your truck will stay in open loop mode and your fuel economy will suffer.. engines are designed to run at a certain temp, removing your tstat is a bad idea

 

I tried that on an engine a number of years ago. It didn't work too well, but I don't remember why I had to reinstall a stat.

Remember the coolant will simply just circulate without a stat an not provide time in the block to heat, or time in the radiator to cool adequately.

The think the reason in the past was that it never warmed sufficiently enough to satisfy the needs of the computer. That was in a 93 F-150 with way older computer technology too.

If you are having enough warming concerns to consider this option, perhaps a good flush at a shop and maybe a replacement radiator should be considered. Any idea if your radiator is clogged enough to disallow sufficient flow back to the engine?

 

That's strange. Aren't you running a v8 radiator with an EFan?

 

I've ways had trouble keeping it cool to a certain extent. It's not in town driving. It's highway. The v8 radiator from what I've been told isn't much different than the i5. I'm going to pull it all out and spray it off. My thermostat should be here Tuesday. It claims it's the 180 degree one from stant. May try switching coolants and run alittle more water.

 

If your experiencing over heating problems even after you have replaced the thermostat, I would suspect that either the DexCool to water ratio is wrong. In the warmer climate like your self it should be 6 qts water and 4 qts DexCool (60/40). V8 radiator in a I5, 7 qts water and 5 qts DexCool.

Also most importantly, is the radiator location. The radiator should be mounted level with the engine with the lower air dam. I have seen to many times were after installing body lifts. The engine temps spike to high. That's because the water pump is working harder to push the coolant from the bottom of the radiator to the top then back in to the engine.

 

I don't have a body lift. My radiator is in stock location. I took the body lift off right before the sas. I may try peak coolant. I'm running their synthetic ATF now.

 

Mud clogging the cooling fins? Make sure that thing is super clean on both sides.


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I've always had better luck with a 60/40 mix.

 

How much hotter are we talking?

Our temp sensor is right next to the exhaust(genius I know) but I actually get heat soak in the warmer temperatures around the sensor. I used a laser temp reader and checked my block compared to the sensor in other places and near the exhaust ports it's was close to the sensor reading but the majority of the block was around normal.

 

About 3/4 or alittle over is where it's been riding.

 

I got bored and installed my power steering cooler. Before I did I undid my condenser and washed it real good. I unbolted my Efan and washed the back of the radiator and then sprayed the front and the back of the condenser. There was some dirt coming out so I'll see how she runs tomorrow when I drive it to work.

 

Do you still have the lower air scoop installed?

Also, if you still have that monster front bumper on that could have an effect also since it looks like it's blocking off any airflow coming through the lower part. I could be wrong, but it looks like the only air going through the radiator is coming through the grill. After that you're talking airflow dynamics since you have a high pressure area in front of the grill but if there is no low pressure area behind the radiator that will restrict the air from exiting the engine compartment efficiently.

 

Lower scoop is gone cause there's no crossmember for it to hook to. My bumper actually sits lower than the stock one. But there is a winch in its way.

 

About 2years ago I played a months worth of phone tag with stant out of I ndiana.
I wanted a 160 thermostat for the i-5. It all came down to a production run manager and he killed it. I say do it gway. The guys that make the stats seemed to be all for it.

 

How about the e-fan? Maybe the motor is either got carbon build up or some crap in the motor from wheeling making it put out less cfm? You could also change the factory temp sensor as well just in case that is reading wrong for some reason. I think they are only $15, I know it was around there when I got a new one.

 

No stat is not a good idea. Too cool or no stat makes for a weak heater and can trigger a CEL......but in Florida, u probably can't spell heater. LOL

U've got to remember, a properly functioning stat does one thing only......determine MINIMUM coolant temp. The rest of the cooling system, it's condition and driving conditions determine maximum coolant temp. A properly functioning stat will not cause overheating.....if the stat is functioning properly, the stat will be wide open at +/-15 degrees above it's rated temp and a wide open stat is essentially the same as no stat, with regard to coolant flow.

