1999 Olds Bravada Heater Problem


thetopdoor
02-20-2006, 08:06 PM
I have a 1999 Olds Bravada that has a heater problem. I have replaced the thermostat twice thinking that the first one was bad. That was not the case, the engine temp rises to normal operatating tempatrue. If I rev the engines RPM's to 2 1/2 it gives a little heat but not enought to bairly defog the windows. If I am going down the interstate at 65mph I get heat just fine. But when I am off the gas it blows cold. :banghead: I have checked the HVAC fuse thinking it was something with the climate control. That wasnt it. My next step is to flush the rad. If anyone else has any suggestions Im all ears.
Thanks

ericn1300
02-20-2006, 08:37 PM
sounds like a vacuum problem. the climate control is operated by vacuum operated motors, ever notice the hissing sound when you move the control from floor to defrost. check your hoses for cracking or splitting. vacuum diagrams can be found here:

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/18/bb/17/0900823d8018bb17.jsp

vacuum changes with throttle postion and rpm. my 1950 GMC has vacuum operated winshield wipers, when i step on the gas hard they slow to a stop.

thetopdoor
02-21-2006, 08:28 AM
I will check the vacume system like you suggested. Also I think I am going to do a rad flush just for fun. It cant hurt it has 100,000+ miles on it and Im sure it has never been done. All I know is if it dont warm up here in Wisconsin I will have to find a different car to drive. (listen to me its been one of the warmist winters on record and Im complaining about a cold spell)

Chris Stewart
02-21-2006, 08:59 AM
Does the heater fan blow plenty of air..even cold air?

thetopdoor
02-21-2006, 09:42 AM
Yup it blows plenty of air, a little warm at first then completely cold. I even attempted to unplug the airconditioning unit thinking that maybe for what ever reason (computer issues) it was running. That didnt change anything. It doesnt change anthing if I turn the fan speed dial to Climate control or on full speed. It also doesnt change anything if I turn the air flow location dial to climate control or from the dash to the floor to an in between settings. It blows cold no matter what.

ericn1300
02-21-2006, 07:26 PM
do a search in the forum for radiator flush, i've seen some good links on how to. also you might have it done by a shop that can also do a pressure test on the cooling system to check for leaks. shouldn't cost to much and they dispose of the old stuff safely.

boldsmobile
02-21-2006, 08:49 PM
its not a vaccum operated heater door, its operated by an electric motor. to know if it is the motor drop the glove box door all the way down and look for a little motor enclosure sitting on the heater box - about 2" x 2" if i remember correctly. pull the electrical plug and remove the two screws holding this gear box on. they are really really hard to get at but you can do it. once the assy is off move the door flap by hand and start it and see if you get heat. you wont be able to move it after the fan is on high due to the vacuum it creates on the low side. also try the door in the other position too.

there are other threads on here about this. i found on mine the gear was cracked - happened when i went to turn the heat on after the coldest morning of the year last year. open the housing and see if yours is cracked too. if you know someone who has access to a lathe you can have an aluminum insert machined, press it in the gear face recess and use it to the hold the cracked gear together. sounds strange but trust me it works. or buy a motor for about 60.

thats what i found in my 98 and others here have had the same pro as well. this is assuming all coolant and engine related things check out.

good luck

thetopdoor
02-21-2006, 09:04 PM
I noticed today that the radiator was low with fluid and the overflow reservoir was empty. I know I had them both up to a full level when I changed the thermostat (for the second time) so maybe I have a leak. But it must leak when its traveling down the road because it doesn't leak when its sitting in one spot. I will try all of your suggestions and post my findings when I figure it out. Or maybe I could just sell the hunk of junk. Just kidding, its a great vehicle.

Chris Stewart
02-22-2006, 03:58 PM
Keep a close check on your oil in case the intake manifold gasket has developed a leak and leaking coolant to the inside of the motor.

thetopdoor
02-22-2006, 06:40 PM
Well I think I figured out what the problem was. I noticed that the input hose to the heater core was hot and the out back to the engine was cold. (weird I know) so we took both hoses off and blew them with a aircompressor first fluid flow direction then back the other way, you wouldnt believe the junk that came out of it. Long story short its heating now not as well as it should but it has heat. I think the next step is to do a flush. The only other thing that I noticed is that when you have the radiator cap off and rev the engine the fluid level drops in the radiator so you cant even see fluid. Im guessing thats normal? I checked the oil and thats clear no sign of water getting into the oil. (THANK GOD) There is to many gagets on that engine to have to pull it to fix the intake manafold gasket. Thanks for all of your help everyone!!

