I have a 2003 protege with the 2.0 non turbo L4 DOHC with about 125k miles that died on my way home and now cranks but won't start. Temp gauge was high when it died so I checked the coolant level. It's fine. Then I checked for fuel and spark. Those are now fine after replacing a coil pack that wasn't giving any spark. So then I checked compression. Very low numbers on cylinders 1-3 and somewhat low on number 4. So I went to the timing belt. It's still intact and in decent shape for the mileage so I checked what I could of the timing by pulling off the valve cover and upper timing belt cover. Seems to be in time. Could the belt have slipped on the crank and I just can't see that at this stage? Any help is appreciated. Thx

 

Yes, the timing could be off at the bottom pulley. It is also possible that the timing belt lost some teeth, unless you turned the engine over to inspect the whole loop of the belt.

I am worried that the overheating damaged the cylinders and pistons so much that the compression is gone.

 

give use the compression numbers

 

The compression numbers are right around 20-30 psi for #1-3 cylinders and about 90psi on #4 cylinder. And far as overheating, it wasn't very long at all. Just touched the warm side of hot and backed off when I turned the heater on, then the heat stopped blowing hot and the temp went back up to same as first time then died. Snap, just that quick.

 

But that's what I'm afraid of too with the aluminum head is that even with the short duration of bein that hot it might have warped the head.

 

Yes, head gasket blew and the overheating caused a warped head.


That's my best guess.

 

Ok so I pulled the head and I checked it out and found there's .010 difference from the outside edges to the middle so the head is definitely warped. So question is, can that be milled flat again with out affecting the motor too adversely?

 

I believe, but don't know for sure, that it is o.k. to mill this head. No matter whether you are talking mm or inches. Your compression ratio gets a little higher. You respond to that with higher octane gas if needed.
If it is a non interference engine the safety space gets squeezed. But that would only come into play if the timing belt snaps.
Talk to the mechanic who will mill it for you. He will probably grin and say: "you are fine!"
When you put it back together get a book or set of instructions for this particular engine. My Haynes manual says you need to chase the threads on the studs to get them really clean and running smooth. If that is not done with care the torque on the nuts will be off and the new gasket will blow. My manual does not cover the '03 model year.