Coolant temp has little to nothing to do with "closed loop".....the "loop" closes when the O2 sensor(s) reach operating temp (not coolant temp) and electrically heated O2 sensors reach operating temp less than a minute after motor start-up. Some heated O2 sensors reach operating temp in as little as 8 seconds after motor start-up, thus quickly "closing" the loop. Plugging a scan tool into the ALDL port under the dash will verify how quickly and when the system enters "closed loop". The scan tool will also show u that coolant temp is no where near operating temp when the system enters "closed loop". Another thing the scan tool will tell u is actual coolant temp so that u can verify that your dash temp gauge is not wacked.

The cooling system is a closed system (nothing to do with closed loop). Coolant flowing too quickly/fast thru the rad/motor is an old wives tale/myth. When the stat is wide open, coolant will/should flow as quickly thru the rad/motor as the water pump will push it. If the stat is wide open and overheating occurs, there's something wrong with the cooling system, or there's poor airflow thru the rad or the rad is too small for the driving conditions it's encountering, or a combination. Again, a properly functioning stat will not be the cause of overheating.

 

Maybe your belt is slipping on your waterpump. My 2000 blazer was doing that and it never got hot just sitting but at highway speed the higher rpms made the belt slip ever so slightly and wasn't flowing like it should. I changed the belt and problem went away. Just a thought.

 

Gway are you running an efan or stock fan-clutch?? I think you and me are having the exact same problem, and i think ive figured out why (if, your running an efan)

btw, like mentioned here before, i properly running T-stat will never be the cause of overheating, either way going with a 180 t-stat is not a bad move, that is what i have as well. Running no T-stat on these trucks will trigger a code that will eventually cause your A/C to shut-off because the truck thinks its overheating, im saying this from experience.

 

........Running no T-stat on these trucks will trigger a code that will eventually cause your A/C to shut-off because the truck thinks its overheating, im saying this from experience.

How will no t-stat cause it to "think" it is overheating???? How will no t-stat ever cause overheating????

 

ive been doing ALOT of reading on various forums and asking around locally to the few i know that have dealt with converting from a fan-clutch to a shrouded efan (on various makes and models), and here is the scoop on this:

At high-way speeds (say, above 45mph) if the shrouded e-fan is kept running (which mine does) it can actually become an airflow restriction, not allowing air to properly flow through the radiator and hence... the higher coolant temp Only when on the high way.

There are two remedies to this issue, one, is figuring out a way for the fan to switch off when hitting the high way, and 2nd adding some vent holes/flaps in the fan shroud to allow the air to properly flow through the radiator when at highway speeds.

next week i will be modifying my fan shroud and report back.

 

We have tested all kinds of air bypass flaps and they do very little to reduce the over all temps.


Here's what we have concluded to be the major cooling issues in our 355 trucks.

1. DexCool to water ratio or aged coolant.
2. Thermostat
3. Radiator location, should be level with engine.
Body lifts strain the water pump and reduce cooling flow.
4. Colorado Grilles do have a higher air restriction, Either install a Billet grille or Canyon grille upgrade.
5. Custom utility bumpers (winches). Almost everyone who has one over heats.
6. Lower radiator air dam is a must.
7. Tune, I have seen some tunes that are running to lean causing hi temp spikes.
8. Over size wheels or heavy payloads stressing the drivetrain.

 

1. My coolant is 3 months old, 40% coolant, 60% distilled water.
2. 180 degree stant thermostat, less than 8K Miles since installed.
3. Radiator is level, (i only have a 1" body lift, like many many others on here do)
4. im pretty sure the stock grill is fine, ive seen worst grills on other cars.
5. my custom bumper is a "tube" bumper, allowing lots of air everywhere, except for the skid plate in the middle, ive ran on the high way with it on and off, and the temp Is slightly lower, but still on the Hot side.
6. I beg to differ, my truck did not have one since the day i bought it (used) and it never overheated.
7. Ive switched back and forth many times with my Diablo intune and no noticeable difference in temps.
8. this i believe to be true, my truck weighs about 350lbs more than in stock form, thus the reason to upgrade all the cooling system in my truck, aside from it being in the 90s year round.


