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**hatzie** · 11-11-2018, 06:52 PM

Your 88 K5 Blazer is a squarebody not a T400. The 88-91 Suburban and Blazers were all RV series squares.
There's a lot more traffic on the 73-87 squarebody area. You should probably ask a mod to move your post to that area.

IIRC 5/8" hose goes from the bottom of the heater core to the intake and 3/4" goes to the water pump or the radiator depending on the truck but it's always the larger hose on the intake manifold. If you have a 3/4" hose barb on the intake someone re-assembled it incorrectly.
My 85 C10 was 3/4 on the radiator and my 75, 77, 78, & 79 C20 & C30 trucks all ran to the water pump.
Can't remember what the 350 in the 76 was plumbed like and it's not even close to any 1976 stock driveline now.

11-11-2018, 06:52 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,915	Re: 88 k5 heater not hot Your 88 K5 Blazer is a squarebody not a T400. The 88-91 Suburban and Blazers were all RV series squares. There's a lot more traffic on the 73-87 squarebody area. You should probably ask a mod to move your post to that area. IIRC 5/8" hose goes from the bottom of the heater core to the intake and 3/4" goes to the water pump or the radiator depending on the truck but it's always the larger hose on the intake manifold. If you have a 3/4" hose barb on the intake someone re-assembled it incorrectly. My 85 C10 was 3/4 on the radiator and my 75, 77, 78, & 79 C20 & C30 trucks all ran to the water pump. Can't remember what the 350 in the 76 was plumbed like and it's not even close to any 1976 stock driveline now. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.