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2005 Chrysler T&C, LTD, 3.8, 166,000 mi
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Discussion Starter · #1 ·
This is a long running issue I've had since the day I bought the van 2.5 years and 13k miles ago. The first thing I noticed is the heater took way too long to work. So I replaced the thermostat and that helped.

After about a month, I took it on a cross country trip and it was a pleasure to drive, plenty of horse powers for a mom van. No real problems except I noticed it was using water. Not leaking. There isn't a single drop of any fluid under this car.

But over the years, and I have discussed it here, we determined it has a head gasket leak. It had oil in the radiator and made a gurgling sound when shut down. The catalytic converter was clogged and I replaced it along with a bunch of other emissions components.

It was running great, getting around 22 mpg. The only indication of a problem is that sometimes plug #3 would be carbon fouled. The others have that gray soot of normal operation.

Then the oil stopped showing in the radiator and I was like cool! It fixed itself 馃榿 But then the gurgling quit and the radiator began hissing, followed by a puddle underneath. I replaced the radiator and both hoses and now it's overheating.

For awhile I doubted that the temperature guage was correct and the fans worked. But at least I know now that they work.

So my question is, is there anything I can do to nurse a few more miles out of this van? The temp guage jumps up in the red zone for a few seconds and drops back to normal. And it's misfiring on high torque again. It has ceased up when hot but if I vent the radiator cap it starts and runs fine. If I leave the cap loose it doesn't overheat, just uses coolant from vaporization.

What do?
 

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How do the top radiator hose and bottom radiator hose compare for temperature?

Sounds like air is getting into the system, hence the temperature jumps for a few seconds.

Seized up meaning what?

Misfiring giving you what code?

How old are the plugs?

Wires in good shape?

Rating on radiator cap? 16 psi?

.
 
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2005 Chrysler T&C, LTD, 3.8, 166,000 mi
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Discussion Starter · #4 ·
Thanks for the reply.

I replaced both hoses along with the radiator and just assume they are fine. But now that you mention it, I can't rule them out being cheapos and possibly collapsing. I will run it to operating temperature and verify.

It does act like coolant is constricted momentarily somehow. I believe your suggestion that air is in the system is correct.

The plugs and wires are definitely due for replacement at 6k miles. So they will be replaced.

I bought a new radiator cap last year that Mopar says is the right one. But I will double check. It is holding pressure for at least 72 hours with the new radiator and hoses. I'm afraid it's putting water in the combustion chamber with the increased pressure.

I can't afford a head gasket job now 馃様
 

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Checking the temperature of the hoses was to see that the radiator baffles are in place and not allowing coolant to go straight through, i.e. not providing cooling. The problems with baffles, on some radiators, has been reported in the past.

Just eliminating possible contributors to the problem.
 
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2005 Chrysler T&C, LTD, 3.8, 166,000 mi
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Discussion Starter · #7 ·
It's 78掳 and I just ran it to town and back, about 18 miles, with the radiator cap loose. It idled a little rough but had decent acceleration and cruise up to 60 mph. No overheating at all.

I will get new wires, clean and regap the plugs tomorrow. Also check the hoses, even though they're new.

I dunno. How is a motor this old getting near factory mpg with a head gasket leak?

I will report back after pulling the spark plugs 炉\(銉)/炉
 

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Discussion Starter · #8 · (Edited)
I haven't bought the new plug wires yet but read through the other thread and decided to check for air pockets. The radiator was about a quart low so I topped it off and idled with the cap on for 20 mins. It never exceeded normal operating temp and the fans didn't activate. I know they work though. This is all good.

But, I gave it a short rev to 2k rpm and lots of white smoke came out, along with a strong odor of unspent fuel. Definitely time for a tuneup. I'll do that tomorrow.

I am confident with the overall integrity of the cooling system. Both upper and lower hoses are new along with the clamps. And it maintains pressure for quite a while after cool down.

I checked the tube to the overflow bottle for blockage and that's okay. I put clamps on even though they didn't have them.

My Owner's Manual says check the coolant level by visually inspecting the overflow bottle, not the radiator. But that presumes everything else is working as intended, and they're not going to advise anyone to pop a hot radiator cap 馃槀

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You could have a small coolant leak which you don't see from coolant on the ground. My sister's 1967 Mustang kept overheating on a 800 mile trip. Cast-iron head 6 cyl, so no damage just kept refilling water every 50 miles. A shop with gomers lounging around said "head gasket must have failed" without even popping the hood and quoted my sister exorbitant cost and 3 days. I was just 17 but knew enough to say "keep driving". Stopped later at a busy shop and the guy quickly found a pinhole leak in a heater hose, so fine the spray was just evaporating. $5 fix and no more overheating all summer. Never jump to "bad head-gasket" conclusion. Oil in the radiator is a sign, but could be something else and a gasket leak almost always gets worse. When I had one in my 1982 Dodge 2.5L, I got slimy brown oil mousse floating in the radiator every day. Kept refilling with straight water to get thru a summer. Made the 20 mile freeway drive to work OK and would boil over right as I got home every afternoon. If yours has the oil cooler, there is a rubber cap on the rear housing of the water pump which can crack and leak. I first blamed the water pump until I found that in mine. Replaced w/ a short piece of stubbed-off silicone heater hose.
 

