Acura RSX Coolant Hose Visual Guide
I've had a leak at one of my heater core hoses lately, and I wanted to find the correct part number to buy a replacement. It turns out it's a little bit of a pain, so I created this guide to explain what each hose is, what the part number is, and provided some easy purchase links. I also drew out the entire cooling system at the bottom to make understanding the flow of coolant and finding leaks a bit easier.
You can find these hoses by clicking on one of my links, or Googling the UPC code or part number I've listed. Not everything is on Amazon, but I put part numbers for everything so it shouldn't be a problem.
Note: If you purchase your supplies from my Amazon links, it will support this website at no extra cost to you. : ) Thank you.
Upper & Lower Radiator Hoses
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| Upper Radiator Hose and Lower Radiator Hose Locations |
This is kind of a weird diagram, because it's from the perspective if you're standing inside the engine bay. The upper radiator hose connects to the engine's metal coolant outlet at the top. The lower radiator hose connects to the thermostat housing, underneath the intake manifold.
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| Upper Radiator Hose, Stock |
This is the stock upper radiator hose, and maybe what yours looks like. They're pretty cheap and usually last a pretty long time.
Acura Part Number: 19501-PND-000
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| Upper Radiator Hose, Aftermarket |
This is an aftermarket upper radiator hose. It's meant to allow more room for aftermarket cold air intakes and the RBC intake manifold. Fits your RSX, EM2 Civic, or EP3 Civic Si.
Upper Radiator (Aftermarket) UPC: 072053056167
(Purchase Link Below)
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| Lower Radiator Hose, Stock |
This is a stock lower radiator hose. Obviously found at the bottom of the radiator.
Acura Part Number: 19502-PND-000
NOTE: You can purchase an aftermarket upper and lower radiator hose made out of multiple-layer silicone, which lasts longer and is more temperature and chemical resistant. I purchased these and I like them. It is more expensive, but required for certain cold air intakes to have appropriate clearance.
Coolant Overflow / Reserve Tank Tube
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| #3 - Coolant Reserve Tank Tube |
This tube connects to the top of the radiator right next to the radiator cap, and sticks down through a rubber grommet into the coolant reserve tank.
Acura Part Number: 19104-PND-000
Bypass Inlet Hose
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| #13 - Bypass Inlet Hose |
The bypass inlet hose routes coolant through the engine while it's heating up, bypassing the restriction of the thermostat. It's connected to the rear of the thermostat housing. Usually a good idea to replace it if you're already in there working on the heater pipe (#14) (I have a guide on how to do this properly; it's an awful thing to have to redo).
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| Bypass Inlet Hose |
Acura Part Number: 19504-PNA-000
(Link to buy silicone version in the section below this one)
Heater Core Hoses
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| #2 - Water Inlet Hose A #3 - Water Inlet Hose B #4 - Water Outlet Hose |
Water inlet hose A connects the heater pipe from the previous drawing to the water valve assembly (#1).
Acura Part Number: 79721-S6M-A10
Water inlet hose B connects the water valve assembly's other side to the heater core inlet, which goes inside the car. Don't mix the inlet and outlet up when you're connecting them at the firewall! The inlet is on top, and the outlet is the bottom connection.
Acura Part Number: 79722-S5D-A00
The water outlet hose brings water from the heater core, back into the engine block.
Acura Part Number: 79725-S6M-A00
NOTE: Acura has discontinued "Water Inlet Hose A" and "Water Outlet Hose". They also can't be found at Acura parts suppliers online, or at the dealership as far as I know. The only source I've found for these is on eBay. The listing includes "Water Inlet Hose A", "Water Inlet Hose B", "Water Outlet Hose", and the above "Bypass Inlet Hose". These are all made out of silicone, and should last longer than their rubber counterparts. They ship from China, so be prepared for 1-2 week shipping times if you're shopping in America.
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| eBay Silicone Heater Hoses |
Throttle Body / Oil Cooler Hoses
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| #2 - Oil Cooler Inlet Hose #3 - Oil Cooler Outlet Hose #4 - Throttle Body Inlet Hose #5 - Rotary Air Control Valve Outlet Hose |
(TYPE-S ONLY) The oil cooler inlet hose brings coolant through the engine block to the oil cooler.
(TYPE-S ONLY) Acura Part Number: 19422-PRB-A00
(TYPE-S ONLY) The oil cooler outlet hose takes coolent from the oil cooler back into the engine block.
(TYPE-S ONLY) Acura Part Number: 19423-PRB-A00
NOTE: You can also buy an aftermarket silicone set of oil cooler hoses. It can be worth it to have better longevity in such a painful place to work in the rear of the engine.
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| K-Tuned Oil Cooler Hoses Installed |
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| Oil Cooler Outlet (Top) (Aftermarket) Oil Cooler Inlet (Bottom) (Aftermarket) |
Hybrid Racing Oil Cooler Hoses
K-Tuned Oil Cooler Hoses
The throttle body inlet hose brings coolant from the upper coolant housing to the throttle body to cool it off. This is a commonly bypassed hose when putting on an RBC intake manifold and Hondata IMG, to further separate the heat of the engine away from the intake manifold to get better intake temperatures.
I recommend capping this off for track-based builds.
Acura Part Number: 19508-PRB-A00
The rotary air control valve outlet hose acts as an outlet at the bottom of the throttle body, and is connected to the heater pipe.
I recommend capping this off for track-based builds.
Acura Part Number: 19509-PRB-A00
Full System Water Flow Diagram
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| What Have I Created |
Oh god my Microsoft Paint skills need some work. You get the point though, hopefully. There's a couple unlabeled hoses on the diagram, but you can figure it out between my article and the picture pretty easily.
I hope this helps you order the parts you need and fix your leak!
Disclaimer:
I may receive payment if you purchase products using my Amazon links. Thanks for helping keep the HID's on : )
