my mother-in-law has a 95 intrepid and for some reason today it had fits with overheating. i'm finding no water in the oil, no white smoke out of the exhaust, the fans switch on and off. everything seems to be working fine. she said this has happened 3 or 4 times now. the first guy replaced the thermostat. this is the 3.5L engine.

also does anyone know where the water pump on this? is it timing belt driven? the car has about 130,000 on it and has never had a timing belt or water pump replaced. oil is changed regularly by me.

any ideas are greatly appreciated. btw i'm getting codes 117, 118, 171. i know 171 is an O2 sensor. and i know 117 and 118 are related to the temp sensor. i am getting 5V at the sensor connector as well as a good ground. i still do suspect the sensor of being faulty but i don't know if it can be intermittent like this.

I.m guessing you have cylinder head gasket leaking.
The pump is deep in behind the timing cover . You have to remove rad , crank pulley and a host of parts, belt , tensioner, its the most poorly built engine i've seen .
My opinion ...................its a piece of chit.
some diff then the little 3.3 that were in the Dynasty's
Good Luck , bet you will have to tear it down again in no time.

One of the best engines we have. Timing belt/water pump is easily done by an experianced tech in 45 min. You don't indicate whether the engine actually overheats, or the gauge just says so. But I can tell you that I've fixed more than one blown head gasket on those engines with a radiator cap that won't hold pressure. Test the cap first.

It is a completely sealed and pressurized cooling system AND it doesn't like air pockets. At 130,000 it NEEDS a timing belt and water pump at the very least. Also, as good as the 3.5 is they are not very forgiving to overheating. Very stout motor otherwise.

There's lots of things I don't like about the LH cars, but the 3.5 is not one of them.

3.5 is an AWESOME engine!! I agree, t-belt should have been done at around 90K, and you might as well do a h20 pump while you're in there, and possibly a tensioner pulley. I'm also betting that you are probably due for a radiator. There is also a module on the fan that would sometimes cause issues of one or no fans working (RFI module).

Check to see if the rad. fan comes on, a bad radiator fan relay could be your problem. 3.5L w/pump and timing belt as stated above are fairly easy to do. 3.5L was one of the better engine made at the time imo

thanks for the ideas... the fans turn on when i disconnect the temp sensor. with my scan tool it looks like the sensor is in the right range for operation. so that brings me back to the water pump/ timing belt.

the fans also seem to kick on at about 230°F and then off around 210. i don't know what the actual on off temps are supposed to be but thats what my scan tool reads. when i hear the fans kick on and off.

Yes those temps are in the ballpark as Nitrousn said above. you may have a w/pump with some rusted off impellers.Esp if your coolant was rusty.

Our shop has fixed many of them by replacing the head gaskets and checking the heads for warpage. Ron

if the heads were warped and the head gasket blown, wouldn't i see milky oil or steam coming out of the exhaust?

You never said that you were actually losing coolant. Also, get a temp gun and get a reading from the coolant. It may be just a bad sender/ gauge. Also, maybe pull the radiator and use a garden hose and flush the exterior of the radiator from the engine side. Many cars have heating problems because debris gets caught in front of the condenser and radiator.

I have 4 1st gen intrepids, 2-3.3L and 2 3.5L. I disagree with the earlier poster who says the 3.5 is junk. Its a good motor that makes good power.

In my opinion you should always take care of the known issues first and the waterpump and timing belt are overdue. Change those and my guess is your overheating problem will go away. I've done both mine 3.5s now. I think the second one took me a couple hours to do. You can borrow the balancer tool from an autozone. Remove the brace accross the radiator and the fans and then you can remove the belt covers and radiator hoses. Pull the old pump and take it with you to the parts store, there are to pump versions availiable 3 and 6 bolt. Total is under $100.00

Ken