Monkey's Summit Racing Heater Install

Based on Mass-n-Trash's well detailed under seat heater install I decided to install a Summit Racing heater in my Viking but under the hood.

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Here is the parts list:

Summit Racing:
$149.97 Summit Racing® Automotive Heaters SUM-991102-1
$34.97 Summit Racing® Heater Duct Kits SUM-991103-1

2x $16.95 Universalpartsinc.com Y-Fitting 1" Radiator Hose to 5/8" Heater Hose Sku: Z17550 Click Here for the Y-Fitting

1 fused battery wire with a 15 amp fuse (I just used the power from the accessory plug)

About 4' of 5/8" heater hose and a bunch of hose clamps.

Something to make a mud guard out of

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If you use the suggested Y fittings you must carefully drill out the 5/8" stub with a 1/2" drill to clear out the welding residue and provide better flow. It makes the difference between disappointment and joy. It won't matter with T fittings but with the Y fittings you need to plan the way the coolant flows through the fittings. On both sides you want to point the 5/8" stub towards the radiator. This allows the coolant flowing to the radiator to easily split and the coolant flowing back to the engine to easily combine.

You don't need to drain the coolant. You just need to clamp the hoses so they are pinched off. I found that needle nose vice grip pliers work best. Just be gentle.

First remove your mirrors, windshield and hood. Take out all of the plastic fasteners and bolts holding the fenders down. Don't miss the two bolt on each side next to the headlights. Unhook the two tabs from the top of instrument cluster housing. Using two bungie cords slowly lift the fenders a little at a time on each side. You will need to gently pull the lower dash out of the way of the cupholders. Once you are clear of the cupholders you can slide it way up. I also propped the front using a fiberglass rod.



Cut the wireties holding this wiring cluster to the side of the support and move it around the front.



Make sure you re-route the accessory jack wire as shown.



Re-wiretie the wiring cluster.



Now you will have enough space to dry-fit the heater core next to the glove compartment, in front of the accessory jack. I chose to orient mine with the hose fittings facing forward and pointing down. Here are the splash shields I made from stuff I had in my scrap box and the unit slid into place. It will be a tight fit until you pass the 'step' in the electrical tray, at which point it will snap into place.





Here is the top clearance with the fenders slid back down.



Next I cut the holes for the vents and mounted the switch. A 3" hole saw is perfect for the vent holes.




The wire you see through the hole behind the instrument cluster needs to be wiretied to the back of the instrument cluster to keep it out of the way.




Wire up the switch and heater fan according to the diagrams and test it out before you take the next step.

Before mounting the unit I measured, cut and attached the heater hoses. The core will come with two rubber plugs in the hose fittings. Pull them out and save them. Once the hoses are attached I filled the core with YamaCool and then plugged the hoses with the rubber plugs I saved.

Mount the brackets to the heater core and slide it into place. Adjust the brackets, screw them into the electrical tray (watch for wires and relays) and the side of the glove compartment.




Time to run the vent hoses.




If you carefully clamp off the hoses you can reduce the amount of coolant you lose. Here are the completed fittings on both sides.




Time to button everything up. As you lower the fenders back into place take it slowly and continually adjust the vent hoses. You will need to move them around a few times but you will be able to get the fenders down without pinching the vent hoses. By the way, if you located a vent behind the instrument cluster you should wait till the fenders are fully seated until you push the vent all the way down.

I bled the air from the system, refilled the radiator and went for a ride.

The fan works well and I could probably add a bunch more vents and not lose any power. I will probably never have it turned up to high but leave it on low or medium.

Sitting in the driveway at idle I am seeing around 140 degrees Fahrenheit at the vents. Driving it is closer to 165 degrees since more coolant is flowing through the heater core.

All in all, I have a little over $225 in the heater project. Considering that a Firestorm heater comes in at $400 and has to be mounted in the cab, I am very pleased.