6.7 Powerstroke Cooling Upgrades: Thermostat, Hoses and Coolant Reroute
Tow a heavy trailer up a long grade in July and watch the gauges on a 6.7 Powerstroke. Oil and transmission temps climb faster than most owners like. Add years of heat cycles and the rubber hoses on top of the engine start to crack and weep.
Here is what we recommend, in the order we would do it.
How the 6.7 Powerstroke Cooling System Works
The 6.7 runs two cooling systems. The primary system cools the engine block and heads. The secondary, low temperature system cools the charge air and other components, and depending on the year it also handles fuel and transmission cooling. That matters, because a fix for one does not always help the other.
Coolant: Ford's spec has changed over the years, so use the coolant listed in your owner's manual or on the degas bottle cap. Never mix coolant types, and check the level cold.
Step 1: SPE Low Temp, High Flow Thermostat
The SPE Low Temp, High Flow Thermostat (S100119) is the cheapest temperature fix on the truck at $65.
- The OEM thermostat opens at 194 and 201°F. The SPE thermostat opens at 175 and 180°F.
- That is a 19 to 21 degree difference in when coolant starts flowing to the radiator.
- Built to bring down high oil temps during normal driving and towing, and high transmission temps on 2017 and newer trucks.
Important for 2011 to 2016 owners: SPE says this thermostat works on your truck but will not drop transmission temps. On those years, high trans temps point to the secondary cooling system, so look there instead.
Step 2: Upper Radiator Hose
The factory upper radiator hose is rubber, and it lives in one of the hottest spots under the hood. Two upgrades:
- SPE Motorsport Upper Radiator Hose, 2011 to 2026 (S100164 or S100165): 5 ply polyester reinforced silicone with a billet CNC aluminum radiator adapter and billet thermostat housing, black anodized. It pairs perfectly with the SPE thermostat.
- No Limit Fabrication Upper Coolant Hose Kit: replaces the rubber upper hose with stainless pipe, in raw, black or polished. A replacement boot is sold separately.
Step 3: Coolant Hose Reroute
On top of the engine, the factory heater coolant inlet tube and degas return hoses run right over the intake. They clutter the engine bay, they are in the way of aftermarket intakes and piping, and every T fitting and barb is another place to leak.
- SPE Motorsport Coolant Hose Reroute Kit, 2011 to 2026 (S100163): form fitted 5 ply silicone lines with an anodized billet heater inlet fitting. Long continuous lines with no T fittings or barbs, plug and play.
- Pusher Coolant Reroute, 2011 and newer: a low profile path that clears aftermarket intake systems. Pusher lists it as off road only.
- No Limit Fabrication Coolant Line Kit, 2011 to 2026
Best for: trucks with an aftermarket intake, piping kit or turbo upgrade, and anyone tired of chasing small coolant leaks.
Small Parts Worth Replacing
- SPE Turbo Coolant Feed Line for 2017 to 2019
- No Limit molded hose for the 6.7 Powerstroke
- Fleece thermostat housing upgrade, 2011 to 2025
Signs of a Cooling Problem
- Coolant level dropping in the degas bottle
- Sweet smell after a drive or crusty residue at hose ends
- Oil or transmission temps that keep climbing on long pulls
- White smoke with a sweet smell, which can mean coolant is getting into the engine. Get it checked before you drive it far.
Our Recommended Order
| Goal | Part | Starting price |
|---|---|---|
| Lower oil and trans temps (2017 and newer) | SPE thermostat | $65 |
| Stop upper hose cracks | SPE upper radiator hose | $259 |
| Clean up the top of the engine | SPE coolant reroute | $139 |
| Stainless look | No Limit upper hose kit | $449 |
Shop 6.7 Powerstroke Cooling
FAQ
What temperature does the SPE 6.7 Powerstroke thermostat open at?
The SPE Low Temp, High Flow Thermostat opens at 175 and 180°F, compared to 194 and 201°F for the OEM thermostat.
Will a low temp thermostat lower transmission temps on a 2011 to 2016 6.7 Powerstroke?
SPE says no. It works on 2011 to 2016 trucks, but high transmission temps on those years point to the secondary cooling system.
What coolant does a 6.7 Powerstroke use?
Use the coolant Ford lists for your year in the owner's manual or on the degas bottle cap. Ford's spec has changed over the years, and coolant types should never be mixed.
Is a coolant reroute kit worth it on a 6.7 Powerstroke?
If you run an aftermarket intake, piping kit or turbo, yes. It removes the factory heater inlet tube and degas hoses that sit over the intake and removes several leak points.
Not sure what fits your truck? Send us your VIN or call 865 640 2097 and we will help you pick the right part.
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