question about coolant hose - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Thursday7 · 01-30-2023, 05:41 AM

I actually found a solution for what I think you're describing by owning an OBS ford truck. Mine is also cut like lok's image, though I did weld the beaded/nipple tip back on it from the cut off portion.

The SR's heater lines here are 3/4", whereas the US S13's heater core nipples are 5/8", at least on my car/engine. You can use stock S13 heater hoses and stretch the 5/8" hose over the 3/4" nipple on the SR, but I imagine that's not a permanent solution and significantly reduces the lifespan of the hose.

What I did was bought 2 small block OBS ford coolant bypass hoses, one for each tube coming from your engine. They are a short 90* bend with a built in 3/4-5/8 reducer. Buy two generic double-male metal 5/8 hose couplers and cut the stock 5/8 heater hose at the right length from the heater core side and put it all together with clamps.

Since the heater hose design on these cars is basically 2-90* bends it should be pretty self-explanatory if you have the parts in front of you, and it's a good reliable solution.

01-30-2023, 05:41 AM	#9
Thursday7 Zilvia Addict Join Date: Jul 2011 Location: PA Posts: 800 Trader Rating: (8) Feedback Score: 8 reviews	I actually found a solution for what I think you're describing by owning an OBS ford truck. Mine is also cut like lok's image, though I did weld the beaded/nipple tip back on it from the cut off portion. The SR's heater lines here are 3/4", whereas the US S13's heater core nipples are 5/8", at least on my car/engine. You can use stock S13 heater hoses and stretch the 5/8" hose over the 3/4" nipple on the SR, but I imagine that's not a permanent solution and significantly reduces the lifespan of the hose. What I did was bought 2 small block OBS ford coolant bypass hoses, one for each tube coming from your engine. They are a short 90* bend with a built in 3/4-5/8 reducer. Buy two generic double-male metal 5/8 hose couplers and cut the stock 5/8 heater hose at the right length from the heater core side and put it all together with clamps. Since the heater hose design on these cars is basically 2-90* bends it should be pretty self-explanatory if you have the parts in front of you, and it's a good reliable solution.