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I have oil in my coolant!


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I have oil in my coolant! I have read up on it here and apparently it could be as simple a fix as changing the plugs under the fins? Is this true? I am going to do the vmax cam upgrade and carburetor ugrade soon so I will have it pulled apart, should I check for any other problems that might be leading to the oil/water mix?

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I'm sorry to say that I think you have misunderstood the information about the plugs. I don't think there is anyway that they can cause you to get oil in your coolant. Unfortunately, I think you have a much bigger problem. I'm not even sure that your Royal Star has those plugs, I don't know for sure but all the posts I've seen here about them has been in regards to the Royal Star Venture.

 

Hopefully somebody else will come up with a simpler explanation but my first thought is a bad head gasket.

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Freebird is correct, the plugs are just an external coolant leak concern, and have no way of causing your concern.

Yours does have the same freeze plug style as the venture.

You must have a head gasket failure to allow oil into your coolant.

Mike

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I may be way off base here, but couldn't the Breather (twinkie) cause oil and coolant to mix either from a failed gasket or an internal crack ? The only place in the manual that I could find that reference's the breather is on page 4-23

 

Remote, yet possible???:detective:

Good call ragtop

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That sux. Ok so even if it is the Twinkie the gasket is more than likely faulty. If there is a crack would I be able to see it?

 

Hard to say if it could be seen, if there is a crack, it may open under heat or pressure. There are methods for finding cracks that are not visible.

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Ok well I will go with the gasket just ordered a set from thumpertalk. I will start pulling the bike apart today and get it ready. Means I probably won't get a ride until after Easter. I'm still waiting for a mate to make up the adapters for the 32 mm carbies so I guess I might need to give him a bit of push to get them done.

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I had this happen on by 98 Royal Star Tour Classic, and it turned out to be the seals on the water pump. There are a set of seals on the driven shaft that runs the pump, one side keeps coolant in and oil out, the other keeps oil in and coolant out. There is a chamber between the two that should stay dry, it has a small vent tube that you can check, if it is wet with either oil or coolant, that should tell you where the issue is.

 

This is not the only place where coolant and oil could mix, but in my experience on this forum and others over the past 15 years this has been the most common cause.

 

The fix is relatively easy and cheap, and you can buy a rebuild kit from Yamaha.

 

I will tell you it is very difficult to get all of the oil out of the coolant system, it may take repeated flushes.

 

Other wise do a compression test and leak down test to determine if you have a blown head gasket, very rare occurance on these motors.

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I haven't dumped the oil yet but will do so today and there was no bubbling in the reservoir.

 

So It could well be the pump seals, would these be parts no 8 and 7 in the attached diagram or do I need something else to do the job?

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Its funny when I did my initial search on this in the forum only the plug results came up and now underneath the posts there are at least 3 links showing on this topic. After reading more into it it would seem to be the pump seal.

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A trick my truck mechanic uses when a oil cooler fails and fills the radiator full of oil. You have to realize were talking about a motor that holds 10 gallons of oil and just as much water you can only imagine the mess it makes. What he uses after the new oil cooler is installed is Cascade dish washing liquid the gel type for dishwashers. For a truck he uses a 2quart bottle poured in the radiator then fills with water. Start truck up and let it run till operating temperature is reached and then lets it run for about 15 mins or longer then he starts flushing. I would suspect a 1/2 a cup or so would be plenty in our bikes to help cleanup the oil. Then flush repeatedly till clear. Just be sure to let the bike warm up good and circulate the soap good before flushing.

 

Hope this helps

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mbelik

Yes as a minimum those are the parts you need, one or both of them is likely to be bad.

I would suggest also as a precaution you should get item 23 and 18 in case they are damaged taking the unit apart, also the shaft on item 2 may be scored depending on how the seal(s) failled, inspect it very closely , if it is not overly expensive or if it is a long lead item, it may be in your best interest to have one at the ready just incase you need it, it may be included in the rebuild kit if you get that as opposed to ordering the parts alacarte so to speak.

 

Good luck

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I have the same issue with my '89, been this way a couple of years, it collects a film of oil (actually more of a grey slime) at the top of the coolant in the recovery tank. It takes about a year to collect the film. I took the breather/water manifold apart, I think this is what some have referred to as the twinkie, and it appears this is the source of my leak. There is an oil pressure passage that is very close the coolant passage. I have not been getting any coolant in my engine oil, my guess here is that engine oil pressure is higher than the pressure in the cooling system and possibly the gasket was probably good enough to keep the coolant where it belongs when the engine was not running.

 

I have my doubts about the water pump as there is a weep passage that allows coolant or oil that leaks past seals to leak to ground. It could be the source if the passage was clogged but my experience with seal setups similar to this (Deere engines with gear driven water pump) is the when the weep passage gets plugged the coolant ends up in the engine oil and not the other way around. In my case it almost definely was not the water pump as I have been intermittently losing a small amount of coolant out the weep passage but no oil. If your passage is not clogged and there is no oil coming from it the water pump probably is not the source of the oil leaking into the coolant.

 

I looked, second gen and first gen use the same gaskets for the twinkie. It's a good idea to check the water pump but If you have not decided to do so already I would recommend removing and disassembling the twinkie, especially since you are already going to have the carburetors off. At that point most of the work is done and gaskets are only about $20.:2cents:

Wish you well in finding your leak.

Jeff

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  • 1 month later...

Thanks to you all for your help. Last week I had a chance to spend a day on the bike so I decided to do the required work to get this leak fixed. I refurbished the pump as well as the breather as it was only a small difference in price. When I pulled it apart I think that it was the breather as the o rings were almost flat and I think they have been leaking very slowly for a long time. The pump seals were a bit worn but I think they were still holding up. Hopefully I will get the new carbies on in the next few weeks and I can take it for a ride.

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  • 3 months later...

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