Need more heat

[dyeager535]

Correct except the part where you said that the waterpump line is return.

The water pump and or (I say and because you can try t'ing them together for more flow!) intake lines are your IN to the heater core.

There are two answers to the above I suspect...A) it's incorrect, or B) it depends on the water pump. I suspect it's B.

The water pump fitting I have is "in" the flow of the impeller, and looks like it probably enters in BEHIND the impeller. It's not past the pump where pressure is built. I've hooked mine up to the pump, and heat was non-existent. I *believe* there are water pumps with the fittings in a different location, but mine faces the passenger side of the truck.

The OP needs to check engine temp first, which it sounds like he is doing. Could be a 160* for all he knows!

 

[CHEVYDADDY]

Update not good heat?

OK... UPDATE... so i am running a 85 k5 350 .40 and was not getting good heat. let it warm up about 15 mins and have ok luke warm in cab but not good hot turn the heater down heat. so i tryed a trip about a hour one way mostly high way running 65-75 mph and feet were cold, when foot is on the skinny pedal i had light cold air flowing let off and very little not so warm are was blowing with fan on high, feet still could..... so i picked up a new t-stat(195 deg) and gasket and put them in to day... drum roll.... well u guess it still warm air blowing but not what it could be? more warmer air coming out on the feet but not good heat. and still when foot is on the pedal there it a cold breeze coming throught the floor seem to be close to the center right behind the shifter?

t-stat new
radiator flushed welded and painted (came in the deal) almost new 1 row alum radiator
heater core new
water pump ???? on the motor when i got it
top heater core hose starts at front of intake
bottom dumps stright to radiator
all lines in and out are HOT not warm but hot!

 

[jonathon]

How do the hoses feel going into the heater core? If the inlet side is hot and the outlet less so to the touch, your good.. if one's hot and one's cold you've got a clogged heatercore..

If the heatercore is getting "hot" coolant, and you aren't getting heat, I'd be looking at the flaps to make sure it's not taking in cold air with the hot air. Might also check and make sure you don't have anything plugging up your vents..

Does your blower blow good?

 

[dyeager535]

X2. Air should always be at least warm coming out of the vents, assuming the flapper door/vent control is working right, and you don't have major leakage there from the foam on the flapper door failing. But even with bad foam I don't think the air would be cold, assuming some of it's coming from the heater core.

 

[CHEVYDADDY]

How do the hoses feel going into the heater core? If the inlet side is hot and the outlet less so to the touch, your good.. if one's hot and one's cold you've got a clogged heatercore..

If the heatercore is getting "hot" coolant, and you aren't getting heat, I'd be looking at the flaps to make sure it's not taking in cold air with the hot air. Might also check and make sure you don't have anything plugging up your vents..

Does your blower blow good?

blower well it does ok but i thinking it could do better?
all 4 rubber hose heater core and radiator are all hot!

back to the flaps i to0k the glove box out and only could move the flap door a hair so do think i can get any adjustment out of it?

 

[CHEVYDADDY]

X2. Air should always be at least warm coming out of the vents, assuming the flapper door/vent control is working right, and you don't have major leakage there from the foam on the flapper door failing. But even with bad foam I don't think the air would be cold, assuming some of it's coming from the heater core.

not sure so today task is to take the bottom vent out(heater core) and check it agian and look over the door and check it better.

one side note where the lower vent meets the upper vent system middle of dash behind the shifter there is about 1-1/2 gap in the two vents so there not touching?

 

[smalltruckbigcid]

To help some people out with flow on a first gen sb, attaching you heater hose to the water pump makes that hose the return because the flow is through the pump and into the block. Remember the lower hose feeds cool water into the block.

From what the OP has stated it sounds a lot like either a partially blocked core or an airflow problem in the heater box itself.

Forgot to add. Some engines came with a flow restrictor outlet on the manifold fitting. Drill that out to full size for better water flow

 

[CHEVYDADDY]

To help some people out with flow on a first gen sb, attaching you heater hose to the water pump makes that hose the return because the flow is through the pump and into the block. Remember the lower hose feeds cool water into the block.

From what the OP has stated it sounds a lot like either a partially blocked core or an airflow problem in the heater box itself.

Forgot to add. Some engines came with a flow restrictor outlet on the manifold fitting. Drill that out to full size for better water flow

ok so are you saying to plug the radiator and route the lower heater core hose in to the pump? im going to look at the heater box and check the doors but would that be a next choice?

