FAQ: Engine Coolant Temperature & Fan Turn-On

regarding accuracy;
when I was having heating and temperature problems I installed a Mr gasket thermocap
to check temperature and gauge accuracy. found it accurately matches instrument temperature
gauge (with thermostat open) . I like to use it to I can keep an eye to temperature when working
under the hood.

117 on the way home today, car temp was under 200. RMI 25, water and a 180 thermostat.

Cool!

Hi guys so I recently flushed my radiator and changed the thermostat in the process. But before all this my temp would stay at 195 while driving and go to about 215 while sitting at a light, I though flushing the radiator and changing the thermostat would be better so I did, now I'm at 180 while driving and then I go to about 210 when I sit. Something's not right I think, help me out?

Your new t-stat is a 180º unit.

It is

And let me further guess that you did not reprogram the PCM to turn on the rad fan at a lower temp, so it does not come on until the car has been sitting and engine temp is above the normal 195F. And you are probably not running A/C, if you were then the aux fan would run.

I can't figure out how to get a software to program my 1996 PCM, and no it's winter I run the heater, but it still goes up to higher then 195 even before the thermostat

When the fans are off, 210 is normal while sitting or light to light driving. The low fan turn on temp for my 95 is 212 and high is 225. I have a 160* Thermostat and it climbs to 210-212 when it gets heatsoaked.

Ok so my car is fine, I thought it wasn't suppose to go higher then 200 so thanks!

im balanced at 188 with my 180 and if I sit to long it ,goes to 208 and it wont come back down and I can smell the water when I get out the car... I need a really thorough tune and ill be okay make sure

208 is normal with a 180 t-stat at idle. The smell is a small leak somewhere, probably the radiator - t-stat or a tune won't fix that.

Hey guys, wheat temp does the rad fan kick on? Im sitting.in trafficand watched my temo.get to 210, its 49 degrees out. Is my temp switch gling.bad? I turned the heat on amd the car cools down quickly

Hey man I asked the same question earlier, the fan will turn on usually around 220(not sure exactly) but it will never go past, what your watching makes me feel uncomfortable but otherwise it is completely normal

Yes that one is PCM controlled and can only be changed by software.

Most of us who have added a few mods have either re-programmed that temperature threshold lower ourselves, or have had it done by somebody else.

220 212ºF is when fan #1 kicks on. #2 (if enabled) kicks on at 226ºF. Your situation is normal for stock engine when stopped idle, even with 180 t-stat. Turn on your AC to activate the cooling fans at any time.

Hey thanks guys, ever since i took that intense pcm out i left the 180 t stat in there. Since its cold out my car actually drives arounf 170-178 degrees.srop and fo traffic the temp goes from 170s driving to 186+. On a side note. When i got the shop to out in the radiator kt came with a thermostat and i specifically told them to not use that and provided a 180 thermostat. Im .startingto doubt if the put the 180 in like i asked, but thats another story. Anyone around the area of va who can program my car to tuen the fans on toaccommodate the lower thermostat?

If your car is showing 170-180º, they installed the 180 t-stat. If not, you would never see much below 195º. The Intense PCM would have reprogrammed the fan turn-on settings, so you would see 180º all the time, even when idling. Without the tune, your temp will rise over 210º if you're stopped long enough.

Alright cool thanks

Over the winter I slid off the road into some thick compact (icy) snow. After that my car seemed to be running a little warm and my coolant light was on. I bled the system completely and replaced with new green coolant when the weather warmed up and I felt that overheating might be an issue. Light went away and it still seemed to run a little warm, but never noticed it above 200 because of the country driving. The other day I was sitting in the parking lot with it idling, waiting for someone, and it just kept rising up to 220 (ac on) so I turned the heat on to try to pull heat out and it still slowly rose, so I shut it off and let it cool for a bit. Checked today and it doesn't seem like either of my fans are working (I suspect they haven't been since I went off the road).

Before this problem my car would never go above 200 degrees. It could be 100 degrees out and heavy traffic and I would sit at 200. My radiator is only a couple of years old and I don't seem to be losing any coolant (flushed about a month ago).

A couple of questions. Which fuse runs the fans? Where would I find the relays, and what else should I be looking for?

I searched on here and it seems like all I found was people that thought they had problems and come to find out they just weren't letting it warm up enough for the fans to kick in.

Sounds like to me normal operation. When it climbs to the 230 range and keeps going that when I'd start to worry. You need to hook up a scanner and look at the live data to see just where it is. Watch it, look for fan operation. You may want to look closely at the coil in front of the radiator and make sure it isn't pack with dirt, mud, debris. If it is spray it out with a garden hose, this will also make the a/c work better if it is still functional in your car. If the impact was hard it may have dislodged some build up in the coolant passages making a poor circulation condition, Dexcool is bad about creating build up if its not flushed correctly before the 100k mile mark. Good luck with your issue.

I know for a fact I've posted this here somewhere before, but here it is again. If you know how to read a schematic, this should be all you need to figure out what's going on. I'd start by jumping the relays to try and get the fans to come on manually. If they don't, you either have a wiring problem or bad fans. If they do come on manually, you need to check from that junction block back. I have the schematics for that as well.

Does one fan come on when you turn on your A/C?

I'll try to jump the relays when I get a chance. Neither fan runs. Before the incident I never really paid attention to whether or not the fans were working, but the car did stay at or below 200 all of the time. Now, if I'm sitting still in traffic or something, I can watch it rise.

@rivi95era, I've looked at a lot of posts on here about the subject and that seems like everyones response, regardless of the situation, yet they also say that with the ac on a fan should be running, and also that at 220 even without the ac on, one of the fans should be running. The second fan is supposed to kick on a little above 220. The car running 220+ on a 75 degree day isn't normal no matter what car you're talking about.

@duster_do_little, my mistake, must have hit a "3" I meant to type 220

My fans turn out as soon as the car starts. Tune is fine, relays are fine. going to try replacing the coolant temp sensor and see if that fixes it per stuff i've read on the net.