This thermostat adapter kit is for the Honda K-Series engines that are fitted in a rear wheel drive setup.
It rotates the OEM thermostat to face forward toward the radiator to allow for easier routing of the lower radiator hose.
It is designed to work with the OEM Honda 19301-RAF-004 thermostat and maintains OEM functionality.
Unlike the swivel type, this is much simpler and more importantly, doesn’t leak. It also retains the use of the OEM thermostat.
The K-Series OEM thermostat design has a dual plunger. As the thermostat opens, it allows lower temp coolant from the radiator into the engine. Simultaneously, the secondary plunger closes off the bypass port, shutting off the hot coolant from the cylinder head, preventing it from recirculating into the engine. WITHOUT the bypass shutoff, the engine will run hotter coolant temps and possibly overheat. Cheaper swivel designs DO NOT support this bypass block-off functionality and DO NOT function like this kit or the OEM thermostat.
IMPORTANT NOTES:
-This kit ONLY works with the OEM Honda19301-RAF-004 thermostat or replacements similar to it. See photos below.
-Minor disassembly of the OEM thermostat is required.
-You will need to reuse your OEM Honda thermostat mounting bolts 90051-PNA-000 or similar M6x1.0 replacements (These will not be provided).
ADDITIONAL PHOTOS:
Zach (verified owner) –
This is a must have if you’re doing a rwd k series. Get to keep OEM tstat housing while being able to rotate it to help with coolant hose positioning. 5/5 would buy again.
ransesjj –
Great product and design. Love the fact that I can retain the OEM thermostat and the fact that it’s simple with 0 moving parts and 0 chance of leaking.
Fit and finish was perfect and now I just need a straight hose to the radiator instead of trying to figure something out.
Looking forward to seeing what else comes from this company.