Olds Coolant Hoses

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I'm working on my first Olds engine so I have a couple basic questions. I'm tearing down Grandpa's engine bay to clean up the 307 Olds a bit. I need to replce the small length of heater hose that comes off the thermostat housing port, do I need to remove the T-stat housing to do that? Kinda looks like I do.

I've noticed on my engine and in some pics the heater hose wraps around the A/C components, see pic below, while other Olds powered G-bodies have the hose go directly from the firewall to the port in the intake. Is there a purpose to wrapping it around?

 

[olds307 and 403]

I have never seen it wrapped around the A/C lines like that. No purpose unless you want to heat your A/C. One heater hose has a bracket to sit against the choke coil, brings off the choke quicker. That little hose can be fit in but takes some struggling. The earlier style thermostat housings use a curved hose, much easier to change. Good luck.

 

[69hurstolds]

With A/C, VIN Y Cutlass RWD heater hoses wrap around the A/C accumulator. This is factory style routing. According to the 85 CSM, the VIN 9 is supposed to as well, but they didn't for whatever reason. Mine sure didn't. Neither did the 87 442. The 85 CSM has the hose wrapping around the accumulator first, then going over to a little clamp/clip thingie by the choke housing and on to the water pump for both VIN Y and 9.

In the 84 CSM, the VIN Y and VIN 9 heater hoses were routed as they came from the factory.

Best guess is the idea perhaps was to ensure you didn't place a strain on the heater core nipples. But, you can look at any factory VIN 9 and they did not do the loop. Why? I have no idea.

85 CSM

84 CSM

 

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Isn't that interesting/ weird that they did that on some but not others. I'm planning to run it straight there, just wanted to make sure I wasn't missing something I should be doing.

 

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Another question- On the rear it has a valve the hose plugs into. That valve has a vacuum hose that IIRC (I'm not near the garage) goes to the air pump. I'm removing the air pump so should I connect that to a different vacuum source or can I plug the port on the valve? Or better yet replace the valve with a simple nipple?

Thanks for any insight. All my stuff has always been old school Chevy small blocks so this is a slight learning curve for me and just want to be sure I don't screw up anything.

 

[69hurstolds]

The tubing going to the coolant cutoff valve on the back of the intake? This line's vacuum is controlled by the HVAC controls when you place it in MAX or the temp valve in COLD, that valve gets vacuum.

The only thing in that vicinity that goes to the AIR Pump system should be the AIR supply hose/check valve going to the cat converter if I'm understanding your question correctly.

But back to the cutoff valve for a second. That's the beauty of the cutoff valve. When the A/C is being used to cool things down, there should be no hot water flow through the hoses, thus shouldn't be heating the A/C lines in that area. Granted, it's an odd way to route the heater hose, but GM never was forward thinking on a lot of things.

 

[olds307 and 403]

The tubing going to the coolant cutoff valve on the back of the intake? This line's vacuum is controlled by the HVAC controls when you place it in MAX or the temp valve in COLD, that valve gets vacuum.

The only thing in that vicinity that goes to the AIR Pump system should be the AIR supply hose/check valve going to the cat converter if I'm understanding your question correctly.

But back to the cutoff valve for a second. That's the beauty of the cutoff valve. When the A/C is being used to cool things down, there should be no hot water flow through the hoses, thus shouldn't be heating the A/C lines in that area. Granted, it's an odd way to route the heater hose, but GM never was forward thinking on a lot of things.

Good point on that A/C shut off valve but unless the A/C is running, it is heating the line, unless GM saw line freezing issues? Lucky that shut off valve isn't leaking, they tend to do that, especially as these cars get up there in age.

 

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Thanks for the insight, I really appreciate it. I was trying to remember in my head where that vac line was directed and was thinking it was the air pump. I labeled everything so I should be able to get it back where it goes. The valve appears in decent shape so I'll just keep it there.