Oh, I gotcha now. Should the engine be hot or cold when filling as you mentioned here?

The steam line is zip tied to the back of the upper radiator hose.

 

 

You could, but in order to get the air out, the thermostat needs to be open. If the car is cold, obviously the thermostat is closed, and personally I don't like working on the cooling system when it is hot. The procedure I described back fills the block and burps any air on the engine side of the thermostat. I know it sounds strange to do, but it has worked every time I have done it.

Andrew

 

I tried tonight but the radiator is full, the overflow jug is full and as soon as I pulled the steam vent off with the engine running coolant poured out. The car was on a hill with the front pointed up.

 

 

 

just brainstorming to cover the bases
stock thermostat is 187 F i believe
are you reading the dakota digital value with a digital readout or analog (needle)?
the voltmeter gauge is off so could the temp be? could check a scanner value vs the dakota gauge to see if they match or not.
stock tune series parallel fan operation fan 1 turn on temp is 226 F fan 2 turn on temp is 235 F
were these values changed in your tune?

 

I am reading the analog gauge on the Dakota Dash, so it is possible it is incorrect.

I messaged the tuner to remind me what temps the fans were set and he got back to me today. Back when I gave him the information I believe I had told him I didn’t want the engine running at 220 because I believed that was to hot ( I still think it should be running around 210 max, but maybe I’m wrong). The low speed fan is set to come on at 199 and the high speed is set to come on at 207. I’ll need to go back through all my receipts, but I think I remember that the parts house didn’t have 190 thermostats so I bought a 205 degree thermostat (It’s been a long time ago now, so I may be wrong, but I’m pretty sure it was higher than what I had originally wanted). So if there is a 205 thermostat and the low fans are set at 199 and the high set at 207, this could be the issue, I think. The car still hasn’t fully gotten over 220 degrees yet on the cold days, but in my mind on cold days with outside temps not getting above the 20’s (F), should an LS engine ever even run over 210?

For the sake of my understanding, let’s pretend like it’s still 20 degrees outside and I don’t even have a high fan setting. Where should the car be running in reference to coolant temp? I don’t think it should overheat in weather this cold without high speed fans. In my mind, high speed fans are only necessary in very hot conditions. Am I correct here?

 

If you have enough cooling capacity (radiator size/condition) -- when the car is moving fast enough to move sufficient air across the rad to cool it, it should be running at a temp consistent with the t'stat you're using. If you're using a 205F t'stat on the INLET, then you should be seeing 215F OUTLET temps - the sender at the front of the driver's side head. Your fans should be set to come on (lowest temp) 5F-10F ABOVE the operating temp you're seeing at your sender. Otherwise once the fans come on they'll stay on. Assuming you have enough thermal capacity to reject the heat being generated - the t'stat controls the MINIMUM temp you should see. The fans control the MAXIMUM temp you should see. As you slow enough to limit airflow, then as heat builds the fans should come on. As you start to cruise again and get sufficient air flow across the rad because of speed, the fans should turn off. Through that, operating temp should vary between the t'stat lower limit (IF you have a 205F t'stat) of 215F and the upper limit of your fans. So one issue right off (IF you have a 205F t'stat) is that you have your fans set too low - they'll be running all the time trying to cool it BELOW the t'stat temp - which they can't do. Sorting this out all begins with knowing with certainty what temp t'stat you have in the car. Only then can you properly set fan temps. Pull it, get it in a pan with an accurate thermometer and see what you have. Then on to fan settings. If you don't want it running at 220F - I'd suggest the LS3 OEM stat which is a 187F (I tested my brand new one in a pan of coolant on the stove) - that should give you 197F or so leaving the block. First fan to come on at 210F, off at 205F; the second one where ever you're comfortable.

Having spewed all that -- something's amiss somewhere. Given your 'facts' about fan and t'stat temps and the ambient temp - I don't think the fans would come on AT ALL in a 3 mile drive; nor do I see the temps getting up to 220F. There's lots of room to 'play' here - uncertainty about t'stat temps, potential uncertainty about fan setting temps; is the Dakota gauge giving you an accurate temp reading? With a brand new, big rad - 3 miles at 20F ambient -- I don't think you should see fans; I doubt the t'stat would have even opened up yet.

Gonna take more good data to figure out what's going on here.

edit note: 350SS comments above mirror what PSI Conversions told me about stock ECU fan operating temps in my E38 (08 Corvette) ecu. It won't hurt a thing to have the motor running consistently in the 225F-235F range -- in fact, it's more efficient provided you have a good source of ambient temp air for the intake. It may pull a bit more timing in the summer to keep you out of detonation - but, literally, millions of GM cars/trucks out there running temps in that range for decades. Now, if you want it lower -- set it lower. But you have to start with your t'stat temp. As mentioned above - the LS3 in mine runs right at 197F with a 187F t'stat on the inlet when my fans are off. I have a PWM controller running my fans - set at 203F. Summer - I see 197F when the fans are off - and 202F-205F when the fans are on. Never varies. If I have the A/C on - then my fans run at 70% speed whenever the clutch engages the compressor. Even during warm summers - I see 197F with the A/C on - because the fans are running most of the time. I have a 24x16 Howe Racing alum radiator with 2 1" coils in the core. Probably smaller than what you're running. During cold winter temps, because of the t'stat bypass, I actually see a bit cooler than 197F - around 190F. Fans rarely come on when its 30F outside. I have to sit for a long time for that to happen.

 

Thanks for the response. One thing to note, and perhaps I typed this incorrectly, my commute is closer to 20 miles, not 3 miles. It seems the first thing I need to do is verify what my thermostat is and if it is 205, then I need to get a thermostat with a lower rating.

 

Even if you get the 187F - the fan speed setting of 199F is too low.....

 

Yeah, I can take the car by the tuners hose and have him reset the fan settings pretty easy. I warmed the car up tonight and checked the digital readout on the Dakota dash. It basically stayed right at 205 degrees while idling. I took it down the road and ran it through the gears and it got up to 208 degrees. With both fans running on low I can hold my hand behind them and the passenger side fan blows hot air, the driver side fan is blowing cold air, so I know the radiator is really cooling the coolant well.

My next question will be to find out how to change the thermostat without loosing all the coolant?? The stock thermostat seems to be a 187 degree unit, so that's what I'll replace it with.

 

Just drain radiator into something clean - and refill when you're done. No?

 

I don't own anything that's clean!

 

garbage bag

 

I ordered a stock temp thermostat this week (and some wiper blades and halogen headlights from Rock Auto. I got one of those fail-safe thermostats. It seem a good idea after the thermostat stuck on my wife's 97 Lumina last year and I was driving. We were in heavy traffic and by the time I noticed it we'd already lost power and the sucker was COOKED!