radiator trouble

i`ve got a `99 grand cherokee laredo that BLEW the radiator after about 10 min. of setting idleing. had a shop replace it and put a new 16lb. cap on it. this one lasted about 800 mi. they said they won`t stand behind it because it probably has a bad head gasket. there is no smoking or water in the oil but they told me it would just blow it again. there is about a 4in. crack just below where the trans. lines go in it. i`m in the process of installing a new radiator and thermastat. anyone have any ideas on whats going on?

4.0 six cylinder? 0331 is your answer.

On 99 and 00 models, DaimlerChrysler used a substandard manufacturer for the heads. They have a casting number "0331" on the head, driver's side, behind the exhaust and intake manifolds.

After 80k miles or so, they develop hairline cracks which act just like a head gasket failure. On my 00 I used a little coolant but had no other symptoms, it ran great, but on an oil analysis they found coolant in the oil.

Do a search for 0331 in the Cherokee section (or Wrangler, I forget) and you'll find lots of posts.

The solution is to get a 98 or earlier head and have it installed. You'll just keep killing radiators (and the bottom end of your engine!) if you keep driving it like this. Make sure to change your oil right after the new head is installed, to get rid of the coolant.