Major coolant in oil issue!

Hi guys, recently completed the full rebuild on my 01 Fe650, went fine I thought, it's really had the full works, alot of time and money. Was very happy with the rebuild and had no concerns over the build and quality. However, after the first fire up, I noticed oik dribbling from the weep hole, I had forgotten the seal on the bearing for the water pump shaft! (not the small shaft seal, but the actual bearing seal.
Anyway, I quickly realised this, and proceeded to strip the side cover, fit a new correct bearing with seal , and replaced all gaskets and seals just fir good measure. All good I thought. However I did notice when I had the casing off, a certain amount of emulsified oil. Didn't think much of it until I ran the bike again fir longer, and my oil went today white!
After some advice, I flushed the engine oil a few times, ran again, and sane happened. So left cover can off. Checked and replaced the oring for the coolant connection between the block and cover, no problem, re assembled, new oil, same issue.

So cam cover off, check head torques, all OK at 44nm per the manual. (have since been advised they should be more like 46 ftlbs which is more) So tightened them up a tad, ran it again, same issue.

Getting fed up now. So engine cane back out, cases apart, check liner seals. No problem can be found!
Any advise on what I may have ballsed up would be great, and anything else I can check. I've looked for cracks, damaged liner, bad seals, warped bits, everything appears perfect!

This thing is breaking my heart, and my wallet! Haha

Some pics to show the oil colour, liner seals and just one to show how good it looked when it was complete! Lol

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OK, so may have figured it after many hours of standing and staring at a pile of bits.

I used a very particular, strong frame sealant for my cases. It's a genuine volkswagen audi product which is primarily used on camshaft frames where you want absolute precision in the tolerances. I have a load in stock as use it in my garage. However i hadn't factored in that the normal application areas of this product, I don't think ever see any coolant or glycol based liquids.
It's definitely a product for oil areas, but I think my failing point is around the cases near the barrel. I seem to still have some tacky sealant which hasn't cured, or has reacted and gone sludgy again.

My best guess is, it's washed it out and left enough gap for coolant to enter the cases.
Would also explain why it was getting worse and mixing quicker after each oil and Coolant flush.

I guess rebuilding it with normal sealant will be the test!

What sealants are recommended? Silicone rtv? What temp range? Don't want to get it wrong a second time! Haha

I was initially concerned this would have changed my crank float measurement. But Im probably overthinking it to much.

Thanks


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I have used "Three Bond" silicone liquid gasket on my rebuilds on all areas where there was no gasket or o-rings. I had no problems until a year ago. But the coolant in the oil was not as bad as yours. I had very slow leakage around the cylinder sleeve O-rings. I still have not got around to assemble my motor yet, waiting on crank rebuild.


Mars
KTM 250sx 2010
Husaberg FC550 2001

Thanks for your reply. I can confirm that after rebuilding my cases using a standard silicone gasket upto 300 degrees C rating, I have run the bike and so far so good. No signs of coolant mixing.

As it was so bad I need to flush it through with more cheap oil to make sure ive got all the bad stuff I can out before refilling it for good!

The just got to put some miles on the engine to run it in and confirm it's all OK.


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Hi can you plz tell me where you bought your blue coolant pipe?

Autosiliconhoses.com
They call it heater channel pipe, available in a few sizes and colours, and had a solid wire strand spun inside so when you bend it to a shape you want, it pretty much holds itself there. Great stuff

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i sell these Samco hoses

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