Heads keep getting cracks in them ,on my third one....

for water to get into all cylinder heads the head bolt tension is not as it should be. This comes from mainly 2 items . one is that the head is warped and is not tightening evenly and two the head stud holes are full of water and a hydraulic lock has formed before bolt tension was sufficient to hold the head down. If there is any water /oil or rust /gunk in the holes then the studs bottom out before attaining the proper head tension. Cracks can be under the exhaust valves

They are getting way to hot, there is not other reason.

It sounds like a blown head gasket to me.

remember new head bolts also, torque to yeild bolts. i would recommend to get a service manual for torque specs and procidures for removal of heads. also head gaskets are leaking for a reason have heads checked for straightness and for cracks at local machine shop, keep all pushrods and rockers numbered for reassembly, pushpods are different and will cause major engine damage if mixed up.

cylinder head gaskets, or cracked cylinder heads, this is a bad problem with the 3400 engine, so bad that we keep a set of heads in stock at the shop.....SORRY

these cars have a bad problem with cylinder head gaskets also they tend to crack heads, the problem is so bad we keep a set of heads on the shelf.....SORRY but it don't sound good.

Hello and welcome. I suspect cracked cylinder heads. this engine is very well know for heads cracking. what you need to to inspect for cracked heads. pull off both valve covers and inspect the cylinder heads using these instructions.

Some vehicles may experience a gradual coolant loss over time. A very low percentage of cylinder head(s) manufactured with an embossed Castech logo may develop a porosity crack in a very specific area.
Inspect the cylinder head assembly to determine if the casting was manufactured by Castech. This can be accomplished by inspecting for their casting logo located on top of the intake port, under the rocker arm support rail and in the spring deck cavity portion of the cylinder head.

If the cylinder head(s) is a Castech casting (1), inspect the area around the five oil drain holes for witness marks indicating coolant seepage over time (2).

sounds like you have a coolant leak or your heads havent been done right or there maybe a crack in the head which has not been found.

Most of the time the heads will have to come off to see what has actually happened.

Have your cylinder heads checked for cracks (aluminum get dye checked, iron get magnafluxed) Also have them checked for warpage. Make sure water passage openings are not "etched" providing a pathway for coolant migration. Problem may also be your assembly technique...If you are making a mistake and repeating it every time you will always get the same result. When torquing head or manifolds divide the final value by three and following the proper pattern use those values and go over it three times increasing by one third each time. This is especially important with aluminum as it helps spread the load better. Also with aluminum, make sure you use a flat washer under the head of every bolt. On race engines I will often run hot water through the block after final tightening, then go over bolts one more time, as most can't be reached after manifolds are installed. You don't need to go that far but it shows just how critical assembly is.
If heads are cracked discard them if warped they can be surface ground or fly cut to regain a level surface. Some shops can also heat them and straighten them. (not iron though) Each time heads are cut it increases compression and on "v" engines alters the intake angle a bit. On inline engines it will change timing belt or chain tension as well. (pulleys will be closer together)
newer heads are not as thick in the deck area either and cutting will remove a degree of strength and can make them more vulnerable to cracks and warpage in the future so don't go too far with that. There are many machine shops that do this work. It requires expensive machines and is beyond the scope of most dealers and general repair shops.(shops send their work them).
Good luck!