Heater Problem

[KRBENS]

I Have A 96 Chevy S-10 Blazer And When I Turn The Heater On It Blows But The Problem Is That It Only Blows Cold Air - No Heat. Can Some One Give Me Some Advice On The Problem Please. I am not getting any Steam coming from the vents no water on the floor board under the dash

[tableman]

when your engine is cooled down, check the level of your antifreeze in your rad, not your reservoir. If level is down fill it up, and then run the engine without the cap of a while to get any air bubbles trap in the system out. Feel that you hoses running to your heater core are getting hot, they should get hot enough that it is uncomfortable to hold them. If that is not it, then there is something wrong with the temperature control mechanism.

[BlazerLT]

Originally Posted by KRBENS

I Have A 96 Chevy S-10 Blazer And When I Turn The Heater On It Blows But The Problem Is That It Only Blows Cold Air - No Heat. Can Some One Give Me Some Advice On The Problem Please. I am not getting any Steam coming from the vents no water on the floor board under the dash

Go and get your cooling system reverse flushed and your coolant replaced if you have never done it.

Your heater core is plugged.

You can tell this by feeling both of the hoses going to the heater core through the engine bay.

One will be hot and the other cold or cool which means that coolant is not flowing through it.

[Heli]

Your heater core may not be plugged. TYHe heater core on the blazers is above the engine it is the highest point in the cooling sysyem. You probably have an air pocket in the system as described above. I've had this same problem for a while. Didn't know it because the weather was warm and I wasn't using the heater. Filled the system and bled the heater core by removing the hoses and filling the system from the top.

Unfortunatly this same problem happened again 1 wk later. Found out the intake gaskets were faulty. I removed the intake and changed the gaskets. Problem fixed . No more coolant loss, and always have heat.

Regards,
Heli

[doug tiemeyer]

Had the same problem with my blazer.
As heli stated , the heater core is above the engine so it's difficullt to blead.I ended up parking it on a hill so the radiator core was even or below engine level and let it run with the cap off. Hope this helps.

[BlazerLT]

The system is pressureized.

You don't have to bleed it.

Replace the rad cap with a new "NON ACDELCO: rad cap and it will force the air out of the system.

[rlith]

Originally Posted by BlazerLT

The system is pressureized.

You don't have to bleed it.

Replace the rad cap with a new "NON ACDELCO: rad cap and it will force the air out of the system.

Untrue... Air pockets can easily develop inside our engines. Try rebuilding an entire motor with nothing in it... You have to unplug the block (usually by the temp sensor) to bleed it out. New heater core will not automatically purge itself of air...Again, air pockets can develope.

[BlazerLT]

Originally Posted by rlith

Untrue... Air pockets can easily develop inside our engines. Try rebuilding an entire motor with nothing in it... You have to unplug the block (usually by the temp sensor) to bleed it out. New heater core will not automatically purge itself of air...Again, air pockets can develope.

My heater core had air in it caused by a defective stock Ac-Delco rad cap.

I reinstalled a new non ac-delco cap, filled up the overflow tank to its proper level and took it for a drive. When I got back, the tank was borderline empty. I refilled it a couple times and the system bled itself and filled up the heater core and I have never had a problem since.

[rlith]

Again, read my post, they CAN delvelop. The solution is not necessarily just replacing the cap. The stock caps are fine. Proper bleeding of the system is always needed for any system involving fluids. The only reason the fuel system doesn't need bled is because it's open at the throttlebody making self purging. (try bleeding out a diesel system oneday). Any enclosed system needs bleeding. (brakes, power steering, cooling, etc)

[BlazerLT]

Originally Posted by rlith

Again, read my post, they CAN delvelop. The solution is not necessarily just replacing the cap. The stock caps are fine. Proper bleeding of the system is always needed for any system involving fluids. The only reason the fuel system doesn't need bled is because it's open at the throttlebody making self purging. (try bleeding out a diesel system oneday). Any enclosed system needs bleeding. (brakes, power steering, cooling, etc)

AGAIN READ MY POST!

Seeing you are saying the stock caps are fine just shows you how much you know on this situation. The fibrous rubber gasket on the AC Delco cap is flawed and is know industry wide to cause the Dexcool Sludging problem due to allowing air into the system.

