cylinder where it meets the engine case. I suppose I can count myself lucky it let go just as I was arriving home.

Who out there has done this job? What kind of project am I looking at? How far into the belly of the beast do I have to go?
 

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#4 ·
You come on up and do it. I'll supply tools, a heated shop, and buy the beer. :wink2:

Unfortunately, this is my year-round ride. I think she's down for a while, so some creative planning is in order. KTM? Honda? My next bike fantasies have just become real. Unfortunately, I just gutted the entire lower floor of my house, kitchen included. While my kitchen looks great, my bike fund is not pretty.

I think I'm driving the Taco for a good while and tearing this bike down over the next couple months. (It's future is the track anyway. Still a stout engine on this thing.)

Does anyone know if this particular job can be done without removing the engine? My initial thinking is that it can be done. I remember having the rad off when checking valve clearances and thinking there was lots of room. Time also for valve shims, maybe valves. I think the rings are still plenty good. Absolutely zero oil use. (Synthetic its entire life.)
 
#6 ·
Well, If you were in a 50 mile radius of Central California, I might consider it...Substitute the beer for Dr. Pepper and even more enticing...But your photo looks to me like a base gasket between the Cyl. and engine case and yes, This not an overnite repair job...
 
#7 ·
Can't tell by your photos, but did you look where the radiator hose goes into the back of the cyl. head. There is a metal fitting the hose connects to. That fitting is held in by a single bolt. There is an O-ring on that fitting to seal it. I've had 2 different 650 motor where those O-rings turned to mush and started leaking(Looking much like your photo).
I fixed mine in a day. It requires removing the injectors to access.
 
#37 ·
TB removed.

Now I'm second-guessing myself. I think the problem is upstream of the base gasket. I couldn't see this prior to the TB removal, but there is a pool of coolant higher up on the cylinder head. I'm pretty sure I did not create this pool while removing the radiator. So where I was seeing the coolant well up earlier was not the source, but the collection place. What this means is that the leak is not from the base gasket, but from the hose or the hose fitting on the front cylinder. You can see in the photo where I have loosened the hose clamp. That seems to be the source. Where the sludge is, below the coolant puddle, is where I thought the base gasket was leaking from. Not definitive yet, but pretty sure. At the moment, I'm thinking a shout-out is deserved to nvr2old. I wish I could observe this particular fitting while the bike is running, but it is impossible. So maybe the cylinder removal will not be necessary. :smile2:



BTW: The Canucks won last night, 7-6. It was a hell of a game, ended on O/T. Glad I watched it. That Petterson is something. I've learned a couple things from him already. Boeser too. But Stecher I've learned the most from. I like his game.
 

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#8 ·
I would make absolutely SURE the leak isn't from above that area.

If it is the cylinder base gasket, I think it could be repaired on the bike. The front cylinder head can be removed while the engine is in the frame iirc. That will give you room to lift the cylinder and replace the base gasket. There are other things that could cause the base gasket to leak, such as loose fasteners or corrosion. You will have to watch for problems as you tear into it. But, if the engine has been doing just fine I don't see any reason this could not be made right pretty cheap. This is a labor job, not so much new parts.

You would need Part #3 in this diagram to fix the base gasket. You would also need a new head gasket and maybe some of the other rubber seals if you want to have them on hand. There are other parts you may want to replace while you are in there like hoses.
 
#9 ·
Honestly, It's a full day of work, if you have every thing you need to do the job and have the skills needed. There's some decisions once you are in there though, like checking cam chain and guides, do I put new piston rings and have the cylinder honed etc. Those things may drag the job on for much longer if you have to order more parts. Do check the valve clearance before the complete teardown, so you can replace the shims if necessary.
 
#10 ·
Thanks guys.

I'm almost positive it's the base gasket and not anything else. I had a good look (well, as good as I could in the dark with a halogen lamp).

I hope to get a closer look this weekend. My plan at the moment is to tear it down and see what parts I'll need. In particular, I'm not looking forward to removing the exhaust. I anticipate some difficulty there. (This bike has suffered a "bit" of corrosion over the last 12 salty winters. I'm hoping that is not contributing to the leak.)

I'll document the process for posterity.
 
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#11 · (Edited)
Larolco, I've mentioned this in another thread, but if you clean the area with spray Brake Cleaner, blow it off with compressed air, and borrow a cooling system pressure tester(auto parts store) you will know for certain the exact origin of the leak.
If you do have to tear it down and are concerned with corroded exhaust nuts/studs, soak them down for a couple of days with a penetrating oil such as PB Blast, Zepreserve, or the best Ive found, Yield. Beyond that, a small Map gas torch flame to get the nuts red will do the deed.
A small suggestion, if you have the wherewithal--perform a compression test and/or a leakdown test before you remove the engine. If both check out good, you wont need to re-ring and hone the engine. If rings arent necessary, Ive raised cylinders above the pistons just far enough to remove the piston pin clip, the wrist pin, and removed the cylinder with the piston still inside. It takes another set of hands to make this easy, and reassembly is simply replace the base gasket,use shop towels to keep the connecting rod centered in the crankcase bore, hold the cylinder/piston assembly above the rod, reinstall the wrist pin and circlip. Slide the cylinder down to the base gasket and proceed with reassembly.
It's just nuts and bolts, how hard can it be?
 
#14 ·
Thanks for the tip re: cylinder removal. I like that idea.

As for penetrating oil, I intend to use a can or two on this job. I hate breaking bolts. This weekend is just remove tupperware, tank, rad, and let the oil penetrate for a good long while. I'll probably do a couple other jobs on the bike while it's apart as well. Fork springs, front rotors, new TPS.

