PT GT blowing water into overflow when normal temp?

Asked by Sep 09, 2015 at 02:05 PM about the 2003 Chrysler PT Cruiser GT

Question type: Maintenance & Repair

I've replaced the head gasket,radiator, took thermostat out, new 18 lb cap. Can
you install a higher pressure cap then the 18 lb?

11 Answers

BTW, the car runs great, no overheating at all until it starts running low on water at about 100 miles. It will boil out a gallon /100mi


Adding more water than coolant will decrease the boiling point, do you have a 50/50 mix? did you bleed the system, check to see if the return may be clogged..


My calculations are coming out to an engine temp of well over 245f. so you are well above the safe heat range of that engine. You must have a small leak in your cooling system ... if you put a cap on that's any higher then you will either blow the radiator core, the hose or both ... I would never go higher than 15 lbs ... Have the radiator pressure checked ... I can guarantee your not sealed

I originally bled the system, then decided to remove thermostat completely, well took center out of it, so, no air in system problem, and yes, it would take a water temp of 245* to open an 18 lb cap, so why would the water get thru the cap at normal operating temperatures. Bathroom scales confirm that the cap does take 18lbs to open. Still baffled.

Oh, and it did the same thing with a 50/50 mix. Straight water now what with using a gal/100 mi

I suppose that if it's getting combustion gas into the water system that it would be easy to open the cap. It doesn't show anything like that at idle with the cap off.


You still have a small leak ... Here is the clue "Water cannot boil under pressure"

And even w/o pressure, it wouldn't boil before 212*, but I know it's blowing out all around my new cap and filling the overflow bottle. It will idle forever w/o overflowing or dropping any water on the driveway.


When water ( liquid) boils it expands to about 3000-1. To prevent water from boiling it becomes pressurized over 211F and remains a liquid because you can't cool anything with steam. If you know any steam pressure you can find the temperature by going to a "steam Table" thus 18 lbs of steam is about 250 degrees F. To me, it's obvious that you only have over 18lbs of pressure or the coolant would not go to the overflow. ... that means the water is boiling inside the radiator then the expansion is increasing pressure .... your system has a small leak

Yep, and it must be an internal leak into the cylinders which is being burned off slowly because there is no white smoke


Is the electric fan working? Turn on the AC and test it. Fans run during AC, that is if the compressor actually works too. There's a pressure sensing switch on the high side of AC that signals the fans ON. No pressure ... no fans either.

Your Answer

PT Cruiser

Looking for a Used PT Cruiser in your area?

CarGurus has 2,231 nationwide PT Cruiser listings starting at $950.


Chrysler PT Cruiser Experts

  • #1
    Tom Demyan
  • #2
    Gypsy Rose
  • #3
    Kelly Little Ashford
View All

Related Models For Sale

Used Volkswagen Beetle
123 Great Deals out of 9,137 listings starting at $1,750
Used Chrysler Sebring
15 Great Deals out of 2,145 listings starting at $1,995
Used Ford Mustang
287 Great Deals out of 38,472 listings starting at $1,995
Used Honda Civic
374 Great Deals out of 51,346 listings starting at $1,200
Used Ford Focus
397 Great Deals out of 70,146 listings starting at $999
Used Honda Accord
553 Great Deals out of 91,963 listings starting at $1,495
Used Nissan Altima
789 Great Deals out of 67,227 listings starting at $750
Used MINI Cooper
175 Great Deals out of 9,966 listings starting at $2,250
Used Toyota Camry
807 Great Deals out of 71,623 listings starting at $1,400

Used Cars For Sale

2006 Chrysler PT Cruiser GT For Sale
14 listings starting at $2,900

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.