95 Suburban rear heater hose questions

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Godholio

OBS Enthusiast
Joined
Jun 10, 2020
Messages
51
Reaction score
53
Location
South Carolina
Ok Burb gang, got a question. This weekend I got a hairline crack in one of the plastic heater hose quick disconnects under the hood (where it splits into front/aux heaters, not actually at the heater core), and a pinhole coolant leak. The heater hoses look like they're probably original, so I want to just replace them all. Under hood looks easy enough, I'm not messing with new QDs, just gonna use new hose and worm clamps. I want to do the same under the back of the truck. But before I do, I just want to double check what I'm getting into.
Two pictures below. The first shows what I think each of these lines are, just want to make sure I'm not crazy. The front of the truck is "up." Blue is AC, red is heat, right? The yellow circle is the connection in the other picture...what is this? The line to the right leads to the front of the truck and seems to be a metal line with a rubber sleeve, to the left the hose just coils and plugs into the rear heater. The weird connection...is that going to be something I can hose+clamp like usual? I don't want to start ripping things apart if I'm going to need to do something special. A friend suggested flaring the end of the metal line, which is probably a good idea.
It's too damn hot here (115 or so) to waste time laying on the driveway.
 

Attachments

  • IMG_1933 - Copy.JPG
    IMG_1933 - Copy.JPG
    355.1 KB · Views: 68
  • IMG_1934.JPG
    IMG_1934.JPG
    252.3 KB · Views: 66

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
10,967
Reaction score
13,746
Location
The Seasonally Frozen Wastelands
GM used high-quality hose permanently crimped to metal ends, because they wanted a durable, leak-free connection. That's what I'd recommend you use--OEM-style crimped hoses.

If you MUST use crappy worm-gear hose clamps, at least make sure you buy "Shielded" clamps, so the hose doesn't cold-flow through the holes in the clamp strap.

Sort of like this, although "fuel injection" clamps aren't available in sizes big enough for heater hoses, that I'm aware of.
You must be registered for see images attach

Regular "shielded" clamps would be, though. Something like this:
xc_hide_links_from_guests_guests_error_hide_media

Yes, you'll need to bead/flare the ends of the metal tubes the hose is clamped to.

Be sure that the hose doesn't collapse from being curved too sharply.
 

Godholio

OBS Enthusiast
Joined
Jun 10, 2020
Messages
51
Reaction score
53
Location
South Carolina
GM stopped making these 15 years ago, and I'm not thrilled by buying a special, single-task tool that I'll never use again. Unless somebody has a source for these hoses, I don't have many options.

But I'm still not sure what that connection is...it's not like the others with the quick disconnects.
 
Last edited:

Godholio

OBS Enthusiast
Joined
Jun 10, 2020
Messages
51
Reaction score
53
Location
South Carolina
I don't think any of the connections are going to give up easily. I marred the hell out of the tool because I had to take a hammer to knock the damn thing off, and I still ended up breaking the plastic connector worse than it already was (I couldn't make any progress on the rear hoses, so I moved up to the one that was already cracked).

Those connections I was asking about appear to just be the factory hose slipped over the steel line, then crimped.
 

Godholio

OBS Enthusiast
Joined
Jun 10, 2020
Messages
51
Reaction score
53
Location
South Carolina
Ok, I'm figuring it out. First off, these quick connects are not the same as what all the videos and images are from later trucks...they're the pinch style, not the spreader style. So I wasted a truly stupid amount of time because I didn't take the time to get a good look before diving in. The reason that connection I was asking about is weird is because the individual components aren't intended to be serviced alone...it's an assembly; actually each line at the rear (inlet & outlet) are a separate assembly. The two lines from the splitter in the engine bay are actually one assembly, starting at the splitter and going all the way down to just behind the front wheel. Note that as of now, the rears have been out of production for at least six years, and while the front is technically still available, the MSRP is like $250 and I can't imagine they're still being made (I just got one on ebay for 90). Seems likely that what's available is just the last of the stock.

So for readers in the future, here are the GM part numbers:
Front- 15961911 (includes both lines)
Rears- 15664399 (plugs into the rearmost port at the aux heater)
15664400 (plugs into the forward port at the aux heater)

Godspeed.
 

Godholio

OBS Enthusiast
Joined
Jun 10, 2020
Messages
51
Reaction score
53
Location
South Carolina
Ok, this is probably the last update for this one, barring an unforeseen disaster.

Parts list...I only replaced the aux hoses. The ones for the front heater looked almost new, they can't be more than a couple of years old. So I only went from the splitter in the engine bay to the rear of the truck.
On my truck, all the hoses were 3/4". I saw some conflicting information out there about that. Dorman 800-411 is the quick connect that fits that hose and the metal lines; you'll need four of them. I used just shy of 6' of hose...if you're replacing the front hoses, you'll need more. I didn't replace any of the metal lines.

A clearer description of how GM set this up: Beneath the air intake box on the passenger side of the engine bay, you can't miss the splitter. From there you can follow the hoses to the regular heater core, and to the engine and radiator. You'll see the two quick connects next to the exhaust manifold, and the hoses they're crimped to are wrapped in some thermal protection stuff. The hoses head downwards and aft, and just out of your reach they are crimped onto aluminum tubing; the two tubes are clamped together in a couple of locations. That aluminum tubing is pre-bent to fit around the frame, with a small bracket that bolts to the inner side of the frame near the front wheel. You can easily see it from beneath. Then the tubes continue just behind the front wheel and bend outward and poke through a hole in the frame, with another bracket that bolts to the frame where they poke out. From this bracket all the way to those plastic quick-connects, both lines, is one assembly. If you can find it, buy it. If you can't, you should be able to take it apart and re-use all the metal parts and just replace the hoses, plastic connects, and the heat wrap. Note that my parts list above does NOT include this, so that's 2 more connects and more 3/4" hose. Shockingly, the assembly is not difficult to maneuver out of there. You'll end up spinning it about 180* and shoving it further back, then getting the front end free first. Installation is the reverse. I expected this to be the worst part of the whole thing, but it took about 2 minutes to actually get it out, and less to slide the new one in place.

