Coolant Temp Concern

I had an Experience yesterday that had me concerned and I wanted to get everyones opinion about. The back round- I have a 95 s/c with the only mod so far being a gutted airbox. I had the radiator and upper and lower rad hoses replaced in march cause the original rad was leaking. Also had 180 stat installed. It would run right around the 200 mark before the new stat, hotter if I pushed it hard. After the new stat it was considerably lower, I would guess around 180-190.
Yesterday my outside temp display read 88 and the humidity was fairly low. My drive home from work is about 9 miles of mostly signal-controlled hi-way with a speed limit of 55mph which takes about 15 min to drive. I shut the car off for about ten mins then I was back on the road, this time about 6 miles down the same hi-way. In New Jersey there is a lot of traffic so by the time you hit the speed limit its time to slow down again for the next light. I'm not accelerating hard and I don't have the a/c on, but I am repeatedly going up to between 55 and 65. Everything to this point is fine, my temp is right around 185-ish. I park the car with it running for about 2 mins and as I watch the gauge starts to climb, all the way up to around 200-205. I take off again going down a 25 mph road and watch the needle move to about 210-215! At this point I'm concerned! I get back on the hi-way, this time no traffic, and with my eyes glued to the gauge I watch as the temps start to fall back down. By the time I got to 65mph the temp was about 200, after a few more seconds it was back to 180. I had no further problems all the way back home. This morning I checked the coolant level and the rad was full but the overflow tank was a bit below the full line. The coolant looks fresh and brand new, not dirty or oily at all. I didn't see any leaks and I didn't have any problems on my way to work this morning. I will check for leaks again before I leave work and I will also check to make sure the fans are running.
This is not normal right? I wasn't pushing it hard and it didn't do this last summer with a slightly cracked rad and 195 stat. I'm concerned because I have 95-100 degree days with high humidity in front of me! What gives guys? What else do I check. Also of note I did not reprogram the fans from their original settings, is it possible to do that on a 95? If you need any further information I will gladly provide it if I can. Any information you can give will be greatly appreciated! I love my baby and would be devestated if anything happened!

It seems like it's due to the stock fan turn on temps. I cant remember exactly what temperature they turn on at but it is probably a little over 200. I would continue to monitor it but in hot weather like you experienced, the coolant temps can get pretty hot (My fan turn on temps are ~190 IIRC and the gauge hits nearly 200 at times).

It sounds completely normal after idling for a couple mins in hotter ambient temps, to see 200 or 210, even 220 after a few minutes. The 180º t-stat only helps you when you are moving. Fans don't start on until 220º, so at idle the coolant gets hot. When you got moving again to 25 mph you saw the delayed heat finally setting in. If you had stayed idle longer, it would have still climbed to 210-215º. Finally after you get moving again, it takes a minute or to before the temps drop. I've found 35-40 mph is enough to cool the radiator adequately.

Even with my fans set to turn on at 180ºF, I try not to let the car sit in park while idling. It makes the engine hot and wastes gas. There really isn't any reason to do it accept to keep the interior cool. I even turn off my car when I drive up to an ATM or fast food window.

Agreed. Sounds pretty normal to me. I have a 160* stat, and sitting for long periods in traffic the temp gauge still gets above 200. Start driving a mile or 2 and it goes back down.....

Well Derek, you've got your answer... now don't you feel much better?

The stock lo-fan turn-on temp on '97+ is 212-215 degrees, and I would imagine '95 is similar. But I have a further test you can do just to confirm everything's fine:

Ironically, unlike previous decades with mechanical fans, when standing still or moving slowly you should actually be able to cool the motor down by turning ON the A/C... Unless the '95 is really programmed differently, as soon as the system demands cooling, the PCM turns the low engine-fan on. I have a 180 stat also, and if I'm stuck in traffic with the temperature climbing above 200, I turn on the A/C and it slowly brings it back down.

Give it a try the next time you drive a similar cycle.

Thanks guys I feel better now. I think I just freaked out cause last year it ran at 200-210 all the time, so the needle hardly moved. Now with the new stat in it runs at 180 and idles at about 205-215. I confirmed this when I got home by letting it idle in the driveway and I watched the needle move up to 215 then down to 205, ect. Also it helps that I didn't find any leaks.
So... That leads me to my second question. Can the fan be reprogrammed in a 95?

Programmed through the PCM, not necesarily or should I say not easily. I think I remember someone mentioning a company that will take your PCM and make some changes to it. But I don't know who that is and from what I remember for just fan turn on setting changes it would be too expensive.
The other way to go is to wire up a switch to manually turn the fan on and off, or have someone that can wire, install the proper relay, etc for you.

you can also bring engine temp down (without the AC load) by opening (all the ) windows and turning on the heater. adjust the heat to 90F, turn the fan on high (press top of fan switch to light up the bar), set the outlets so they don't make you too uncomfortable (most likely defrost) and the HVAC head will run engine coolant through the system.

Albertj

I don't know about you and what the weather has been like in your neighborhood this past week or two, but I wouldn't get in the car today until i let it run with the AC on MAX cold for about 10 to 15 minutes, it's been humid and the interior temp of the car was easily in the upper 90's.
Put on the heater, I don't think so. I'd much rather flip a switch to keep the coolant temp down.
But, that's just me.

Rickw wrote:

I don't know about you and what the weather has been like in your neighborhood this past week or two, but I wouldn't get in the car today until i let it run with the AC on MAX cold for about 10 to 15 minutes, it's been humid and the interior temp of the car was easily in the upper 90's.
Put on the heater, I don't think so. I'd much rather flip a switch to keep the coolant temp down.
But, that's just me.

