[5thgenmaxima]

DO NOT let the temp gauge go to hot.. I'm putting a head gasket on an in-laws car right now because he drove the car for 3 miles after the temp gauge went into the red...
If you drive an overheated car you WILL need a new motor.

BTW: Heater Core part #271404Y900....Price $197.02 for an oem one..
Labor..6.6 hours + evac and recharge A/C...Figure an additional hour for evac and recharge.....or 7.6..

Now for the heads up...Alot of shops will tach on an hour or two labor or raise their labor rate per hour if they know you're stranded...
Knowing "book time" and parts needed will help you make sure you don't get screwed at the shop..In addition to this most dealers actually charge more than M.S.R.P. for an OEM part.. I.E. our dealer pays $35 for a part from GM.. M.S.R.P. might be $95..Our parts matrix would list that part for $190.... They can sell the part for any price they wish, but you have the option to purchase elsewhere.... Call around and get estimates for a heater core. It should go something like this.
labor rate x amount of hours(between 6.6 to 7.6 hours)= Somewhere near $600-$800 labor
Parts= heater core and maybe hose clamps...between $175-$270...
Shop supplies =
1 gallon coolant
1-2 LBS R134... Somewhere near $50.00-$75.00 for "refrigerant" and coolant... Also watch out most places double dip and charge you for all the supplies plus an additional fee for shop supplies.(Another $50 just because they can).... It's a way to increase their effective labor rate.. Usually if you pick thru their estimate they will work with you on certain items to get the job...Unless of course you're car is stranded at their work..
depending where you go it should cost you around $600-$800 +$200 + $50-$75...
Low side $850 plus tax.. high side $1100 plus tax.....When you get an estimate get a break down of the price......Make sure you ask what their labor rate is and how many hours their charging you...It should be 6.6 hours plus A/C recharge/recover....Like I said most places will fudge the amount of hours or change their labor rate to a higher amount to unsuspecting customers.