Doug's heater

[vigman]

Lack of heat in cabin
My screen name is "dugr."
I am a member of CAC. I e-mailed you through them.
It's a great web-site. I really enjoy it. The reason I did not post this to CAC was because I was not sure if you would see it or not.

Subject: RE: 94 heater problem
Conversation in progress.

Doug
As far as I can tell, the electronics seem to be working fine.

Mike
Does the AUTO light flash for 60 seconds after fire up of car OR do you get a flashing sys display in the speedo?

Doug
The AUTO light comes on and is constant at fire up.
There is no flashing of anything is the seedo display panel.

Mike
THAT'S GOOD

Doug
I can run the temp up and down. All of the buttons and their lights on the Automatic climate control do what they are supposed to do. However,
I am not getting much heat into the interior.

Mike
Do the lines to the heater core BOTH get hot?

Doug
No. The long one is hot, but the short one that goes to pressure cap area does not get hot, it may be a little warm. -- Does this indicate a plugged
heater core?

Mike
There should be two lines both going back to the engine.. but I'll look in the book tonight
THEY BOTH NEED TO BE HOT! THIS MIGHT INDICATE A PLUGGED HEATER CORE!( or lack of flow )

Mike
What is the condition of the coolant... clean & RED( or green depending of the coolant you use?)

Doug
The coolant is clean & GREEN. Like I said, I just bought this car in December and this is the first Vette I have owned. Is the coolant supposed
to be RED?

Mike
THE NEWER STYLE COOLANT IS RED... BUT IF YOURS IS GREEN DO NOT WORRY OR CHANGE IT.

Mike
Do you know what type of thermostat you have?

Doug
No

Mike
WE MIGHT HAVE TO EXPLORE THIS.


Mike
What's the engine temp?


Doug
Usually, about 190, according to the instrument
gauge. It does go higher if I get stuck in traffic. But, it cools right back down to 190 after I get back to 25 or 35 M.P.H.


Mike
190 SHOULD GIVE YOU SCORCHING HEAT.. BUT THESE VETTES USUALLY RUN AROUND 225-235


Doug
I have read that a door is supposed to open to allow the heat from the heater core to enter the duct work. I am thinking that this door is not
opening all the way. I do get enough heat to defog the windows and take the chill off, but not nearly what I should be getting.

Mike
This is true..if it fails..it will give you an error code......

Doug
I have never seen an error code.

Mike
TURN OFF KEY..FIND ALDL CONNECTOR
(UNDER DASH LOWER THAN YOU KNEE WOULD BE)

To read the CCM
Key Off
Have pen & paper ready
Jump pins a & g in tha ALDL connector
(Top left A bottom right G)
turn key on
This will start the Auto diag of the CCM
The numbers where the speedo lives will give you codes eg C 51 or H 51
(the C means current H means History)
and below there will be another number
( eg 1.1, 2.1 etc)
These will tell you the MODULE at fault.
To exit
Key off
remove the jumper
Write this info down

Doug
I do not know where this door is (let alone how to get at it), nor do I know what is supposed to activate it. I don't know if I am on the right track here, or not, but any help you
may be able to give me would be greatly appreciated.

Well dudes & dudettes
comments invited

Mike

 

[vigman]

More heat

The heater core

Input
The line from the passenger side of the throttle body is a home run to the heater core inlet.
High on the inside( twds engine) of the A/C air box.


Output
The loop line going to the bottom of the surge tank
to the A/C air box is the output of the heater core.

If these two lines( In & Out) ARE NOT at the same relative temp...your clogged.



The input line to the throttle body ( coming from the front of the engine) Is a T fitting.
One line (big) comes from the block and into the T
One leg of the T feeds the throttle body, the other side goes to the top of the radiator.

Sometimes people bypass the hot water going to the throttle body to get more HP. Make sure it's not capped or restricted in any way.

There is a bleed screw on the top thermostat housing, this is to remove any air trapped in the Stat housing you MIGHT want to replace the stat just for good measure.

The bleed screw ( with system cold )
unscrew it, coolant should be streaming out, if not
Add distilled water until it does cap it off & top off the surge tank, fill the coolant recovery tank with 50/50. let the car idle up to temp.


The cooling system is not very straight ahead..
and there are many lines running around, check to make sure that all the lines are tight and there are no seepage marks on any hose connection points.

When the car's up to temp.. squeeze a hose is should feel like there's a few LBS of pressure in the system..If not there's a leak someplace.

Mike

 

[dugr]

Mike,

I did some more checking and found some puzzeling things.

1. When I checked the inlet hose, it is hot to the T and from the T to the throttle body. However, from the T to the heater box, it cools off until it is barely warm by the time it gets all the way to the box. The outlet hose is cold. I am thinking that if the heater core is blocked, it is probably preventing the hot water from ever getting to it; at least it is restricting the flow.

2. The bottom radiator hose that feeds into the thermostat housing remains cold even when the engine is at full operating temp. The port radiator fan cycles at engine temp. I know it is the job of a radiator to cool the coolant, but this good?

3. It does not look like we are headed for reading trouble codes, but exactly where is the ADAL connector and what does it look like? There is what looks like the receiver of a connector bolted to the lip of the dash, about where my right knee would be. It is about two inches long. It has two rows of contacts. Not all of the slots have contacts in them. There are no markings indicating which contacts would be A - G. Is this the ADAL?


I will check the bleed screw on the thermostat housing in the morning, when the motor is cold.

Thanks for bearing with a rookie.

Doug

 

[dugr]

Mike, and all,

Today, I removed the "radiator cap" and opened the bleed screw on the thermostat housing. There was a little bit of air (some sputtering from the bleed opening and some gurgling from the filler neck); not much, though. The coolant level didn't drop enough to warrent adding any.

