Heater hose fitting leaking at manifold 5.7

[MAY03LT]

On my 1998 C2500 5.7, the heater hose that goes from the heater core to the intake manifold is leaking. There is corrosion around the plastic retainer and it looks like the piece that screws into the intake will have to be replaced as well.

If anyone has done this repair and has any tips that they would like to share, I'd appreciate it.

Thanks

MAY03LT

[snowdog]

be careful it will most likely brake off in the mainfold! try some penatrating oil and some heat............its a poor design

i got an adapter from my parts store its threaded into the manifold and a slip fit with a hose clamp on the other side made out of steel.

[cancritter]

theres a ton of stuff on the fix if you use search...best follow advise stated above includeing replaceing the part with a after market piecie so you dont have to do this again

[NotLifted]

I had one break off and I had to dremel the remaining out and then take a screwdriver to get the chunks left in the threads...that SUCKED!! Put in one that has just a standard hose fitting on th end and its been good since.

[tatoodkelt]

be careful it will most likely brake off in the mainfold! try some penatrating oil and some heat............its a poor design

i got an adapter from my parts store its threaded into the manifold and a slip fit with a hose clamp on the other side made out of steel.

Mine broke off right at the threads and I had to pull the intake and drill the rest of the metal out. Definitely go for the threaded/hose clamp set up.

[ma96782]

heater quick connect broke

You take a hacksaw blade, flie down one end so that you can saw the fitting into 3 pieces and pry the pieces out. try to svae as much thread on the intake as you can.

If you start the truck for a second it will pump coolant out of the intake pipe so that debris doesnt gp to the heater core.

A GM MAster tech told me about teh Vortec LAST resort hacksaw blade idea. It worked.

just buy a regular old brass or metal nipple and use a conventional hose clamp and heater hose. The quick disconnect is there simply to speed up the vehcile assembly process on theassembly line. I leared my lesson years ago. dont reinstall a stock quick/disconnect.

peace
Pauly


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I too suffered from this heater fitting. I'm not sure the welder trick will work, my fitting seemed to be aluminum or some sort of cheap pot metal (I could be wrong on that). Torching and spiral extractors did nothing. I ended up buying at tap and die ($60 for the pair! Ace Hardware has these but $$$$!) I think it was a 1/2-NPT, and I used a 5/8 Drill Bit. 5/8 is smaller than the required 45/64 drill bit, but nobody stocks these. The 5/8 is approx 1/16 too small but it will work because this fitting drills easily and taps easily, remember its a cheap metal fitting. Tap SLOWLY and I did 5/4 turns in for every 1 turn out. (A quarter turn at a time.) Load the drill bit and tap with heavy grease so the shaving don't go into the engine. Also, dont bother with the quick connect (ditto Pauly). buy some 3/4 heater hose, and a tall 1/2NPT to 3/4s hose barb from the HELP aisle. Test the fitting constantly as your tapping because if you tap too deep with NPT, the taper causes the hole to get too large and nothing will seal or torque down. This wasn't really as hard as it sounds but patiences is a HUGE part of making this a proper and painless repair. If you've never tapped threads before, get someone who has, or buy something to practice on. -McKenzie

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I just broke the coolant connector on my 1993 5.7L; it broke off flush with the intake manifold. Mine has 180,000 miles and the remainder of the connector just crumbled when I tried to use an EZ-out and an inside pipe wrench. A great source for the required tap is www.wttool.com (Wholesale Tools). Get the OSG 1/2"-14 NPT pipe tap (made in Mexico but a nice HSS piece with oxide coating) for $14.25. You will need a 45/64" drill bit and they have those with a 1/2" shank for $5.64. I live in Tampa and they have a store here but they have stores all over the US so they can ship quick if they don't have a store close to where you live. They also have a US made tap for about $26 but whatever you do, DO NOT use a high carbon steel tap. If it breaks off in the connector you will have one hell of a time trying to drill it out. FWIW, I looked at the Vermont American taps (Home Depot, Ace, etc) and they are high carbon steel (and they cost over $20). They might just work but why take the chance!
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http://www.fullsizechevy.com/forums/...saws+all+blade


http://www.fullsizechevy.com/forums/...intake+fitting

Aloha, Mark

[TheStorm]

Hi May,
Yours is probably way finished by now but for anyone else looking, here is what worked for me:
97 suburb k1500 5.7, no rear heat. 130K miles.

Heater hose failed, (it was due) hole in rubber at swaged end near sleeve. Taped the hose with decent tape, refilled with water, and drove her home (don't use your AC).
Discovered the replacement hose was 40+ bucks and was advised to also replace intake connector fitting. (another $18.00+ dealer price). -- Parts only price --
Decided to replace the OEM hose and fitting with regular 3/4 hose and 1/2 - 14 NPT to 3/4 hose connect brass fitting. ($40.00 including coolant and a foot of extra hose)

Used a 1 1/16 socket to facilitate removal, at around 7nm of removal force the factory fitting shattered flush with intake inlet. (Nice.... no wonder we've lost to china..)
The force applied was not enough to remove bonded fitting, but more then enough to exceed design specification.

Ok, more money for a 1/2 - 14 NPT ($16.00) and search for a cutting tool to machine remaining broken material to .709" minor NPT tap diameter.
Luckily, thanks to my wife organizing some stuff in the garage, I found an old tool I used to use when actively building aircraft tooling. This was a .695 radius tip 4 flute counterbore with a removable 1/2" pilot and heh, heh, 1/4" shank.
!!SCORE!! Not quite .709, but I can take it easy on the tap.
Chuck the counterbore into my 3/8 drive craftsman electric drill, out comes the rest of the old crappy connector.
Run the tap through new .695 hole, out comes the rest of the leftover crap from the old failed part.
Install new brass fitting with orange permatex. I'm letting it sit over night.
Should be good to go now.

Cheers !

BTW: Intake removal was not required when drilling out old material. Vacuum chips out then flush system before reconnecting to heater core. I used permatex because it was what I had and advertises heat compatibility. For accessing the area, I also removed the throttle cable bracket and valve cover riser tube, cover the tube hole to keep the chips out. You may want to disconnect the battery so you don't practice your arc welding skills near the alternator power lug.
I tried the hacksaw method and after about 15 minutes of hackin around I looked for another way... Good Luck with yours.

[KUGS]

You can get a steel replacement from the parts store (dorman#800-401) thats better than a barbed fitting and a clamp. if it brakes dorman also make a tool to get the pieace out.

[ewdoyline]

You dont have to remove the intake. Take a rag and stuff it into the hole in the intake to catch the shavings and pieces. take a blade or cutting tool ( I used a hacksaw blade that I ground the back off of ) and cut three slots in the old fitting thats letf in the intake. Cut all the way through the theads but not past them in to the intake. Put a screwdriver in the slots and twist. The pieces should just pop out. Run a tap in after that to clean up the threads. Use teflon tape on the new fitting.

[SolMan98]

Hi May,
Yours is probably way finished by now

After 3 years, I'd hope so.