thanks to the replys about which heater core i needed.
i bought the heavy duty one and it seemed to fit ok.
Unfortunately i still dont have much heat.
I have more but not enough.
I changed my thermostat and it is operating correctly.
I have a question abotu the hoses .
Apparently my truck does not have the original engine and
i am geting suspicious about whether it was put together correctly.
When i run the truck my heater core hoses both seem to get warm.
They dont seem to get red hot though.
Anyway, there is one hose coming fro the back of the engine into the heater
core. The other hose comes from the heater core and goes into the
top of the rad .
There does not appear to be any valves etc on the heater core hoses.
Does this sound like it is setup right ?
It seems to me that if my thermostat is closed , then how is fluid suppossed
to go from my engine and through the heater core and then back into the rad.
Wouldnt it have trouble going into the rad, if the thermostat is closed ?
i think that if the thermostat is closed nothing is circulating through
the rad , and i dont see how output from the heater core could enter the rad.
any advice ?
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?
2. Yank both hoses and verify they aren't plugged or collapsed internally.
3. Check the heater blend door function to see if it's allowing air to be
passed over the heater core.
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
On Mon, 24 Jan 2005 16:52:41 GMT, email@example.com (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.
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
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 ?
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 ?
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.
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 .
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
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
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
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.
On Tue, 25 Jan 2005 13:50:09 GMT, firstname.lastname@example.org (argos)
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
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.
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 ?
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)
VERY unlikely. The t-stat piston comes down HARD with the spring
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
2. Massive amounts of air in the system that needs to be purged.
Quit confusing the poor guy.
No Really.. The spring Is Strong, But Crud gets lodged also!
I never saw him Mention a Heater Core outlet being cool, and Outlet
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.
I was more in likely repairing Vehicles Before you were out of Diapers.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.