Need to bypass the heater core - The 1947 - Present Chevrolet & GMC Truck Message Board Network

lmac1210 · 07-13-2010, 09:09 PM

What is the best way to bypass the heater core for a short time? Can I just go from the water pump straight back into the engine? My core is shot and I don't have the time to fix it just yet...more projects than time right now.

lmac1210 · 07-13-2010, 09:10 PM

Sorry...that heater core is on a 1970 GMC 350 without AC

gonzo6869 · 07-13-2010, 09:11 PM

That is the way I have it setup right now. I don't think its a problem.

Sinister · 07-13-2010, 09:12 PM

You could do that or just get some NPT pipe plugs.

lmac1210 · 07-13-2010, 09:17 PM

Quote:

Originally Posted by Sinister

You could do that or just get some NPT pipe plugs.

Thanks...where would one find those plugs?

Sinister · 07-13-2010, 09:19 PM

I got mine at Kragen or Autozone, one of those kind of places.

lmac1210 · 07-13-2010, 09:20 PM

Thanks for the quick answers guys....I will just bypass it for now and maybe get those plugs as I get around to it.
THanks again!!

**El Jay** · 07-13-2010, 11:38 PM

Pipe plugs are cheap, but they may be even cheaper at Homie, Lowe's, Ace, etc.
Since the repair is only temporary, just bypassing the heater core with you existing heater hose is even cheaper still.
Sometimes pulling the hose barbs to install plugs can be a real PITA if the are corroded in place.
I'd just use the 3/4" hose and then just double clamp it on the 5/8" manifold hose barb.

Just be sure you put some kind of anti-seize in the plug threads so you can get them out later, if you go that route.

JesseH13 · 07-14-2010, 12:18 AM

i didnt even run my hoses to the waterpump at all i just plugged them also

turner15 · 07-14-2010, 08:32 AM

Same I just plugged mine at the pump and intake. Got some nice chrome ones so it even looks good.

tk-mpl · 07-14-2010, 09:40 PM

I was kind of wondering the same thing, but mine is a 5.3L.... I don't have the heater box back in it yet and would also like to bypass or plug the outlets on the water pump.

raycow · 07-15-2010, 03:07 AM

Quote:

Originally Posted by lmac1210

Can I just go from the water pump straight back into the engine?

The problem with bypassing the heater with a length of hose is that you are also bypassing the thermostat. This will cause slow engine warm-up, and it will be especially bad if you live where it gets cold.

As already mentioned, the best way is to plug the ports at both ends. If you want a cheap and dirty fix, use the hose, but stick a short length of close-fitting dowel into one end of it first.

Ray

69c10step · 07-15-2010, 12:22 PM

What size are the plugs for the intake & water pump?

Sinister · 07-15-2010, 12:40 PM

Quote:

Originally Posted by 69c10step

what size are the plugs for the intake & water pump?

1/2" npt

lmac1210 · 07-15-2010, 01:08 PM

Not sure what has been said from someone about bypassing the thermostat...I went with the larger hose straight from the output of the engine right back into the engine...I am a newbie (and like most newbies don't understand everything) but I have only bypassed the heater core and nothing else. Started up and no leaks as of yet. I have a lot on my "plate" right now (son got his license and took over my daily driver, I am in school full-time, have a job as well) so I just needed the quickest fix I could use for now....plus I live in HELL HOT Georgia and don't need the heater core right now. I just hope I did the right thing for now

*Shane* · 07-15-2010, 01:36 PM

Quote:

Originally Posted by raycow

The problem with bypassing the heater with a length of hose is that you are also bypassing the thermostat. This will cause slow engine warm-up, and it will be especially bad if you live where it gets cold.

As already mentioned, the best way is to plug the ports at both ends. If you want a cheap and dirty fix, use the hose, but stick a short length of close-fitting dowel into one end of it first.

Ray

how does bypassing the heater hose bypass the thermostat?

Alvin · 07-15-2010, 01:59 PM

Quote:

Originally Posted by Shane

how does bypassing the heater hose bypass the thermostat?

It all depends where you stick your thermostat

lmac1210 · 07-15-2010, 02:09 PM

Quote:

Originally Posted by Alvin

It all depends where you stick your thermostat

I just ran the in from the heater core straight back into the engine. Nothing else was touched....two hoses made into one basically (if that makes sense)....the only thing bypassed is the heater core.

