running hot mtx 94

[shocar]

My 94 mtx with 175k has a problem and I am at wits end. The car seems to run fine except for a cooling issue. Here is what I have done recently. New water pump, timing belt, cps. Both temp senser next to throttle body have be replaced. I have checked the thermostat and it is opening up as it should. The cooling fan will not kick on as it should. It does come on if you run the climate control. I have also replaced the crcm module recently. It will run between N and Red on the gauge. Any ideas on what might be going on here. If for some reason, the timing might be off would it make the car run hot like this. Performance wise the car seems fine.

 

[stangeater]

My 94 mtx with 175k has a problem and I am at wits end. The car seems to run fine except for a cooling issue. Here is what I have done recently. New water pump, timing belt, cps. Both temp senser next to throttle body have be replaced. I have checked the thermostat and it is opening up as it should. The cooling fan will not kick on as it should. It does come on if you run the climate control. I have also replaced the crcm module recently. It will run between N and Red on the gauge. Any ideas on what might be going on here. If for some reason, the timing might be off would it make the car run hot like this. Performance wise the car seems fine.

How do you know the thermostat is working correctly? A new one only costs like $8. Does the car cool down when the fan is on with the climate control? This may be a dumb question, but is the coolant level okay? When you changed the waterpump, did you burp the system to get all the air out?

Last question.....was the car running hot before you replaced the water pump?

 

[kevinspann]

Did you replace the CCRM with the same letter?

Not being as well versed in SHO CCRMs, is there the possibility that the relay for the fan isn't working, and that there is another relay that will kick the fan on when the AC is on?

 

[shocar]

has a new CCRM, from last year. I have a spare do I will put in if the next thing I try doesn't work. I checked the thermostat by heating up water on the stove to 195 and it did open. I just went and purchase a new one so I am installing it now. Hopefully that is the problem. I did notice to that the front air conditioner cooler is a bit dirty. I will power wash it also. The car ran fine when after I put the water pump except I had to tear it down again to loosen the tension on the timing belt. It was making a bit of noise. I will post again in an hour or so and let you know what the out come is.

 

[shocar]

Just replaced with new thermostat and the car does exactly what it did before. Runs on the N -O idling. Take if for a drive and it stays on the N but when you stop it begins to shoot up to the redline. The radiator is hot up and down so I don't think there is a problem with circulation. I even shot the hose at the radiator panels with cold water and the car still stayed above the N . I am beginning to think the panel gauge is wrong. The cooling fan does kick on but only when the car get to almost the overheat line. Are there any other sending units that would affect the gauge?

 

[rubydist]

have you actually measured the temp of the water? the gauge will read high if there is a poor ground between the engine and the firewall, or if there is a poor ground between the threads of the temp sender and the housing, or if there is a lot of corrosion on the connector that the wire slips on. make sure you have a real problem first.

keep in mind that the cooling fan comes on by command of the pcm, which gets the coolant temp data from a different sender than the gauge. so, your next course of action would be to see if the temp sender for the pcm (the 2-wire one) is bad.

 

[shocar]

So here is some more info. I have an exact twin to this car so I compared them after they ran a while idling. I took a kitchen meat thermometer and took some measurement of both cars. They were within 5 degrees of each other on the main hose going in and inside the radiator with the cap off. I am thinking the temp gauge is giving a faulty reading for some reason. The one car was showing almost red and the other one was on" O" I am going to get some electronic solvent and clean the grounds and see if that is the culprit as you suggest. At any case, I don't think I can overheat the car by driving it.

 

[shocar]

I drove the car today 300 miles and it ran between N and O almost the entire trip. Only ran higher in stop and go city driving and later in the day when the outside temp was in the 60's I am pretty convinced at this point that the after market sensor is not the right one. and that the reading is false. I will get a better sensor as recommended to me by a couple of folks on the NWSHO forum and will post the results later.