Overheating/smoke coming out the a/c vents?

O

Odog87

Member
Joined
Oct 5, 2010
Got a 87 GN. 133,000 miles. Took it out for a lil spin after sitting for 7 months and I noticed smoke coming from the passenger side a/c vents and the center console by the ashtray.You could hear the sound of bubbling coolant along with a slight knock in the engine. After pulling over I noticed smoke coming from the two hoses next to the trans dip stick which got me to thinking it was over heating. What are your thoughts? I just bought a scan master yesterday (should be here in a few days) because I dunno whats going on under there. Im clearly having some kind of cooling issues so Im thinking mabe I should flush the cooling system and replace the thermostat (160 degree, still got the stock one), water pump and hoses just to see if the problem goes away. Any suggestions or input would be greatly appreciated thank you.



Later on down the road I want to put in a bigger radiator, not sure which to go with…. the aluminum 2 core radiator from Alradco $425 or the Gbodyparts 3 core aluminum radiator for $450. I live in Lemoore CA and it gets HOT here, so which is best?
 
Im guessing leaking heater core or cracked heater hoses. Is there coolant under the hvac unit. Have you tried pressure testing the cooling system to see if it holds pressure? Just a thought.
 
pull the carpet up on the passenger side under the glove box and see if it is wet +2 on heatercore is leaking
 
If you are still using the factory radiator you should flush it especially since the car has been sitting for a while. If the car sits for a while you will have sediment settled at the bottom of the radiator. I dealt with this and fought it for half a summer then I decided to put in the f-body radiator that was a $100. Now the car runs at 160-170 degrees all the time.

I do agree that you probably have either a bad heater core or a hose leading to the core is leaking.
 
vapor in the dash says the core is leaking(or as mentioned a loose split hose thats pushed into the box can do same) but the overheating could be as simple as a stuck thermostat or not uncommon with our little 6s a blown headgaskets heating and over pressurizing the coolant system

check the radiator level and fluid condition,
check the overflow bucket for signs of oil contamination froth
do a coolant pressure test ..im sure youll find the heater core is leaking so you will most likely have to loop the hoses to it to do a pressure test.. you can start the engine and see if the pressure jumps up
do compression test
 
Im going to pull the carpet on the passenger side to check to see if its moist. I have not pressure tested the system, you can fine a pressure tester at autozone for cheap correct? Im going to pull off the cover cover to the heater core and check what I see. Im going to buy a thermostat today since its a cheap part and is an easy fix. I didn't know you could use and f body radiator they are alot cheaper too, is this a direct bolt on? Im just hoping its not a blown head gasket.
 
You may be able to rent/loan-a-tool from Autozone - or Harbor Freight for a cheap one. Not sure that you can get a 160 tstat from local parts houses.
 
Just rented a pressure tester from auto zone for 75$. Also just ordered the 160 degree thermostat and purchased a duralast water pump. Thermostat wont be here until tommorw after 3pm so I got to wait another day. Looking at the heater core what am I looking for? I figure thats something I can do today while im off work.
 
pressure test and if it doesnt hold look for leak by the heater core hoses under the hood , if they are leaking it could be the hose clamps need a little tightening or move where they sit , if it isnt leaking at the hose connections then the core most likely is leaking.

to remove the core you need to pull the windshield trim , then remove all the bolts holding the top cover into the firewall , and the small bracket that holds the winshield trim, then remove the blower motor and all the small screws holding the top half of the ac box to the lower half , there's more screws down inside after you remove the screen

pry the top half out and replace the heater core


or just loop the hoses that go to the heater core and leave it that way and it wont leak
youll also be able to test the system with the heater core leak out of the way


for thermostat you could have purchased a 52mm stant 160 stat for a chevy and trim it down to 44mm with a pair of tin snips (cut along the groove).. they always have those chevy stats on the shelf and they run about $4ea
 
If you need a heater core, I think I have one. Let me know if you need it. Free with a radiator :D Just kidding, you can have it either way if you need it.

Peter
 
When I had steam like smoke coming out of my passenger side top dash vents, it was the heater core. Make sure you get the right one, a lot of the newer ones are junk. Glen at 4NOS or Brian at Gbody should be able to hook you up.
 
Car ran good. Changed heater core but still got a leaking problem,not sure of where but think its a hose or something in the line of the radiator. We seen smoking and steam evaporating along with burning water fumes. We pressure tested the radiator cap and it wouldn't hold any pressure. We replaced the new radiator cap and it sealed well at 16psi. We pressure tested the radiator and heard a leak/air escaping somewhere, couldn't tell where. We are going to flush the radiator out tomorrow and change the thermostat to a 160 degree.

Would you recommend changing the water pump(duralast)? I have purchased one but its not installed yet.
RED C5 I will take that radiator you offered……… LOL


We have a problem with the signal lights and tail lights. The signal lights stopped blinking, they just come on and stay on when signal is turned on. The tail lights not working while the car is running but the brake lights work. Any suggestions or answers to what maybe be the problem?

The inside lights just stopped working also. They don't come on no matter if the car is on, all light switches or turned on or anything. Any ideas?
 
I would fix the other leak before putting more parts on it, unless they are due for replacement. Alot could happen within 7 months, usually plugging up the hole with least resistance (heater core) will bring up smaller leaks. Pressurize the system again and wait a couple hours. Look for a puddle somewhere under the car (or inside) then go from there. A system that does not hold pressure will most likely overheat.
 
If it ain't one thing its another. Went in to change the thermostat and found the thermostat housing rusted to **** with an even rustier thermosta. Just ordered a new housing from autozone and am trying to locate a stainless steel one for the next time I pull it off. I still havent flush the cooling system yet. I figure if thats what was in the thermostat area god only knows whats in the radiator and block. Should I flush the cooling system with the thermostat removed then install the new thermostat, housing and water pump? Im in the process of getting a new radiator im thinking of going the F body route with an external oil cooler since its cheaper $100 bucks for the radiator and $60 for the oil cooler vs $425 for the adradco radiator. But at the same time im trying to do it right and not skimp or cut any corners. What do you think I should do?
 
I got it out thanks. WD-40 and a hammer. Bent easy but the new one is alot thicker. Now i have a stuck thermostat. I believe that is the source of my overheating problem.
 
Odog87 said:
I got it out thanks. WD-40 and a hammer. Bent easy but the new one is alot thicker. Now i have a stuck thermostat. I believe that is the source of my overheating problem.
Click to expand...

I'm late to this party, but this was my first thought: the cause of your overheating.
The core is leaking too. Easy replacement. When you get all the screws and trim pieces for the cover out, there's one screw hidden down real low.. (been a LONG time, under a screen maybe??)
 
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