Originally Posted by JMAC1
Hello. I am new to these forums. Not quite sure how to use it. But I have a chevy 350 crate motor in an 87 toyota pickup that will not run cool. I just read the thread about Jeff79 having issues with his back in "09. Did he ever get it resolved?. I have tried all the same stuff. Timing,water pump new plus correct rotation, three different t-stats 160-195, new hoses, 3 1969 fj40 radiator, Two pusher electric fans, V-Belt system, New guages, Infrared temp checks along with digital thermometers, Water pump seems 1:1 ratio with crank, manually checked TDC on Crank pulley, Set timing to 10 degrees as instructed. Flushed engine. This engine will climb temperatures sitting still or driving. Does better driving it seems as long as I am going down hill, light cruise, on cool eve. Coming back, It will get start About 190 and get to 215. Then I pull into house and it climbs to 225, and I shut it down. It gets hot enough to make the fuel boil in the carbureator. Any thoughts. I am extremely frustrated. thanks
When the temps just climb under any and all situations it's a pretty good indicator that the radiator is way too small or is plugging up and not flowing. There of course or other issues that relate to this such as the pump being a serpentine drive that turns counter clockwise instead of the Vbelt pump that turns clockwise. Unfortunately with the SBC the only difference between them is the side the vanes sit on the impeller, the casting numbers on the pumps are the same. They do have different part numbers but in this age of the goof-off, underpaid employee you are 100 percent dependent that the pump in the box has the physical characteristics of the impeller that the part number on the box says it has. Or not!
The 350 needs a radiator that has about 500 square inches of core face area. This can be a bit smaller or larger but close to this. A production copper brass radiator for a 350 of 200-300 horsepower would have 3 rows of 1/2 inch wide tubes set on 7 to 9/16ths centers with about 8 to 10 rows of fins per inch. A high performance version would be 3 to 4 rows with the tubes on 5 to 7/16th centers with 11 to 14 fins per inch. For an aluminum radiator this would look like 2 rows of 1 to 1-1/4 tubes on half inch centers and about 10 fins per inch or for heavy duty high output 1-1/4 to 1-1/2 inch tubes with 11 to 14 fins per inch. If your ancient fj 40 radiator doesn't meet this criteria it just won't cool a 350 no matter what you do with water wetter and electric fans.
You really cannot clean a radiator with off the shelf compound cleaners. In the case of a copper brass unit, the core and tanks can be seperated and the core tubes run through with rods that chop the gunk loose and push it out. This is really the only effective way to clear a core. The down side is that you usually find the gunk on the tube wall was the only thing keeping the coolant in. So it's just cheaper and easier to replace the thing. Sell the old copper brass unit to a metals dealer they are worth about 20-30 dollars as recycleable scrap.