57larry · 07-15-2010, 08:33 PM

Quote:

Originally Posted by lmac1210

I haven't stuck anything anywhere...I apologize up front if this is rude, I just ran the in from the heater core straight back into the engine. Nothing else was touched....two hoses made into one basically (if that makes sense)....the only thing bypassed is the heater core.

will work just fine

07-13-2010, 09:09 PM	#1
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Need to bypass the heater core What is the best way to bypass the heater core for a short time? Can I just go from the water pump straight back into the engine? My core is shot and I don't have the time to fix it just yet...more projects than time right now.

07-13-2010, 09:10 PM	#2
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Re: Need to bypass the heater core Sorry...that heater core is on a 1970 GMC 350 without AC

07-13-2010, 09:11 PM	#3
gonzo6869 Cops, ha, catch me if you can! Join Date: Jun 2009 Location: Santa Barbara, CA. Posts: 271	Re: Need to bypass the heater core That is the way I have it setup right now. I don't think its a problem. __________________ 72 C-10 Stepper 350/TH350 3.73 in the back Edelbrock intake and Carb Hooker Comp Headers 275/60R15 on Rallies

07-13-2010, 09:12 PM	#4
Sinister Between Trucks... Join Date: Mar 2002 Location: Los Angeles, CA. Posts: 3,830	Re: Need to bypass the heater core You could do that or just get some NPT pipe plugs. __________________ Beat it to fit, Paint it to match...

07-13-2010, 09:19 PM	#6
Sinister Between Trucks... Join Date: Mar 2002 Location: Los Angeles, CA. Posts: 3,830	Re: Need to bypass the heater core I got mine at Kragen or Autozone, one of those kind of places. __________________ Beat it to fit, Paint it to match...

07-13-2010, 09:20 PM	#7
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Re: Need to bypass the heater core Thanks for the quick answers guys....I will just bypass it for now and maybe get those plugs as I get around to it. THanks again!!

07-13-2010, 11:38 PM	#8
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	Re: Need to bypass the heater core Pipe plugs are cheap, but they may be even cheaper at Homie, Lowe's, Ace, etc. Since the repair is only temporary, just bypassing the heater core with you existing heater hose is even cheaper still. Sometimes pulling the hose barbs to install plugs can be a real PITA if the are corroded in place. I'd just use the 3/4" hose and then just double clamp it on the 5/8" manifold hose barb. Just be sure you put some kind of anti-seize in the plug threads so you can get them out later, if you go that route. __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche "Never kick a fresh turd on a hot day." Harry S. Truman GUN CONTROL: Never having to say, "I missed you." Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck Last edited by El Jay; 07-14-2010 at 02:33 AM.

07-14-2010, 12:18 AM	#9
JesseH13 AMBITION Join Date: Nov 2009 Location: Fresno Ca Posts: 389	Re: Need to bypass the heater core i didnt even run my hoses to the waterpump at all i just plugged them also Attached Images __________________ 1979 Nova-daily-R.I.P 1976 c10 "daily"- 1968 c10 -project CROOKED68 (PROJECT)

07-14-2010, 08:32 AM	#10
turner15 Registered User Join Date: Jan 2007 Location: Toronto Canada Posts: 265	Re: Need to bypass the heater core Same I just plugged mine at the pump and intake. Got some nice chrome ones so it even looks good.

07-14-2010, 09:40 PM	#11
tk-mpl Registered User Join Date: Jan 2008 Location: Lacombe, Alberta Posts: 353	Re: Need to bypass the heater core I was kind of wondering the same thing, but mine is a 5.3L.... I don't have the heater box back in it yet and would also like to bypass or plug the outlets on the water pump. __________________ 1968 short box stepside. 2007 5.3L 4L60, tuned w/EFI Live 2005 Silverado bucket seats. Dominator 2600's all around. Porterbuilt tubular control arms. Magnaflow 3" dual exhaust.

07-15-2010, 12:22 PM	#13
69c10step Registered User Join Date: Mar 2007 Location: Carroll County, MD Posts: 165	Re: Need to bypass the heater core What size are the plugs for the intake & water pump? __________________ '69 short step with dreams of being a hot rod You only need two tools in life - WD-40 and Duct Tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape.

07-15-2010, 01:08 PM	#15
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Re: Need to bypass the heater core Not sure what has been said from someone about bypassing the thermostat...I went with the larger hose straight from the output of the engine right back into the engine...I am a newbie (and like most newbies don't understand everything) but I have only bypassed the heater core and nothing else. Started up and no leaks as of yet. I have a lot on my "plate" right now (son got his license and took over my daily driver, I am in school full-time, have a job as well) so I just needed the quickest fix I could use for now....plus I live in HELL HOT Georgia and don't need the heater core right now. I just hope I did the right thing for now



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