Chocolate milk oil....and oil in my coolant hoses.

[slavia631]

Hi all,

I have a 92 B4, and have been working hard to get it running smoothly.  Yesterday, I began to drain the oil and it came out milky.  Having spoken to another member about this on the phone, he told me that it could be condensation from having sat for a long time; or that it could be either my headgasket or water pump seal leaking water into my oil (and/or vice versa).  I immediately went and disconnected my coolant hoses, and indeed my coolant came out milky as well (albeit a little thinner). 

So, it is evident that my coolant and oil are indeed mixing.   
I guess the issue now is whether this is a water pump problem or a headgasket/o-ring problem.  How can I tell?  And what should I do once this has been determined?

Any help is much appreciated!

[slavia631]

Update:  I took off the water pump and the o-ring seal looks fine, but I did find milk on both sides of it.  I also found an additional issue, which is that the inside portion of the water pump smells like gas.  

To me, both signs point to this being a headgasket and/or internal engine seal problem.  Any thoughts or advice?  

EDIT:  Okay, I am convinced that I have a blown head gasket.  I got the engine out of the bike, and got the head-covers off.  Now it is time to get the head off...any tips on this or my whole situation?

[tomacGTi]

Don't forget the one nut on the very front of the motor between the head pipes.

That's about it and a couple of gentle taps and the head should pop off.

[tomacGTi]

Download the manual from the FAQ section, it'll walk you through the whole process.

-Everything to TDC

-Undo tensioner

-remove cams/Remove oil feed lines

-Undo headnuts

-head should pop off

[slavia631]

I have the manual.  I actually did all of those things tonight, except for removing the oil feed lines.  The allen head bolts that hold on the oil feed lines are on SO tightly that I am afraid I will strip them.  

Do you know exactly what size the allen heads are for the inner oil feed?  5mm seemed right, but when I tried one it really seemed like it was liable to slip and strip the head, since I had to twist so hard.  Could it be 5.5mm?  I really don't know what to do about removing these...and they are blocking two of the headnuts, so I'm at a standstill until I can get them off.

[tomacGTi]

I would recommend an impact screwdriver with a known good bit.

There is no odd hardware on these bikes, the metal is just soft and old. They did install them with a bit of threadlock so a little heat may be in order as well.

[slavia631]

Well folks, after months of time, energy, and heartache, I FINALLY figured out my problem.  

On the cylinder head, there are two dime-size holes towards the center on either side of the cam chain channel.  It seems that these holes are supposed to have a press-fit button cap over them, so that they are sealed.  Mine were open.  I didn't really notice this the first time I had it apart. but today I did...and my telescoping magnet pick-up device found the caps hanging out in the bottom of the engine, below the crankshaft sprocket.  

It seems obvious to me that this is my problem, as there is sure to be a free flow of oil through these holes into the water jacket below, and vice-versa.  Who woulda thunk?  Well, I now have the caps snugly pressed back in their holes, and hopefully tomorrow I will have a clean-running Bandit 400 under my belt.  

My question is, why do these holes even exist in the first place?  My only guess is that for other applications (GSXR400 perhaps?) they may allow for a link between the two sides of the engine for better coolant distribution...  Any ideas?

[tomacGTi]

In alot of cases, those holes could have been freeze-plugged for access to remove sand from the casting of the head.

Repeated heating and cooling can loosen them up and they'll pop open. Rare, but you never know. I'd advise against reusing them and getting some similarly sized ones from NAPA or other FLAPS.

[slavia631]

Ah, thank you.  Would you suspect that these are a universal piece that could be found at a place like NAPA?  Or might I try to order them from Suzuki?

[tomacGTi]

Doubtful through Suzuki. I haven't gone through the fische to make sure though, so you never know.

NAPA should be good as I know they carry metric freeze plugs. Wouldn't hurt to try APE either since they work with cylinder heads. Just have a measurement for them when you call.

[slavia631]

Cool.  I actually just talked to my girlfriend's dad's mechanic who works on his Lotus's, and he also recommended that they should be replaced or re-seated using some Red Loctite.  What thinkest thou of the latter suggestion?

[97af]

Andrew! Keep plugging away (no pun intended  ) Its worth the effort. Give me a ring and let me know all about it. Too cool on finding the culprit!

Keepeth the updates a coming...................

[tomacGTi]

Cool.  I actually just talked to my girlfriend's dad's mechanic who works on his Lotus's, and he also recommended that they should be replaced or re-seated using some Red Loctite.  What thinkest thou of the latter suggestion?

Agreed. Either that or use some hylomar or similar gasket sealant.

On past motor projects, I just made sure the surfaces were clean and tapped them in sans lube/sealant but YRMV.

[slavia631]

Andrew! Keep plugging away (no pun intended  ) Its worth the effort. Give me a ring and let me know all about it. Too cool on finding the culprit!

Keepeth the updates a coming...................

Thanks Mike!  Good to hear from you.  The bike had sortof been on hold since we last talked, due to me going out of country for a while, moving, and other things.  Classes start Wednesday, so this is all coming together just in time.  I'll give you a call next time I am with the bike.  ...oh and I have yet to change the valve seals, but that's next on the list.

Cheers!