340 Stroker not warming up when driving

[Dan416]

Hey, I have a 416 stroker in my challenger, that is running very well with fitech. I started with a 160 milodon high flow stat and in the summertime here in georgia on the highway I an around 170, when idle it goes to close 200f. Cooler fall temps made my temp go down to 155 when driving. In idle still goes to 190. I changed to a 180 stat and that did not really do anything. How cab I be running so cold? Can the TA hood add so much cooling air? But the stat should be closed. I have no heater hooked up, just the ports connected. Any ideas?

 

[bfunk]

Heating up at idle is most likely insufficient air flow through radiator
My temp went down 200 to 180 at idle by adding a decent shroud and a new fan clutch.
The low temp at cruise is a thermostat.
Good luck Bryan

 

[70Barracuda]

It should warm up when not moving. Put a 190 in it.

 

[aussiemark]

To warm it up you need to keep the thermostat closed longer, to cool it when it's stationary you need a good radiator, fan and shroud. To cool it when cruising the fan and shroud are not so important once you get over a certain speed they are useless. The thermostat should never be removed (some people do) it is needed to create some restriction to slow the flow down enough to give the coolant enough time in the radiator to cool down if it goes through too quick it will come out nearly as hot as it went in. On one of my cars I have the original temp gauge which has the sensor on the engine side of the thermostat, then I have another temp gauge with the sensor in the radiator lower tank this set up lets me see what engine temp the thermostat opens. Another benefit is if the lower radiator hose fails I will get a high temp reading from the sensor in the radiator lower tank with only a sensor high up you will actually get a cool reading because once the coolant level is below the sensor it can no longer detect the temp as it needs to be submersed in coolant to work. A good cooling system should get the engine to operating temp ASAP and keep it there with minimum variation regardless of outside air temp or engine load. Fuel/air ratio can also effect engine temp if it is lean it will run hot (diesels run cool when lean hot when rich) and if it is only lean at a certain point it can trick you into thinking it is a cooling system fault when it is actually fuel related.

 

[moparleo]

You could also have a faulty gauge. Get an infrared temp tester. Around $20.00. Ideal for spot checking temperatures in the cooling system, manifolds, brakes, a/c, etc...
https://www.amazon.com/Arctic-Star-AR550-Infrared-Thermometer/dp/B000MX5Y9C

 

[Dan416]

Thanks for the replies, I have a FITECH EFI unit on the motor so the temp reading is digital and compares to the manual one very well. I have a new be cool radiator with shroud and double electric fan so I am sure that is not the reason for the close to 200 F idle temp. I suspect either the serpentine belt (bigger diameter pulley water pump) or the high flow thermostat that does not restrict the flow at all. But why I fall below my 180C when cruising does make no sense. Unless my TA hood lets so much cold air in....

 

[BcudaChris]

Might try making a cardboard cutout to block off say 1/3 of your radiator core and see if that gets your cruise temp up. I don't know your fan setup, but a faulty clutch and/or no shroud will cause you to heat up at idle as stated above.

I have to run a block off like that from late October until April or so (I'm in CO) if I ever want it to get warm up for around town driving driving. Otherwise it takes 10 miles or a fast blast on the interstate to get to operating temp. Or, let it idle for 15 minutes. I run a 190 thermostat.

To add as well, I don't think the extra air to the engine compartment from your hood is having an impact here. That air doesn't go through the radiator.

 

[Dan416]

Hey Chris, but why would worry about blocking off the radiator if you run a 190 Stat and the motor is at 170 or so there should be close to nothing going through the radiator anyways...

 

[BcudaChris]

BIG radiator, cold air. I pull the cardboard when ambient temps get to about 50 average.

I like to drill a 1/8 hole in the stat, or this time I'm using a Stant super stat (I think that is the product name) and it bleeds a little coolant past on its own. This is theoretically to allow the cooling system to "burp" more easily when initially filled or air bubbles get in the system for whatever reason, but it does allow constant (minimal) coolant flow. With colder ambient temps, that radiator sucks what little heat there is right out of the minimal coolant flow, and pumps cold coolant through the engine, albeit at a minuscule rate. After a cruise around town this time a year, not getting above 40mph, I see less than 130 coming out of my radiator and 160ish going in. With the blockoff and the same drive, I'll see 180ish going into the radiator and 145ish coming out.

In summer weather without the cardboard, it likes to run low 200's (coming out of the engine, into the radiator) with the AC blasting, a little less w/out AC,no matter what the conditions, little variance in temp. Extended cruising in the 70-80 range will get it to the 210's. Magnum engine, 904, 3.55s.

Around here in the winter you'll often see larger pickup trucks and big rigs with vinyl grill covers that that have a cutout in them to keep the engines in their operating temp range.

 

[Mickie Lulu]

engines requires a 195 degree thermostat to properly burn today's gasoline.
200 degrees is not hot
220 degrees is warm
240 degrees is hot
195-210 is normal