Heat On the Fritz - Help Please!

[walloftruth]

Hey...

I purchased a 1993 Cadillac Seville SLS three months ago. The heat wasn't working as well as it should so I brought it to a mechanic to get it checked out before I bought it. The guy told me I needed to replace the coils and gave me an estimate of $300. I was fine with this and bought the car anyway.

It just started to get cold out and I tried using the heat one day and noticed the following:

1. Drivers side door, floor duct, defroster and all rear ducts blow ice cold air no matter the setting.
2. The air coming out of the passenger side vents is warm but not hot.
3. Under the hood I hear a loud click every 15 seconds or so. Sounds like the compressor is turning on and off.

Brought it to a mechanic. He checked the doors behind the glove box and said they were fine... Pointed out how the upper tube going into the heater core and that "T" was boiling hot while the lower tube was just warm. He flushed the heater core with no results.

Three hours of this had passed and I was growing tired so I took a walk to the store. Came back and somehow he was able to get hot air coming from the passenger side but the drivers side vents were just blowing warm.

He said this was the result of a "bad computer controlling the doors" and that I'd need to purchase a new one. However, I was satisfied at the time with whatever he did and after $300 worth of labor I couldn't wait to get out of there.

Came home, parked the car in my driveway, went back out a few hours later to see my friends and now everything is back to the way it was when I brought the car in.

I've tried lowering the temperature to 60, bringing it back up to 90 and back down again a few times. I've tried every combination and setting possible.

Now I'm sick from being in a freezing car all day, frustrated and running low on money. I just want to know if he diagnosed the problem correctly and if this is REALLY the result of a "bad computer" which I need to replace for $500 or if some other issue could cause this.

If there is any other info which you need that I left out please let me know.

Thanks...
Eddie

[Ranger]

Is this a 4.9? If so, there is supposed to be a restrictor in one leg of the "T". If missing, or in the wrong leg, you'll have heat problems.

[walloftruth]

Hey,

Yes, it's a 4.9. I just looked into all three hoses and I didn't see anything, just coolant. What is it supposed to look like, exactly? If it's noticeable, then I guess it isn't there. These hoses don't look 14 years old... they're in really great shape, actually. I'm guessing they were replaced at one point and someone didn't put the restrictor back in?

Would that really cause cold air to come out of some vents while warm air comes out of others, though? Warm air, not hot.

Annnnnd I just noticed some green and red fluid leaking from the very front of the drivers side.

Ugh. =/

Thanks so much.

[Ranger]

I am not exactly sure what the restrictor looks like. I never had to replace mine. Basically it is just a plug with a smaller hole to restrict the coolant flow. Can't cost too much at a dealer. The problem is, I forget which leg it goes in. You might find it by doing a search if you don't have a manual or someone who knows does not chime it.

Yes I think it might be the cause of you heat problem. Easy enough to find out for sure.

[walloftruth]

Back with pictures!

I found the restrictor and ended up breaking it in the process. When looking at the engine from the front, the restrictor is in the left leg of the T.



Hoses disconnected, obviously.

Here is a close up inside the LEFT leg of the T:



As you can see by the picture below, the restrictor is in the T but also extends inside of the hose.



Now I need to find out the part number and get a new one ASAP.

The restrictor was in there and intact before I broke it, so I really don't think this is the cause of my heating problems. Anyone have any other ideas?

So far I've ruled out the doors behind the glovebox, the heater core, possibly the restrictor and the flow of coolant in general. I don't know where to go from here other than have a mechanic look at it and rape me out of money.

[walloftruth]

ACD# 15-5390
GM# 01648454

It's called a heater control valve.

Got it two minutes before closing at my local Cadillac dealer for $30. Removed the pieces from the hose of the old broken valve and everything went right in. If you can hold a screwdriver you can do this.

Topped off the coolant, ran the car for 25 minutes, and I still have the same exact problem. =( Cold on drivers side and warm on passenger.

Anyone?

[Cad tech]

What u need to look at is the programmer, make sure that vaccum assist is working on the doors...you will have to check them with a vaccum pump to do so...if they work you need the programmer...