Possible to Flush Heater Core on E34?

[Victor]

After pouring a bottle of head gasket stop leak into my engine, and living to regret it, I'm now getting no heat and suspect a clogged heater core. I've seen vids on YouTube
(Eric the Car Guy) where he back flushes a heater core, removing tons of gunk. Can we do that? I only see threads on removing the embedded thing, which looks like a nightmare.

Thanks!
Vic

[632 Regal]

Hi Vic,

If you are not getting heat because of air trapped in the heater core, could also be your bleeding issue from your other thread. Other than that:

I would first think the heater valves have clogged. They say that some have a fine mesh screen that clogs. None of the ones I opened had those screens. By default they are supposed to let the water pass so trapped air/clogged heater valves.

[Victor]

Interesting ... I had no idea there may be trapped air in the heater core.

I also have the following strange behaviors going on: A/C continues even when the A/C button is not depressed. And I could swear I'm feeling some cold air even when the fan is not running. (Call me ...).

I'm unclear on the purpose of the heater valves, but would still wonder if they (and the rest of the heater core) can be back flushed. Eric used compressed air sprayed into the lines. Another guy used a garden hose similarly. Seemed much better than digging for the core to clean / replace it.

[632 Regal]

I'm sure you can flush it with a garden hose to get the junk out of it. Probably a good idea to flush through the heater valves to see if they are clogged.

Yes your supposed to bleed it with the heat on hot and high, not sure why they say to have the fan on high but they do. You need to get the air out of the core or you will never get it to bleed.

Strange about your AC though

[Victor]

The A/C strangeness seems to have stopped, so that simplifies matters. I looked at the tangle of hoses around the heater valves. Someone has to have flushed one of these things before and I just
wouldn't know where to begin.

Question for you please: Since I'm getting no heat, it's probably fair to assume no AF is going through the core. So when it comes to bleeding, running the heater isn't going to move air through the system. So this leaves me to guess I must have trapped air, though no more is bleeding out. Is there anything I can do or isn't this something to be concerned with? ;-/.

[shogun]

Disassemble the heater valves and clean them. Relatively easy. On my website http://twrite.org/shogunnew/topmenu.html click on the left fixes>>>see under climate control , plenty of pics how to do

[genphreak]

Shogun's right.

Of course...

The way it works on an e34 is:

Hot coolant from the engine is drawn by the electric coolant pump (in the heater valve assy) into the heater valves. If the thermostatic cabin controls direct these to open, hot coolant will flow to the right and left side of the HVAC/IHKA unit in the dash and heat the cabin. Yu need to 'hose in' to the pump, and hose out from the heater core return pipe/s.

Once the heater valve assy is disconnected you can flush by disconnecting the input hose for the left and right core feeds in turn and connecting your garden hose. Then point the output hose (you might need to attach a short piece of hose to directs the waste water down away from you).

That's about it, but whilst you are at it you should flush the block and the radiator and replace the coolant with the correct stuff to see you through the next couple of years. I usually flush my system with water by draining once a day for a few days, replacing with local (thankfully soft) water. Do not do this in a hard water area. Because I drain it fully each time a number of times the car ends up just running water. I do this to be sure I get all the coolant out and avoid removing the block drain which is hard to get to at the back under the exhaust manifold. By contrast, the radiator drain can is a neat little blue plastic plug that I can operate by hand. After flushing every few days (with heater controls fully on and bleeding to remove the air), I drain again once more and add enough coolant to get a 33% mix.

In your position though you must drain from the block primarily (so jack the car up and support it high enough for you to be comfortable working behind the manifold) as you will remove more gunk that way- the radiator drain doesn't allow anything large through it, and a lot of the gunk will be hanging around in the block

BTW: An M50 takes 10.5 litres/11.1 quarts, and M30 roughly a litre/quart more.

[Victor]

Thanks so much guys! I'll see what I can do!
Best, Vic

[Victor]

Hey Shogun - Saw your pages and am encouraged to undertake the valve cleaning project. I would imagine if the valves are gunked-up (recall I poured head gasket sealant into my engine, which has caused my nightmare), so must be the heater core. If I'm cleaning the heater valves manually, wouldn't their removal present an opportunity to back flush the core? Any link to someone's experience doing so would be very helpful. Thank you!

[632 Regal]

There are only 2 hoses going to the heater core, the others just control the direction of flow through the heater core.