But none of the above addresses the E-fan issue, which is what ive basically nailed it down to.. i have an almost-new v8 radiator, with an almost-new acdelco waterpump, thermostat, oil coolers, etc etc..

the "over-heating" on the highway issue began after i installed my efan, and im really not going to link the 10+ threads ive found online on various forums (pirate4x4, m5boards, tacomaworld... etc) so take my word for if you want or not, but the issue is in the e-fan itself, and how the shroud is completely sealed up agains the radiator, causing the fan to actually block airflow after a certain speed on the highway, slow down or come to a stop, and the truck cools down quickly and perfectly fine, cruise at a moderate speed on the highway without putting the engine under much load, and the temp stays steady, accelerate to 70+ mph and try holding speed (the engine will be under constand load) and the temp starts rising above the 3/4 mark, slow down to a stop, and the temps will lower quickly, you can idle all day long if you want and the truck will remain cool, ride around town, beat on it from light to light, and it will remain cool, but go on the highway and do what i just mentioned and the temp will start rising... That is the issue im having.


anyways, as i said before, im gonna try something out next week and i will report back.

 

My problem is at highway speed. Around town it's fine. The problem didn't arise until I installed my Efan and I've had this problem since. I have it dialed to its coldest setting. What if some vents were cut in the shroud?

 

were on the same boat. that is what im planning to do but right now im away and wont get it until next week that im back in town and i can get my hands on the truck.

 

The lack of a tstat would cause the truck to never enter closed loop, which would throw a code. I'm not a programmer, but my guess would be that it is programmed to assume that the sensor is faulty and enter a "limp mode" to minimize possibility of engine damage.

I'm just talking out of my ass here. I don't know shit about GM's programming.

As for heating up on the freeway, I have the same fan, a smaller radiator, and a boat load more power/cooling needs and only see temps like you are claiming when in stop/go traffic blasting the A/C. I'm curious to know your engine load, RPM, and if you have installed any aux. cooling solutions like a larger trans cooler. I'm betting with that lift and wheels/tires that you're working the motor harder than we think. James is also correct in that the lower air intake contributes quite alot to the cooling capacity.

Take my input for what it is, but I think that the issue is a mix of regular maint. and airflow. New tstat and a good flush of the system for starters, and making sure your fan shroud has a good seal around the rad. core. Make sure it's getting the airflow the factory intended.

 

The lack of a tstat would cause the truck to never enter closed loop, which would throw a code............

Yes and no.......The "no"........the "loop" closes in less than a minute after a cold start due to the O2 sensor(s) reaching operating temp, not the coolant reaching operating temp. Plugging in a scan tool will verify the switch from "open" to "closed" loop and how quickly it occurs after cold star-up.

The "yes".......the ECU measures how long it takes for coolant to reach a predetermined temp. If that measured amount of time is longer than the pre-programed amount of time, a code may be set. Gutting a stat will cause a slower coolant warm-up which could set a CEL.

Remember, a properly functioning t-stat does one thing only.....determine MINIMUM coolant temp. The rest of the cooling system components, their condition and driving/operating conditions determine maximum coolant temp.

 

My turbo v8 with stock i5 rad and $30 junkyard escort fan does well.

Fan on at 204 and off at 197. Like clock work regardless of speed

 

I run a 170deg stat= 184-189 water temp in my truck. as verified by my Scan Tek.
stock fan. water temp will go to 200+ deg in the heat of summer with the A/C on.
I am getting ready to install a Mustang Cobra 2spd e-fan with the Volvo 2spd 180/195
controller. the fan is unshrouded 19" dia and thin enough to fit in a V8

 

Unshrouded eww