Its an 84 13b from a gslse. Heater core is currently not installed and I just want to fire this bad boy up. Its sitting in an 84 mazda b2000. I think theres 3 water ports on the engine??

1. on intake manifold
2. driver side engine right below oil filter
3. right below thermstat housing

Questions:

1. Can I block all these off for now and just test run the engine?
2. Can I block them all off and drive it causing no harm?
3. Which goes to heater core adn which is return?

 

If you block the ports and prevent the engine from cooling down, you're going to damage the engine. If you're changing the intake manifold to an RB you can block them with 2 quarters and silicone.

 

The smaller pair of hoses heat the the BAC, you can leave those connected. The other 2 5/8" heater hose barbs can be looped together and you'll be good to go.

 

GSL-SE rotor housings don't have coolant ports. They are unmachined castings.

 

"Which goes to heater core, and which is return?"

On that question, the bung under the oil filter is the feed for the heater core - it provides hot water fresh from the engine block to the heater core radiator which air blows through as part of the ventilation system. The inlet and outlet for the heater core are both right next to each other on an SE (but I remember you saying it's in a B2000... so,... nevermind!).

The return from the heater core to the radiator goes to the lower radiator bung - i.e., ON the place where the lower radiator hose attaches. This is the 'cool' side of the radiator where the water pump picks up cooled water to pump through the engine.

Yes, you can block the bung under the oil filter and run it just fine. Mine is blocked right now with a rubber plug with metal bolt to expand the plug due to a heater core leak that would squirt hot coolant on my right foot when I drove it - very distracting, so now my car doesn't have a heater.

Did I mention I live in the AZ desert? No heater required.

The water pump feed for the intake manifold should be obvious, and you can block that and the return pipe at the top of the lower intake manifold if you just want to run the engine. HTH,