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Discussion Starter · #10 ·
Thanks Bill. I'm at the point where I feel like I've ruled out everything but the thermostat being oil fouled.

I drove it to town today, about 10 miles, and it started overheating to the red zone around 8 miles in. I pulled over, let it cool some and vented the radiator cap. I left it ajar, not off, then completed trip the back home. It cooled and ran as expected.

This overheating problem has only occurred after replacing the radiator (which had an air leak at the top but not a visible water leak), hoses and clamps and maintains pressure long after the motor cools down.

So I'm pulling the thermostat even though it was replaced fairly recently. It's supposed to open and close with water temperature change, but pressure and temperature are interrelated.

As an old plumber and HVAC mechanic, I know pressurizing a liquid reduces the boil point, which in turn raises temperature. Antifreeze raises it back up with its higher boiling point.

This van will run at proper operating temperature when the cooling is not under pressure, as long as enough coolant is in the system. So it is circulating through as designed. Something else is going on.

It may yet be a defective hose, clamp or water pump. I'm process eliminating those now. But I'm leaning towards an oil fouled thermostat.
 

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Did you, on a cold engine, start her up with the radiator cap off and observe the coolant following through the radiator and the radiator fans turning on? This will indicate if the thermostat is operating correctly. Also, check the coolant/water mixture percentage.
 

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Discussion Starter · #12 · (Edited)
Gunked up thermostat is most likely culprit at this point. Sorry about the blurry pic.

Yes I purged the air. As I said above, it will run at proper operating temperature with the radiator cap ajar. Gonna trying with no thermostat and radiator cap tight for a short test drive. BRB.

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Discussion Starter · #13 ·
Yep, it was the thermostat. The gauge remained steady just above the 1/4 mark the entire 18 miles. It's running way too cool but that's easy fix.

With all that oil and antifreeze in the water jackets, only a matter time before it also becomes a problem. But flushing it means possibly knock loose whatever clot is keeping even more oil out of the combustion chamber.

Catch 22 sitchyation.
 

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Dude. You have a blown headgasket. You have to fix it before anything is going to get better. I never saw what motor you have but american pushrod v6s are one of the easiest to fix headgaskets on. Last set I did took 6 hours and about $200 in parts. If you keep overheating it, it's going to crack a head.
 

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seeetdee
As an old plumber and HVAC mechanic, I know pressurizing a liquid reduces the boil point, which in turn raises temperature. Antifreeze raises it back up with its higher boiling point.
Not exactly. Pressurizing a liquid INCREASES the temperature it boils at. Antifreeze (actually, any impurity) added to water also increases the boiling point.

Temperature/pressure relationship is really a gas thing, not a liquid thing.
 

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Discussion Starter · #17 ·
seeetdee


Not exactly. Pressurizing a liquid INCREASES the temperature it boils at. Antifreeze (actually, any impurity) added to water also increases the boiling point.

Temperature/pressure relationship is really a gas thing, not a liquid thing.
Ignores the entire axiomatic law between temperatures, liquids and gases.

Put a pot of water on the stove. It boils faster if you cover because it lowers the boil point under pressure. Too easy.
 

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Ignores the entire axiomatic law between temperatures, liquids and gases.

Put a pot of water on the stove. It boils faster if you cover because it lowers the boil point under pressure. Too easy.
That鈥檚 silly. It boils faster because the heat is retained better by a covered pan. Water boils at room temp if you lower the pressure enough.
 

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Discussion Starter · #19 ·
In any case, these comments only reinforce my pretext that people have it backwards what a thermostat does.
 

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Discussion Starter · #20 ·
Water boils at room temp if you lower the pressure enough.
EXACTLY! If you raise the pressure of the vessel, the water boils at a lower temperature. This is no dispute. It's unerversal thermodynamic law.

Likewise, if you lower the pressure of a coolant of certain fluorocarbons by subjecting the to vacuum, like freon or amomia, you reduce the temperature.

The same axiomatic exchange of pressure/temperature takes place in the cooling system of a car. Not to stay cool enough, but to provide a climate control system that works that works in both extreme heat and cold given economic factors.

But back to my original point, the thermostat is there to keep it warm enough to operate efficiently in most climates. But also to provide a means of cabin heating.

Pretty simple.
 
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