Engine running hot

[marlonius]

I've got a 95 MTX and the engine temp has been doing some funny things. I recently replaced the radiator and thermostat (about two months ago). I just returned from a trip from Philadelphia. On the way down the engine temp needle stayed right in the middle, but sometimes when I got stuck in slow-moving traffic or was running the engine hard to pass, the needle would creep up to the "N" and "O" in "NORMAL". And eventually it would settle back down around the "R" and "M". Is this something I should be concerned about? If so, what could be causing this? Driving the car on city streets to and from work (stop and go for 30 minutes), the needle stays around the "R" and "M". Weird.

 

[Rob94]

Is the cooling fan coming on?? And, when you say running the engine hard to pass, are you running the air conditioner?

 

[marlonius]

Yes and yes.

I don't know if the fan is coming on too late. Or maybe the air is not circulating properly. I just thought of something else: would hot air being sucked into the engine cause the engine temp to go up? I noticed that the foam gasket between the fender and stock airbox has a hole in it. I have not gotten around to fixing it yet. Anyone have any ideas on how to plug that up effeciently without taking the whole airbox assembly apart and trying to find a foam gasket?

 

[mhodzic]

I got the same problem when I am in stop and go trafic my needle stays around O and R, but when I am on the highway it comes down to A. I have recently replaced my theremostat with the origional Motorcraft one. My guess is that I have to switch to lower temp thermostat or replace my coolant temp sensor. My fan is working perfectly. Another funny thing that happens only sometimes is that when I park after some driving my coolant bootle gets overfiled and it leaks, I think that this is caused by faulty radiator cap that tends to get dirty and it leaks coolant back in the overfill bottle and it leaks out. Any coments or suggestions are welcome

 

[Ishodu]

About the coolant overflowing the bottle, try testing the coolant, u just may have too much water to coolant ratio. water expands more than pure coolant, at it will also boil alot lower temp.

 

[Rob94]

A faulty radiator cap could also cause your engine to run hot.

 

[sdpatt]

The higher the water to coolant ratio, the greater the heat transfer capability of the cooling system. 100% water will not cause the engine to run hotter, but it will allow the liquid to boil at a lower temperature.

Your situation sounds like a lack of cooling air flowing through the radiator at the low car speeds. The electric cooling fan(s) is designed to provide a flow of air through the radiator to remove the heat from the engine. Does the fan(s) run when the climate control is on either MAX A/C, AUTO, defrost or PNL/FLR? It should.

Air flowing through the radiator will get hot, but it is the heat from the engine that it is removing that is getting the air hot. This hot air is helping to cool the engine, not heat it up.

 

[mhodzic]

yes the fan works fine and it does turn on when you set the climate contorl to Max AC and the rest of them that you mentioned. But I remember a year ago my car temp would be around A in stop and go trafic and when you are driving it on the highway. I think that my thermostat is causing this by keeping it closed until reaching higher temp and opening up, which turns the causes colant temp to turn on the fan. I think that I should replace my thermostat with the lower max temp required for it to open up. Has anyone tried using one of these aftermarket thermostats with lower max temp than the motorcraft one? Got to try to keep my engine running cooler in this 90 degree weather.

 

[Chrisssssssss]

I heard that adding some of that Redline "water wetter" will help this situation. I haven't tried that yet, but I have the same problem. My fan comes on fine, but I have all water in my rad right now. I will be adding coolant soon, as when I was doing my engine swap, I put coolant in before I flushed the system and it ended up fouling my coolant really bad. I think that the engine was in the boneyard for a while and it had a lot of rust in the coolant passages. My coolant turned brown real quick.

I will be adding coolant and water wetter and let you know how this affects my temp readings...

 

[ant-live]

I've added the water wetter and still have the same problem. How exactly do you know when the fan is going out?

 

[Chrisssssssss]

I think that with my car is that the fan just is not coming on at the right time. Is there any way to get the fan to come on sooner? It was never a problem with my other engine. A coolant temperature sensor maybe? Where is the coolant temp sensor? Is it located in the block or the rad somewhere? If it is on the block, then is it the same sensor on the 3.0 as the 3.2?

 

[Dave Ladely]

wondering how rust appears in an aluminum engine?

 

[Slo-Sho]

The block is cast iron, the heads are aluminum.

 

[ant-live]

If my memory serves me correct the coolant temp. sensor is in the coolant resoivor at the end of the cap.

 

[aberdeenSHO]

i've had the same overheating problem for months now(only overheats when you turn the a/c on, otherwise it fluctuates). My problem was a blown head gasket. I replaced everything you could possibly replace, and finally this guy i knew did some trick where he just felt one of the rad hoses and said there was too much pressure... sure enough it was a blown head gasket. I would have that checked before replacing anything and everything.

 

[CincyBearcat]

Have you checked your engine temp with a heat gun or infrared sensor of some sort to make sure you are really having heat problems? The temperature sending unit to the gauge cluster absolutely stinks and will go bad in no time flat, giving you a bad reading. Just make sure you're really having problems before you get too deep into looking for a solution.

 

[Axianator]

ant-live:
If my memory serves me correct the coolant temp. sensor is in the coolant resoivor at the end of the cap.

Actually, there are two sensors. One is the ECT (engine coolant temperature sensor) and reports the temperature of the coolant after the themostat to the PCM. The other sensor is for the temp gauge on the instrument cluster, and is located behind the thermostat to the left of the throttle body (looking from the driver's side towards the passenger side). There's a little black L-shaped connector that snaps onto this sensor and can be unplugged and replaced to verify it's operation. I didn't think that these two sensors went out in the SHO very often, but it's possible in your case that one or both are faulty.