Heater Core Bypass 2.8L

[neophile_17]

Hello,

I'm prepping the backup engine for our Fiero endurance racer. I'd very much like to plug the heater core lines rather than create a bypass loop. However I'm concerned the heater core lines are a relief mechanism to prevent over pressure before the thermostat opens. Am I going to be in trouble if plug these ports? Thanks.

~sam

[geoffinbc]

You should create a bypass loop. There is no issue with pressure buildup but coolant still needs to circulate inside the engine because some parts heat up much faster than others. The heater core loop allows hot coolant form the heads to exit out the intake manifold through the heater core and back to the intake of the pump where it will be pumped back into the block to circulate around again. If this cannot happen then you risk having water sit in the heads for too long.

An alternative would be to plug the ports but drill a couple 3/8" holes in the thermostat which would slow the coolant flow through the rad until the thermostat opens.

[neophile_17]

Thanks! I'll keep the loop.