ok im having overheating issues with my 79 f150. it has a 1982 302 in it. the problem is there is this red sediment rust colored stuff all in the radiator and i cant get it out. i have flushed it several times, even taking it out of the truck once to flush, ive ran cleaner through it and it still hasnt fixed the problem, it runs fine at speeds up to 50, but once i get on the hwy and go 60+ the temp gauge creeps up until the point of boiling out .. At first i thought i had got the sediment out and believed it to be a thermostat issue so i replaced it with a 195F thermostat and it has not fixed the problem? Next solution is replacing the radiator but there are so many i do not have a clue which one to buy, any suggestions? has anyone else had this issue??

 

champion rads on ebay,reasonable priced alum rads,Hows your water pump?

 

I think you are on the right track... hot at speed usually means the radiator is not effective enough.

I ran a parts store "3 core high capacity" unit for a while to replace the 35 YO original (78 400M). After a year or two, I had some "temp creep" in hot weather pulling hard. Not boiling but did not care for it. I changed to a Champion "4 core" and problem solved. Maybe a bit overkill but that is OK.

The Champion seems like a good product at reasonable price. Probably 3 core would be fine with a 302.

For the rust, suggest you pressure flush before installing a new rad. You can buy or make a setup that uses a garden hose and compressed air to really clean the cooling system. Fill it with water and hit the air to blast out dirt. Air pressure needs controlled to avoid damage.

Flush and fresh anti freeze should keep it clean.

 

Hot at speed can also mean engine trouble. Have you been adding/consuming coolant? Head gaskets and cracked heads will cause this.

I have a Champion 3 core on my stock 400, going down the highway it almost overcools.

 

sounds like the champion 4 core is the overkill to go. i also bought back flush kit the other day and plan to flush the system before installing new rad. Also water pump is working i believe? i dont know how to really test it or see if its working properlly. hopefully the new flush along with new t-stat and radiator will solve probem. any more thoughts? i will keep updated

 

Yes you flushed the radiator what about the block itself? What about taking it to a radiator shop and have them professionally boil it out?

Tried 1800-radiator....?

 

Lots of good suggestions. I would also bypass the heater core when flushing the system and flush the heater core separately. No sense in plugging your heater core up with scale and sediment from the block.
Just my 2 cents... Happy motoring.

 

3x... if there is sediment in the radiator, the same sediment will have settled in the nether-reaches in your block. Remove the pipe plugs on the side of your block.

Refer to the pipe plugs in the images below.





Hindrances to cooling:

 

Not to be confused with the "freeze" or "knock out" plugs, also in the above pics.

 

once pipe plugs are removed you jus flush through radiator? and it cycles through block and runs out? any special way to remove and or reinstall them?

 

For the flush, best to ignore the radiator since you are changing it anyhow. I like to remove the T stat then re-install the housing (no gasket needed). Hook up the top hose and adapt your flush kit to the top hose. 1 1/4" or 1 1/2" pipe usually works... PVC is fine. Clamp the top hose end to the adapter then turn the hose on. Let it run out the lower WP connection. When the block is full of water, hit the air to blast out the crud. Repeat several times until it runs clean.

Best to clean it when you are almost ready to put it back together so it does not sit too long without corrosion protection in the coolant.

My flush setup is home made but here is a ready made one for reference.

Save on OTC Tools 6043 at ToolTopia.com

 

the brown "gunk" in the system could support this. this kind of stuff could be in there to fix a previous issue.

 

Are you mixing two kinds of antifreeze? Some types of antifreeze are not compatible with others particularly with aluminum radiators and when mixed create the type of gunk you are describing.

 

i have ordered a champion aluminum 4 core and it should be here by the weekend. i plan to flush the block one more time before i install it. hopefully this will fix the problem. should i run straight antifreeze or 5050??

 

50/50... always unless you live where there is a deep freeze.