Chrysler Repair: Bubbling Engine, head gasket leak, antifreeze mixture

Question
QUESTION: PT Cruiser 2004. == I'm a complete car idiot, but # of problems. 1. leaking water & overheating - have to refill about 1 a month.  2. air conditioner doesn't blow cold / & heat not hot -- while idling - - must be driving.  3.  those problems 3+ months -- just started yesterday - - bubbling sound in engine -- especially after turning car off - but doesn't always happen -- sometimes no bubbling even though 20 min trip.  Please help - broke - 2 kids - 1 on way & 3 jobs.  Don't trust many mechanics.first told me 1000 to replace water pump & I'm not sure that's the problem.

ANSWER: Hi Brian,
Where is the water appearing to leak from? If it is at the water pump area then you will probably need a water pump. If you are getting copious amounts of white smoke out the tail pipe when you start the car from a cold resting condition then you have a head gasket leak. If it is leaking from some other part and appears on the ground identify where it is leaking and tighten up a fitting or replace the part if it isn't a simple hose clamp situation. Also, is there any possibility that the original warranty on the vehicle is still in effect and Chrysler might pay for the repair? Check the paperwork that came with the vehicle for that possibility.
The bubbling means that there is enough fluid loss that instead of holding the water as liquid under pressure which prevents bubbling, there is a space where the coolant is not effectively removing the heat from the local metal so the temperature in that area rises high enough to cause the boiling even though the system is still pressurized. So it is all part of the same problem...loss of coolant. You can reduce the bubbling by keeping the coolant mix at 50-50 water/antifreeze mixture, but it costs money if you are loosing it at a great rate.
Let me know about where the loss appears to be occuring, and also which engine you have should you need to send a follow-up question.
Roland

---------- FOLLOW-UP ----------

QUESTION: There is a little leak on the ground - but I don't know how to tell where it is coming from.

It is not under warranty b/c already over 70k miles.  (I do a lot of driving for one of my jobs).  

I will put antifreeze in it today & see if that helps
Does the boiling = damage being done or is it just a wierd sound?  

Your answer thus far has been very helpful - I will tell everyone I know about this site.

Answer
Good, but figure to add it in diluted concentration (50/50), unless you only have water in there now, then add straight antifreeze so the mix might approach 50/50. There shouldn't be damage from boiling after you shut off the engine, but anytime you see the temp gauge go toward the top end is the time to stop and let it cool down and add some more coolant after it has cooled down. I would try to determine where is the leak and resolve the issue a.s.a.p.
Also check the coolant level every day so you don't start out with inadequate coolant. It will leak the coolant a bit more rapidly with the 50/50 mixture than with pure water.
Roland