CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

2009 Dodge Grand Caravan overheating

My van is overheating…
I’ve replaced:The radiator &
the cap/ Fan assembly /water pump /hoses/thermostat. The dealer says there’s nothing wrong. But they can’t tell me why it’s overheating.
I asked the dealer & 2 other mechanics to check for a head gasket leak or cracked head - they all say there is no leak or crack.

I’ve discovered over the past few weeks that the coolant does not flow back into the radiator when it’s needed. It does flow out into the reservoir - but not back.

Any suggestions?

Overheating and losing coolant may be two different things. If you have a coolant leak or even an air leak in the coolant recovery tank, your van will overheat just from low coolant. Does your temp gauge go high.?

When does it overheat÷ Is it at idle? low speed? or highway speed?

If it is at low speed or idle, see if your radiator fans are running when it overheats.

Thanks for the info.

It does overheat while at idle (stop light) but not while driving.

The fan is running before and during the overheating. 

The temp gauge goes to about 3/4 (well past middle).

The reservoir is always at MAX - I've drained and flushed the cooling system.

Brought the coolant level to normal in the radiator and the reservoir.  Then after a few days the reservoir is at MAX again. - and it stays that way for about a week then the overheating starts again.

I check the radiator and it's almost empty - but the reservoir is full.

I do see evidence of coolant sprayed all over the inside of the engine compartment on the side where the reservoir is located.  I have a feeling that it just sprays out of the overflow spout at the top of the bottle.

I guess the problem is the fact that the coolant not being "sucked' back into the radiator.

I just can't figure out why.

The dealer wants me to replace all the parts I just replaced less than 6 months ago. (thermostat, fan, radiator & cap) - claiming they are all bad. 

Daniel

Any coolant leak will admit air into the system and stop the coolant recovery system from working as will a defective radiator cap, an air leak in the hose to the recovery tank or a leak in the tank itself.

If you have a good radiator shop in your area, they may be better at diagnosing this than the dealer.

A member of our church had donated a Dodge minivan to our minister and the minister was having trouble with it overheating. The donor was unavailable to ask anything but the repair receipts where in the van. The radiator had been replaced twice, and “rodded” once the thermostat had been replaced three times and the cooling system had been flushed. This had all been done at the dealer.

I drove the car and confirmed that it was overheating, and in a peculiar manner. It only overheated between 45 and 55 mph. it cooled down while idling or at expressway speed. When I stopped the car and walked to the front the heat just blasted you so there was no doubt it was overheating, I was stumped.

The minister took it to a local independent garage where they spotted the problem almost instantly, by noticing the clue that the dealer and I had seen but overlooked. The heat was blasting out from the front of the car.

The electric radiator fans were running backwards, pushing air forward through the radiator! That air would cool the car at idle and low speed but between 45-55 mph the air trying to flow in and the air being pushed out reached a stalemate.

When the previous owner came back that the van had been in a left front collision and the radiator, battery fender and grill were replaced and some wiring repaired. Whoever fixed the wiring had cross connected the fan wiring. Countless trips to the dealer had failed to spot the problem they had caused.