coolant lines on 4bt

[MikeN]

I'm in the process of putting a 4bt into an '89 Chevy.



My 4bt has a total of 5 coolant ports coming out of it. Two are large diameter and obviously go to the radiator.



Three are about 3/4" ports and I'm not sure which one I should use to run the line to my heater core, and whether I should just cap off the others.



One of the small outlets is on the passanger side of the thermostat housing. One is on the driver side of the thermostat housing. And a third is next to the large diameter inlet where the lower radiator house is connected to the block.



Which one should I use to go to my heater core? Can I just cap the others off? What were they for originally? I have a Frito-Lay truck motor. The guy I bought it from said that it had an air-to-air intercooler, but maybe it had a air to water?

 

[bgilbert]

Mike, the top coolant port on driver side of t-stat housing is coolant flow TO heater core. Then coolant return out of heater core drops down to a port near the lower radiator hose. Then I think on a manual trans equipped -no transmission cooler-, the third port is a coolant t-stat bypass. Should go from bottom of t-stat housing to lower rad hose area. Now this is all from the top of my head and memory, not looking at a manual or at the engine itself. I can get some pics if you need any.



If it has an inline fuel injection pump it should be air to air. Only way the Frito lay truck could be air to water is if it rolled into a river or something like that. Bill

 

[MikeN]

Thanks.



I ran a hose from the top coolant port on the driver side of the t-stat housing to the inlet of the heater core. On a Chevy, the heater core outlet runs back into the radiator, so I just capped off the other two ports on the Cummins. Seems like it should work... .

 

[MikeN]

Thanks.



I ran a hose from the top coolant port on the driver side of the t-stat housing to the inlet of the heater core. On a Chevy, the heater core outlet runs back into the radiator, so I just capped off the other two ports on the Cummins. Seems like it should work... .