heater cold.

[farmerchris]

x 2 on the intake gaskets, did you make sure it match up to the water passage for the t-stat housing.they can slip also and get gasket sealer blocking passages ,especially using rtv

[84burb]

I doubt the wrong intake gasket would cause the heater to quit working. If that were true, you would have other, more obvious problems than the heater. Like water in the oil or a vacuum leak.

5 minutes to get the engine to temp sounds about right.

Getting the heater to work is really pretty basic and has few moving parts.Let's go back to the beginning and see if we can't do a diagnostic and pinpoint your heater problem. Please don't be offended but this is going to get really basic but don't skip a step. I know I sometimes have to backup and start at step one.

The engine cooling system seems to be working correctly. Warming up to temperature and not overheating.

We still haven't confirmed if there is actually coolant circulating through the heater core while the engine is running. (warm, not hot hoses) Or where your hoses are connected. Until we actually know this, everything is just a guess on our part. You have to help us here by being very specific with your answers.
We know the heater core is new and clear.
Did you replace the heater hoses? Are they running clear? No kinks or crud plugs.
Is the hose fitting into the intake clear of blockage/restrictions?

Here's one way to check coolant flow through the entire heater system without disconnecting anything.
If you have the hose connected to the radiator tank it is a simple check. It can even be done while the engine is cold.
Drain enough coolant out to get the level below the heater hose connection on the radiator.
Leaving the cap off, start the engine.
Look into the radiator filler neck and see if you are getting any coolant coming from the heater hose outlet.
There should be a strong stream coming from the heater into the radiator at all times. Even when cold and the heater turned off.
A dribble means a partial blockage and no flow means a complete blockage or the hoses are hooked up incorrectly.

If your return is going to the water pump, it's a little more involved but not as much work as you have already done.. You will need a buddy to help.
Do this while the engine is cold to prevent burns.
Disconnect and plug the w/p heater hose port.
Run the hose from the heater core to the radiator filler neck or a bucket.
Refill the system but leave some room in the radiator for coolant from the heater.
Have your buddy start the engine while you hold the heater hose into the radiator fill or the bucket and watch for coolant flow. (Keep the end of the hose higher than the top of the engine. It should only take a few seconds to see if there is any circulation.

If little or no flow, check each individual item starting at the heater hose connection to the engine. Fitting, hose, core, hose. Eliminate each piece as a problem along the system. If you have a good flow we can move on to other alternatives.

Keep us posted on your progress.

[ncguy89]

ok, to start off with there is coolant flowing through the heater core. i have already checked and confirmed this. the heater hoses are hooked up like this. the top hose coming out of the heater core goes to the water pump, the bottom hose from the heater core goes into the radiator. i put a piece of cardboard big enough to cover half of the radiator down between the radiator and a/c condenser yesterday and drove it to town and back and got a little warmer but still blows cool. just for sh*ts and giggles i put a piece of cardboard in front of the whole radiator and never overheated but heater started blowing warm air but not hot. the heater hoses get warm to the touch but not HOT. the radiator hoses get warm to the touch but not HOT. seems as if the truck is over-cooling. iv been doing automotive work for over 8 years professionally and NEVER seen this problem so this is a learning experience for me.

[bd]

...the top hose coming out of the heater core goes to the water pump, the bottom hose from the heater core goes into the radiator....

I think you just identified your problem.  The heater hose that routes to the water pump should, in fact, connect to the intake manifold.  The way you have it plumbed, the water pump is drawing water through the heater core in the reverse direction from the radiator.

The heater hoses should route this way:  hot water from the 5/8" intake manifold fitting flows to the heater core inlet; the 3/4" return hose flows from the heater core outlet to the radiator.

Cool reverse flow through the heater core may be why the prior core accumulated so much sediment.  Correct the hose routing and your heater will likely drive you out of the cab.

[84burb]

I believe BD is correct.
Your temp gauge says you are running 190-200. Whether the hoses are warm or hot is kind of subjective as is the amount of water flow. What is hot for me may be warm to you. Trust your temp gauge. It sounds like your engine is running at temp.
It's worth a try to re-route your heater hose. It will only cost you time. (and some teflon tape)
If that's not it, we have some other suggestions.

I've been working on cars both professionally and as a hobby for over 50 years. (Yikes... it's been that long?) I still have to back up and tell myself not to assume anything... more often than I care to admit.

[ncguy89]

well the only reason i have not done this yet is because its how my 84 was routed when i bought it and it still runs me out if i set it on LOW. and this is how the hoses were routed before the intake change and it worked before ( routed to the water pump is what i mean). idk i will try that tomarrow and see if i can get anything different.

[thirsty]

Is your blend door working correctly? Maybe it's just pulling in mostly outside air.

[ncguy89]

i took the heater duct apart late last night and everything seems to be working correctly but could be one of them that work right apart but don't work together. so im doing some more investigation on that. ill let ya know what i find.

[zieg85]

To rule out intake gaskets just remove the hose to the heater core from the intake manifold.  If you have a problem the flow will be just a trickle.

[VileZambonie]

You should have the hoses routed as described by BD or to the waterpump and intake but if you have the nipple on the radiator use the radiator.

[ncguy89]

i little update. everything in the heater box is free and moving. still going back and double checking everything. will be working on it a little tomarrow after church.

[ncguy89]

ok guys i got it figured out. BD was correct. i swapped the heater hose going to the water pump to the intake and the heats working fine now. i still do not understand how this past january before i done the intake and carb swap it was routed to the waterpump and working fine and now it didnt. makes no sense but since iv been working on cars have they really ever made sense? NO lol. anyways i appreciate all the help from you guys and glad i got it fixed it was starting to get cold lol.

[VileZambonie]

The old intake didn't have a nipple on it? Maybe your plugged up heater core was heating up because of the restriction.  Either way lesson learned - next time you hear us ask you questions several times (like how your hoses are routed) you'll listen to the experts   Heat is good this time of year

[ncguy89]

as said numerous times in this thread. the heat DID work before the intake swap. and i hooked it back up exactly as it was hooked up before i swapped intakes. why it wouldnt flow afterwards i dont know. but i was not saying anybody was wrong i was just trying to figure out how an intake swap made a difference in the way the coolant flow through the heater core. but after thinking about it i figured it out. anyways your right lesson learnt. thanks for the help!!!