Contaminated engine coolant

[Guest ssparks905]

Shortly after I got to work on Wednesday, I got a call from another rider that there was a puddle under my 1st Gen Venture. I wasn't able to check it out until about an hour later... no puddle. Just to be sure I pulled the radiator cap and found a nasty light gray scum about the consistency of toothpaste coating the inside of the radiator and cap! Well I know it is an oil leak into the cooling system... the short hose that connects to the radiator near the cap failed from the oil contamination. I'm currently working to get the goo cleaned up (including a Water pump seal kit and thermostat since I had it apart). I'll replace the hoses since they show signs of bulging now.

 

I'm worried that it may be a head gasket since there doesn't seem to be any coolant in the oil. I wasn't ready to dig that deep into the engine. Does anyone have other suggestions for me to check before I pull the heads? Also, can I pull the heads without pulling the engine?

[Venturous Randy]

In the valley under the carbs there is an oval cover that if leaking internally can contaminate the oil/water. This has been reported several times this year from riders who thought they had a head gasket leaking.

RandyA

[Guest ssparks905]

Thanks! That thing looks a lot easier to get to than the head gaskets. I'll open it up tomorrow and have a look if I get time. I was thinking about pulling it apart anyway just to clean out as much of the contamination as I can.

 

I really need to get into the forums more often.

[Guest ssparks905]

Finally got time to pull that oval coolant assembly from between the front and rear cylinders. It looks like the oil from the pressurized line that runs through the assembly did manage to find a path into the coolant channel.

 

I've ordered the custom o-ring seals and some other miscelaneous stuff from the local Yamaha shop. While I'm waiting for the parts to come in I'll probably clean the carbs again. I pulled the airbox to get access to the mounting bolts for the oval assembly and forgot to cover the carb throats when I used compressed air to clear out the junk that had accumulated in that valley area. I need to seal up some pinholes in the diaphrams anyway...

 

SSparks905

[6m459]

I have a similar problem, except my coolant disappears into parts unknown. I also suspect the oval thing which I believe is part of the crank case vent system.

 

I sure would like a picture or two of what this baby looks like when it is apart.

 

Would it be possible for you to post some pix?

 

Thanks,

 

Brian H.

[Gearhead]

So does anybody know why Yammy saw fit to design such a complicated crankcase vent? What possible purpose does it serve to have the oil, coolant and vent go thru the same box?

 

Thanks,

Jeremy

[Condor]

So does anybody know why Yammy saw fit to design such a complicated crankcase vent? What possible purpose does it serve to have the oil, coolant and vent go thru the same box?

 

Thanks,

Jeremy

 

Possibily a half hearted attempt at an engine oil cooler???

[Guest ssparks905]

Brian H, I forgot to take pictures! Just so everyoone knows where that thing is, the parts fische shows it in the "Radiator Hose" drawing. line drawings, but not bad. The seals are convoluted o-ring type things that fit in grooves between the pieces.

 

Now for the really bad news. First, I used solar energy and gravity to get as much of the mayonaise-like stuff (that the oil and antifreeze made) out of the radiator. I pulled all of the hoses, swabbed out the larger ones and used compressed air to purge the smallest, disassembled and washed the water pump, and Thermostat assembly. then reassembled everything with new seals in the waterpump and that oval thing, new thermostat and radiator cap.

 

I ran three full radiator flushes to clean out the rest of the goo and the third flush was still milky colored. The worst was that it had new dark oil floating in it. I haven't repaired the oil leak.

 

I have relocate to a larger garage where I have more room to move around the scoot and am preparing to pull the engine to replace the head gaskets.

 

 

I promise to take pictures this time! I'll be working from a great article in the Tech Library and I have the shop manual. I'll check any problems in the Clutch and transmission, that oil gallery o-ring failure, and lifter clearances while it is out. Looks like several more weeks without a ride.

[okscooter]

I would buy or build a cylinder leakdown tester and pressurized each cylinder one at a time if you think its a head gasket. Remove radiator cap, bring the piston to TDC, valves closed, apply air pressure into the cylinder. If a head gasket is leaking into the coolant jacket it should bubble in the radiator.

There is also another part that may be causing your problem. Yamaha parts finder calls it a "Joint", part #17, 26H-12469-01-00, on their diagram, its behind the sparkplug and held in place with a spring pin, there are 3 Orings on it. Its made of plastic and can be a real SOB to remove. If I remember right this also separates oil & coolant. Someone else may chime in here.

I'd be surprised if its a head gasket, their 3 layers of steel plate laminated together to make 1 gasket. When I pulled the heads on my 86VR, I thought somone installed 3 head gaskets on it, its actual just 1.

[Guest ssparks905]

okscooter,

Thanks for the info. I did read about that part in the Service Manual. It said not to mess with it unless performing a full teardown. I'll investigate and then make a decision re. tearing down the engine. I am getting quite a lot of noise from the back right side of the engine and I may still tear down to find out if the tranny and clutch are OK.

 

I am concerned that the Yamaha dealers I've checked don't list the head gaskets in their online parts catalogs. MRCycles skips item 28 altogether and bjsyamaha (Albuquerque dealer) has a part number, but doesn't offer a price or option to add that part to the shopping cart! BJsyamaha also lists most of the bearings as backordered.

 

I'm open to recommendations for parts suppliers! I'll be researching availability and pricing for the case and cover gaskets, (I've been making my own for the couple of covers I've had to remove so far, but that is pretty time consuming.

[Gearhead]

I have great luck with Zanotti,

https://www.zanottimotor.com/shopping/partLookUp.html

 

Also try RonAyers.com and Flatoutmotorcycles.com

 

Jeremy