02 Chrysler Town & Country - 3.3L Flex - High Eng Temp

I have a 2002 Chrysler Town & Country, 3.3L Flex. It has 172,000 miles on it.

Recently, the engine temperature has been red lining. The coolant level is typically good, but when it red-lines, the coolant boils and the level drops, so I keep an eye on it, so I top it off once every couple of weeks. The radiator would be 50% full at that point. I only fill it with water, which of course cause it to boil off quicker the next time.

That being said... I haven't replaced anything yet, as its only been an annoyance.

One thing I noticed is that if I turn the vehicle off and back on again, within 10 seconds the engine temp drops back down to normal. This makes me think that this is an electrical issue where a valve is not operating correctly (not turning on) to allow the coolant to flow around the engine.

What should I change?

Is this the thermostat, or the sensor switch, or a valve or something completely different?



Fulcrum

Are the cooling fans turning on? Should start spinning around 10-15 minutes after starting or within seconds of turning on the A/C. Is the check engine light on? Is it overheating at speed or in city traffic? Only valve in the system is the thermostat. You risk serious engine damage if this continues. You also risk decreasing the life of the water pump running with water only.

It happened again on the way home from work today. It red lined again, with the alarm going off.

Leading up to that I could see the temperature creeping up, slowly, so I'd throw it into neutral, and turn off the engine while driving; my speed was around 55mph to 70mph. To no avail, the temperature did not drop, and each time I restarted the engine to get up to proper speed, I'd see the temperature continue to rise. When it hit the red line with alarms, I pulled into a gas station just off the highway. I did buy a gallon of water, but I'm smart enough not to take off the radiator cap. So instead I put 1/2 a gallon in the overflow reservoir.

Then I called my wife and told her it might be a while before I arrived home. So I waited 10 mins, but the temp gauge did not budge.

Then I decided to give it a go because I was impatient. I drove my van another 1/2 mile, and then suddenly, the temperature dropped down to normal, which is slightly lower than the 1/2 mark.
I think I hit every red light on the way home too, and I had to sit there a good minute or so for each light, and I must have hit 6 red lights. Amazingly the temperature remained at normal. It took me 20mins to get home from there.

So go figure, traveling highway speeds with the engine off wouldn't drop the temperature, but then later I was sitting at several traffic lights the temperature stayed in the normal zone.

Yes I realize that the engine might have sucked in some water from the reservior to help drop the temp, but even so, I've experienced the same strange temperature drop phenomenon without ever adding water, so I'm ruling that out.

So before I went home, I stopped off at the local auto store and picked up a thermostat & gasket; $12 total. I'm waiting for the car to become stone cold before I change it out.

If it doesn't work, I'll change out the sensor switch which is another $20.

I haven't tested the fans yet to see if they are turning on. Also my AC is not working, so I can't say if the fans are turning on with that.

I wonder if it could be my water pump that is being intermittant.

I'm keeping my fingers crossed for the thermostat (the guy at the auto store said his thermostat stuck on is Carvan too, causing his engine temp to sky rocket.)

Cheers!

Fulcrum

OK, I've replaced the thermostat. There was a fair bit of corrosion. I had to use a rubber hammer to get the original thermostat out of the plastic tube.

I recommend doing this type of change during the day or in a well lit garage. I choose to do it in my driveway at dusk, so it took a little longer than normal... 20mins.

I also turned on the air conditioning to see if the fans started up on the engine, and they did not. So to clarify, my AC compressor is bad, but everything else in the AC system is good. So I'd expect the fans to turn on, but they did not.

Tomorrow I'll be driving into work, a 30mile trip one way, so I'll see if the temperature issue becomes appearent again or not. I'll let you know.

Fulcrum.

Fans will not come automatically when the AC is turned on. PCM controls them; and are turned by engtemp or by pressure in the AC system.The link will explain fan operation. http://www.automotiveforums.com/vbulletin/showthread.php?t=909708

Compressor has to actually be cycling and pressurizing the system for the fans to operate.

Update.

After I changed the thermostat last night, I filled the radiator and reservior with water (no coolant).

The 30 mile trip into work today went well. The eng temp was a hair lower than normal, and no issues at all. At lunch I took it out again for another 30mile trip for additional testing, and the temp continued to look good. Before going for the test drive I took a look at the radiator water level, the water level was approximately 2.5 inches lower than full.

However the 30 mile trip home was a whole different story. Within 3 miles I saw the temp rise to the 1/2 mark, and by mile 10, the temp gauge was upto the 3/4 mark.

Worried, I pulled off the highway and put some water (that I brought along) into the reservior. The reservior took 2/3 of a gallon. Then the temperture rollercoaster ride began. The temp fell to the 1/2 mark. Then 1 or 2 mins later it was at the 3/4 temp mark. Then a minute later it was back down to the 1/2mark. This repeated itself at least 20 times on the way home. Only once did the gauge hit the bottom edge of the red line, at the 7/8 mark. So I turned off the engine, and coasted in neutral. When I restarted the engine, the temp fell back down to the 1/2 mark.

I noticed that my engine is running rough. Now when I'm at the traffic lights I can definitely feel the vehicle's engine moving... putt putt putt.

I checked the oil, but it is up to level. Now I'm wondering if the belt for the water pump is bad, or if the water pump is bad altogether.

Cheers!

Fulcrum

Update 8/18,

I checked the water level in the radiator in the morning before I left for work. It was about the same height as yesterday morning, about 2.5 inches low. I filled it up though with water.

