Chev 1989 4x4 heater core hose connections ?

Inline..............

Yep, that's it.

It pumps from the back of the intake manifold thru the heater core to the rad, then thru the waterpump back to the engine. It's a "thermostat bypass" if you will.

See above. It is circulating, just not in the volume it would be if the t-stat was open.

1. Is the truck reaching correct operating temp?

1. Yank both hoses and verify they aren't plugged or collapsed internally.

2. Check the heater blend door function to see if it's allowing air to be passed over the heater core.

Doc

Hi

Im not sure what you are saying with "inline..."

Ahh i forgot about the bottom rad hose :)

The temp is going up to about 95 C (203F) and down to about

75 C (167F) or something like that . Its not going up above 100C ever . I think the winter thermostat i put in was rated at 198 F or so .

By the way it is now about -25C (-13F) where i am !!!

That heater door blender thing is a real bugger to get at. I had my dash half apart and i still could see what was going on. I may have to take it apart again.

I will have a look at the hoses and see if they are blocked etc.

thanks for the info

argos

Your heater hose routing sounds right. On my 92 K 1500 (350 engine) the heater hose runs from the rear of the intake to the heater core. The other heater hose runs from the heater core to the right hand tank of the radiator. If your truck gets to operating temp, then the heater hoses should be hot to the touch. Is your truck running somewhere between 180 F to 200 F when its at operating temperature?

If the heater does not work righ there are a few things to check. One iis the heater core which you replaced, the other is the thermostat which you replaced. So assuming the thermostat is working correctly and both heater hoses are hot to the touch when the truck is warm... I would think that you need to make sure the truck is full of collant and if so then my guess is that you have a problem in the cab with the temp door (which is part of your A/C -heater duct work.

What is the normal running temp of the truck?? and is the radiator full? I'm also assuming this is a gas engine...

There are no valves on the heater hoses on this truck, and the heater hoses should be of similar temp. as your radiator hoses...when truck is at operating temp. the hoses should be fairly warm to hot to touch.

Hi

thaks for the reply.

i think my truck is running around the temp that you describe. around 175-202 F it starting to sound like i might have to take the dash apart and find that heater duct etc. I REALLY dont want to do that :) yes this is a gas engine. its full of coolant too. i had to add lots when i was fooling around with the thermostat and core, but i topped it up after a few times.

one thing that i have noticed is that my heater core hoses are not as hot as my top rad hose gets.

the heater hoses get pretty hot, but the top rad hose gets so hot you cant even grab it with your bare hand . the heater ones i can easily grab and hold onto. so maybe my heater hoses are blocked a little ?

i might unhook the heater hose fromt he end connected tot he rad and start the truck and see what comes out, into a bucket. Im assuming it should just shook out of there like crazy ?

Do you think it could be affected if the heater core is not seated exactly right insite it's panel ? I had a real hard time getting that panel back on, and im wondering if the core is letting some air around it ?

thanks argos

Inline.......................

They should be just as hot. Like I said remove the hoses and check for obstruction.

Sounds like a strong possibility.

BAD idea. Just take the damn hoses off, hold one end up to a light and the other to your eye.

The heaters in these trucks are so powerful that even a missing panel would still heat the truck up. Did you check to see if the core is getting hot after replacing it?

Doc

ok i will check the hoses for obstruction.

i didnt check to see if the core was getting hot. but im guessing that its getting about as hot as the hose coming out of it . which isnt terribly hot.

so if my hoses arent blocked, maybemy heater vent is not closing properly etc, and its letting outside air mix with the hot air.

Is it possible that my water pump is not working well and causing this problem ?

thanks argos

I would look and make sure your issues under the hood were correct before you mess with the dash. The simple answer is that both heater hoses should be pretty much hot to the touch just like the radiator hoses... THere really should be no real difference in the temp of these hoses.

Did your heater just stop working all of a sudden...has anyone done any work to the engine (like change the intake gaskets or heater hose fitting on the intake)?

If you don't have hot water running to the heater core you will not get heat no matter what else happens.

If both heater hoses are hot with the truck is at operating temp. then look for the problem in the cab, if the heater hoses are not "hot" then you have a problem under the hood.

I think if you managed to get the heater core back in thet truck and hook up the hoses you should be ok.

THe heater hoses have to be hot...so at this point I would say you have a restriction somewhere ...most likely on the intake or heater hose fitting.

These trucks do not have a heater control valve so there should be no prolem with the circulation of coolant. Is the radiator in good shape? no sludge or crap in it?

