Electric fan won't cool at highway speeds

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Prine said:
I would add that it is possible the cooling passages in the block are full up to the freeze plugs with Scale...and coolant flow is taxed as well....
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TylerW said:
I bet there is an undersized or clogged radiator behind all this.
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That could have been a possibility if he didnt state that this problem didnt exist until he swapped to the electric fan and shroud. High speed cooling was not an issue previously, which suggests his system is capable of cooling his engine once this is sorted out.
 
I have a brand new 26 aluminum rad from b cool. After doing some searching I know that the problem is the shroud is blocking the air from going through the rad. I was gonna try to rig up some flaps but right now the 160 stat seems to helped for now. Once I rig up some flaps or go back to the clutch fan the 180 will go back in. The problem with my electric fan is there isn't any flat surfaces to rig up flaps. I'm still leaning towards the clutch fan cause my alt won't keep up with fan, fuel pump and ac...... Snowball effect.
 
The other problem with radiators..........I seemed to have had...........OldmanMopar once posted that he believes the FINS can crack loose from the TUBES and do not transfer heat, even thought he rad is clean and flows good coolant

I seem to have had this with the original rad out of my (original) 273, then later put a /6 used rad in out of a slant, (now) in front of a mild built 318. INSTANT cooling!!!

Both were 2 row cores

Unless you rigged up some sort of coolant / airflow / btu experiment, this could be VERY difficult to verify
 
The key in the diagnosis is the statement that it cooled at speed before the conversion to an electric fan. I didn't catch if it was thermostat controlled. It might just be as simple as that. If the fans are still powered at road speed, they could just be acting like a big spinning wall. Try disconnecting them and running down the road to see what happens.

If you go back to the clutch fan, is it a standard fan (five blades)? Or, is it the HD fan for A/C cars (seven blades)? I might be wrong on the blade count, it's been awhile. That might solve your issue at traffic lights. Oh, and a fan shroud.....
 
moot advice, the man said he will put the factory intended fan back on and cure all this.... if it was cool before, why go to electric anyway....i personally like a mechanical fan than can chop my fingers of if im not paying attention.
 
Electric Fans need to be on a thermostatic control, I.E thermo-switch, to prevent turbulence that will cause air damming at cruising speed.
Try this before you switch out the fans & go back to the clutch fan. Un plug or disconnect, pull the fuse or whatever, to the electric fan & take it for a drive at highway cruising speed. (Obviously you don't want to sit in traffic or drive slowly with it like this for too long or it will overheat!) If the temps stay normal you know you need to put in a thermo-switch because the fan is causing turbulence. Also make sure it is wired correctly. If polarity is reversed you turn a "puller" into a "pusher"!
 
Have you checked the lower rad hose? It could be collapsing at higher (highway) rpm, thereby limiting coolant flow and causing your issue.
 
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