96 Town & Country overheating

I have been working this issue for a while and tried everything I can
think of.

The radiator eventually boils out all the water from the radiator
causing the engine to not cool properly. Once I fill it back up it runs
fine. It takes many weeks and possibly months for this to happen and I
give up daily checking for a while and then before I know it the water
is low and it's hot.

I have changed the thermostat. I had a diagnostic code that said the
fan relay was bad, so I replaced that. I flushed the system. I
replaced the draincock (because I broke it doing the flush) and that is
tight and leak free as ever. The system doesn't lose water at rest when
parked. No fluid lost while stopped. It has to be lost when it is
running and on the road.

One thing I am wondering about is the A/C. It is cooler now in
California so the A/C is mostly off (though the wife loves to have it on
once it hits 70 degrees outside.) The last few days warmed up to above
80 and I know the A/C was turned on. Is there a place that could lose
water in the A/C?

 

Since you say that it does not overheat at idle, it is probably safe to
assume that the fans are coming on correctly. Also, since it is a Town
and Country, it probably does not have the 2.4L which has a known
problem with headgasket failure.

Have you done a flow check on the radiator and checked the belt to
ensure that it is not slipping? It looks like you have checked all the
usually stuff.

-Kirk Matheson

 

One thing that often gets overlooked is the radiator cap. It is supposed
to hold a certain minimumum pressure before venting. As radiator caps
age, they sometimes will hold pressure, but not the FULL rated pressure.
What happens then is that water in the engine boils very slowly and the
vapor is slowly released through the radiator cap. Eventually, enough is
lost that the level drops significantly. That's the first thing I'd
check. Heck, I wouldn't even CHECK it, I'd just replace the darned thing
and see if the problem goes away.

Do you mean coolant water getting into the AC system? No way, absolutely
impossible- they're two COMPLETELY separate systems. Now, running the AC
does put a heavier load on the cooling system because the radiator only
gets cooled by air that has already been pre-warmed by the AC condensor.
If you have a cooling system leak (like the radiator cap I described
above) its entirely possible that running the A/C will cause coolant to
disappear a little faster.

 

Slow, slow leak.

Have you had the cooling system pressure-tested? Try putting it up to
16psi when cold, and look for drips.

 

Sounds like you have a slow leak in your cooling system. It might be hard to
find because if it is a really slow leak, most of the coolant will evaporate
before you see a drip. I would check all the hoses ends to see if there are
any signs of a leak.

 

Your two most likely problems are either a bad head gasket or a leaky
water pump. On the 3.0 engine sometimes the water will pool on the
engine and boil off and you'll never know it until it's all gone.

 

Hi...

A really old guys olden days trick, if I may?

Grab one of the ready to be thrown out white towels from your house.
Cut it into strips, perhaps three inches wide. Slit both ends of
each of the strips for a few inches.

Wrap one around each of the possible suspect hose ends, and the rad
cap. Tie it with the slit ends.

Then drive around for a while. If any of the connections is bad
it will be wet and a little stained. And perhaps HOT, so be careful

Take care.

Ken

 

Have you checked the hoses and such for the rear heater?

 

Replace the radiator cap. It may no longer be holding pressure and you lose
fluid out the overflow drain tube. make sure fans run properly and the
radiator is not plugged. Short of that, it could be a head gasket, but
check the other stuff first.

Bob

 

I found a small leak in the radiator itself by letting it idle hot for a
while. I assume that is where I am losing pressure and how it is
leaking while driving. It stops leaking when cool and it is very slow
when hot and doesn't ever deposit on the ground.

I am trying some radiator stop leak for now, but it seems not to be
working in the brief time it has been in.

Where is the best place to get a new radiator? Autozone has a standard
two row for $179 and a HD 1 row for $209.

Should I get a better one? I only do standard, local driving.

 

Don't use stop leak as it just plugs up the radiator.

HD radiator usually is three rows (regular is two) not one. IIRC, most
Autozone low end radiators are made in China.

Bob

 

Update:

Sorry, I used stop leak. I only care to make the van run for another
two years before replacing it so I hope it doesn't screw it up too much.
Not worried that it will screw up the radiator especially since I'll
replace it if that is still the issue.

After a day of light stop-n-go driving, the leak has stopped. I was
surprised. A brown powdery substance remains where the leak was, but
when running and under pressure there is no more water flowing out. The
car runs great as it has before, but we'll see how long before it boils
out.

Still would like advise on where to buy a radiator if this fix doesn't
work for the long haul.

 

Buy from the radiator shop that supplies the other radiator shops.