Hightone64

I have the same issue I tryed to bleed it but couldnt get it too work. never bled the heat core, the weird part is if I rev about 3500 constant it will produce hot air, does it do this with anybody else?

Teknic

I had these same symptoms, and it was due to a cracked cylinder head.

ruslankirpach

hi did you ever fixed it i replaced a heater core stll cold air???

franco90

I got mine professionally flush and the mechanic told me it took a while to flush with air/water system he has and all he charge me was $40 to do it. he is in Long Island NY. Now the damn car it's to hot LOL

A1EK

Just thought I would add my fix for this issue as I too had no heat when I recently brought my car unless I drove it fast or for a long time.


On removal of the expansion tank cover I found brown sludge which I have found to be a combination of two issues:

• Mixed Coolant types
• Blocked breather hoses and PRV and split hose atPCV

First I flushed the coolant out, I tried to drain it via the bottom of the radiator tap but found removing the small sensor was easier. This improved for a while but there was still sludge in the system.


Second I removed the two pipes into the heater core (Flow and return), then back flushed the system with a garden hose connected to the house hot tap for a good 10 mins so that the hot water entered the return and exited the flow, then flushed the other way for a further 5 mins.


Thirdly I then flushed the engine side with hot water via the removed hoses from the heater core leaving the bottom radiator tap closed. I then removed the expansion tank and this is where the bulk of the sludge was as loads collects inside and you need to shake it around then blast with the hot water to clear. I also used some whitespirit which really gets the oily sludge out and finished it off with a little washing up liquid and hot water.


Then connected the heater core pipes back on, fitted the expansion tank and then filled the system with G12 Audi Coolant 1l and distilled water.


Now the car heats up on idle after 3-5mins without revving the engine and holds the heat when stationary.


I will do the flush another time I think later on in the spring, its not that difficult and it takes a while to get rid of all the sludge completely.

Lastly the root cause for the sludge I believe was due to the blocked breather hoses, PRV valve (Hockey Puck) and a split T-Piece wherethe PCV valve sits. Once I remedied these three items the smell of oil has goneand so far the coolant system looks a lot better, however time will tell. The last thing I want to check is the oil cooler above the oil filter.


Hope this helps.

infamous107

make sure to bleed any excess air in the system. As weird as it sounds, I had to rev the engine to build up the air, then, under the hood, squeeze the right side fluid tube of the exchanger until coolant started leaking out. Do this a couple times until hot air comes out of the vent. Tubes are located against the fire wall there should be two of them. One for input and the other for output. They are black and covered in an insulation tube. Remove the clamp and squeeze the insulation, air should come out followed by coolant.

ekellock

I've been reviewing this thread and others quite a lot lately and finally took the plunge. I went for the CLR method. I just wanted to fill up the core and let it sit so I routed the upper hose to a catch bottle and set up a funnel to fill the core from the bottom hose. As soon as I poured any in, it came out to the catch bottle right away. So I plugged the top hose and poured in less than a cup and it filled the funnel. Nothing is going in. Does this mean the core is completely plugged??

lyleswk

Maybe, but if you are back flushing with some pressure, you should be getting at least a little flow and sludge; I don't think just "gravity head pressure" will move the sludge out. I used clear tubing from a hardware store attached to the core inlet and outlet and held a garden hose on the outlet side to get pressure to do the back flushing. I did 2 back flushes with the CLR sitting for only a couple hours (I was doing my coolant flange) before I decided to let the CLR sit over night twice, and was still getting some sludge when I had to put the car back together so I could get to work. I get OK heat now, but not what I would consider really good, but it takes the edge off if it's really cold.

turbo510

That's doing it wrong. The engine should not be running, otherwise the pump will continually keep the coolant level low in the supply hose from the heater core. Revving up only makes this situation worse. Note that they don't run the engines when coolant is filled at the factory.

ekellock

Update: I left what little CLR mixture I was able to get into the core overnight thinking the level in the funnel would go down once it ate through whatever blockage I thought there was. The next day I just wanted to put it back together so I started flushing the CLR out and was getting some scale. I kept doing it and kept getting more. I would fill it up and blow it out and then I started putting more CLR in and blowing it out until I got little to no scale. Then I hook the garden hose to the hot water heater in the house and really flushed it out, filled it with distilled water, hooked it all back up, lifted the coolant tank, pulled the top core hose back until the bleed hole was exposed and let all the air out until it was a steady stream and tightened everything back up. I do have heat now, although not as much as I feel I could but way better than before. I left the climate control on HI for a couple days as I drove around in 70 degree weather and then today when I really wanted the heat, it was there, but not wonderful. I plan on doing a full coolant system flush next because I have no idea what coolant is actually in there. I'll see what happens and let you know. Bottom line was that initially I really overestimated how much volume the heater core could hold.