Crack Head, Looking for some advice....... Options

[John]

I am of the opinion that I have 2 cracked cylinder heads but am looking for advice....

I have a basically stock 2.0L engine (euro pistons & cylinders done 12 years ago or so), and have been noticing what sounds like an exhaust leak but only when the engine is hot (after driving at highway speeds for about an hour). After the car sits for an hour or so and is started back up, there is no more exhaust leak sound.

The exhaust leak seems to be coming from the drivers side so I am assuming that the driver side cylinder head may be cracked.

I have had the heat exchanger off numerous times and tried many times to seal it up better, but the last several times, I have not noticed any black leak marks on the copper gaskets. (So I am past thinking it is a leak between the head and the heat exchanger.)

One strange note: About 10 years ago, I had a similar occurance and I had a spare head so I had new valves and seats installed in it and I put that one on. I don't drive the car very often so I don't put that many miles on it over time.

Is it common for 2.0 cylinder heads (driver side) to develop cracks?
Can they be detected and repaired?
Who does a good job at finding and repairing them?

Do spark plugs sometimes leak when hot? (Come to think of it I haven't checked them in a while....)

Any and all advice/suggestions will be greatly appreciated.

[John]

They crack going away from the seat in the exhaust port. I have also seen them crack in the short turn radius.

Well then I may be in luck, as I can't find any evidence of any cracks. I even tried the wipe them down with solvent and blow off with compressed air trick and couldn't find any places where solvent would wick out of any cracks.

I've heard it's also a good idea to take a large file to the SS HE tubes. I used a black marker on the ends of the face of the tubes where they connect to the heads. Take the large file to BOTH tubes at the same time and slowly file them square to each other. When the black is all gone, they should be pretty square.

It may be that when I swapped heads way back that i temporarily solved the leaky heat exchanger to head. I spent a bunch of time back then filing the ends square (and square to each other). Perhaps over time the stainless has moved enough to cause another leak or they may have developed cracks at the ears.

In any event, it sounds like I will once again remove the heat ducts and heat exchanger from the drivers side and re-file the ends and check for any cracks (and re-TIG weld them) in the pipes near the ears.

Brad, since it sounds like you do many more of these than I do, what do you recommend as far as torque for the nuts holding the heat exchanger tubes to the heads? Also do you use copper lock nuts (or what fasteners do you use)?