From here I'll only mention one line, but both of them are virtually identical and run alongside each other. The only differences is a couple of inches of rubber hose just based on bending radius. At the connection point poking through the frame, there's a quick connect hidden under a boot (the front assembly comes with the boots, and I wish I could've found them to use on every connection), then 6-10" of rubber hose crimped onto more aluminum tube. I didn't mess with that tube at all...it's well mounted and in good shape. It's prebent to go all the way back and over the rear axle. At that point, another crimp to a rubber hose that makes a large bend (make sure you don't kink the hose), then a quick-connect into the aux heater core. I'll be wrapping these quick-connects in electrical tape or something...the boots GM used elsewhere really made a difference in being able to remove these things, so I want to do something to protect them and keep crud out in case I ever have to mess with them again.

Here's the FSM diagram, which isn't of great help. On View B, you can see the vertical quick-connects plugging into the core, then the large loop of rubber hose terminating in those wide crimps (a dremel works great, just be careful not to go too deep). Everything else in that diagram is just aluminum tube running forward. A couple more feet and you'd see the next section of rubber hose right behind the front wheel, which bends inward to the frame-hole-connects.

Hopefully this helps someone at some point. The part numbers are probably the most useful.

Edit: I forgot to mention, if you do find that front assembly make sure you compare the new to the old after you remove it. The small bracket on my new one was roughly backwards compared to the old one. I didn't compare before trying to install and the bolt hole was like 3" out of position. I removed it again and compared, and realized it was never going to be able to line up so I had to swap brackets. Not a big deal, but a minor hassle. You can see the difference in the photo. Otherwise the fit was perfect.
 

Attachments

  • Heater Hoses - Aux.JPG
    Heater Hoses - Aux.JPG
    88 KB · Views: 97
  • IMG_2088 - Copy.JPG
    IMG_2088 - Copy.JPG
    83.9 KB · Views: 90

termite

Definitely NOT Awesome
Joined
Feb 18, 2018
Messages
986
Reaction score
2,399
Location
wv
Recently acquired a 95 K2500 Burban and going through getting the rear heat functional. Good info and I very much appreciate your sharing.
 

1998_K1500_Sub

Nitro Junkie
Supporting Member
Joined
Jan 28, 2019
Messages
2,144
Reaction score
3,244
Location
Rural Illinois
I replaced my rear and front heater "hoses" using Gates molded hoses that I fitted together to replace the OEM pieces while retaining the hard lines, e.g., see images attached in this and my other posts in this thread.

This includes the squirrel's nest of hoses in the engine compartment that interconnect the front, rear, and (in some vehicles) coolant shutoff - bypass valve, as well as those to / from the engine and water pump.

I also used bulk hose where appropriate.

Notably, I kept all the OEM coolant hardlines to the rear but removed the deteriorated rubber hose from their ends (i.e., by using a cutter wheel and slicing through the OEM crimp collar - see my later post - and/or removing all quick-connect fittings). This left the bare hard lines from (a) the engine compartment to mid-frame (under the passenger's door), and (b) from mid-frame to the right rear.

I then added rubber hose to (re) join the various hard lines together, as follows. Note that I did not bead / flare the ends of the metal tubes; while I think it's a good idea, I didn't do it. The clamps I used create a tight "hose to pipe" fit that's been working now for four years. Read on...

In the rear, I used off-the-shelf Gates 19129 molded hoses, then cut, trimmed and spliced each with a brass PEX connector to get the proper fitment, and finally "clamped" the two pieces together with Gates PowerFlex (heat shrink) hose clamps. More on this in a later post.

Mid-frame, where the hoses splice the front and rear pipes together, I used Gates 18082 molded hose, 5/8" on one end and 3/4" on the other, to accommodate the different pipe sizes, and simply sized, cut and bent the hose to fit.

In the engine bay, I used bulk 3/4" and 5/8" heater hose in most locations, and molded hose, e.g., Gates 28480 3/4" with molded 90-degree bend, to connect to the intake manifold, and a Gates 28474 (or equivalent) to join some connections at the front / rear coolant splitters (see picture). Again, these were sized and cut to fit.

In all cases, I used the Gates PowerFlex host clamps. I discuss these more in a later post.

My list of parts:

Gates 19129
¾”dia to 5/8”dia 15" long, qty 2, modified for rear heater connections. I cut them and spliced them as shown in the picture and discussed in a later post.

Gates 18082 - 5/8"dia to 3/4"dia 18" long, qty 2, to join the lines mid-frame, i.e., beneath the passenger’s door. See my comments earlier in this post.

Gates 28480 ¾”dia 52" long, cut to fit, to join the intake manifold fitting to the tees and water valve in the engine bay.

Gates 28474 ¾”dia 10" long, cut to fit, as noted above, in the engine bay.

Bulk hose, ¾” or 5/8" as necessary, to join the lines in the engine compartment.

Constant-force clamps were used throughout; more on this in a later post.
 

Attachments

  • Rear.jpg
    Rear.jpg
    260.2 KB · Views: 120
  • Rear 2.jpg
    Rear 2.jpg
    268.9 KB · Views: 111
  • Midframe.jpg
    Midframe.jpg
    259.3 KB · Views: 120
  • Engine compartment.jpg
    Engine compartment.jpg
    471.5 KB · Views: 101
Last edited:
Top