Radiator Hoses: 1966 Olds Napa Part Numbers
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Radiator Hoses: 1966 Olds Napa Part Numbers
This may be codified somewhere, but I just replaced the main radiator hoses on my '66 98.
I thought I'd pass along the latest Napa part numbers for upper, bypass and lower hoses. These may help you all if you have an Olds big block from '65 to '76.
What I can confirm is that these part numbers work for a 1966 Oldsmobile big car big block 425. The hoses below work for both A/C equipped & non-A/C cars in my experience.
Upper (Engine Outlet) Hose: Napa 7315
Bypass ("J") Hose: Napa 7082
Lower (Engine Inlet) Hose: Napa 7357
Note that in my application I had to trim about 3/4" from the radiator end of the lower hose for best fit. My definition of best fit is that that radiator end has a very close to 90° bend when it turns up to the engine inlet. I suspect that these part numbers work for many, many years of Oldsmobile big blocks, so I accept that trimming is part of the game. What I didn't want was a 110° turn putting additional pressure on the lower hose to make it up to the engine block. Trimming 3/4" or so got me to the 90° I believe Olds intended.
Couple of related notes:
1) Napa has greatly reduced the parts variety they carry with respect to hose clamps. My parts guy mentioned they've gone from 60 or so down to around 30. That means you may also want to trim your hose clamps to length and unsharpen those trimmed edges with a dremel to prevent hand slices on the ends of protruding sharp metal. It's not that we can't get hose clamps to work, it's just that they're often too long and need trimming. But after you trim, you're well advised to unsharpen the edges with some kind of tool to reduce hand slicing when you're torquing on something else...
2) In case you want the best bypass hose solution, Olds discontinued the inverted "J" shaped hose in the late 60's in favor of a metal tube sprouting off the thermostat housing to make the "J" 180° turn. This allows the use of a straight length of hose instead of the more exotic inverted "J" bypass hose. From what I've read, Olds had enough field failures of that weird shaped hose that they elected to make the J turn in metal as the 425 eventually became the 455. I suspect that the metal part is more durable, though I use the rubber version, correct for both of my '66 big Olds's...
3) When I remove the hoses, if the old ones are stuck on, I just slice 'em with a razor to weaken the stick and eventually pull free. They're going to be discarded after all, so no harm in harming them. When I put on new ones, I spray the insides with Silicone lubrication for easy slip on to their various mounting points. I also pre-install the hose clamps oriented in the way I'd most like to work on them in the future. More or less I put the clamps on in the center of the hose, loosely, so getting them in place is just a matter of sliding them where they go and tightening with a 5/16"'s hex head or small 5/16"'s socket on an 1/4 drive wrench just to be sure they're snug.
4) What prompted the job this time around was that my hoses were from 2019. That's not old, but I found that my PS pump was so close to my upper hose that the spinning nut had worn into the hose. Once I felt the wear divot, I figured it was time. So this time around I made sure the top hose had a bunch more clearance (>1 finger width) than the old one had. I suspect that between the older hose swelling with age/pressure, knowing my PS pump is too far forward and motor mounts wearing along the way, the motor movement was just enough to begin wearing at the hose. I think it's solved. Just a note to check the integrity of your radiator hoses in case clearances are tight.
Cheers
Chris
I thought I'd pass along the latest Napa part numbers for upper, bypass and lower hoses. These may help you all if you have an Olds big block from '65 to '76.
What I can confirm is that these part numbers work for a 1966 Oldsmobile big car big block 425. The hoses below work for both A/C equipped & non-A/C cars in my experience.
Upper (Engine Outlet) Hose: Napa 7315
Bypass ("J") Hose: Napa 7082
Lower (Engine Inlet) Hose: Napa 7357
Note that in my application I had to trim about 3/4" from the radiator end of the lower hose for best fit. My definition of best fit is that that radiator end has a very close to 90° bend when it turns up to the engine inlet. I suspect that these part numbers work for many, many years of Oldsmobile big blocks, so I accept that trimming is part of the game. What I didn't want was a 110° turn putting additional pressure on the lower hose to make it up to the engine block. Trimming 3/4" or so got me to the 90° I believe Olds intended.
Couple of related notes:
1) Napa has greatly reduced the parts variety they carry with respect to hose clamps. My parts guy mentioned they've gone from 60 or so down to around 30. That means you may also want to trim your hose clamps to length and unsharpen those trimmed edges with a dremel to prevent hand slices on the ends of protruding sharp metal. It's not that we can't get hose clamps to work, it's just that they're often too long and need trimming. But after you trim, you're well advised to unsharpen the edges with some kind of tool to reduce hand slicing when you're torquing on something else...
2) In case you want the best bypass hose solution, Olds discontinued the inverted "J" shaped hose in the late 60's in favor of a metal tube sprouting off the thermostat housing to make the "J" 180° turn. This allows the use of a straight length of hose instead of the more exotic inverted "J" bypass hose. From what I've read, Olds had enough field failures of that weird shaped hose that they elected to make the J turn in metal as the 425 eventually became the 455. I suspect that the metal part is more durable, though I use the rubber version, correct for both of my '66 big Olds's...
3) When I remove the hoses, if the old ones are stuck on, I just slice 'em with a razor to weaken the stick and eventually pull free. They're going to be discarded after all, so no harm in harming them. When I put on new ones, I spray the insides with Silicone lubrication for easy slip on to their various mounting points. I also pre-install the hose clamps oriented in the way I'd most like to work on them in the future. More or less I put the clamps on in the center of the hose, loosely, so getting them in place is just a matter of sliding them where they go and tightening with a 5/16"'s hex head or small 5/16"'s socket on an 1/4 drive wrench just to be sure they're snug.
4) What prompted the job this time around was that my hoses were from 2019. That's not old, but I found that my PS pump was so close to my upper hose that the spinning nut had worn into the hose. Once I felt the wear divot, I figured it was time. So this time around I made sure the top hose had a bunch more clearance (>1 finger width) than the old one had. I suspect that between the older hose swelling with age/pressure, knowing my PS pump is too far forward and motor mounts wearing along the way, the motor movement was just enough to begin wearing at the hose. I think it's solved. Just a note to check the integrity of your radiator hoses in case clearances are tight.
Cheers
Chris
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