Chris Stewart
02-23-2006, 08:05 AM
Way to go TopDoor!
Since you've changed the coolant and disloged some sediment from your heater core, your heater core may clear up even better as you drive it.

thetopdoor
03-03-2006, 09:26 AM
Here is an update and question. Well I figured out the cause of the heating issue thanks to your guy's help. Well it blowing back the heater core fixed the heat issue but more problems occured over the next few days. I noticed that the coolant wasnt staying full in the radiator so I crawled under the vehicle to find that it was leaking from above the crank pully area. Being that I couldnt see exactly from where I figrued that I would change the water pump just to be safe. I went and pulled the dealer recipts to see that it had an intake gasket replacement just before I bought it. I replaced the water pump which by the way was really easy, GM really made it easy to get at.
Now it doesnt leak coolant but here is my question when I accelerate I hear a rushing noise sorta like a turning the water on in your sink coming from the heater core what could this be? It happens every time I accelerate.

Also I had my check engine lite on so I had a friend figure out what the code was and its P0410 which from what I can find tells me that the air pump has water in it. Where is the air pump? Is it that pump below the radiator? Is it something that I need to be conserned about? The vehicle has 100,000 + miles on it. Is it expensive to repair?
Thanks in advance for your help.

Chris Stewart
03-03-2006, 07:24 PM
Your water sound is likely a leaky radiator cap, clean it under a stream of water and under the rubber seal ring. It may have to be replaced. Recheck your coolant levels as air gets trapped on water pump replacement.

Regarding your airpump code:
http://www.automotiveforums.com/vbulletin/showthread.php?t=502716&highlight=PO410

ericn1300
03-03-2006, 08:00 PM
Your water sound is likely a leaky radiator cap, clean it under a stream of water and under the rubber seal ring. It may have to be replaced. Recheck your coolant levels as air gets trapped on water pump replacement.

Oh man Chris, and i thought i was cheap, but cleaning and reusing a critical cooling system part with over a hundred thousand miles when you suspect a problem with it? i'd say go ahead and splurge. spend the whole 6 to 8 bucks to get a new one.

thetopdoor
03-03-2006, 08:15 PM
Oh man Chris, and i thought i was cheap, but cleaning and reusing a critical cooling system part with over a hundred thousand miles when you suspect a problem with it? i'd say go ahead and splurge. spend the whole 6 to 8 bucks to get a new one.

Actually I was thinking of looking for one on ebay :grinyes: Maybe a used one from a bravada with less than 100,000 on it. Washing it with soap and water isnt to far fetched for me, I come from a long line of duct tape users.

All humor aside, so its a lack of preasure in the cooling system? Maybe air in the system because I changed the water pump. That would make sense.

Chris Stewart
03-03-2006, 08:19 PM
Well you know a fella can't be squandurin' hiz resources these days.:grinyes:

Chris Stewart
03-03-2006, 08:28 PM
Actually I was thinking of looking for one on ebay :grinyes: Maybe a used one from a bravada with less than 100,000 on it. Washing it with soap and water isnt to far fetched for me, I come from a long line of duct tape users.

All humor aside, so its a lack of preasure in the cooling system? Maybe air in the system because I changed the water pump. That would make sense.

There's a check valve built into the cap that keeps pressure on the system below the 15lb. spring pressure only to open when the coolant system goes negative pressure after the motor cools off, then the open check valve allows coolant from the coolant reservoir back into the motor. When this check valve wears or gets dirty, it can't get a good seal and under pressure, it makes noise and allows coolant and steam back into the coolant reservoir before the 15 lb. valve/seat... opens.

ericn1300
03-03-2006, 08:31 PM
most likely air making the noise. if you have no overtemp or cabin heat problems you can just wait for the air to make its way to the the radiator during normal operation and replace it with coolant.

My 4.3 used to shoot up to about 225 on warm up, then I could watch as the termostat opened and the temp would drop to 170 or less in seconds. Turned out to be an air block under the termostat insulating it and delaying opening.

My dad's farm mechanic showed me a trick to solve the problem. He drilled a 3/16th hole in the thermostat flange to allow the air thru before the thermostat opened. Fixed the problem and doesn't seem to affect warm up much at all, if any.

ericn1300
03-04-2006, 08:30 PM
you might want to check to see if you have a pond in the heater core housing. just loosen the bottom screws and pull it out to see if coolant pours out. also check the passenger side carpet for oily feeling wetness.

thetopdoor
03-04-2006, 08:50 PM
Here is an update, We drove our bravada for about 65 miles today, not once did the temp variate one bit (COOL) I did notice that the sound that it was making earlier is going away. I had to add more antifreeze but it is not leaking. I think it is just working out all the air. It blows heat perfectly with no lack of like before.
I was almost ready to give up on it and get rid of the darn thing, but I am a firm believer of Oldsmobile products. I have a Olds Alero and think it is the greatist car in the world, maybe thats because its payed off and still going strong... As far as the bravada, before I purchased it the dealer gave me recipts of all the things that had been done to it. Here is what they were, Replaced intake manafold gasket, replaced alternator, replaced the transmission and transfer case, replaced rear break pads and rotors, replaced battery, they said they did a rad flush and replaced antifreeze (questionable) before I purchased it I noticed that the rear wiper motor wasnt working they were not willing to replace it (cheepo's) Geeeze...... I was able to by it for just $7,000. Not bad because that is what blue book was at. I think they had so much stuck in it they just wanted to get rid of it and break even.

