3.1 running too cool

[Guest TurboSedan]

i went down to Denver and back yesterday and my car is running WAY too cool - the digi-dash only read like 2-4 bars the whole time and my gas mileage sucked ass - like 24-25mpg

 

thermostat stuck open? the heater seems to work ok. lately it's been running cool but it seems to be running cooler than ever now. even while i'm delivering pizza ie. city driving i only get 4-5 bars lit up on the gauge.

[THe_DeTAiL3R]

Try a coolant flush and new stat. Maybe your current coolant isn't the right mixture water/coolant or something.

[Guest TurboSedan]

Try a coolant flush and new stat. Maybe your current coolant isn't the right mixture water/coolant or something.

 

i dunno, the car seemed to run cool 'suddenly' starting about 2 weeks ago or so, but after that trip yesterday it ran REALLY cool. i think it was the 1st highway trip i've taken since the problem started so the highway driving made the engine run even cooler with the air flow @ 75mph. the coolant was all changed last October or so (always 50/50) when i had the engine and tranny out for the 2nd Getrag swap. i never have swapped the thermostat since i've owned the car - the thing probably has 218,000 miles on it i'll change it tomarrow; even if that is the problem (probably is) it could probably use a new one.

[sl3196]

Lol yours is running cool, mine is running hot. I actually found out why mine is running hot. Cause the airdam for the radiator broke off.

[Guest TurboSedan]

Lol yours is running cool, mine is running hot. I actually found out why mine is running hot. Cause the airdam for the radiator broke off.

 

yeah i was thinking the same thing!

[Waterboy]

Almost always the t'stat when running cool. You will still get some amount of heat from the cabin heater. Computer thinks that the engine is cold so gives it more fuel, kinda like the old days of carb and choke which is something you may see on the History Channel.

 

GM t'stats are notorious for failing, usually in the open mode. Sometimes they will will fail in the closed mode i.e. instant boil over. And, when they fail in the closed mode, it does not happen at start up. Usually after you have been driving for awhile.

 

There are t'stats that are "failsafe" which means that if they fail, they will fail in the open mode.

[93CutlassSupreme]

GM t'stats are notorious for failing, usually in the open mode. Sometimes they will will fail in the closed mode i.e. instant boil over. And, when they fail in the closed mode, it does not happen at start up. Usually after you have been driving for awhile.

 

indeed they do

[supreme_style21]

So when the tstat fails in closed mode, it should all start boiling? Mine runs extremely hot.. usually a bit under the redline. It always ran hotter than usual before, so I flushed the cooling system, checked the temp sensors and whatnot. After I did that, it runs even hotter, but nothing boils.

[93CutlassSupreme]

So when the tstat fails in closed mode, it should all start boiling? Mine runs extremely hot.. usually a bit under the redline. It always ran hotter than usual before, so I flushed the cooling system, checked the temp sensors and whatnot. After I did that, it runs even hotter, but nothing boils.

 

when a thermostat goes bad it will boil over

[THe_DeTAiL3R]

So when the tstat fails in closed mode, it should all start boiling? Mine runs extremely hot.. usually a bit under the redline. It always ran hotter than usual before, so I flushed the cooling system, checked the temp sensors and whatnot. After I did that, it runs even hotter, but nothing boils.

 

If its stuck closed then it will run hot and boil over, and will come out of the reservoir and steams up too.

[GPdriver1986]

change ur thermostat and use an AC Delco one. Oh yeah and also check if your fan is stuck on because that might mean that your relay is stuck on.

[luminator94]

So when the tstat fails in closed mode, it should all start boiling? Mine runs extremely hot.. usually a bit under the redline. It always ran hotter than usual before, so I flushed the cooling system, checked the temp sensors and whatnot. After I did that, it runs even hotter, but nothing boils.

 

 

My 94 GP SE did the same exact thing...thermostat would read that it was overheating when it really wasn't, happend on my Lumina to. Probly the wiring for that year was bad.

 

Aaron

[supreme_style21]

So when the tstat fails in closed mode, it should all start boiling? Mine runs extremely hot.. usually a bit under the redline. It always ran hotter than usual before, so I flushed the cooling system, checked the temp sensors and whatnot. After I did that, it runs even hotter, but nothing boils.

