Radiator cap too much pressure

[rigid]

2002 3.7 Driving home the other night as i was pulling in the driveway there was a bunch of steam etc. I figured a blown hose. It turned out that the cap must have pressurized too much and popped. No blown hoses. leaking from the reservoir.
I changed the heater core a couple years ago and it has never been right sense. Multiple times I raised the front and fill through the hex plug and tried bleeding it off. Many times over the last couple years. Sometimes heat worked well and other times no heat at all. When it worked good it was until I slowed down to turn or at a stop light. It would be cool until back up to speed. Just sitting idling in the morning it would hardly clear the frost on the windshield. Here lately at times I could hear air moving through the system.

Water pump was replaced also and everything re-bleed multiple times. I had noticed that when i needed to top off the reservoir it had quite a bit of pressure when I took the cap off even after sitting overnight. When it blew the other night it was not showing hot. Gauge was right in the middle. No water or moisture in the oil according to the dip stick. Any ideas on where to start? Thank you




W

 

[LibertyTC]

What brand of cap have you been using ?
The Mopar cap is rated at 16 Psi. Only use Mopar HOAT coolant or Zerex G05 ONLY- at the correct temperature rating.
With correct coolant adapters, pressurize the cooling system and listen for a leak, & see if it holds pressure.
If the wrong coolant had ever been added to the system, it can turn into gel/gunk up the system, in which case a complete flush is required.
You may have to replace the expansion tank, IDK if a Mopar reservoir is even still available.

 

[KJowner]

Sounds like an air lock or blown head gasket.

I'd start by getting a garage with a test kit to check the cooling system for a blown gasket, they can check the pressure in the system and the presence of exhaust gas.

 

[Johnny O]

I'd put money you have air in the system. Pay the pros to do a complete flush. If problem persists after that time to start leak hunting with fluorescein and a UV flashlight.

 

[AFT2008KK]

Hate to add my input. But definitely check for head gasket issues. Based on past experience. With other vehicles those symptoms always ended with head gasket. Oil in coolant or vice versa? Thats a quick test but not always definitive. Chances are its a small leak and that would explain the intermittent heat issues and such. Only way to rule out is get it tested. Best of luck