The Qmax coolant reroute is a must have for any Miata experiencing cooling issues.
The B series engine in the Miata was designed for a fwd car. As with all inline 4 cyl engines, coolant entered one one end of the head and exited the other end in the fwd application. This simple path is the most efficient way to extract heat from the head. Mazda turned the engine 90° and tucked it up against the firewall in the Miata. This meant moving the coolant exit to the front, the same end of the head as the inlet. This poor flow path is the primary cause for overheating which is so common in the 90-05 MX5. Our reroute has a carefully engineered low profile adapter for the back of the head to retain the original front to back coolant path. Just this one modification will significantly reduce coolant temps. Even a bone stock Miata will run a bit hot, and the stock ECU will reduce ignition timing which hurts power and fuel economy.
The Qmax Reroute Features
- Internally machined to maximize coolant velocity which is key to improving cooling efficiency.
- Retain the use of your EGR pipe for emissions or CEL.
- The OEM coolant temp sensor location is retained so the wiring harness does not need to be modified.
- Spare 1/8 NPT ports are provided for aftermarket coolant temp or coolant pressure sensors.
- All important hardware is stainless steel to increase service life.
- High flow Stant Superstat is utilized to increase coolant velocity.
- Simple sealed adapter housing elminates gaskets and finicky, leak prone threaded fittings.
- Convenient bleed port allows system bleeding with car level if you have COPS ignition.
- No remote thermostat housing for easy fitment and improved reliability.
Installation takes the average mechanic a few hours with common hand tools.
Download instructions here
Contents of Qmax Reroute kit
1x Reroute housing, Supermiata, 7075 T-6
1x Thermostat cover, Supermiata, 7075 T-6
1x Head coolant port block off plate, Supermiata, 7075 T-6
1x Coolant neck block off plate, Supermiata, 7075 T-6
4x M8 x 1.25 x 25mm SHCS, black oxide
1x 1- 11/16 inch retaining ring, HO-168SS
3x 1/8 NPT plugs, SS
1x Bleed screw assy Wilwood 220-0627
1x Worm drive hose clamp, 5/8" Breeze 9416, liner SS
2x Worm drive hose clamp 1.25", Breeze 9424, liner SS
1x 3/8" NPT M- 5/8" hose barb, brass
1x M16 x 1.5 drain plug, zinc
1x 1.25" reinforced silicone hose, 44"
1x Thermostat, 45849 Stant Superstat, SS
1x Sealant, Permatex 22071
Specialty Tools required: Internal snap ring pliers
Suits NA/NB MX5's 1989-2004