As for finding the leak, it won't be a problem. I just have to fire it up and watch where the gush comes from. I'm fairly certain it's the base gasket based on what I saw last night. It was the only wet area on the bike, and definitely towards the left side. It's not a weep; it's a considerable leak that drained a couple of cups of coolant in the time it took me to put the bike on the sidestand and dismount. Just have to replicate it once more.

I don't intend to bother with a compression test unless maybe just for kicks. I'm certain it doesn't need rings. New plugs for sure, though. You'll be pleased to hear that.

And valve clearances and look at the cam chain. I think if all looks well on the front cylinder, I won't bother with the rear.
 
#12 ·
Not be make lite of your situation, but this sounds like something I saw on a ZZ-Top video!
 
#15 ·
Sounds like a winning plan!
Make sure you have a shop manual with torque specs, an accurate 3/8" torque wrench....and you know the rest, I'm sure.
I generally do a couple of heat cycles, back off the stud nuts 1/4 turn and re-torque them.
If you have a straightedge, place it between cylinder stud bores and measure for warp between them. I use a hand-held Scotchbrite pad and brake cleaner to clean up gasket surfaces. ANYTHING you can do to ensure a 1-time repair will be in your favor.
 
#18 ·
I'm definitely thinking about it. Two problems: Don't know what bike I want and the bike fund is not yet sufficiently grown. And this repair is going to eat into the fund.

I like the versatility of the Vee, but now with the DRZ in the stable, maybe I just want something for the street. Has to be touring capable, have some giddy-up, be capable of running a full complement of heated gear, and tote around my hockey bag/stick. I do like the look of that VRF Crosstourer but insurance rates here are ridiculously high and tied to engine displacement. It's way cheaper to insure a 650 than a 1200.
 
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#19 ·
You have had your clutch cover off...the two holes surrounded by black sealant on the clutch cover gasket are where the water pump pushes coolant into the front and rear cylinders. It goes up the cylinders and into the heads then to the thermostat/manifold and back to the radiator.

You can see the coolant passage in the cylinder base gasket in the link I provided earlier. Not the large opening for the cam chain, but the smaller odd shaped one opposite the cam chain opening is the coolant passage.
 
#22 ·
The 2012 and newer, at least to 2016, DL 650 has much higher insurance rates than the older DL 650's. Why cannot be explained by any insurer I checked with.

I pay more for the 2012 DL 650 in insurance for the same exact coverage than I do for the 2014 BMW R 1200 RT!
 
#23 ·
I can insure my Tacoma for what it costs me to insure the Vee. My DRZ is peanuts.

And now I have to go add insurance to the Tacoma so I can use it to go back and forth to work. It's currently insured only for "pleasure use."
 
#24 ·
Fired it up when I got home from work this afternoon. The leak is definitely from the top of the base gasket. I can watch the coolant well up there as the engine warms up. It is not from anywhere else. Hard to see in the photo, other than a little bit of green. You can't see, but further back, in the hollow where the head turns upwards, there is a big pool of coolant. That's where the breach is.

Crash bars and plastics off.

Fool around with the diagnostics plug a bit in the morning to see what's up with the TPS before I start breaking it down.

Hockey game to watch in the meantime... Colarado 4 Vancouver 4
 

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#32 ·
"new bike over all that work/hassle,"

Lucky you. Not everyone's wallet is as fat as yours!
Find a running salvage bike. Sometimes you can score one at a good price.

It's not a fat wallet thing, I just hate big repair projects like such. Bike isn't worth much anyways, might make more sense to part it out and recover some money......just my 2 cents.
 
#30 ·
I would attempt to repair this instead of sourcing and fitting a salvage engine. A good engine is $6-800 I figure. A lot more work to install the engine properly than you might think, engine mount torquing needs to be done just right on these.

Since I am pretty sure the front head can be removed while the engine is in the frame, this job won't take all that long. If this is simply the gasket failing and not a problem with the castings the repair should be permanent. We know these engines can run well into the 100,000+ range with no problems.

A gasket set and maybe a couple new hoses and other goodies is cheap compared to other directions to go.
 
#31 ·
One more thing...
In some cases Ive been able to eliminate leaks by backing the head nuts off 1/4 turn ONE AT A TIME and re-torquing them to spec. I'd like to know if the base gasket is a steel shim/teflon coated type, and if so what failed. Did the gasket distort from a lack of clamping force? Is the underside of the cylinder or top of the crankcase gasket surface corroded?
These are things that can contribute to repeat leakage.

Years ago i had a coolant leak in my '92 Mazda MPV. It never showed up under pressure testing, but one every 3 weeks I had an 8" coolant puddle under the front of the engine. It took 8 hours under constant cooling system tester pressure to reveal that the front corners of the V6 intake manifold were leaking. I removed the manifold, and the aluminum surrounding the intake manifold front coolant ports were corroded, leaving small paths for the coolant to flow over the embossed steel shim coated intake gasket. 1/2 hour of careful hand sanding restored the surface, a thin bead of RTV sealant was applied to both sides of the gasket coolant ports....and it's been fine ever since.
 
#33 ·
Big B, let me tell you...
Its not easy being a mechanic in today's throw-away society. I've missed out on a lot of new technology keeping my old bikes as-new through the years.
Ive been told by many that they envy a mechanic's skills and knowledge. Little do they know that I used to envy many that could simply go out and buy a new bike whenever they wanted.
 
#40 · (Edited)
I'm decent with a wrench, and have mad respect for those who are REALLY good at such. I'm not part of the throw away society, as I try to take care of and maintain anything that I have within reason. It's not like I would go out and buy a motorcycle tomorrow on a whim, I save up and or buy when the time is more appropriate. I'm not made of money, but I also won't polish something which I may consider to be a turd. :smile2: The OP will/has made the best decision for "himself", but it's interesting to see who all here would fix compared to replace.
 
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