 

[dyeager535]

What he's saying (pardon my intrusion) is that if you have a hose to the water pump and the radiator, you'd have no "hot", highly pressurized water source. Pump moves cold water into the block from the radiator, the fitting on the passenger side of the water pump (typical) will be very low pressure, with little heat. Unlike the fitting on the intake, which is about as hot as you can get the coolant, and under high pressure.

Coolant moves through the heater core by the differential in pressure between the engine block and the radiator.

 

[CHEVYDADDY]

What he's saying (pardon my intrusion) is that if you have a hose to the water pump and the radiator, you'd have no "hot", highly pressurized water source. Pump moves cold water into the block from the radiator, the fitting on the passenger side of the water pump (typical) will be very low pressure, with little heat. Unlike the fitting on the intake, which is about as hot as you can get the coolant, and under high pressure.

Coolant moves through the heater core by the differential in pressure between the engine block and the radiator.

ok got ya both but... i have the top heater hose coming out of the intake to the heater core then the lower return hose is going stright to the radiator. my line do not use the water pump at all???

 

[dyeager535]

Thats right. No line to the water pump in MOST instances. You could theoretically have the water pump as the return line, but you still need the intake for the hot, pressurized water.

But the return isn't the issue unless it's simply not flowing due to a restriction in the line.

 

[CHEVYDADDY]

Thats right. No line to the water pump in MOST instances. You could theoretically have the water pump as the return line, but you still need the intake for the hot, pressurized water.

But the return isn't the issue unless it's simply not flowing due to a restriction in the line.

no i got flow when u take the top off if following good.

 

[dyeager535]

If the coolant is flowing, either its not hot enough, and/or your heater door isn't working right.

 

[smalltruckbigcid]

Heater repair tip#1 How or what to use to seal air gaps. If you use the stuff the automotive stores sell you'll pay by the inch for it. But go to the hardware store and buy the stuff that looks like modeling clay that electricians use. Pretty close to the same stuff and way cheaper plus you get a lot more for the money. Roll a ball of it in your hands to make a rope out of it and you have a new gasket to seal the box to the firewall

 

[Metrodps]

one side note where the lower vent meets the upper vent system middle of dash behind the shifter there is about 1-1/2 gap in the two vents so there not touching?

Gm used this type on the ducts when it was new to help seal them. It looks like home weather strip. As stated in post above the the other stuff for the metal and box seal area. http://coloradok5.com/forums/showpost.php?p=2407426&postcount=34

 

[4xcrazy]

ok got ya both but... i have the top heater hose coming out of the intake to the heater core then the lower return hose is going stright to the radiator. my line do not use the water pump at all???

this is the way i have mine hooked up on the Burb, and i have excellent/too much heat at times...although, and i have a feeling this is where your problem is,,,,i ONLY have heat when i have it set to the middle dash vents...

If i set the controls to defroster or floor heat, the heat goes cold.

i haven't gotten into why this happens, obviously a vent door mixture/movement problem, but i have heat, and very little use for defrosters here in Arizona, so not a big deal for me.

again, sounds to me like you have blend door movement issues.

 

[CHEVYDADDY]

AC causing heat isseus?

Hey heres a question i have not give any thought to when doing my motor swap i took my AC pump out and the condenser and extra rubber hoses and the ac radiator(small one in front of the radiator) and to night i took the my dash pad off and i see a ac core (i guess) in the middle upper part of my dash? i say im getting cold air when foot is on padel so does this have anything to do with the cold air?

 

[bigjohn79]

If your inlet and outlet hoses at your heater core are HOT, then the problem is not in your "hose routing". You for sure have a problem inside the truck.

 

[muddybuddy]

what t-stats is everyone using? i thought i swapped in a 180*, but whenever i drive the truck a bunch, it never gets over ~160. is that warm enough to get good heat? i think my blower relay is bad cuz nothing is working (no a/c, no defrost, no heat), but i just wanted to see what t-stat everyones' running, cuz im pretty sure they got 195* stock

 

[CHEVYDADDY]

Yes stock is 195 but u can run any temp u want i ran 160 in the summer on other trucks. but from what i hear 195 is the winter t-stat to go with! 180 is ok some times but alot of people will tel u 195 in the winter.