• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

How hot is too hot?

Godwick

Sr. Member
Joined
May 14, 2011
Messages
407
Loc.
Santa Barbara, CA
My bronco runs a nice 180-190 around town and in the freeway. However, I notice that when I turn the key off (like when getting gas) and turn it back on, the temp will hit about 210. It quickly returns to 190 or so, so I feel like it's fine. Just wondering if it's something I should pay attention to.

Thanks!
(351w with aluminum radiator and a shroud)


Sent from my iPhone using Tapatalk
 

jasonv

Sr. Member
Joined
Jan 7, 2002
Messages
355
Maybe I'll join in, I was going to start a thread about the same thing. Rebuilt 302, .030 over, 9:1, retrofit roller cam, stock radiator/fan/shroud, 180 degree thermostat. Temp gauge reads 170-180 when driving around but when I turn it off it will go up to 220+ Engine smells hotter than I am used to. Maybe getting a little bit of steam out of the old cap. Coolant Recovery tank looks like it works and I burped the system after I filled it.

Is this normal or reasonable? It's different from when it was old and worn out, never got that got.

Thanks
Jason
 

BUCKWILD

Full Member
Joined
Jun 20, 2016
Messages
350
Loc.
Butte county
Yes normal for them to do that the coolant continues to pull the heat out but its not circulating.. You start it and it circulates the coolant again and instantly cools down.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
Completely normal.
Even though there is no coolant or air flow after shut-off, the heat in the motor is still being transferred into the coolant. This is why the pressure cap usually will open only after the engine is shut-off.
 

sriha

Sr. Member
Joined
Jul 28, 2010
Messages
683
I would start worrying about 220-230. I had mine up to 250 when I forgot to turn on the fan.:-[ I have a 302 with stock radiator.
 

sprdv1

Contributor
REBEL
Joined
Mar 8, 2007
Messages
81,734
I would start worrying about 220-230. I had mine up to 250 when I forgot to turn on the fan.:-[ I have a 302 with stock radiator.

Same here.. mostly okay at 210....
 

Steve83

Bronco Guru
Joined
Jul 16, 2003
Messages
8,980
Loc.
Memphis, TN, USA, Earth, Milky Way
The hotter the engine runs, the more fuel-efficiently, powerfully, and cleanly it runs. So hotter is better.




...up to the lowest temperature that damages any of its components. In the case of modern engines, that component is almost always the oil. Most engine oils can tolerate ~250°F for a few thousand miles without breaking down excessively.

So to answer your question: 260 is too hot. But 180 is too cold. You should work to make it run 190-230.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
According to my "seat of the pants" dyno, mine runs peppier since I replaced my old 180* thermostat with the 195*.
It really does run better when it's hotter.
 
Last edited by a moderator:

savage

Contributor
Bronco Nut
Joined
Apr 18, 2007
Messages
2,482
Loc.
Renton
Mine runs at around 190 to 200 on a warm day and when I shut it off, it goes up to 220. on a regular day it runs 180 to 190, and on shut down it goes to 210.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
According to my "seat of the pants" dyno, mine runs peppier since I replaced my 180* thermostat with the 195*.

Probably so. But you are giving up engine life and efficency for it.

I once had a thermostat in my hand that was rated at 103°C. And to think that 100°C is 212°F. This was a factory thermostat, and they wanted running that hot.

My F250 I pulled the 180 out and am putting a 192 in. I doubt you will ever feel any power difference. But the heater sure works a lot better with the hotter thermostat. Hoping for a better wear and economy in the end as well.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
The hotter the engine runs, the more fuel-efficiently, powerfully, and cleanly it runs. So hotter is better.



...up to the lowest temperature that damages any of its components. In the case of modern engines, that component is almost always the oil. Most engine oils can tolerate ~250°F for a few thousand miles without breaking down excessively.

So to answer your question: 260 is too hot. But 180 is too cold. You should work to make it run 190-230.

The NASCAR engine builders want it to run at 210 to 220
The oil lubricates well, the engine produces excellent power.
If cooler was better they would build for that.

Synthetic oil has even higher breakdown temperatures.

Not sure why all the 'panic' about running at that temp range.
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,609
Loc.
Conway, AR
EFI engins run 195 stats and the gauge will read 210 all day long everyday on most.

My 2500HD sat on 210 for 6 hours yesterday. 80-90mph during that time....outside temps were 95-100 the whole way.

Tim
 
Top