I checked the reservior and it took 3/4 gallon of water. So all the water I put in last evening on my way home from work had dissipated.

Now my understanding is that water without coolant boils off at a lower temperature. So by adding coolant to the system, the mixture should keep the fluid around longer. My pet peeve is paying for coolant when a solution is not know as gets to be expensive fairly quickly.

I had no issues with temps for my drive into work.
I'm still at work, so no update yet for the return trip.

Fulcrum

update.

Well my van went from bad to worse. Now the engine is beginning to stumble. Perhaps, the engine got too hot. Anyway it idles poorly and my gas mileage is down from 18mpg to 13 or 14 mpg.

So I had my codes read and at local auto store. P0300 and P0303 were given, and there was a mention of the O2 sensors.

So, I replaced the spark plugs and wires. That was not the problem.
I changed out the fuel injector #3, and that helped, but it still stumbles, and it sometimes takes more than once to start. By the way, the codes P300 & P303 are gone... no mention of the O2 sensor. But it still stumbles.

My engine check light is still on... P1491.

So I replaced the PCV. No, that did not fix the engine stumbling.
So today I bought the EGR for $70. But my van doesn't have one. I have a chilton's manual, and it shows my exact underhood picture on pg 6-22, fig 7.2e, but the EGR is not in my van. There a plates covering the connection ports, and the plates look like something that came from Chrysler. I'm not sure why I don't have an EGR, but my van is a Flex Fuel vehicle, so go figure.

Does any one know why my van doesn't have an EGR?

By the way I now know if you turn the key on-off-on-off-on, the check engine codes are displayed on the mileage counter. That is one nice feature for this van.

The P1491 is for the fan relay switch. It took me a little while to find where it was but the picture at this link shows exactly were it is... behind the grill, but in front of the radiator on the top side of the sheet metal that supports the bumper also known as the GOR (Grill Opening Reinforcement).

See Link. http://screencast.com/t/6kaLLTcHgKE

There is a nice BIG heat sink on the top of it. I can see why they placed it in this location.

Tomorrow, I'm going to replace the Fan Relay, and then see what happens. Hopefully the check engine light will go off, or maybe a different code will be shown.

Now I'm reading about the MAP and IAC sensors. Both are a pretty penny. What do you experts think?

Fulcrum

Have you done a compression test on this engine? I would not spend another penny on it until I had and verified that there is indeed no internal leakage or blown headgasket. IT sure sounds like you are tossing money into a losing situation.

As for the EGR, some have them and some do not. My van also is EGR delete from the factory and it is not a flex-fuel so I am not sure the exact reasoning some have it and some do not.

Thanks for the suggestion, I think I will run a compression test. The Equipment runs $30 at the local auto parts store.

However last night, as I left work, 7PM, it ran very poorly. It ran through 1/4 tank of gas in approx 8 miles of driving. My top speed was 25mph, but mostly 10 - 20mph. A new code appeared P0139, so I called my wife who looked it up on the web, which said O2 sensor.

So after the first 8 miles, I stopped at a store, parking it in a inclided parking space and spent 30mins in the store. I came out started it up, drove across the street to a gas station. My fuel level was near empty, so I filled it upto the 3/4 mark, and gave it another go.

To my amazement, I was able to get upto the speed limit, 45mpg, fairly easily.

After 5 miles of travel, I got onto the express way and drove at 75mph with no problem. My van continued to run good, until I stopped at the local auto parts store. I bought the rear O2 sensor there and proceeded home.

The car again began to stumble, but 0.5miles later there was a noticeable "kick" and the van ran great.

Anyway, I put that rear O2 sensor in this morning. I fired my van up, and it ran like dog crap, and black smoke came out the tail pipe, marking my garage floor. :mad:

I had purchased the front O2 sensor earlier in the day, yesterday, during my work lunch hour, and I was thinking to putting that in next, but I can't figure out how to remove the original front O2 sensor. There just isn't enough space to get a wrench in there. However, I do have the Cowl removed for good access, but even vise grips can't get a good hold of it. I imagine a 7/8" socket could be used, but I'd have to cut the wiring.

Does anyone know how to remove the front (up stream) O2 sensor in a 2002 Chrysler Town & Country? :confused:

Fulcrum

Does anyone know how to remove the front (up stream) O2 sensor in a 2002 Chrysler Town & Country? :confused:

Fulcrum

It requires an O2 Sensor socket or wrench, most parts stores have loaners kits available. Be sure to use copper anti-seize lube. Not the silver stuff, it may kill the O2 sensor.

Oh crud...

I went to Sears and bought a longer 7/8" socket, it was a good 1" longer than what I needed. I also decided to cut the wiring on the existing O2 sensor so I could put the socket over it. The O2 sensor came right out.

I grabbed the new sensor, and put anti-sieze on it.... yes the silver kind. Well, no I didn't read the last post until now.

So tomorrow, I will take it out, clean the the threads out the best I can on both the O2 sensor and the pipe, and put the copper stuff on the threads instead.

The good news is the P0139 code disappeared. Also the engine is running smoothly. I'm keeping my fingers crossed. I didn't see any smoke, but it was close to 9PM and it was already fairly dark outside (I should have used a light). :smile:

Oh, I did buy a "condensor fan relay" for my vehicle to get rid of the P1491 code. Turns out the Auto parts store sold me the wrong one, and the connector is wrong, the right one is $12 more than the $40 one I bought. :mad:

I'll be picking that one up tomorrow.

Fulcrum