A A A A Author Topic: Coolant in Oil  (Read 357 times)


Coolant in Oil
« Started on: 03-Dec-19, 13:04 »
Hi CX Gurus

Looking some mechanical advice/guidance.

I recently purchase a 1983 CX650 Turbo (US model with about 45k miles on it). When I got is the head gaskets had be done (water leaking into oil) but these was still a water leak into oil. The owned had had enough and wanted to move it on so I took it knowing the issue was most likely the mechanical water pump seal. So I changed the seal using the Shep method. All looked OK (no more water in oil and then I had a brain snap. Flushed the radiator and did not fully bleed "DOH". Went for a ride, overheated motor and you guessed it, now got water (coolant) in oil.

Thought I would tackle the easy job 1st so fully replaced the water pump mechanical seal. PS: This was easy. Now this is all good but still water in oil.

Guessing (hope) it is a blown head gasket.

Symptoms are strange:
1) Water (should say coolant) in oil.
2) Compression test is all good. 150psi both cylinders (full throttle).
3) No white smoke.
4) Inconsistent bubble in coolant (at radiator cap) when thermostat is open.
5) Lots of condensation (water) dripping from exhaust when running.
6) Potentially a small oil (moisture) weep from left head gasket.

Any ideas, suggestions and or comments?

Thanks in advance



Re: Coolant in Oil
« Reply #1 on: 03-Dec-19, 13:14 »
Not greatly familiar with turbos or their access to the mechanical seal.

 But - did you remove the rear engine cover to do he seal replacement?

 If not, another point where coolant can leak internally from the cooling system are the two O rings in the upper rear cover where the coolant passes through from the pump/rear cover to the block.

 If leaking these will thickshake your oil with no other symptoms.

 Just a thought.

Is it condensation or coolant coming from the exhaust? If coolant .....


Re: Coolant in Oil
« Reply #2 on: 03-Dec-19, 13:50 »

Thanks for coming back to my post.

On the CX650 (not sure if its because it is a turbo or fuel injected), getting to the water pump mechanical seal is easy peasy. Do not have the remove the engine. Just disconnect the water from the water pump cover, remove water pump cover and then remove water pump body. Mechanical seal pushed out easily and new one went in the same.

Saw the o-rings (they looked a bit flat) so I cleaned them in hot water and the soaked them in ARMOR ALL. Put the back in with a good quantity of gasket glue. Pretty confident I did a great job on the water pump.

Condensation from exhaust pipes seemed like water (i.e. did not taste of coolant and was clear), but certainly seems excessive.


Re: Coolant in Oil
« Reply #3 on: 03-Dec-19, 19:30 »


Re: Coolant in Oil
« Reply #4 on: 05-Dec-19, 08:16 »

Have been thinking more about the 2 seal on the water pump body. If they leaked, I would see coolant leaking out of the weep hole long before it got past the oil seal so I am very sure that is not the problem.

Pretty sure it is a head gasket. Oil is weeping from the left head gasket.

First I will try re-torquing the head bolts. Doubt this will fix things but a easy first step and then time to removed the head.




Re: Coolant in Oil
« Reply #5 on: 05-Dec-19, 14:57 »
Condensation from the exhaust? If it wasn't a turbo, you would be able to tell which side it was coming from and therefore, possibly, which was the faulty head gasket. That's what you get for having all that extra power!


Re: Coolant in Oil
« Reply #6 on: 06-Dec-19, 17:58 »
Oil is weeping from the left head gasket

It's worth getting it right if you can.  Replacing the head gaskets is ideal, but unbolting the turbo & finding new manifold gaskets can be tricky.


Re: Coolant in Oil
« Reply #7 on: 08-Dec-19, 15:12 »
Hi All.

Firstly thanks who responded to my post and special thanks to Joe Hovel.

The plan for this weekend was to a) re torque head bolts if problem is not rectified, replace head gaskets

- Removed left tappet cover, re torque head bolts (needed tightening). Was obvious signs of oil / water cream.
- Removed right tappet cover. More oil / water cream plus actual green coolant. Noticed coolant seeping from the welch plug. Welch plug was loose and I was able to undo with my finger. BINGO!!!!!!

Set right to top dead centre. Removed tappet assemble. Tightened welch plug. No more coolant. Replaced tappet assembly and both tappet covers.

Checked and topped up coolant.

Refilled oil (cheap oil) without oil filter. Ran engine for 5 minutes. Drained oil. Was still signs of coolant but oil looked cleaner.

Drained oil and repeated. Oil good a lot better.

Replace with quality oil and oil filter and repeated. Oil look near perfect.

Went for a 1 hours ride watching coolant temp. All good and the boys at Bikebiz Granville enjoyed checking out the CX650T.

Check oil and still clean.

-Oil still clean, so time to give the bike a well deserved tub.




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