1966-74 BB With Air Conditioning Owners

[Howard H.]

Re: 1966-74 BB With Air Conditioning Owners

Thanks everyone; I just couldn't see how the long fitting shown above from CC would allow enough clearance for the hose without it kinking. I wonder if the correct one is still available from GM.
Howard

[Mark E.]

Re: 1966-74 BB With Air Conditioning Owners

Without understanding the nuances of heater hose nipples, years ago I installed a long style nipple on my '70 LS5 AC car.

No issues with heater hose kinking.

Of course, installing the proper nipple is a better option.

[Joe L.]

Re: 1966-74 BB With Air Conditioning Owners

Thanks everyone; I just couldn't see how the long fitting shown above from CC would allow enough clearance for the hose without it kinking. I wonder if the correct one is still available from GM.
Howard

Howard------


The GM #3739798 is discontinued. However, reproductions are easy to come by.

[Howard H.]

Re: 1966-74 BB With Air Conditioning Owners

Thanks Mark and Joe. I have the long one on the water pump now in the car and will try to use it but will get a correct one in case I have problems.
Howard

[Keith K.]

Re: 1966-74 BB With Air Conditioning Owners

'74 454 with A/C has the short nipple

[Leif A.]

Re: 1966-74 BB With Air Conditioning Owners

Joe,
I know you started this thread 8+ years ago but it has received recent traction. I didn't see where you received any pictures you asked for. This is my '67 L79 with factory A/C lower nipple.

[Tom K.]

Re: 1966-74 BB With Air Conditioning Owners

Hello - My first post - MY 73 LS4 with C60 has the short nipple on the water pump and I was told it was original when I purchased the car last June. Missing items are due to starting to remove the radiator so it can be re-cored.

[Mark E.]

Re: 1966-74 BB With Air Conditioning Owners

Welcome to the forum, Thomas.

You have one of my favorite Corvettes- the unique '73. And a big block too! My first Corvette was a '73 L82. Loved it.

[Tom K.]

Re: 1966-74 BB With Air Conditioning Owners

Thanks Mark,

This one was 'too of a deal good to pass up' so I am slowly learning about the C3 and I have found great info on this site. There is an amazing amount of knowledge and experience here.

[Mark E.]

Re: 1966-74 BB With Air Conditioning Owners

Check the routing of the heater hoses. If like 70-72, they both go up and over the AC compressor.

[Jeff B.]

Re: 1966-74 BB With Air Conditioning Owners

My 67-390 air car (#8902), having owned since 1979, with 54,000 current miles, is still running the original water pump. It has the short nipple.

[Mike B.]

Re: 1966-74 BB With Air Conditioning Owners

I'm resurrecting this very informative thread on '66-'74 BB AC Water Pump Heater Hose Nipples with a question for Joe and the other experts who've responded here.

The photo here of an NOS #3739798 nipple that Joe posted surely resembles the nipple I'm posting of a 1966 L36 intake manifold heater hose fitting. My question for you all is this. Did the 1966 L36 intake manifold #3866948 use the #3739798 nipple when the car came equipped with air conditioning?

See the photo that Ric Sauve took of his original 1966 AC L36 intake manifold fittings. His heater hose fitting certainly resembles the NOS water pump nipple that Joe shows. It has the earlier style rounded hose barb.

Mike
'66 AIM C60 sheet D3 (edited).jpgRic's '66 L36 #3866948 Intake Manifold Fittings.jpg#3739798 AC Water Pump Nipple (2).jpg

Dale-----

The fitting you require for the water pump heater hose nipple is the GM #3739798. A photo of an NOS example is attached. However, this is a later version with the "ramped" hose barb. The version in use at the time your car was built used a symmetrical, rounded hose barb. Of course, this feature cannot be seen once the hose is installed.

The configuration of the hose barb was changed via a revision to the specifications for this part in the later 70's.

[Joe L.]

[Mike B.]

Re: 1966-74 BB With Air Conditioning Owners

Thanks Joe,

As my heater hoses are in a box I assumed they were the same diameter nipple. My mistake. But now I know what's the proper L36 intake manifold nipple part number thanks to you. And here's a great photo of what's most probably an original #3838094 intake nipple on Ric's '66.

And also thanks to you I know how the proper water pump nipple should appear as described in my '66 AIM section C60 sheet D3 item #3. Very important to many of us when selecting proper parts for our cars.

Mike
Ric's '66 L36 #3866948 Intake Manifold Fittings.jpg'66 AIM C60 sheet D3 (edited).jpg#3739798 AC Water Pump Nipple.jpg