Most RB26 overheating starts with something simple, so check the system before you buy parts. We supply parts; your engine builder or mechanic does the work.
Five checks first
- Pressure-test the system and the radiator cap. A cap that no longer holds pressure lowers the coolant's boiling point.
- Bleed out trapped air. Air pockets cause overheating.
- Check the thermostat. A sticking thermostat stops coolant flowing through the radiator.
- Check the fan clutch and shroud. Overheating in traffic but not at speed points to airflow.
- Check the hoses. A cracked or badly routed hose can cause overheating.
Cylinder 6 and the head cooling mod
If you're worried about cylinder 6 temperatures, ask your engine builder. Some builders add coolant outlets at the back of the head during a rebuild, a machining job known as the head cooling mod. Epic GTR does not sell the mod itself.
Water pump: N1 or standard?
| Pump | Part number | Suits |
|---|---|---|
| NISMO Heritage N1 | 21010-RHR30, formerly 21010-24U27 | NISMO Heritage replacement for the N1 pump |
| Nissan standard | 21010-21U26 | Standard replacement |
NISMO lists the N1 pump 21010-RHR30 as the replacement for Nissan part 21010-24U27. Ask your engine builder which pump suits your block and use.
NISMO Heritage N1 water pump | Nissan OEM RB water pump | Bullet billet RB water pump | NISMO
Supporting parts we list
We also list the HKS S-type radiator cap 15009-AK006, rated at 88 kPa (0.9 kgf/cm²), Plazmaman silicone radiator hose kits for each GT-R and Superforma radiator brackets. The billet brackets are universal, so confirm fitment first.
HKS radiator cap | Plazmaman silicone radiator hose kit, R32 | Plazmaman hose kit, R33 | Plazmaman hose kit, R34 | Superforma radiator brackets, Skyline | Superforma billet radiator brackets | Plazmaman
Oil temperature is a separate issue
Oil temperature is separate from coolant temperature. An external oil cooler holds oil temperature down on track, and we list HKS S-type oil cooler kits for each GT-R.
HKS S-type oil cooler kit, R32 GT-R | HKS S-type oil cooler kit, R33 GT-R | HKS S-type oil cooler kit, R34 GT-R
Ordering
All the parts above except the Superforma brackets are Price on application. Use Request a price on the part, or get in touch for a parts check. The NISMO, Nissan OEM and HKS parts come from Japan:
Imported parts: usually 1 to 2 weeks at the minimum. The exact time depends on which country the part is coming from, whether you choose express or standard shipping, the courier used, and how quickly UK customs releases the shipment. We'll confirm the options and timings when we send your quote.
The Bullet and Plazmaman parts come from Australia, and we confirm their timings with your quote.
Contact | Delivery and returns | Skyline GT-R cooling | R32 GT-R cooling | R33 GT-R cooling | R34 GT-R cooling | GT-R parts interchange
FAQ
What should I do about cylinder 6 temperatures on an RB26?
Ask your engine builder to check it. Some builders add coolant outlets at the back of the head during a rebuild, a machining job known as the head cooling mod.
What should I check first if my RB26 runs hot?
Start with the basics before buying parts. Pressure-test the cooling system and the radiator cap, bleed out trapped air, check the thermostat, and make sure the fan clutch and shroud are working. A weak cap or an air lock can make a healthy RB26 overheat.
N1 or standard water pump for an RB26?
NISMO lists the NISMO Heritage N1 pump (21010-RHR30) as the replacement for Nissan part 21010-24U27. We also list the standard Nissan pump (21010-21U26). Ask your engine builder which pump suits your block and use.
Can a bad radiator cap make an RB26 overheat?
Yes. A cap that no longer holds pressure lowers the boiling point of the coolant, and the engine can boil over even when everything else is fine. Pressure-test the cap. HKS's 15009-AK006 S-type cap for the R32 to R34 GT-R is rated at 88 kPa (0.9 kgf/cm²).
What is the RB26 head cooling mod?
It is a machining job some engine builders do during a rebuild, adding coolant outlets at the back of the head. Epic GTR does not sell the mod itself.