Thermostat - lower or higher

[n0c7]

On a hot summer day without the A/C on, my car's temperature sits in the middle like it should. If I turn the A/C on, within 5-10 minutes of driving(not idle) it will gradually begin to overheat. I want to know if installing a lower or higher temperature thermostat may help this issue? Regardless, can someone explain the difference between the two?

 

[tsitalon92]

A lower thermostat will open at a lower temp, as a higher thermostat will open at a higher temp.

If your having overheating issues, I would definatley NOT recommend a higher thermostat. Also, check your coolant level.

I've always ran a 180 degree thermostat in my car.

 

[Irrational]

I guess a lower temp thermostat would help. but with that fmic blocking airflow the radiator and your ac on all on a hot day. your best bet would be some fans that pull more cfm or even a after market radiator. what I'm getting at is the thermostat is not the "problem" its a mix of the hot day the fmic and the ac all adding up. a colder thermostat will only let more water flow at a lower temp but once the thermostat is all the way open witch it is on a hot day with a fmic and ac on it wont make a difference.

 

[n0c7]

I'm about to take the car out from the winter and I'm in the process of tuning it up and dumping all of the fluids. I'm dumping the coolant, changing out the thermostat, and the rad cap so I figured this was a good time to ask. What temperature does an OEM one open at? I'm thinking about going with a lower temperature one.

 

[n0c7]

I guess a lower temp thermostat would help. but with that fmic blocking airflow the radiator and your ac on all on a hot day. your best bet would be some fans that pull more cfm or even a after market radiator. what I'm getting at is the thermostat is not the "problem" its a mix of the hot day the fmic and the ac all adding up. a colder thermostat will only let more water flow at a lower temp but once the thermostat is all the way open witch it is on a hot day with a fmic and ac on it wont make a difference.

Makes sense, but until I can fork out money for an aftermarket radiator, I was hoping I could throw in a lower temp thermostat and hopefully keep the car a few degrees cooler overall?

 

[Defiant]

Thermostats don't cool engines. Radiators do. The thermostat restricts most coolant flow when cold, then regulates itself to try and keep the coolant at its level. However, in a DSM that usually runs around 205°F and a bit more, a 160° thermostat will only open too soon. It won't "cool" anything other than to let your car run in closeed-loop condition longer than usual.
How long since you blew the dead bugs out of your radiator/condensor/FMIC?

 

[n0c7]

Thermostats don't cool engines. Radiators do. The thermostat restricts most coolant flow when cold, then regulates itself to try and keep the coolant at its level. However, in a DSM that usually runs around 205°F and a bit more, a 160° thermostat will only open too soon. It won't "cool" anything other than to let your car run in closeed-loop condition longer than usual.
How long since you blew the dead bugs out of your radiator/condensor/FMIC?

I ended up putting an OEM replacement thermostat that opens at 180F. I havent owned the car all that long, so I better go look and see what the buildup of crap looks like in those components. How much would dead bugs, grime, dirt etc affect efficiency of those components?

 

[way2slowtalon]

I ended up putting an OEM replacement thermostat that opens at 180F. I havent owned the car all that long, so I better go look and see what the buildup of crap looks like in those components. How much would dead bugs, grime, dirt etc affect efficiency of those components?

Enough to mess your car up. I had that problem on my old SMIC.

 

[Mindslayer]

I have the same problem. In the winter it didn't warm up every. But I change to a 180 and a 192 stat and I run hot all te time not in this heat. I flush the radiator and everything and its good for 15-20 minutes and then it be burning up.

 

[GTM]

On a hot summer day without the A/C on, my car's temperature sits in the middle like it should. If I turn the A/C on, within 5-10 minutes of driving(not idle) it will gradually begin to overheat. I want to know if installing a lower or higher temperature thermostat may help this issue? Regardless, can someone explain the difference between the two?

I would be interested to know if both fans come on when the A/C is turned on. Have you any reasont to not suspect a blown head gasket?

I am a firm believer in running a cooler T'stat especially on older cars when there are cooling system complaints. That gives you an additional margin before possible boiling. I also grind a small notch which is placed so that bubbles can escape as well as pass a small amount of coolant which helps the T'stat regulate.

Your cooling fan temp sensor(s) could be failing and cycling too late or turning off too soon.

Cheers,
GTM

 

[Mindslayer]

For me it was the head gasket. IT blow on the way home today. But its' all good I have a strip/street race prep head ready with FP2's and arp head bollts I'm going to drop on my car this weekend. Just mad I don't have a cherry picker yet to drop in my 2.3L and ACT fly and PP. Hope its not the same problem for you.

 

[jcranfill]

Similar problem with my '92, 188k on the clock. I commute 122 miles each day to work, and since it;s started getting above 75 here during the day, it wants to overheat. Last year I had to put on a new water pump, went ahead and replaced all hoses and flushed extensively in the process due to mileage and expected mileage.

I had 180 tstat in it, and removed it completely last week. It definately takes it longer to get to operating temp, but still gets there. The car does NOT overheat when driving around town, but instead after about 30 minutes on the interstate. The 2nd fan DOES come on with the A/C. If I turn on the heat, it will slowly (havent had any 85+ days yet tho!) return back to normal operating temp.

Coolant isn't low now, and wasn't low when I removed the tstat. Oil came out looking like...well, oil.

I really need this car to hit 250k. Any suggestions on a specific aftermarket fan or radiator that can help me out? I really, REALLY like my 31mpg!

 

[jcranfill]

I forgot to mention - I can definately feel the water circulating by feeling the top/bottom hoses. Also, if I pull over or exit the interstate, the car will slowly drop back down to normal temp. Even if I just pull over and idle...

 

[400HP1GT]

It could be a bad thermostat. I replaced a 180 degree with a 160 degree stat. Set the coolant offset at 20 on the DSMlink, ECU thinks the 180 is still there. No problems with setup. thermostat is a failsafe style. Fails open.

 

[Defiant]

thermostat is a failsafe style. Fails open.

Sure it does. Unless that part fails, too. Which happens.

NEVER run a modern car without a thermostat.