Board logo

1994 CBR900RR engine with oil in coolant
HappyFather - 14/2/18 at 12:58 AM

Dear all,

During my last track day, after the 3rd (out of 4) session, I noticed some dirty spray coming from under the bonnet. After some inspection it seemed to come from the radiator (a leak?). Checked the coolant expansion tank and it was full of a brown foamy liquid. Oil in the coolant. Obviously, the dipstick showed my engine had near to none oil inside.

So, I looked online for possible failures and how to diagnose them and I'm now lost. Let me explain what I checked:

1) Oil cooler failure
I read that if it was the oil cooler (or heat exchanger), behind the oil filter, I could test it this way: take the coolant hoses off. Turn the engine on and rev it to 5000rpm. If it was a cooler failure, oil would drip from the lower hole.
I filled the engine with a bit of oil until the dipstick was a bit above minimum. Revved the car up to 6500rpm 3 or 4 times, but just for short 1 or 2 seconds periods. After all, there is no cooler running around and I'm afraid to damage the engine.
No oil dripped from the lower hole.

2) Engine (head gasket failure)
I didn't open the engine. I don't have the tools to do pressure or compression test. But I removed all 4 spark plugs and all 4 were dry and clean. There seems to be no oil on the cylinders. Also, looking down the hole it seems all cylinders are dry although black of a coal-like stuff.
Took the exhaust line off to reach the oil cooler. Noticed the exhaust ports were dry, no oil there. More of the black dry stuff.
So, at first glance, it doesn't seem that my head gasket failed (but maybe my engine could use an internal cleanup).

3) Water pump
I didn't open the water pump yet. For what I read, if it failed I would have the coolant on the oil and not the other way around. Nonetheless, I noticed it had red stains in the case as if it was dripping and the dripped liquid was rusting.

So, my questions...
Did I test the oil cooler adequately or should I put more oil/rev for longer/rev higher/just get the part out and test it some other way/other ideas?
Do my initial analysis of the spark plugs and exhaust ports rule out failed head gasket or should/must I really do a compression or pressure test?
Could the faulty bit be the water pump? How can I test it?
What should I do? Replace oil cooler and water pump and just try it out and see if it is fixed? Just replace o-rings and gaskets on the oil cooler and water pump retaining the parts and test it out? Additional tests I can do? Corrections to the test I did?

I'm feeling really lost! Help is appreciated. I can only perform additional checks next weekend but I have a few photos I took today and can put them online if of use to anyone.

Thanks to all! Cheers,
Duarte "HappyFather" Loreto
https://happyblade.blogspot.com/
https://www.youtube.com/user/dnloreto


sam919 - 14/2/18 at 08:32 AM

A couple questions.

Does the engine run ok now you've topped up the oil?

Was the oil level ok before the track day?

Compression testers are cheap, probably worth buying one to check. Sounds like its overheated, did you look at the temp gauge at anytime, no oil and reduced coolant through the leak would compound the rise in temps.

If the engine isnt siezed and turns over by hand/ on the starter with fuel pump off, or leads out, i'd fix the radiator, top up coolant and oil and see if its runs up to temperature ok.


CosKev3 - 14/2/18 at 09:05 AM

You need to remember a head gasket can leak between the oil ways and the coolant galleries without leaking into the cylinders, so compression testing won't show up a fault,likewise your inspections of the plugs/exhaust ports etc won't show up any oil or coolant as none is leaking into the cylinders


ReMan - 14/2/18 at 10:18 AM

When was the last time you checked you oil level, before you started racing on the track?
That's a lot of oil to have gone somewhere
If this is a very slow bleed either head gasket or oil cooler it could have been like it a long time and i doubt the check you made on the oil cooler would show the problem
Its more likely head gasket.
Is there any water in the oil? Drain and check even if you put it back in again
Flush the water out with clean no antifreeze Put clean water in and see how quick it contaminates again


HappyFather - 14/2/18 at 02:43 PM

quote:
Originally posted by sam919
A couple questions.

Does the engine run ok now you've topped up the oil?

Was the oil level ok before the track day?

Compression testers are cheap, probably worth buying one to check. Sounds like its overheated, did you look at the temp gauge at anytime, no oil and reduced coolant through the leak would compound the rise in temps.

If the engine isnt siezed and turns over by hand/ on the starter with fuel pump off, or leads out, i'd fix the radiator, top up coolant and oil and see if its runs up to temperature ok.


The engine runs OK. I run it yesterday to see if oil cooler was leaking and started on the button.
Last time I checked the oil was maybe two track days ago (the car only does track days, 80 miles per track day). It was near maximum level on dipstick.
During track day I'm not always with my eyes on gauges but when I looked it was not hotter than usual. I don't consider it overheated but I may have missed a peak. I always do the exit lap slowly and keep the fan blowing and engine idle when I exit the track. That is when I look at temps, could have gotten down before I noticed.

quote:
Originally posted by CosKev3
You need to remember a head gasket can leak between the oil ways and the coolant galleries without leaking into the cylinders, so compression testing won't show up a fault,likewise your inspections of the plugs/exhaust ports etc won't show up any oil or coolant as none is leaking into the cylinders


True! But then that means I'd have to open up the head and replace the gasket without knowing if anything was wrong. I admit I'm afraid of the idea of opening up the head...

quote:
Originally posted by ReMan
When was the last time you checked you oil level, before you started racing on the track?
That's a lot of oil to have gone somewhere
If this is a very slow bleed either head gasket or oil cooler it could have been like it a long time and i doubt the check you made on the oil cooler would show the problem
Its more likely head gasket.
Is there any water in the oil? Drain and check even if you put it back in again
Flush the water out with clean no antifreeze Put clean water in and see how quick it contaminates again


Maybe 2 track days ago. The car only does track days, 80 miles per track day. Goes to the track on a tow truck (still trying to import it and drive on the road).

I'll drop the oil and check how it looks. I'll post about it after. I'll only be able to do this next weekend, though.

Do note the coolant looked clean before the track day. I always check the coolant level (although not the oil level) because I usually have to top up the coolant (and the oil was always up to the mark). So I know the coolant was clean before the track day.

Thank you all for answers so far. I'll post as I have the chance to look further into the issue. Cheers,
Duarte "HappyFather" Loreto
https://happyblade.blogspot.com/
https://www.youtube.com/user/dnloreto

[Edited on 14/2/18 by HappyFather]