Another guess at this point would be to look at the heater hose fitting on the rear of the intake....those things are a real pain in the ass to replace. I removed my OEM heater hose and fitting and replaced mine with a lenght of regular heater hose and a "old style" heater hose fitting. I had an intake coolant leak and changed the hoste becasue the one on the truck at the time was the originial and needed replacement.

I don't know what year they started using the molded heater hose with the metal end, along with the special "reciever / female" type fitting on the intake, but those things suck.

Inline..........

Pay close attention to the inlet hose where it attaches to the intake manifold, and for god sakes be careful removing it so you don't fubar the connecting mechanism. If you have to really tug, you're doing it wrong. Push in the two tangs and it should pop right out. Make sure the engine is cold before doing this. Also make sure the inlet at the rad isn't partially blocked thereby restricting flow.

If the WP was crapping out you'd most likely have an overheating engine.

Doc

IIRC they started in 87', my 88' has one, and I'm pretty sure his 89' will have one as well. And yes, they do suck!

Doc

Hey I''m tearing down my 88 4.3 Blazer engine.I noticed mine has that metal tube on the intake connected to the heater hose,whats the purpose of it?My best bet would be use it for a handle to pull intake,and do what you did replace it with a brass fitting.Good info! Another piece of crap out of the way!Later Bobby

from the back of the engine there is an aluminum tube and the rubber hose is clamped to that, and the hose goes into the heater core. i will be carefull ..

good point baout the WP, the engine is not overheating , so it must be working .

arogs

ok i will drive it around and take a closer look at the temp of the heater core hoses.

never had much heat in the truck since i got it. but the engine was replace just before that.

i have the scraped knuckles to show for getting the bugger back in :)

Rad is only 2-3 years old. When i emptied out the old heater core i didnt see and crap coming out of it .

yeah i was considering just replaceing both hoses, since that should be easy compared to what i have done so far .

i dont think i have this but im not sure, i will have to have a look.

thanks for the info argos

is it possible that the metal part that connect to the engine is clogged. someone told me that , that would be unlikely.

obviously i havent had a chance yet to try out all of your ideas, but im going to asap.

thanks argos

Put a large piece of Paper in front of the RAD, and Run it.. SEE if the Heater starts putting out HEAT better !! if So.. Change the Themosstat

argos argos wrote:

hi

that's a good idea, ill try that.

However, i see now that my temp is not going up above about 165F. Is it possible that my brand new thermostat stopped working after a week ?

the temp was going up to 200 and then down to 160-170 when i first put it in. Now its going to 165 and staying there. It was about -30C here yesterday , but it shoudl still go up to 200 i think, it didnt even go there when parked.

I re-checked my heater hoses and the one going in is very hot like the top rad hose, and the one coming out of heater core is definately less hot.

the other thigni noticed is that my top rad hose was very hot even though the temp never went high enough to open the thermostat. this leads me to beleive that my thermostat is stuck open ?

thanks argos

You have air in the system most likely. Did you burp it after swapping the heater core and thermostat? Have you yanked the hoses yet and checked for obstruction?

Doc

Crap in your cooling System is Getting in between the Valve that closes when your Water temp get too low.

Also Does your Clutch Fan turn off ? Clutch Fan cud be ON all the Time... ( FAN ROARS all the time)

Inline.............

VERY unlikely. The t-stat piston comes down HARD with the spring dude.....................

Now that is a possibility, BUT his hoses would not be getting hot. He has a hot inlet and a cool outlet with a NEW heater core. This means two things:

1. Outlet hose is clogged or partially restricted somewhere between the core and rad

OR

1. Massive amounts of air in the system that needs to be purged.

Quit confusing the poor guy.

Doc

No Really.. The spring Is Strong, But Crud gets lodged also!

I never saw him Mention a Heater Core outlet being cool, and Outlet Being Cool..

Which is IMPOSSIBLE with todays Heater Cores. THERE IS NO WATER SHUTOFF in the Heater Water FLO these Days, EVEN if a Core Gets plugged up.. Take one apart and you will See how it works.. The INLET and The OUTlet ARENOT on oposite Sides of The Core !! There used to be a Shut off Valve in the 50' & 60's They now use a Flapper to Redirect the Air

This means two things:

Then He needs to Replace the RAD CAP,, Rad Cap Releases this So Called AIR.. into the overflow tank.

Doc ..

I was more in likely repairing Vehicles Before you were out of Diapers.