When you turn off the truck and it cools, it draws air into the rad instead of drawing in coolant from the tank.

Don't question what I friggin said because it isn't theory, I DID IT TO MY TRUCK! AND IT WORKED!

Here is an article if you need more proof:

http://www.imcool.com/articles/antif...l-macs2001.htm

[coketrash]

Originally Posted by BlazerLT

AGAIN READ MY POST!

Seeing you are saying the stock caps are fine just shows you how much you know on this situation. The fibrous rubber gasket on the AC Delco cap is flawed and is know industry wide to cause the Dexcool Sludging problem due to allowing air into the system.

When you turn off the truck and it cools, it draws air into the rad instead of drawing in coolant from the tank.

Don't question what I friggin said because it isn't theory, I DID IT TO MY TRUCK! AND IT WORKED!

Here is an article if you need more proof:

http://www.imcool.com/articles/antif...l-macs2001.htm

Again, here I am looking for anything I missed in my 40 some odd years of building engines, big and small, and in between. The rule of thumb, and common knowledge in any repair shop worth it`s reputation, is that, for any reason should coolant be needed to bring the level in the radiator back to full in a pressurized system, the air, MUST, be bled off. Not via the expansion tank, but by actually bleeding the air from the block, and most importantly the heater core. The bleed procedure LT described will work, but while it`s working the heads and block are being cooled by air pockets that are trapped in the closed system. Too big of a risk to take, when proper bleeding is so easy, and quick. Remember the plastic tank you add fluid to is an expansion tank, not a recovery or over flow tank. As for the a/c cap being flawed, if so replace it w/ an aftermarket. BUT BLEED YOUR SYSTEM

[BlazerLT]

It is a recovery tank and is where my rad draws in coolant when the system is cooling and retracting.

This is what is causing the many overheating and air pocket problems with the 15psi system we all have in our blazers.

The stock AC Delco cap has been known to have a poor fibrous rubber gasket that will fail and harden over time.

When this occurs, it will suck in air through the defective seal instead of recovery the coolant is needs during contraction.

This is where my problem with my Blazer was occuring 3 or so months ago. All that was required was a new cap (not from the dealer) and the system replenished itself.

Also, with a defective rad cap seal, 15psi pressure will not be maintained seeing the pressure is there to counteract the boiling point of the coolant.

With the pressure not being maintained, the coolants boiling point will dimish quite significantly and can often be seen as high than normal running temperatures over 210.

[coketrash]

Originally Posted by BlazerLT

It is a recovery tank and is where my rad draws in coolant when the system is cooling and retracting.

This is what is causing the many overheating and air pocket problems with the 15psi system we all have in our blazers.

The stock AC Delco cap has been known to have a poor fibrous rubber gasket that will fail and harden over time.

When this occurs, it will suck in air through the defective seal instead of recovery the coolant is needs during contraction.

This is where my problem with my Blazer was occuring 3 or so months ago. All that was required was a new cap (not from the dealer) and the system replenished itself.

Also, with a defective rad cap seal, 15psi pressure will not be maintained seeing the pressure is there to counteract the boiling point of the coolant.

With the pressure not being maintained, the coolants boiling point will dimish quite significantly and can often be seen as high than normal running temperatures over 210.

Hold on to your hat, here it comes !! I totally understand, and agree w/ your description on the workings of a pressurized system(never implied otherwise) my only issue is your re-fill procedure, it`s only correct in theory, not in practice. While your cooling system is waiting for the expansion tank to replenish the coolant, the entire system is left vulnerable. Manual bleeding, will in less time, avoid hot spots, or worse, heat cracks

[BlazerLT]

Very true, I understand your theory and it is indeed perfectly correct.

I was just suggesting a way for the system to do it itself which in some cases can be the simplest and easiest way.

For minor things such as the gurgling heater core, the bleeding doesn't really need to be done, the cooling system will force the are out by displacement.

But that is only my way of doing things.

People have other methods which are perfectly fine too.

All is good.

[Mikado14]

If using straight water, the boiling point of the water with a 15 psi cap would be 249 or 250 degrees F. Just in case anyone was interested. And that is at sea level.