very little heat front/rear

[braddaddy]

I had different shops look into this back in spring.... They flushed radiator (2x), replaced thermostat (2x),...checked core hoses...said everything was good and had heat on and it was nice and warm...I told them it wont be once temps drop into the 30's... --I had the time and funds to have them look it over so it would be ready for winter.
Well its cold out and the heat is the same....very little at both the front and rear.

 

[Bowesmobile]

Its either the blend doors or its the heater cores. This has been gone over many times here. I have to flush my cooling system again because a vane from the water pump disintegrated and clogged my heater cores. When you flush them, use either white vinegar or buy a heater core flush from a parts store. Then hose them out really well. Both in normal water flow and reverse of flow. If that doesn't work make sure the heater core lines are not blocked at the connection to the engine. If that doesn't work, then replace the heater cores with new ones.

 

[braddaddy]

So how does one verify whether or not its the blend doors?

I thought it was not the core because it happened at the same time and the level of heat front and rear is the same.... but dont the front and rear each have their own core??

 

[Bowesmobile]

Front and rear have their own cores. They are fed from the same plumbing. If you pop your hood and look on the passengers side. There's a rubber hose "T" that comes from the engine and feed the heater core for the front on the firewall. Then two lines go to the bottom of the engine compartment and run to the rear heater core, under the vehicle. The disconnect is a white nylon clip inside of a black circular housing. You have to depress both side of the clip to release it from the male connector. The you can take a garden hose and use the pressure to flush the system out. Just be sure to add some antifreeze to the de-gas bottle on the drivers side when you're done. That will mix with the water you used to flush the system and make sure nothing freezes or boils.

To verify the blend doors are working you can try and take apart the dash around where the doors are located. Then watch them operate. Or you can actuate them and feel colder air and warmer air. They are not easy to get to.

 

[jbanks]

Am I mistaken or, are there some check valves somewhere in the system under the hood? Maybe one of them is stuck? or gunked up?

 

[braddaddy]

Ill be checking the cores this week....

My "T" in the lines do not have the type of quick connect the manual shows. My "T" has black plastic between the hoses.

Not sure if they remove the same...I tried pinching and there really wasnt anything to pinch.

 

[braddaddy]

IDK.... The more I think about it the more things do and yet don't make sense...

1- I cant believe its the blend doors... because both front and rear heat is the same...luke warm. I cant believe both blend doors are bad at the same time and resulting in the same temp--luke warm...I would think one (front or rear heat) would be different from the other.

2- The core issue makes sense... but it looks like both cores are fed separately....coolant doesn't run into the front core THEN into the rear core. It looks like the coolant lines "T" before the front core....so coolant runs separately in and out of the 2 cores....parallel...not in series....right?

3- My temp gauge inside the truck sits right in the middle where it should be...but my hoses are lukewarm / hot ....but i can hold them all day after driving for over an hour....not hot as in "ok these are hot I better let go now"...more like "ok these hoses are nice and warm".

4- There is no pressure build-up...I can squeeze the upper hose with little resistance...when I let go I can hear/feel little bit of surge. Like my t-stat is always open--not allowing pressure to build-up. I have replaced the t-stat 3 times. once myself and 2x at 2 different shops.

5- Thought maybe water pump impellers were worn off....but wouldnt I overheat? Took a 5200 mile trip 2 years ago from Illinois across country to Utah down into AZ/NM/TX and back to Il....In July (still had same low heat issue then) and never had any over heating issues.

I had the Expy in pepboys and they said they flushed the cores...I didnt see it...so I cant be sure...of course it was warm out and they said heat was fine...which it is until temps drop. The colder it is, the less heat...not cold then hot while driving which would be low coolant.

Ill try flushing the cores but I think Im chasing the wrong rabbit.

 

[braddaddy]

I just went out after the truck had been running for an hour and opened the coolant cap...it fizzed like opening a 2liter bottle of pop and that was it.... upper hose was then way easy to pinch closed so I am getting pressure but not the pressure I would think I need.

I should have 16lbs pressure at that cap....I know I dont....

I think I will try to install a gauge in the upper hose to see what kinda pressure I am building up. Maybe using a tee in the upper hose and a gauge in the middle. I still have the old cap....I might tap the top and put the gauge there.

 

[JOEY5.4]

my 98 navigator does a similar thing i notice thought it only happens when my heater control is on automatic so i belive that the blend door from hot to cold is the colprate in my case bolth of my front and rear temps are the same also but only get lukle warm on automatic if i leave it on heat and vent after a startup or two it tends to make heat like a pizza oven.

 

[JUST4FUN]

what brand T STAT are you using? if its stant replace with motorcraft

 

[braddaddy]

Im not sure what brand.... this is my 3rd one in there .... Ill replace it again with a motorcraft.

 

[stamp11127]

Before throwing more parts at it do this simple test.
1) Warm up the engine to normal operating temp
2) Feel how hot both heater hoses are under the hood

If they are both cold there isn't flow through the core. If one is hot and the other colder the core may be plugged or the restriction valve is blocked.

Is there rust in the cooling system?

Also burp your cooling system to remove air pockets.
What ratio was used with the coolant? This isn't the problem but never hurts to know. Tap water, distilled or premix?