No, that makes sense - I just posted an alternative for folks to be aware of if the A/C - on approach did not work. The conditions that might favor my approach:

- radiator fan malfunctions but heater fan still works
- radiator got muddy or otherwise coated for some reason--my approach basically forces the car to insert another radiator into the engine cooling loop

I kinda doubt folks would have to use my approach. However, it will work if the other fails, as long as the cooling system is intact and the heater/fan are operable. Just an alternative, not a directive.

Albertj

So with the AC on, is the fan suppose to be on constantly, or is it suppose to cycle on and off? Mine cycles on and off when the AC is on.

The fan will cycle on and off. That Lo fan is made to cycle with the A/C on to cool off the condenser (commanded by PCM when A/C line pressures get too high and require cooling).

There might be an air pocket in the system and didnt notice it until the weather got really hot. Try taking your rad. cap off and run the car for about 15 mins or so. I like to run it until the coolant really starts to flow over. This cant hurt anything.

moldymac wrote:

So with the AC on, is the fan suppose to be on constantly, or is it suppose to cycle on and off? Mine cycles on and off when the AC is on.

Well, Scott has a '98 while you & I have '97s. Moreover, even the '98 book actually says 2 different things in 2 different sections... In one, it says that the fans only come on when the ambient temp is over 122* or when the line pressure is over 190 PSI. In the other, it simply says that the fans are commanded on low at the same time the compressor is commanded on.

Obviously, when the compressor is running in the winter, they're probably not needed, and I wouldn't doubt that there IS either an ambient temp cutoff, or possibly no fan-command when the system is asking for heat.

As for my own experience, I know that I can have the system off (no pressure) at a helluva lot less than 122 degrees outside, and my fans do kick on as soon as I push the AUTO button... In fact, I just double-checked it:

- 78 degrees ambient
- Stone cold engine
- Hood open & Climate Control off
- As soon as I reached in the window and hit the temp button on the steering wheel, turning the system on at AUTO-66 degrees, the compressor clutch grabbed and the fans came on simultaneously...

I noticed something else that makes this programming logical: even with a cold engine & radiator, those fans were blowing quite warm air within a minute... That condenser gets hot quickly. And remember, in the days of mechanical fans, even with clutches, there was always some air being pulled through the radiator/condenser - after all, you need the A/C the most when you're sitting in traffic.

Hmmm so the concensus is that it would be too difficult/expensive to have the fans reprogrammed via pcm adjustment...
Rick I'd like more information about that relay idea of yours if you have any. If I re-call correctly there was a plug in dohicky for my 95 talon that would let you adjust the fan setting from 160-210. Is it something of that nature, only custom built? I really like the idea of it doing it automatically as needed, plus I'd like to keep the interior as stock as possible and save all my mods for under the hood. A drivers door boost gauge on the other hand... Lol
Thanks Albert I was aware of the heater as a second radiator from my days driving an 85 camaro. They had a very small grill opening design on those cars that did not let in enough air to the undersized radiator. Add in New Jersey traffic and my car became a sweat box from the combination of heater on full blast and 220+ heat pouring in through the inadequately insulated firewall. I had hoped the days of having to drive with the heat on in 100 degree weather were over and it appears they are.
I'll give that idea a try Curt, I haven't done that yet and like you said it can't hurt.
Thanks to everyone who wrote in about this even tho it turned out to be a non-problem. Its really nice to have a place to turn to when you need help, or even just a little information and guidance.

When you run the motor with the radiator cap off, try to do it at a distinct uphill angle... this helps get air out of the heater core.

i turn on my fans manually. i should say, my A/C is inoperable so i'm not sure of possible implications with a working A/C.

what i did is in a post lower on this page. it works 100% for keeping things cool. i sat in bumper to bumper memorial weekend for 45 minutes at 185* with 85* ambient.

as soon as i see a traffic back-up or know there will be extended idling time, i flip the switch and forget about it. the " mod" took all of about 5 minutes and was free.

With your A/C inop, how are you getting the fans to turn on.?
You mention somewhere on this page or in this Topic, but I can't find where you have written the solution to your problem./

I think he wired a manual turn-on switch.

Rickw wrote:

With your A/C inop, how are you getting the fans to turn on.?
You mention somewhere on this page or in this Topic, but I can't find where you have written the solution to your problem./

i should have put a link, i didn't make myself very clear, sorry. https://rivperformance.editboard.com/series-i-engine-transmission-f13/cooling-fan-relay-location-t7131.htm


like i said, i can't really speak about how it might affect the A/C.

but i just connected wires to the switch in the a/c line behind the passenger headlight ( bypassing the switch). ran those wires inside the cabin. when the circut is open, the fans run on high. so when i flip my switch, i hear a relay click, then my fans run on high. ... dunno, i just stumbled on the idea. it works very well for me, i hate the idea of getting a high milage engine to hot!

Yes, I was going to mention that, but I had a phone call & had to leave... With a working A/C system, you would not want to use Nathan's method.

Eldo wrote:

Yes, I was going to mention that, but I had a phone call & had to leave... With a working A/C system, you would not want to use Nathan's method.

cool, thanks for the clarification, i'd never want to instruct someone to do something potentially harmful to there ride, thats why i put it in bold that mine is inoperable. matter of fact, i,ll go back and edit my other post to make sure people know not to do it with a functional A/C.