I was wondering as a rule do aluminum heads run cooler that their cast iron counter parts? I always have had trouble on hot days and slow traffic,will I notice a difference with aluminum heads?
johnsf

 

I had aother SUV with a bb engine had this type problem i replaced the thermostat buttoned everything up then used a home coolant flushing system on it Prestone type
Flushed it till i got clear water out drained the water and refilled system with 50/50 antifreeze. Problem solved for me

 

They don't run cooler, per se, but they do transfer heat more efficiently than cast iron.

If the engine is running hot, particularly in the situation you describe, it is probably because your radiator/fan combination isn't up to snuff.

 

This is a personal opinion. I don't like installing aluminum heads on cast iron blocks because of the differences in the thermal coefficient of expansion. The heads and the block will expand at different rates and induce greater stresses than I would like to see.

 

Excellent answer. I live in wyoming and cold winters are hard on engines let alone a aluminum headed engine on cast iron. Wears into heads and have to machine heads a lot to clean up due to head gskt grooving into head. We had our last snow about 2 weeks ago this month. My truck is outside a lot and not able to keep plugged in to keep warm all the time.

 

I would recommend flushing your cooling system and replacing the thermostat for starters. sometimes running a cooler t/stat can fix it but it can cause a swing in operating temps - if you run a hotter t/stat the coolant running through the rad is at a greater temp and therefore you increase the efficiency/ability of the rad to get rid of a greater amount of heat. i know it sounds a bit daft but if the coolant is at 200deg and the ambient temp is at 80 deg the 120 deg difference gets rid of more heat than if the coolant was at 170 deg as there would only be a 90 deg difference. If it still dont keep up - have a look at the radiator - maybe partially blocked or just plain rooted.
Good luck
Kiwi

 

If your cooling system is up to par then it should not mater what heads you have. I have aluminum heads on my 429 for over 5 years and I drive it in the winter in Mn at -20 and below and have never had problems with it. Do not plug it in at work at all. Actually last winter got below -35 and started and ran fine with no problems. Not sure if machine problems might show up later.