Coyote Coolant Flow & Fitting Guide

How The Coyote Cooling System Works

The Coyote uses a cross-flow style cooling system built to control temperature at the heads and around the exhaust valves. Knowing the flow path matters as soon as the engine goes into a swapped chassis.

• Coolant leaves the bottom of the radiator and gets pulled into the water pump.
• The pump pushes it into the block and up around the cylinders into the heads.
• Coolant moves through the heads toward the front of the engine.
• It exits at the front head outlets and goes back to the top of the radiator.
• Smaller ports feed the heater core and the degas / expansion tank to purge air and keep pressure stable.

From the factory, the thermostat sits on the inlet side, between the bottom of the radiator and the pump. A bypass lets coolant keep circulating through the engine while the thermostat is closed, so the engine warms up evenly and the thermostat actually sees engine temperature.

Whatever layout you pick, the fittings and hose routing have to respect this flow direction. Get it wrong and you end up with air pockets, hot spots and temps that won't settle.

Pick Your Layout

• Layout 1: BPS billet thermostat housing. Keeps a thermostat in the system on a full AN setup. This is the one for street cars, cars that sit in traffic, and anything that needs to warm up and hold a steady temp.
• Layout 2: no thermostat. The simplified swap layout, common on race cars running an electric pump.

Layout 1: With The BPS Billet Thermostat Housing

The BPS billet thermostat housing (EN058) is -20 ORB on both ends and uses an OE style thermostat, so the whole cooling system moves to AN hose and you still get a parts store thermostat when it's time to service it. It takes the place of the water pump inlet fitting (EN014), so you don't need that one with this layout.

Routing

1. Driver and passenger front head outlets, -12 each, into a 16-12-12 Y-block.
2. The -16 side of that Y into one branch of a 16-16-16 Y-block.
3. The single side of the 16-16-16 Y, -16, to the top of the radiator.
4. The other branch of the 16-16-16 Y, -16, down to the top of the thermostat housing. This is the bypass.
5. Bottom of the radiator, -16, to the bottom of the thermostat housing.
6. Expansion tank to the heater core return fitting, -8.

Why the top of the housing ties into the upper Y

That line is your bypass. With the thermostat closed, coolant coming out of the heads still has a path back to the pump without going through the radiator. Skip it and coolant stalls in the heads on warm up, the thermostat sees cold coolant while the heads are already hot, and the temp overshoots before it finally opens.

Tips

• Thermostat is not included. Run a quality OE style Coyote thermostat.
• Use a thermostat with a jiggle pin or a small bleed hole, and put it at 12 o'clock so air can get past it while you fill.
• The expansion tank is your high point and your fill point. Fill through the tank and let the system purge with the engine running.
• ORB to AN adapters are sold separately. The Low-Pro ORB to AN adapters come in -20 ORB to 16AN and -20 ORB to 20AN.

Parts for this layout

• BPS billet thermostat housing (EN058), includes the EN055 thermostat -20 ORB inlet
• Front cylinder head fittings (EN011)
• Heater core return fitting (EN013)
• Low-Pro ORB to AN adapters
• Dry decked heads: add the rear head coolant fittings (EN048), see below

Layout 2: No Thermostat

Below is the port by port reference for a swap with no thermostat. Match each location with the right BPS fitting.

1. Passenger and Driver Front Outlets (Upper Return to Radiator)

Main outlets from the heads back to the radiator. In a swap, this becomes your upper radiator hose connection.

• Use: BPS EN011
• Options: dual -12AN into a 16AN Y-block (match your radiator inlet).
• Function: sends hot coolant from the engine to the radiator.

2. Pump Inlet Side (Lower From Radiator)

The bottom of the radiator feeds the Coyote pump inlet. This has to stay the main feed into the engine.

• Use: BPS EN014
• Route: bottom of the radiator to the BPS fitting to the pump inlet.
• Running an electric pump instead? The mechanical pump comes off and the front cover opening gets closed with the water pump delete plate (EN037). Take the -16 ORB inlet version if coolant returns to the engine at that point, or the blank version if you feed it somewhere else. Belt length changes when the pump comes off, so sort that out before the car is apart.

3. Heater Core Return

If your setup doesn't use a heater core, route the heater core return port to the bottom of the expansion tank. Coolant then flows into the tank under normal system pressure.

The expansion tank becomes the highest point in the system and your main fill point. Fill through the tank cap and let it purge with the engine running.

• Use: BPS EN013

Rear Head Ports (Dry Decked Heads Only, Both Layouts)

If the heads have been dry decked, the coolant that normally crosses from the block to the head at the rear of the engine has nowhere to go. Those rear ports have to be plumbed, not plugged.

• Use: BPS EN048, sold as a pair, accepts -12 ORB. Fits Gen 1 and Gen 2 heads.
• Skip this if your block and heads still use the factory coolant transfer.

Common Questions

Do I need a degas or expansion tank?

Yes. The Coyote cooling system is designed around a high point. A properly located tank purges air and keeps the system stable.

Should I run a thermostat?

If the car sees the street, sits in traffic or has to warm up before it runs hard, yes. Layout 1 with the BPS housing gives you that on a full AN system.

Which AN sizes should I run?

Common setups run dual -12AN into a -16AN Y for the upper outlet, -16AN on the bottom depending on the radiator, and -8AN for heater lines. With the BPS thermostat housing, the layout above runs -16 for the bypass and both radiator lines, and -8 from the expansion tank to the heater core return.

Is there a way to buy all of this at once?

Yes. The mechanical water pump AN fitting kit covers the four major connections: both head fittings, the thermostat housing and the pump side. If the mechanical pump is gone, the electric water pump AN fitting kit swaps the pump fitting for the delete feed. Keeping the factory housing and outlet location? The thermostat -20 ORB inlet (EN055) is sold on its own. Everything individually is in Coyote coolant adapters.