Chris Stewart
03-05-2006, 04:14 PM
Tell me about your Olds Alero...motor, trans, accessories & history. I'm thinking about getting a car for my daughter.

thetopdoor
03-05-2006, 04:42 PM
Tell me about your Olds Alero...motor, trans, accessories & history. I'm thinking about getting a car for my daughter.
Well ours is a 2000, it has a 3.4l v6 motor (great motor very easy on fuel) I dont know much about transmitions but its an automatic 3 speeds then drive, its very snappy. I have heard of lots of storys where people complain about them and say how many times it has been in the shop. As far as ours the only time it was in the shop was for an alignment and a recall it had for the blinkers. Its handling great, its a car you can take on a long trip and not blink an eye at it. It has the quality of a Olds 98 built in to a mid sized car. Oh I forgot to mention we had to change the thermostat twice, and its an all day job its way down on the engine where you have to take most of the engine apart to get at it. All in all its a great car, probably one we will have for several years to come. When we purchased it, it had something like 15,000 miles on it. Now we have 80,000 miles on it with no huge issues. Olds did their research when making this car.

Chris Stewart
03-05-2006, 06:18 PM
OK, thanks for the info. I wish they still made the little 2.5L 4 banger Pontiac Iron Duke. I have one in an '86 Ciera the boy drives...very reliable piece w/plenty of room to work.

boldsmobile
03-07-2006, 09:39 PM
when you say it was cool does that mean the temp gauge reads low? what temp actually?? or the air coming from the heater box is cool but the engine is the correct temp?

if its heater hose temp is cool as opposed to engine temp .... if i remember correctly the hose orientation matters. can hoses be backwards? and per my other post if all other coolant things check out (engine temp and etc) check the heater box flapper electric motor.

maybe you checked some of this stuff already but im still not clear if its a cool engine, cool heater core or cool air from the heating system

ericn1300
03-07-2006, 10:25 PM
when you say it was cool does that mean the temp gauge reads low? what temp actually??

the way i read it was the temp didn't vary from norm which was kewl. try rereading the post and substitute the word Great, or Fantastic for Cool.

cdalmata
03-08-2006, 03:24 PM
I had the exact same problem with my '99. Replaced the water pump, flushed the ht corel, filled system and then heard the gurgle noise from the passenger side. Replaced the Rad cap and topped off fluid for a couple of days and all was better! By the way....had this vehicle 3 years and this is my third Rad cap......gurgle comes back...I get a new cap!

jharris26
03-13-2006, 10:52 AM
i've been struggling with the same problem with my 99. i have the gurgling and fluid also seems to be leaking when not sitting. when it gets a little warmer, gonna flush the system, replace the heater core, thermostat, and replace the cap (never thought of that one). thx for all the good suggestions and solutions.

ericn1300
03-13-2006, 03:35 PM
By the way....had this vehicle 3 years and this is my third Rad cap......gurgle comes back...I get a new cap!

i like the Stant caps with the lever pressure release, seem to last longer. i change mine at the same time i change the serpentine belt, before they fail, and i put the old belt and cap into the jack storage well as emergency spares since i drive across the desert often.

keep your coolant clean and fresh, any contaminants in the coolant can lodge in the cap gasket during normal operation and reduce its life.

spddmn1
04-04-2006, 10:28 PM
My wife's 2001 Bravada just started doing the same thing tonight. The overflow jug was empty, the oil is OK, The upper radiator hose is hot but the bottom is luke warm to almost cold. :banghead:

Chris Stewart
04-04-2006, 10:50 PM
My wife's 2001 Bravada just started doing the same thing tonight. The overflow jug was empty, the oil is OK, The upper radiator hose is hot but the bottom is luke warm to almost cold. :banghead:

The bottom radiator hose should be luke warm, that water has been cooled by the radiator and is on it's way back to the motor too draw out some more heat.
The empty overflow jug is another matter entire...you need to find out where the coolant is going asap before hot summer gets here!

jharris26
04-20-2006, 09:26 PM
well, my problem is solved. i believe the final problem was with the radiator cap. i replaced that and haven't lost any more fluid. i also replaced the thermostat since the engine wasn't warming up properly. so my advice is to replace those caps whenever you change your fluid.

thanks
josh

Add your comment to this topic!