YAY, I think I have a blown headgasket

[trav1856]

So here's a good example of why it's probably a good idea to change the rear main seal when you swap a clutch. (and they're only $15, and add maybe 30min to an hour to the clutch swap....me I'm taking my time, so add a bit, and it's incredibly easy...I wish I would've taken pictures to do a howto)...


...anyway, so I'm doing the clutch on my engine, before I put the new transmission on, and I get to the rear main seal. Get the carrier off, and as I'm scraping off the old gasket material, I notice something green. Thought at first it was just some over-spray.....then my little head-lamp shines in along the crank, and I see more green. I think the oil I had in the coolant reservoir is definitely from a blown (or getting ready to blow) head-gasket.  (or G-d forbid a cracked block).....but I am afraid I have coolant in the oil, not much, but enough that I can see green in the crankcase while changing the rear main seal.

So I'm going to drain the oil again, and hopefully there won't be enough in there to matter, if so...I guess I'll be pulling the head. (which sucks, because I really wanted to start driving the little beasty)

[trav1856]

So when I pull the head, I just have to look at the notches on the gasket and replace it with the right one? Or should I go with one of those sandwiched metal head gaskets? I also saw some posts were someone was talking o-rings?

[745 turbogreasel]

So when I pull the head, I just have to look at the notches on the gasket and replace it with the right one?

Only if you know for sure the right one was put in last time.

[trav1856]

oh lovely...so the idiot could've put in the wrong one all together then....I never thought of that.

So how do I know which one's right?

[8v-of-fury]

So when I pull the head, I just have to look at the notches on the gasket and replace it with the right one?

Only if you know for sure the right one was put in last time.

oh lovely...so the idiot could've put in the wrong one all together then....I never thought of that.

So how do I know which one's right?

If its been running fine, chances are its the right one HOWEVER! the piston protrusion needs to be measured. Specs can be found in the Bentley.

[maxfax]

A lot of guys would would take the easy route and just slap a 3 notch (thickest) gasket in these.. It will work okay that way, but not necessarily optimally... Like Jeremy said, changes are good that it does have the right one, especially if it's an 11mm engine cause it's probably original...

Measure how far the pistons stick up out of the deck.. Take the one with the highest reading and use that measurement..  There is a chart in the Bentley that gives protrusion specs to HG thickness..

.67mm - .82mm     1 notch
.83mm - .92mm     2 notch
.93mm - 1.02mm   3 notch  


To measure, clean the deck and the crown of the piston..  Turn the crank to TDC, lay a strait edge across the piston and stack feeler gauges till you have the measurement.. Or you can use a dial indicator if you have on available..   Measure all cyls, and measure them in at least 2 places to be absolutely sure..

[trav1856]

So when I pull the head, I just have to look at the notches on the gasket and replace it with the right one?

Only if you know for sure the right one was put in last time.

oh lovely...so the idiot could've put in the wrong one all together then....I never thought of that.

So how do I know which one's right?

Well it *has* been running swell, aside from the oil in the coolant, and now the found coolant in the oil. So the leakage is minimal, but while I've got the transmission out it's probably a good time to do it. While I've got it all torn down, I guess. (Might as well do it all at once, rather than wait for something to die later)
If its been running fine, chances are its the right one HOWEVER! the piston protrusion needs to be measured. Specs can be found in the Bentley.