Our 03 Caravan has been overheating. A friend suggested bleeding the air out of the cooling system, which I did. He also said the thermostat or water pump could be bad. I decided to replace the thermostat, since it is a lot cheaper and easier to do than the water pump.

After replacing the thermostat and bleeding the air out, the temperature gauge read a little below the halfway mark, with the heater running. I turned the heater off and the temp rose to 3/4 of the way up, at which point I turned the heater on, which brought the temp gauge back to halfway.

I let it cool off while I ate dinner, then I drove it around for about 20 minutes (heater on) and the gauge remained just below halfway. I turned the heater off and continued to drive it, but the temp gauge shot up almost to "H" and the temp indicator came on. Turned on the heat, the temp came back down.

I parked it and left it running to see if there were any coolant leaks, but I didn't see any. The overflow tank was just above the "max" line (which is where it was when I filled it earlier), and the coolant level in the radiator did not go down (I checked the radiator after turning the engine off. The cap was cool right after I stopped the engine.)

While it was idling I turned the heat off to see if it would get hotter, but it didn't. Felt the top radiator hose, which was a little warm but not hot. Also, the radiator (towards the top, below the cap) wasn't warm at all, the cap itself was also cool. At one point while holding the hose it seemed to get really warm for a minute of two, but then it cooled off again.

I'm thinking the water pump will also need to be replaced. Not really looking forward to it, so I'm wondering if anyone else has any ideas? Thanks in advance.

[EDIT]

Since I have insomnia I took it out for another drive. Temp gauge stayed about halfway. When it got up to halfway I hopped out and felt the upper radiator hose - cool. Radiator was also cool. Drove it some more until the gauge went up a little more, got back out and the upper hose and radiator were cool, but I noticed steam coming from somewhere around the front (passenger) of the engine, but it was dark, cold and windy so I couldn't find where it was coming from.

As I pulled into the parking lot, the gauge shot up from a little over halfway to almost the first red line. Parked it, got out and checked the upper hose - felt warm, but not hot. Almost burned my hand on the thermostat housing, though - it was extremely hot. Managed to get my arm down to the lower hose and felt it - warm, not hot. Radiator was not hot at all. Radiator cap was still cold so I opened it while the engine was still running and noticed the level was a bit lower than it had been before. Topped it off and put the cap back on (after squeezing the upper hose to get rid of any air bubbles.)

Let the engine run and kept checking the temp gauge (back down to half after turning the heater on). Also squeezed the upper hose and heard air (?) moving around somewhere. Then all of a sudden coolant started pouring from somewhere near the bottom of the radiator, then stopped. Also noticed the upper hose looked collapsed. Also noticed the overflow tank was now empty. At this point I was getting really cold, so I shut the engine off and went inside.

I had replaced the thermostat earlier in the day, but is it possible I got a bad one? Planning on pulling it out and testing it tomorrow. Was thinking of leaving the thermostat out temporarily and running the engine to see if that makes any difference. I'm also going to check the overflow tank hoses, and take a look at the radiator when I have some sunlight.

At this point I'm thinking I need to make sure the thermostat I have is good (or replace it with a good one) before I start throwing new radiators or water pumps at this goofy van. Also wondering about blockage in the radiator itself as another possibility besides the water pump.

 

I would think water pump too now but im no expert. sounds no flow. steam mm that caint be good either. diff try find issues and dont drive around overheating it

 

Have you also ck to see if the cooling fan is coming on?

 

Cooling fan does kick on.

 

I agree with the 2nd post. You may have a blockage somewhere in the system. You may need the radiator shop for your problem.

 

Well, there is no blockage and the water pump is fine. Pulled the thermostat and ran the engine with no thermostat. With the radiator cap off and engine running I could see the coolant flowing through. Drove the van to the parts store - temperature was about 1/4 the way up, as soon as I got ont he road the needle dropped to 1/8 of the way up. Returned the new thermostat and got a new one. Hopefully the new one will work.

I did pressure test it at the parts store and it won't hold any pressure. I didn't see any coolant, but I smelled it. Maybe this explains why the coolant is steaming out. As long as the damn thing doesn't overheat I can live with topping off the coolant every week or so.

 

well if its not holding pressure you got a leak. possible check your head gaskets? i try get this fixed so you dont get the engine replaced. 2. i caint follow how ya know 4 sure pump is ok. did you remove it for inspection? see flow is something like hard to do unless ya got a hose disconnected while engine running out the fluid? i diff try to chase the source of the issue first.