 

 

My 94 GP SE did the same exact thing...thermostat would read that it was overheating when it really wasn't, happend on my Lumina to. Probly the wiring for that year was bad.

 

Aaron

 

Awesome. Thanks General Motors!

[supreme_style21]

Actually... now that I think about it, we used one of those laser thermomitors (sp?) on it, and it was running quite hot. Again, this was before it started to run even hotter, so perhaps the wiring is messed like he said. Nothing boils over, thats for sure.

[93CutlassSupreme]

So when the tstat fails in closed mode, it should all start boiling? Mine runs extremely hot.. usually a bit under the redline. It always ran hotter than usual before, so I flushed the cooling system, checked the temp sensors and whatnot. After I did that, it runs even hotter, but nothing boils.

 

 

My 94 GP SE did the same exact thing...thermostat would read that it was overheating when it really wasn't, happend on my Lumina to. Probly the wiring for that year was bad.

 

Aaron

 

there's no wiring in a thermostat...have you guys ever seen a thermostat? :read:

[91oldscutlass]

Ok maybe I am lost here...but running cooler is a plus....not a bad thing...so why worry???

[GPdriver1986]

Its a bad idea running cool because the engine can never warm up to full operating temp, this causes the metal to expand and contract. Also during winter it takes long for the coolant to warm up, this makes it dangerous because you don't have heat and no defroster for a long time. If you want the engine to run cool only temporarily use the coolant fan override switch.

[91oldscutlass]

We used to take the thermostats out and cut the middle out of them....kinda like restrictor plates for our V8's to run cooler. I have gotten to the point to takeing the thermostats out in the summer.

[93CutlassSupreme]

We used to take the thermostats out and cut the middle out of them....kinda like restrictor plates for our V8's to run cooler. I have gotten to the point to takeing the thermostats out in the summer.

 

yup, back in the old days, before these new fangled engines with somin' called fuel injection and ecm dohickies...

[Waterboy]

I had a '63 Rambler that I had to wear a blanket in the winter because the heater would not put out.

 

Found out later that there was NO t'st. The water was moving so fast it could not pickup any heat.

 

Usually, the 50/50 coolant is never the problem. Most of the time it is the t'st. But, if the coolant is old, there could be a film of crud causing a poor heat transfer.

 

First thing first...always always start with the t'st. Cheep and ezzee.

 

IMHO

[Guest Gp crazy]

Boy i wish i could figure out why my two 3.1's run cold new stats and new water pumps on both never get to temp 50\50 mix & both flushed and both were nasty dark \green rusty color & smelled like shit also.flushed with water until clean & clear then 50\50 mix any ideas ? stats are stock gm and the temps were 195 on both? they never get up to 195 the temps are 180 or lower

even at high way speeds :dammit:

3.1 ste

3.1 block and 2.8 top end stock ecm se 5 speed

[93CutlassSupreme]

you ever let it idle for a really long time?

 

i get up to 200 degrees all the time in the summer in fast food drive through lines

[Waterboy]

Remember, after a cooling flush, there is always water in the system that does not drain out. When filling up the system, do not add 50/50 already mixed. Calculate the system capacity. Add the correct amount of 100% antifreeze then top off with just water.

 

Also, if you have 190* t'st and your temp does not go above 180*, then your radiator hose going into the radiator will be cold because the t'st never opend.

 

My 1-1/2 cents worth.

[god910]

Yeah, computers don't like it when the coolant doesn't get hot enough. 2) NEO, KISS MY ASS. 24MPG, I'll take IT!!!!!

 

I hotwire my fan at the track because it's good to keep as many things consistant as possible. 130* coolant temp. no matter what the temp. outside is. (Okay for 1/4 mile runs, wouldn't suggest it for longer.)

[93CutlassSupreme]

I hotwire my fan at the track because it's good to keep as many things consistant as possible. 130* coolant temp. no matter what the temp. outside is. (Okay for 1/4 mile runs, wouldn't suggest it for longer.)

 

thats a good idea, waterboy is right too if your upper raditor hose isn't hot then the thermostat didn't open