I have a friend that I work with that has an 04 pacifica with the 3.5 L engine. It has a little over 100 k miles. I am not at all familiar with this engine, but did have a really bad experience with a 2.7 one time but thats another story.

Here is his issues and it is sporadic:

The upper radiator hose blows off. Usually this happens when driving in the hilly terrain and is sometimes months before it happens the next time. The radiator hose was originally held in place with the spring clamp and I could not pull it off but he replaced it with the worm gear clamps. The t-stat was replaced 2 times now at this point. The fans work. I have not witnessed it but he says it feels like a lot of psi on the upper hose. Today he told me that he filled the coolant to the cold mark the day before and it was low again the next day but still in the reservoir. He thinks too that the oil is slowly rising. I told him to let it sit overnight and drain to see if water/coolant came out of the oil pan before he cranked to be sure.

This is one of the nicest guys u will ever meet. He is on the verge of begrudingly trading it off for fear of an expensive engine repair.

All that for the question, is there anything that could cause these symptoms beside headgasket? If it is headgasket, Would u recommend main bearings as well since coolant is liable to damaged them?

If u could offer me a little insight on it, I would appreciate it.

 

Did anyone ever answer this?

 

My wife's 2004 Chrysler Pacifica just had this problem last week out of the clear blue. She was at a drive through and heard a pop and then some steam. I had her go by a nearby auto shop and have them look at it as I was about 45 minutes away at work. They said the upper hose had blown off. The mechanic told her that is very rare and usually there is an issue that causes it but that they were slammed and couldn't look at it right then. They re-attached the hose and filled the radiator back up for her.

Well, when she pulled into the driveway (less than 3 miles) it happened again. We had it towed to the shop so that it could be checked out. Ends up, the hose was very rigid and was routed over the engine block. Engine movement was literally pulling the hose off. They said that the motor mounts are worn and will need to be replaced in the future but not right away. They put a new longer hose on it and routed it away from the engine so that it would not be pulled off again.

Needless to say, I was thrilled that it was a blown head gasket or anything like that!

 

Happened to my '04, as well. For nine years, I never ha a problem with the radiator hose, and then one day, out of the blue, I pulled into the garage and smelled antifreeze. I followed the hoses, thinking one had blown, only to find that the upper has pulled off the inlet. I replaced it with a real hose clamp, and haven't had a problem since. Go figure!

 

My radiator hose blew off twice yesterday. After changing from manufacturer clamp it now stays on however there is no pressure in the hose. Yhe antifreeze reservoir is at the cold fill line and I have heat inside vehicle. Could this be a thermostat issue? Yesterday the thermostat had pressure but wouldnt open which caused pressure in the antifreeze reservoir as well. Im taking to a reputable mechanic tomorrow, but since im a woman I like to know in advance generally what the problem could be to get an idea of what the problem might be. Thank you for your time.

 

Pressure in the system is controlled by the radiator cap.

Note the previous entries in this thread about failing engine mounts causing the hose to pull off.

Have the cooling system, including the radiator cap, pressure checked for leaks.

 

Maybe investigate a bleed valve on the intake. Just a thought

 

I chased this problem in my 08 Pacifica - first I put a new upper hose on with worm-gear clamps - still it blew off. I went pack to the original factor clamp, and it didn't blow off, but I noticed I was losing a little radiator fluid, and every time I loosened the overflow bottle cap, it acted like it was under large pressure, and fluid level in the overflow bottle would raise an inch or two. I wondered if the pressure was getting so high it was blowing some fluid around one of the clamps. I went and put a new overflow bottle cap (with a pressure relief at 18psi I believe), and all my "loosing coolant" problems went away, and when I remove the overflow bottle cap, there's no big release of pressure. I assume the old cap's pressure relief device was jammed, and the system was building too much pressure. I haven't needed to add coolant in months.

Dave