Aluminum vs Castiron water pumps?

[mpack88]

What's the pro and cons of castiron vs aluminum water pump? My 75 LTD with a 400m engine overheats at idle. Was thinking about getting a high flow water pump as I learned these engines are prone to over heat at idle. I see cast and aluminum options as well as a aluminum timing cover. Original timing cover is castiron. Should I not worry about it, use aluminum pump with iron cover or switch cover aswell?FYI, radiator is a new 3 core, hoses are new. Thermostat is new and at 195°. I have a 180° on hand. Have a 7 blade fan from a 460 and new clutch.

 

[kstanf150]

I would think the 180 thermostat and 7 blade fan would help more to reduce temp at idle

 

[Chris142]

Is the fan clutch working? Just cause it is new does not mean it's good. Especially if it was made by Hayden. Turning up the idle speed helps also. How many fins per inch is the radiator core? I have seen low quality ones with 4-6 fins per inch. Original was 12

 

[Lubener]

Do whatever you can do to improve airflow. Running hot at idle is an airflow issue, running hot on the freeway is a waterflow. Clean the radiator fins of any debris and replace the radiator if the fins are rotted out. Make sure your fan is in good shape and the shroud isn't missing. I doubt a different water pump will help in your situation.
I thought back in 1975, Ford used a flex fan driven directly off the water pump with no clutch. Even though it is new, I am suspicious of that fan clutch working properly and might consider going without the fan clutch in favor of direct off the pump..

 

[slacktide_bitog]

aluminum doesn't rust

 

[supton]

Add an electric fan up front to help?

Any value in changing pulley sizes so as to drive the water pump (and fan) faster?

 

[Kestas]

Originally Posted by slacktide_bitog
aluminum doesn't rust

No, but it does corrode.

 

[DBMaster]

Originally Posted by supton
Add an electric fan up front to help?


This^

Plus, I don't think it really matters which material you go with. My 1972 Pontiac Catalina used a aluminum timing chain cover and cast iron water pump. My preference would be aluminum due to lighter weight (like it matters on those old road boats).

 

[mpack88]

You are correct. I took it off because it roars all the time and installed a fan clutch and a 7 blade fan from a 460. The ac wasn't working good at idle and it works better with the clutch. The clutch seems to be working now the ac works good but overheating at idle. FyI, it went from 10mpg to 12 mpg after installing the fan clutch. 20% gain in fuel milage is pretty good to me.

 

[mpack88]

As far as the high flow water pump. All 23 reviews were positive in quality and all claimed it helped reduce temps at idle. Brand is flowkool at summit racing.

 

[mpack88]

It's a duralast from autozone. What brand do you recommend?

 

[DBMaster]

I tried a 7-blade flex fan on the old Pontiac and it didn't improve the overheating. It made a lot of noise and ultimately produced more vibration than a clutched fan and the water pump started leaking. My problem was that the car was always on the verge of overheating in the summer and actually did run hot frequently when running the AC in traffic. If I had kept the car I would have gone with the electric fan on the front option to supplement the belt driven fan. Mercedes used to do this routinely on cars of the same vintage. I had even replaced the 3-row radiator with a 4-row radiator. On my car airflow was the issue.

 

[slacktide_bitog]

Get the GMB aluminum

 

[Randy_R]

Check out Stewart Components. I think Summit has them but I bought mine direct, SBC stage 2 aluminum and 180 thermostat.

 

[joegreen]

If you run an aluminum water pump do you have to change the coolant you use? If it's conventional green with silicates there might be cavitation issues that cause the aluminum to get eroded away? I would do some research on that.

 

[tomcat27]

my 1970 Cougar ran hot. I did all of the tests: radiator flow, head gasket leak, timing, thermostat. added the proper factory fan and shroud. for me, nothing helped until we pulled the engine: the block was full of horrible nasty stuff. It runs nice and cool now! even stroked and with higher compression!

 

[tomcat27]

I installed an aluminum pump to save weight. also saved weight with aluminum heads and stainless headers. also have an aluminum raditaor. as far as coolant, you probably dont want to use green.....

 

[mpack88]

I'm using what ever the all makes and models is

 

[bullwinkle]

If you can find an aluminum radiator, with a good fan clutch & water pump, it'll help a lot. I would lose the 195F stat & make sure the lower radiator hose isn't collapsing, and make sure the cooling system is holding pressure, that will improve water pump efficiency. I had this problem with the original brass radiator on the F-450 in my sig, turned out that a nice boil out at the radiator shop fixed it.

 

[mpack88]

The radiator is a brand new 3 core copper unit. Should be more than capable. I'm going to install gauges in it this weekend to get accurate temps. Also will install oil pressure and voltmeter.