Heater Hose Connector

[rktuck]

I have a 1999 GMC K1500 Suburban 5.7l with front and rear A/C & Heat. The heater hose connector on the intake manifold has broken off. It appears to have a thread size larger than 1/2"NPT and smaller than 3/4"NPT. The dealer (and all local parts houses) only list and stock the 1/2" size. Is there a replacement? Or do I need to bore it out and tap it to 1"NPT and use a bushing? Help! Thanks, Robert.

[grosss]

I have a 1999 GMC K1500 Suburban 5.7l with front and rear A/C & Heat. The heater hose connector on the intake manifold has broken off. It appears to have a thread size larger than 1/2"NPT and smaller than 3/4"NPT. The dealer (and all local parts houses) only list and stock the 1/2" size. Is there a replacement? Or do I need to bore it out and tap it to 1"NPT and use a bushing? Help! Thanks, Robert.

 

Have you actually tried screwing in an NPT thread into the hole to see that they don't fit? NPT I believe is tapered... Does the profile of the thread itself look like NPT? It could be another type of thread (JIC?) 99 was the transition year so the dealer might be looking at the wrong model since both old and new styles existed in 99 (though I don't think the old body style was produced for the 1500's, but the dealer could still have made a mixup). If it's between 1/2 and 3/4 it and neither one fits, I'd say it's probably a metric thread. Find a local hydraulic/air hose supplier if you can, they'd have a wider selection of those kinds of parts than a car place.

 

Hope that helps.

[rktuck]

It is not a NPT fitting. I could not match it to anything. There were 12 TPI. I know that some of the 1"-2" NPT fittings use 11.5 TPI. It did not match any of the specs for any metric thread. The closest thing that I could identify it to was a 1" -12TPI straight machine thread. I had already tried the dealer, parts houses, and a hydraulic hose place. I made a bushing to adapt it to a 1/2" NPT fitting and that solved my problem.

 

Thanks.