I started the Vette and let it warm up until the port side radiator fan was running constantly. The temp guage in the speedo readout read 193F. This would drop to 189F when I ran the RPM's up to 1800 for a short period. NOW the "bottom" radiator hose is warm like I would expect for it to be.

However, the inlet and outlet hoses of the heater core are the same as what I described in the previous post.

I am thinking plugged heater core.

Any other trouble shooting procedures to check out before the heater core gets yanked?

Doug

 

[vigman]

Ok

Test #1

DANGER..IF YOUR HEATER CORE IS MARGINAL THIS MIGHT MAKE IT LEAK... PROCEED IF BRAVE!

Get a buddy to help.

Remove the line going to the Throttle Body.

Remove the line going to the surge tank( firewall side ).

COVER THE OPTISPARK AREA WITH PLASTIC, A BIG PIECE OF PLASTIC TO COVER THE FRONT OF THE ENGINE AREA ( behind water pump..the one with the plug wires on it) IF THIS GETS WET YOUR $400.00 lighter in the wallet!

Get a hose nozzle shove it into the line going into the throttle body have some body help you to keep the hose in.

Get a piece of hose to now attach from the heater core ( Dissconnect the line on the firewall side that went to the surge tank)

Put the new piece of hose into a bucket.. or something else so you can see what comes out.

Turn hose on SLOWLY.

Keep hose from dripping on engine!!!!!!!!!!

Watch the bucket.

What comes out.. and how is it flowing?

If it's dribbiling ( on the bucket side ) .. but you have the hose at medium pressure on the feed side.... Well repeat the test but now attach on the OUTPUT side of the throttle body hose..

If it still dribbles you loose..plugged core

If its flowing OK you win.

Now most Los Angeles garden hoses have a pressure of 18psi which is OVER where the cooling system would vent.. so do not go WIDE OPEN.


Mike

 

[dugr]

Mike,

I'm not sure if I am following all of that.

Are you basically saying, flush, or backflush, the heater core; or are you saying to flush something in addition to the heater core?

Sorry for being so dense.

Doug

 

[vigman]

I'm saying

Flush is what I'm saying, actually I'm saying is Check flow.

I'f you want to chat...vigmannn@aol.com IM me

ps you will probably have to remove the Surge tank.

Mike

 

[dugr]

Hi Mike,

I tried the instant messenger, but I am not on AOL and I evidently do not have the required software.

If I am going to check the flow in the heater core, why can't I just direct connect some hoses to the in and out portals? I could have the "out hose" go directly to the ground.

Doug

 

[vigman]

Well I wouldn't

I would have some kind of hose to direct it to a external bucket.. Getting a C-4 opti-CRAP wet is DEATH! and you dont want the goop coming out of the heater core getting everywhere in the engine compartment.

Color me ANAL

As far as the ALDL goes it is a female connector, where you described it ..and there are a few pins not stuffed.

With the widest part of the plastic connector facing down ( how it is in the car )

F E D C B A
G H J K L M

What about the feeling of the hoses? Does the system build pressure?

I'm betting there NO thermostat in there now, or it's stuck open.

If you have good flow ( which in betting you do thinking about it more) remove the hose from the stat housing and look down the neck.


Install AOL IM it's a good thing..

Mike

 

[jjones]

What is this thing called a heater?

 

[dugr]

Hi Mike,

Sorry, I did not mean to be taken literal when I wrote, "on the ground." Nevetheless, if I connected a hose to the input of the heater core and had another hose drain into a clean bucket, would that check the flow you are suggesting to be checked? If not, please tell me what I'm missing.

Yes, there is pressure in all of the hoses when the engine is running.

Thanks of the info on the ALDL.

You may be right about the stat. But it may have had a cooler than stock stat installed before I bought the car. Nevertheless, even if the stat is wide open, or absent, shouldn't the temps. in the heater core hoses ("in" and "out") be the same as the temps in all of the other hoses?

 

[dugr]

What is this thing called a heater?

O.K., rub it in.

Do you want us all to move to Florida?

 

[vigman]

One would assume

That the temps would be the same. but if the water is not that hot.. and is flowing quickly it might be a 20 degree difference. But thats why were doing what were doing..Investigating.

The logical flow is
Output of garden hose
Input to throttle body
Output from throttle body
DIRECT
Input of heater core
Output of heater core
Into bucket

2nd test
Output of garden hose
connect to
Input of heater core
Output of heater core
Into bucket

Oops din-Din time

Be back in 20
JJ the heater is an option for colder climates

It was deleted for California,Texas& Florida
And windsheild wipres were optional for those areas

LOL
Mike

 

[dugr]

Mike,

Thanks for the clarification. I'll check it out, but it will probably be Monday before I get to it. I'll post the results.

Thanks again.

Doug

 

[vigman]

Standing By

Go PACKERS Go


Mike

 

[Drewser]

Re: Standing By

Go PACKERS Go

I think your pack will be in just a leeeeeetle trouble. Can you say, "Backed into a buzzsaw?" Yeah...I thought you could.

 

[jjones]

Com'n down!

Doug - just think it ya did - ya wouldn't be going through all this!

But I enjoy reading Vig's techno babble. Should I ever turn mine on and find it kaput, I'm driving straight away to Cali and dropping it off at his door.

Good Luck!

 

[vigman]

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Presented in Dolby Surround,
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Last 4 times longer,
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WADDYA MEAN BABBLE
( In stereo...where available)

Shifting into Overdrive


:J

Mike

And PS
Go PACKERS GO! ( never mind the buzzsaw!)
Gotta support my team,
(even though I'm a CA boy.)

 

[jjones]

babble

errr - bad choice of word! Can we still bond?

 

[vigman]

Like WOW

( getting out the Epoxy)

Mike