What's the maximum temp you should let your engine run? I have a 160 thermostat in it but on these really hot days it's getting to 200-210. Also, my engine seems to run hotter going down the road at 70 mph that it does at lower speeds or even idle. I would think I have max air flow at highway speed to help cool it.
maximum engine temp
- Thread starter freshayr
- Start date
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AdamR
Big Member
Ive been told 200-210 is ok. I still dont like to see it on my old cars. New cars all run hot. My 70 Cuda use to run 210 all the time no matter what I did. As soon as you put a load on the motor it would hit 210 and detonate.
dgc333
Well-Known Member
FWIW, my 74 AMC Hornet 232 6cyl came new with a 205 degree thermostat from the factory. Back at that time I was working for a company that made OEM thermostats for the big three. A lot of them were specing temps in the the 200-205 range in an effort to squeeze a couple more mpg out of the engines.
We also made temp senders and the idiot light senders did not trip the light until 230-235 degrees.
We also made temp senders and the idiot light senders did not trip the light until 230-235 degrees.
moper
Well-Known Member
generally, the hotter the better, in terms of milage, emmissions, and power. But, an old V8 isnt designed to take advantage of that. With aluminum heads, I want to see a minimum of 190°. Any less, and things like valve lash and gasket load can fluctuate, and weird things can happen. They dont always, but they can. Iron, if you want to run it at 160, go for it. You may run into fuel issues and foul plugs, but if that's what makes you happy...lol. In your case, you have a T stat opening at 160...but it runs at 210 at speed. IMO, your cooling system is not optimized, and can just barely do the job. My guess is, a typical small V8 2 or 3 core brass radiator? If you have a cowl seal, try removing it. Also, block off any extra holes in the from radiator support. Use a fan shoroud if you dont have one. It makes the fan more effective, and can help smooth the flow thru the fins while you're cranking down the highway too. Todays rebuilt engines generate more heat (higher hp=more heat generated) and the blocks get thinner, aluminum heads are used, and more heat is forced into the water than what used to be. The brass radiators can only get rid of so much heat before they are "not enough..."
Moper, thanks
I am running a brand new 4 core brass rad from US Radiators. I paid $500 for the thing, which kind of upsets me because I get the feeling that I just don't have quite enough. I am running a fan shroud. It actually seems to do ok at idle....temp doesn't creep. That's why I can understand the cruise temp creeping because i am getting max flow. My temp guage is a stock non numbered guage. I am shooting the engine all over with my infrared temp sensor. I am getting about 200-210 at the sensor. Maybe 220-230 at the head right by the spark plugs but my headers are right there so i assume I am getting more heat there. My top rad hose runs no more than 180. The rad itself 160 on top, 130 bottom. My therm houseing 190 max. Based on what I've read here, sounds like I am OK. These are all max readings.
I am running a brand new 4 core brass rad from US Radiators. I paid $500 for the thing, which kind of upsets me because I get the feeling that I just don't have quite enough. I am running a fan shroud. It actually seems to do ok at idle....temp doesn't creep. That's why I can understand the cruise temp creeping because i am getting max flow. My temp guage is a stock non numbered guage. I am shooting the engine all over with my infrared temp sensor. I am getting about 200-210 at the sensor. Maybe 220-230 at the head right by the spark plugs but my headers are right there so i assume I am getting more heat there. My top rad hose runs no more than 180. The rad itself 160 on top, 130 bottom. My therm houseing 190 max. Based on what I've read here, sounds like I am OK. These are all max readings.
moper
Well-Known Member
What kind of thermostat? a typical parts store poppet thing? I might suggest a balanced performance one, Mr Gasket makes some, some companies like RobertShaw and NAPA have them too. Sounds like it may be closing off or down a little under higher rpms. You could also try gutting a stat and see if the highway temp stays down. From 180 to 130 isnt too much really, for a 4 core brass unit. But it may be limited by how much water the Tstat is letting by.
i just spoke with a local radiator man. He said it sounds like a typical situation where the fan is not big enough. In other words, when I am doing 70 mph the fan is actually reducing the air flow beacuse it is not aggressive enough. Makes sense to me, I have a little stock fan on it. Going to try an more aggressive fan.
demon seed
The Original Demon Seed
freshayr said:
Sorry, but the rad. man makes no sense to me. You say you got a 4 pass aluminum, shrouded rad, which is the ultimate, you shouldn't have a heating problem going down the highway. You would need an aggressive fan for tooling around town but you'll sacrifice some horsepower. Another caution is to be careful using an infra red temp. gun. Don't point it at shiney surfaces like stainless steel cause it'll give you a faulty reading, unless you can adjust the emissibility setting. One thing that will cause the engine to overheat is if the water pump impellor has a lot of corrosion on the impeller blades. At high RPM the pump is being asked to increase the cooling flow and can't hence try overheating.You'd think the opposite would occur but I've had this happen to me. :evil2:
moper
Well-Known Member
I agree with Demon, I dont think the fan slows much, but it's worth a try if it can be done cheap, even temperary as a diagnostic deal...
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