C3 Heater Hose Debate?

[Don L.]

1972 SB, no A/C.

I'm preparing to correct my "service replacement" water pump issue, and figured I'd tackle heater hoses, etc. while I have the system down.

I currently have the red and white "GM" stamped hoses on (as pictured - I hope. This is my first attempt to attach a file), and have picked up a set of plain, no stamp grooved ones, thinking they're more like original. I've spent some time in Archives, trying to learn which variation will be better for judging points, and have come up confused. Apparently, neither is exactly right. The grooved hoses I have each show 5 grooves, with this orientation: l llll.

Which hose will bring a better score in judging?

One more question: What's the best way to show paint on the exposed, back side of the correct water pump? I've read here that the back side got little paint, however, I've personally not seen this in any original car to date.

[Jeff G.]

Re: C3 Heater Hose Debate?

Hoses seem to be a more challenging area to me too. I've been told that Dr Rebuild has the best in repro hoses. I don't know about the 72 hoses but Patrick has a nice photo file online of his 72 Bowtie. He might chime in on this...
Jeff

http://rides.webshots.com/album/563832912SazBoi?vhost=rides

[Pat M.]

Re: C3 Heater Hose Debate?

Don - as a side issue, should the fitting where the hose connects to the water pump be painted on a 72? I know I got dinged for having mine painted on my 70.

[Don L.]

Re: C3 Heater Hose Debate?

Hah! Thanks, Pat! I picked up a restored original nipple from R. Fortier, after learning from this board, which one is correct for the non A/C engine. It has the vendor (?) notches in the hex. Right. No paint, as it was apparently installed @ St. Louis.

I also will be replacing the fan clutch and temp sending unit, hopefully healing more of the service replacement blues. Since this photo was taken, I've had the original carb restored (thanks, B. Kunz) and will be installing it soon. I've also added elec. harness wrap to the TCS wiring. See anything else that needs attention?

Jeff, I had seen Patrick's photos, but notice he's had a water pump transplant. Hoses show the repeating GM logo, which archives frowned on. Did the water pump have a double-bypass when it was transplanted? Patrick will be ringing in. Let's see.

[Jack H.]

Re: C3 Heater Hose Debate?

On the issue of hoses, I'll bet there was more than one supplier of hoses to GM and the different sources had different configurations in terms of rib structure...

On the issue of the engine paint on the rear of the water pump, I'd expect the degree of coverage to vary randomly from engine to engine in lock-step to the 'aggresiveness' of the individual shooting engine paint at that specific point in time. I've seen more than one original from the era where there was little/no paint coverage in the rear center to rear bottom area...

On the water pump's inlet nipple, check your copy of the AIM. I'll bet you see the nipple and its GM PN called out in the AIM which says it was installed during final vehicle assy in St. Louis meaning it wasn't there at St. Louis or Tonawanda when the engine sub-assy was painted...

[Patrick H.]

Re: C3 Heater Hose Debate?

Hah! Thanks, Pat! I picked up a restored original nipple from R. Fortier, after learning from this board, which one is correct for the non A/C engine. It has the vendor (?) notches in the hex. Right. No paint, as it was apparently installed @ St. Louis.

I also will be replacing the fan clutch and temp sending unit, hopefully healing more of the service replacement blues. Since this photo was taken, I've had the original carb restored (thanks, B. Kunz) and will be installing it soon. I've also added elec. harness wrap to the TCS wiring. See anything else that needs attention?

Jeff, I had seen Patrick's photos, but notice he's had a water pump transplant. Hoses show the repeating GM logo, which archives frowned on. Did the water pump have a double-bypass when it was transplanted? Patrick will be ringing in. Let's see.

The majority of the pictures in my link were taken over at least 3 different "sittings." If you look closely, the GM logo disappears in some pictures. Lacquer thinner does wonderful things.

