PRODUCT DETAILS
Mishimoto Silicone Heater Hose (MMHOSE-CIV-88HH) - 1988-1991 Honda Civic
Everyone upgrades their radiator hoses and forgets the heater hoses, which are the same age, the same cracking rubber, and the next thing to spring a leak. These Mishimoto silicone heater hoses handle the coolant running to and from your heater core, and like the rest of the cooling system on a 30-year-old EF, the factory rubber is well past its best. Replace them with silicone rated to 330°F and stop a leak before it starts.
The Hose People Forget
Worth calling out, because the heater hoses are easy to overlook until they fail.
The heater hoses carry hot coolant from the engine to the heater core (the small radiator in your dash that makes heat) and back. They see the same coolant, the same heat, and the same pressure as your radiator hoses, which means they age and fail the same way, the rubber dries out, cracks, and eventually leaks.
The problem is they're less visible than the main radiator hoses, so people replace the obvious ones and leave the heater hoses as the weak link. A heater hose leak dumps coolant just like any other, and often in an awkward spot near the firewall. If you're refreshing the cooling system on an EF, these belong on the list.
Why Silicone
Same reason the rest of your cooling system should be silicone.
Rubber hoses degrade from the inside out over decades of heat cycling, cracking and ballooning until they leak. Silicone doesn't have that failure mode, it handles heat and pressure far better and holds up without drying or cracking. These are built from high-grade silicone with heat-resistant embedded fibers, rated to 330°F with greater pressure tolerance than the factory rubber. Fit them once and they're not something you'll revisit.
Direct OEM Fit
These are engineered for a direct OEM replacement fit, so they route and connect exactly where the factory heater hoses did, no modification. Pull the old rubber, fit the silicone, done.
Do Them With The Radiator Hoses
The sensible way to approach it.
If you're replacing the radiator hoses on your EF, the heater hoses are right there and the same age, so doing both at once means the whole cooling system's soft lines are fresh rather than leaving the heater hoses to fail next. Together with the radiator and fan shroud, fresh silicone hoses throughout are the complete cooling refresh for these cars. It's the difference between fixing the cooling system once and chasing leaks one hose at a time.
Fitment
1988-1991 Honda Civic
Part number MMHOSE-CIV-88HH. Silicone, 330°F rated. OEM replacement fit.
Who Should Grab These
This is for the EF owner refreshing the cooling system who doesn't want to overlook the heater hoses, and for anyone chasing a coolant leak near the firewall where the old rubber heater hoses give out. Silicone rated to 330°F, a direct OEM fit, and the hose most people forget until it leaks. Do them alongside your radiator hoses and refresh the cooling system properly.
Fits: 1988-1991 Honda Civic. Part number: MMHOSE-CIV-88HH. Construction: high-grade silicone with heat-resistant embedded fibers, 330°F rated. Fit: direct OEM replacement. Pairs with: Mishimoto radiator hoses. Warranty: Mishimoto lifetime.
1988-1991 Honda Civic