Issues with running HOT on freeway after switching to aluminum heads

[19Walt93]

Don't go backwards, just get a bigger radiator or you'll end up kicking your own butt.

 

[Shran]

210 is not a problem. Our old race truck survived hours of us relentlessly beating on it while it trucked away at 240, 250... That was over the course of four races, two years and it's still going strong after being redone as a rock crawler rig. It even survived an entire race with no air filter! And it was a junkyard, unknown condition 302 engine at that.

A lot of newer vehicles run at 210 no matter what. My 2010 Silverado does, all of my old Jeeps did. I'd be concerned if it was going much higher than that but if that's as far as it goes... No problem.

 

[19Walt93]

Your location isn't listed so I don't know if you have freezing weather to contend with but a 50/50 antifreeze mix will raise the boiling point of your coolant,if that's a concern.

 

[painterdude923]

Just concerned about too hot with aluminum heads. I'll get to finishing my profile on here at some point. From Michigan but in central Florida these days. Wish I would have kept the air conditioning in the truck! Lol

 

[gw33gp]

One thing to consider, aluminum heads should take out more of combustion heat because it has better thermal conductivity than cast iron. So, you should have less heat in the exhaust and more to the radiator. This could mean you need a larger capacity radiator for aluminum heads.

I run an aluminum radiator on my race car with cast iron heads and it cools better than the heavy three core copper radiator I was originally using. The total capacity of my cooling system is only 1 gallon and I don't run a fan, (I don't let it idle very long). My compression ratio is almost 15:1. It is a small engine (1100cc) but runs pretty high rpm at 8,200 redline. It normally runs around 180 -190 and will get up to around 200 on very hot days. Maybe you could look into a higher thermal capacity aluminum radiator that fits your truck.

 

[Junglejoe]

I forgot, as mentioned.. are you sure you dont have the headgaskets on backwards? The front two coolant passages should be blocked off by thw headgasket

 

[85_Ranger4x4]

When I started using Dashcommand on my aluminum headed factory stock F-150 I was surprised to see it usually ran around 208 on the highway.

When I first did my swap mine would get hot and ping on the highway, it was an intake gasket leak.

 

[Eddo Rogue]

It could be a few things. First off maybe put a thermostat back in (a new one)....sounds weird but the waterpump may be spinning the coolant "too fast" at highways speeds, not letting it flow through the radiator long enough to cool down. Also check the waterpump, its the heart of the cooling system. If its easy to get to, maybe pull it and just check the passages, impeller, give em a spin etc...

Last thing some guys mentioned this as an airflow problem with certain mods, and would raise the hood up where it mounts to the latches as a fix, which somehow lets the air flow through the engine bay more properly.

 

[19Walt93]

It could be a few things. First off maybe put a thermostat back in (a new one)....sounds weird but the waterpump may be spinning the coolant "too fast" at highways speeds, not letting it flow through the radiator long enough to cool down. Also check the waterpump, its the heart of the cooling system. If its easy to get to, maybe pull it and just check the passages, impeller, give em a spin etc...

Last thing some guys mentioned this as an airflow problem with certain mods, and would raise the hood up where it mounts to the latches as a fix, which somehow lets the air flow through the engine bay more properly.

Just be aware that engine compartment air will get drawn into your heater through the cowl vents. I second the motion about keeping a thermostat in there for the reasons stated, keep in mind the thermostat controls the minimum engine temp, not the maximum.

 

[Junglejoe]

You take that thermostat out and it definitely will run hot. The coolant will just keep getting hotter and hotter until it boils. It could be used as a temporary fix though..ive done it when the thermostat was bad. But only to get home.
Id almost be willing to bet the 1 or two things..
(1) bad thermostat
(2) head gaskets on backwards.

The aluminum heads are not the reason why its running hot if it didn't before you switched them out