440 big block getting hot

[Jimmy01]

..I've got a 1974 Challenger, 440 big block - how hot can it get before causing damage? In traffic it sits at 180 spot on for about 10 mins, then it will climb from 180 to 205/210 fairly quickly

 

[aussiemark]

I wouldn't feel comfortable with it getting that hot and there are a lot of things that could be causing it, you just have to find the cause of the problem and fix it. Does it have any leaks? this will cause a loss of pressure and that will lower the boiling point of the coolant. Is the radiator core clogged up? what type of fan have you got? do you run a shroud for the fan? is the thermostat opening properly? Start with the cheap and easy stuff and work your way through it.

 

[DetMatt1]

Does it come back down fairly quickly once you get moving again?

 

[moparlee]

If you don't have one get yourself an infrared temperature gun and do some checks to compare with your temp gauge. Rad cap should be 14-16#. I have read that if you don't exceed 230* you should be fine. I had a '68 Charger and the operating range on the gauge was 170-230 with 195 being normal.

 

[1972 AAR Cuda]

I have had heat issues with my 440 in a Barracuda. I pretty much solved them by adding a shroud for the fan, using an 8 blade clutch fan, a 4 core radiator and hi flow (A/C) water pump. I believe I also went with a high flow thermostat - but I don't remember who I got it from...

 

[69hemibeep]

If 210 is as hot as it gets I wouldn't worry, if it keeps going up and passes 225 you have issues. Tell us about the cooling system.

 

[moparleo]

Tell us more about the engine. Is it stock ? Aluminum heads ? More compression than stock ? Cam, carb, intake, headers ??Does it run smooth ? A lot of variables. Could just need a tune. Timing ? Carb lean ? More info for us, better quality diagnosis for you.

 

[Mastertech]

First of all the temp of 180 tells me that you have the wrong thermostat. It should be a 195. A 180 is too cold and will result in fuel wash damaging the rings and cylinder walls. The temperature of the thermostat is when it opens and it controls the lowest temp that the engine should run at. The upper temperature is controlled by the radiator, fan, and shroud. 210-212 is normal operating temp and can even be a little higher on a hot day. This is why you have a 16 lb rad cap as at this pressure the boiling point is raised into the 225 to 230 range. Are you running water or anti- freeze 50%. Anti- freeze also raises the boiling point and improves heat absorption and conduction as well as having corrosion inhibitors. The original stock rad in your car was a 24" with only a two row core and a three or four core 26" is needed with your 440. Is it a new rad or the original? It might need to be boiled out at a rad shop if it is more than 5 years old. Are you using the factory 7 blade fan with the thermostatic clutch and is the clutch working properly? It should roar for a few seconds on cold start up and then cut back to about 30% until it reaches operating temp and then cut in and out to control upper temperature. It will operate more when you are stopped or driving slow then cut in less when you speed up and air flow increases thru the rad. The correct shroud is also mandatory otherwise the fan pulls air from the sides and not thru the radiator. Are your rad hoses new? If soft they can collapse at higher engine speeds and cut off coolant flow to the rad. In 45 years of practice many heating problems I have seen in muscle cars was because of aftermarket fans and not being spaced properly from the rad and missing shrouds. Hope this helps.
Terry

 

[Dodgeboy]

I solved my 383 overheating issues with a new alum. rad, high flow thermostat, high flow water pump, 2 fans, electric pusher and new clutch fan, new rad shroud. Also had to redirect airflow thru the rad (fiberglass hood didn't seal against top of rad support). Factory hood has a rubber seal going side to side sealing the hood, I bolted the rubber seal onto the rad support but realized the hood didn't touch it. Thats a overlooked idea that might help you. It took me a bit to solve my issue, hopefully you solve yours. Also some aftermarket w/p housings can be restrictive on the inlet side.