Those clips holding the heater hoses on have always been a ***** for me - even with the tool to release them. If you think the cores are clogged an "easy" test is to remove the heater hoses and run water through the core. Logically if the front core is plugged so is the rear one. Dorman makes replacement connectors to make up a water feed line.

How many miles on the engine? Other than throwing parts at it, has any maintenance been done on the cooling system in the past? Has any stop leak type of product been dumped in?

 

[bigfry]

Not to highjack the thread, but this is exactly what I came on here tonight looking for myself. Thanks for the tips so far.

 

[braddaddy]

I bought the '02 used so I dont know about previous radiator repairs or additives....
180K miles....

Warmer today and my upper hose and 2 core hoses are hotter than on colder days....I couldnt hold them for long bare handed. Also the hoses seemed to have higher pressure inside inside.

these hoses are always the same temp in relation to each other.....just cooler when its colder outside and hotter when its warmer outside.....which of-course allows my heat to be warmer when its warm out and cooler when its cold out

I had 2 different shops look at it and of course they say what they find is ok...but I had it in the shops in late spring when the heat "felt" normal due to it being warm outside.

They both did rad flush and replaced tstat and said they flushed core and checked water pump.

Its directly related to the outside temp....the colder it gets outside the less heat I have inside.

 

[stamp11127]

Since both hoses are "too hot to handle" then the core probably isn't clogged. I would move on to a flow test of the feed and return ports on the engine. With the heater hoses disconnected you will be able to see if there is a buildup of junk inside the hose.

What temp tstats have they been using? When changing the tstat are you placing the little hole in it towards the fan side? When I changed my water pump & rad, I parked on an incline with the radiator being the highest point. Then bled the usual way.

Once the engine is warmed up the heater hoses shouldn't change temp in relation to the outside temp. This could indicate a flow problem.

 

[braddaddy]

Yes Im thinking low flow /blockage also....

Yesterday after driving the Expy I turned it off and started looking for the fan motor resistor and I could hear gurgling coming from the heater core area under the passenger side dash.... And thats right away after turning off ignition, getting out and walking over to passenger side, opening door, turning on phone flashlight and sticking my head under the dash.

 

[mjlcobra]

I joined this forum after lurking for the past year specifically to reply to this post. I also had NO heat or defrost for over a year. I bought the truck in July of 2012 and found out the hard way I had no heat (around November). I did hours and hours of research to decide that surely my heater core was bad. I ran water via a garden hose through the core in/outlets followed by compressed air. I noticed that "not much" water was going in before it began to come out. I determined that my core must be severely plugged. I roughed it out through the Indiana winter determined to change the core when it warmed up. I waited until last month and finally tackled it! There's a nice youtube video that covers about 85% of the job. Man was I excited once it was all back together with only 2 extra screws (out of probably 80 or so - I'll take it)... Well, I still didn't have heat. I did everything as directed to bleed the system properly. Hmmm well I ran a flush and that didn't fix it, so I know I didn't have huge deposits in there. I pulled the inlet hose off and started the truck. Nothing. I determined that my water pump must be bad. Mind you, I had NO coolant leaks OR overheating. I wish I had saved the picture, but the fins on my old pump WERE INEXISTENT, and the impeller was literally as thick as maybe... 3 sheets of notebook paper. Changed the water pump and once burped free of air I have awesome heat. Not to mention, my passenger side head gasket leak DISAPPEARED. I have a 4.6 Windsor and had planned on doing the head gaskets but decided it wasn't worth the money for the. $4000 I bought the truck for (109,500 mi - 120,000 now). It's been a month since doing this, the oil was changed and has the full six quarts. I've not lost a drop on my garage floor and the familiar burning smell / smoke cloud is GONE. I know this post was cumbersome, but if wanted to achieve a lot of information on one shot. I hope this helps at least one person because I found exactly zero people with this experience online! Good luck and PM me or email me with questions (anyone).

 

[stamp11127]

And that is why we flow test not only the core but the supply to it.

 

[mjlcobra]

I agree with ya, stamp. This was definitely a learning experience, which is why I wanted to share my story. I never thought to test the flow until the new core didn't fix it. I had my mind made up that my core was blocked. The HG oil leak was not there when I bought the truck. I incorrectly assumed that the car lot I bought it from put a stop leak as a band aid to hide the leak and sell the car. I had no leak until my 3rd week owning the truck. I also theorized that the previous owner was informed of the "head gasket oil leak" and only heard "head gasket leak" and dropped a bottle of bars leaks or something similar to the cooling system and it settled in the core. I mean, with theories like this and self-convincing... I made myself believe it! I had no idea that a water pump could properly cool the engine and still have insufficient flow! Again, I truly hope my experiences save someone else's precious time. Unfortunately as a weekend warrior, I am forced to follow my gut or the oh-so-wrong concept of throwing parts at it.

 

[IMINYOURCHAIR]

the quick connects on the heater core lines. I would and did replace mine with the screw clamps. they are much easier to remove and they do not leak. Good to see you all fixed it. but I do agree that it's a good idea to first check that the water pump is indeed pumping before going to the measure of removing the dash.