Its an '01- it has a cracked head. I only have a dozen 00-01 engines underway at this present that had intermix from this.
You probably lost the water pump first, you just didn't know it and you didn't know that it would lead to this type of symptomless failure.
We've had one single heat exchanger fail and lead to this. We have NEVER seen a head gasket blow. We just saved another car with intermix this week.
Good thing you are changing the IMSB, as 1% of coolant intrusion into the IMSB equates to an increase in bearing wear of 83%. Lots of people don't realize this and then after an intermix experience they lose an IMSB shortly thereafter.
Of all the failures out there, this one is taking out more engines than anything else at the present. See a ton of pics of engines we have saved in our photo albums at
www.facebook.com/fixabrokensix