Ugh, how bad is it? (M42 in pain)

[Wschnitz]

It burns oil on start, goes through coolant, and wont stay running.

I checked for leaks and I'm only seeing a really tiny coolant leak, looks to be coming from the front.

[lolcantturn]

youve been on this forum since 2011 and don't know about a compression test? geeze

[chance]

I would say the profile gasket is toast. Might be a cracked head.

I have an m42 for sale btw

[Dj Buttchug]

just pull it out and fix it already. fuuuu

[AndrewBird]

Due to the fact you are going through coolant and oil, I would say a blown head gasket. Do a compression test and that will tell you.

Is there any oil in the coolant or coolant in the oil?

[Wschnitz]

Due to the fact you are going through coolant and oil, I would say a blown head gasket. Do a compression test and that will tell you.

Is there any oil in the coolant or coolant in the oil?

Oil seems to be staying at a fine level, Its the coolant I'm losing.

I plan on doing a compression test.

[Wschnitz]

What is the Stock compression per cylinder in an M42?

[wazzu70]

Oil seems to be staying at a fine level, Its the coolant I'm losing.

I plan on doing a compression test.

Hes asking if the two are mixing. Your oil will look more like a milkshake. Drain the oil and see if you get coolant/water coming out of the pan. Its easy to tell if thats the case.

You can also get an exhaust gas analyzer kit at the parts store which you put on your coolant expansion tank. If the exhaust gasses are in the coolant, the liquid inside the tester changes color.

Overall, sounds like a head gasket issue to me.

[Dj Buttchug]

What is the Stock compression per cylinder in an M42?

you should see no less than 150 psi on each cylinder. An accurate reading can be had in 5 full revolutions of the engine.

[iamsam]

cool story bro time:

So my M42 started eating coolant, and belching gargantuan smoke clouds in mornings, and I finally ended up getting around to taking the oil out of the M42 and it looked like this:



No, that is not a picture of what happens after three big macs and a mountain dew with no nearby restroom. That is the actual material that chugged forth from the oil pan drain.

So I summarily sallied forth and removed the head gasket only to find myself befuddled at the lack of any obvious gasket failure. The old gasket looked perfect.



So i slapped in a new gasket anyway, put it all back together, and to my dismay, it still ate coolant every morning for breakfast on the way to work.



So I deduced that the head was warped, and decided to put in an M20, since fixing the M42 would have been far more expensive.



And I lived happily ever after!

[lolcantturn]

^well why would you go through all that trouble of replacing the HG on a DOHC engine and not even check if the head was straight? ;) every cylinder head warps

[roguetoaster]

cool story bro time:

So my M42 started eating coolant, and belching gargantuan smoke clouds in mornings, and I finally ended up getting around to taking the oil out of the M42 and it looked like this:
So I deduced that the head was warped, and decided to put in an M20, since fixing the M42 would have been far more expensive.
And I lived happily ever after!

Cool story with pics, boo to the M20 (although innovative).

OP you probably have a cracked cylinder head, it happens, get a new one (head or engine) and move on. First check should be to pull the plugs to examine them for poor combustion, second check should be to look into the cylinder bores and look for a pool of coolant in cylinders 2 or 3.

Good luck, don't give up!

[iamsam]

^well why would you go through all that trouble of replacing the HG on a DOHC engine and not even check if the head was straight? ;) every cylinder head warps

yep, I shoulda done that, but in my hurry and stupidity, I did not. I was trying to get to a rally event in time, but I should have put that off. Either way, M20s are better for rally...

[iamsam]

also: I do have a spare M42 head in my garage (recent acquisition, post M20 swap) that is for sale...

[Wschnitz]

Cool story with pics, boo to the M20 (although innovative).

OP you probably have a cracked cylinder head, it happens, get a new one (head or engine) and move on. First check should be to pull the plugs to examine them for poor combustion, second check should be to look into the cylinder bores and look for a pool of coolant in cylinders 2 or 3.

Good luck, don't give up!

Cylinders 2 and 3 didn't have pooling coolant or oil in the cylinders, but there was a little coolant where the spark plugs were.