2000 3.5L Running hot. Need help

Ok, I purchased my 2000 intrigue back in November of 2004. I live in KY and we can have some cold days during our winters. Anyway, as it got colder in the next month of December, I noticed the temp gauge acting funny. I looked online and saw that the thermostat was redesigned and needed to be replaced. I thought I purchased the new updated one (I do remember it looking identical to the one I pulled off) but just thought maybe something internal was changed in the housing. Well, that did take care of that issue.

Now we get to the present day. This thing is acting up again but much worse. My wife has been saying for weeks now about a noise (like someting flapping under the car) and then the temp gauge goes up to Hot but will come back down to normal. No red light has yet come on indicating overheating. I finally got to hear that noise tonight and witness this event. I'm pretty good with cars, yet have no idea what that noise it. There is nothing loose under the car but it kinda sounds like someting under the car flapping. It was 23 degrees tonight while driving it. Other times when cold outside, the gauge will do the up and down thing. Most of the time not going to far above the 1/2 mark.

Guess my question is, should I try another thermostat? Does anyone know if this enhanced flow thermostat that I saw on the most recent post on here about overheating is different than the one that came on from factory? Does it phisically look different?

I'm just to the point that I want to say, if it overheats and blows up, who cares.

Just a follow up here. I found my receipt for when I purchased that thermostat back when I bought the car. Same part number as the one listed as the enhanced flow or whatever. 12570248.

Anyway, guess I won't go get another one of those. So much for the new thermostat design.

Ok, I purchased my 2000 intrigue back in November of 2004. I live in KY and we can have some cold days during our winters. Anyway, as it got colder in the next month of December, I noticed the temp gauge acting funny. I looked online and saw that the thermostat was redesigned and needed to be replaced. I thought I purchased the new updated one (I do remember it looking identical to the one I pulled off) but just thought maybe something internal was changed in the housing. Well, that did take care of that issue.

Now we get to the present day. This thing is acting up again but much worse. My wife has been saying for weeks now about a noise (like someting flapping under the car) and then the temp gauge goes up to Hot but will come back down to normal. No red light has yet come on indicating overheating. I finally got to hear that noise tonight and witness this event. I'm pretty good with cars, yet have no idea what that noise it. There is nothing loose under the car but it kinda sounds like someting under the car flapping. It was 23 degrees tonight while driving it. Other times when cold outside, the gauge will do the up and down thing. Most of the time not going to far above the 1/2 mark.

Guess my question is, should I try another thermostat? Does anyone know if this enhanced flow thermostat that I saw on the most recent post on here about overheating is different than the one that came on from factory? Does it phisically look different?

I'm just to the point that I want to say, if it overheats and blows up, who cares.

I would take the car to the dealer and get a cooling system flush. You don't want those aluminium engines to get scale build-up.

Just returned from having the coolant flushed and filled at a instant valvoline. I thought mabye just start by getting the old stuff out and all new fresh in.

Anyway, on the way back when I would slow from about 60 to 45 or below it would ease up to the 1/2 mark. Now I know thats nothing to be alarmed about but why is this thing acting so weird?

Also, as someone else posted on here, my bottom coolant hose that runs from the radiator to the thermostat housing is cold as it can be. all other hoses are hot. IS THIS NORMAL??? Doesn't seem like it should be to me.

Can someone please check there car and see if after driving it and the car is up to normal operating temperature, is that bottom radiator hose on your car still cold? If someone could help me out on this I would feel much better.

Well youre supposed to run right around the halfway point, usually just a shade below it.

It makes sense that the car would run hotter going 45 than it would 60, there is less air moving across the radiator that way, however I wouldnt think you could notice it on a gauge.

Not sure about the lower rad hose, Ill try and remember to take a look tomorrow.

I also wouldnt completely rule out the idea of the coolant temp sensor being a little bit off.

Just returned from having the coolant flushed and filled at a instant valvoline. I thought mabye just start by getting the old stuff out and all new fresh in.

Anyway, on the way back when I would slow from about 60 to 45 or below it would ease up to the 1/2 mark. Now I know thats nothing to be alarmed about but why is this thing acting so weird?

Also, as someone else posted on here, my bottom coolant hose that runs from the radiator to the thermostat housing is cold as it can be. all other hoses are hot. IS THIS NORMAL??? Doesn't seem like it should be to me.

Can someone please check there car and see if after driving it and the car is up to normal operating temperature, is that bottom radiator hose on your car still cold? If someone could help me out on this I would feel much better.

Make sure you keep the overflow tank full of coolant. I keep mine at the HOT mark when the engine is cold. Also, I change the coolant in the overflow tank once a year to add fresh additives to the coolant.

You might want to review past posts to see the procedure for purging air from the coolant system just in case the Valvoline guy didn't do it.

As for the bottom hose being cold, that doesn't sound right to me but with outside temps being so low who knows.

I always drive with the A/C on even in winter because I think it triggers the radiator fans at a lower temperature even if the A/C compressor isn't working.. There is so much embedded software in these cars/system it pays to pay attention to how the different components affect each other.

Also, the fact that the temp eased up to the 1/2 mark when you slowed down isn't what my Intrigue does. Once it warms up it stays very steady at just below the 1/2 mark. The only time that it didn't was when I went up the mountain road to Yosemite Park from the Nevada side. I had the car fully loaded with 4 passengers and luggage and that mountain grade was very long and steep. Had the Intrigue in 3rd gear and went up that mountain like a turbo. The temperature gauge moved to the 1/2 mark but quickly went to the normal position once we drove for 5 minutes on the top.

Anyway, check to make sure you radiator fans are working!!

atoyota4x4,

Your two threads concerning what appears to be the same issue have been merged together. One thread only please.


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Ok, I think I am going to just buy another thermostat and replace it. Its not that big a deal to do so why not just be on the safe side and do this.

Here is a question for you guys. I was planning to purchase direct from a local dealer. I noticed that Autozone (local retail parts store) offers one called a fail safe. Its supposed to be designed to lock open if temperatures reach 280 degrees. you can get it in the 192 or 180 temp. Any thoughts on this? Seems like this may be a nice option. Would you get the 180? I think that is what came factory on it if I'm not mistaken.

I will let you huys know if this solves my issues.

Ok, I think I am going to just buy another thermostat and replace it. Its not that big a deal to do so why not just be on the safe side and do this.

Here is a question for you guys. I was planning to purchase direct from a local dealer. I noticed that Autozone (local retail parts store) offers one called a fail safe. Its supposed to be designed to lock open if temperatures reach 280 degrees. you can get it in the 192 or 180 temp. Any thoughts on this? Seems like this may be a nice option. Would you get the 180? I think that is what came factory on it if I'm not mistaken.

I will let you huys know if this solves my issues.

Sounds like a winner. I would just double check and get the SAME temperature as came stock. The computer and all that jazz.

Just another update. I went to the dealer and bought anothr thermostat/housing. Still acted up after all that work and everything I have done. It has settled down a bit. I'm keping the reservoir pretty full. Maybe air just need to work its way out. I don't know what else to do.

Purging the air from the radiator is very simple. There is a black "wing nut" (valve) on the radiator, (passenger side near the top facing the engine). Unscrew the "wing nut". Run the car and close the valve when coolant starts to continually come out. Then add coolant to the overflow tank if needed.