My lower hose is original, the water pump is replaced. If you look in the photo below, all 3 hoses that connect to my overflow tank and run to the front of the car are original. The two hoses that actually connect to the heater core have been replaced. Note that I didn't quite get all the "GM" logos off the heater hose that attaches to the back of the overflow tank.

I would not personally worry about how many ribs run along your hose, as each manufacturer had a different rib code. Just be sure to remove the logos -> the hoses you already have installed might be fine, Don, if you remove the logos.

Patrick

[Alan S.]

Re: C3 Heater Hose Debate?

Hi Don,
I enjoyed your engine picture.
I'm curious about the fuel line and how it passes below the upper heater hose connection/nipple. On my 71 it's below, but so close to the nipple that the fuel line left a DEEP impression in the heater hose. Yours seems to have considerably more clearance. I'm wondering if the part was changed 71-72, or is there any sign that yours may have been massaged at one point?
Thanks very much.
Regards,
Alan

[Mike E.]

Re: C3 Heater Hose Debate?

My 30k mile 71 LT-1 convertible (late production) has JI stamped on the larger heater hose about every twelve inches. Both that and the smaller hose have a 4-groove longitudinal pattern, with the two center grooves slightly larger than the two outer grooves.

[Don L.]

Re: C3 Heater Hose Debate?

Patrick: I can wipe the GM logos off the hoses pictured, however, those hoses have no grooves in them. Other than the logos, they're vanilla. The hoses I bought, thinking they'd be better, and planned to add with the water pump, have no logos at all, but have grooves. That's why I think both sets I have are not exact to original, and I don't think exact ones can be found any more. I'm looking for advice as to which one of my hose sets will score better (grooves only vs logos only).

Alan: Hmmm. I don't have any impressions in the upper heater hose. If they weren't changed for '72, perhaps one of us has a massaged fuel line. I don't see any sign of shaping modifications. How close is your fuel line to, say, your rocker cover when viewed from the same angle as my photo?

[Terry M.]

Re: C3 Heater Hose Debate?

Grooves GOOD -- [GM] BAD

[Dennis D.]

Re: C3 Heater Hose Debate?

I have a different Q. Is that the correct source for the TCS? I've seem that long nipple on many carbs. I thought it was vacuum for the smog?

[Don L.]

Re: C3 Heater Hose Debate?

Dennis: I'm gonna guess from the color in your avatar that yours is a '70. Not sure if they're the same set up as '72, but my plumbing is based on my understanding of the '72AIM (UPC 6 / Sheet C4 - page M191).

Interested in what others think.

[Dennis D.]

Re: C3 Heater Hose Debate?

Dennis: I'm gonna guess from the color in your avatar that yours is a '70. Not sure if they're the same set up as '72, but my plumbing is based on my understanding of the '72AIM (UPC 6 / Sheet C4 - page M191).

Interested in what others think.

Don: correct 70 for me. The carb pic was from research I was doing on the advance tube. It is from, what I was told to be, very original.

I checked the TIM&JG and 70-71 has a steel advance line, and 72 just the rubber hose as your pic shows. I guess that is as it should be.

Still wonder what what that capped off nipple on my pic belongs to. My L-46 carb,(7040207), does not have that nipple. I assumed it was from the calif version of the L-46 with the 7040507. Sure someone can shed some light on this.

[Patrick H.]

Re: C3 Heater Hose Debate?

Grooves GOOD -- [GM] BAD

Yes, that's what I said - because you told me years ago.

FYI I've seen the "code" that shows what the grooves mean. I mentioned it above and I'll say it again - each pattern of grooves refers to different manufacturer. So, Gates may have 2 bumps, space, then 3 bumps while Goodyear has 1 bump, space and then 4 bumps. Make sense?

You're getting hung up on the bump pattern like you did the front license plate.

Patrick

[Don L.]

Re: C3 Heater Hose Debate?

Thank you Terry.

I will use your advice and scrap the current/install grooves.