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No heat, lukewarm, bad heat

 
Old 01-31-2017, 09:34 AM
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Default No heat, lukewarm, bad heat

Thought I'd make a new clear topic.

Have had really bad heat in my car, same problem with the earlier 2006 W12. Only like lukewarm coming out from vents, and barely anything from the other side.

Checked temperatures from HVAC with VCDS today and saturday after engine was hot and driving for more than 30min on the highway both times. Coolant 87-90c, outside -1c and 15-23c from passenger side vents and 18-35c from driver side.

Took out the heater valve with the circulation motor, inspected, and concluded only a minor inner leak on passenger side solenoid. A few drops of coolant inside solenoid housing.

Then i blew out the remaining coolant from passenger side heat exchanger.... WHOOOAAH holy moly, got like 20-30grams (an ounce) of sh**TT, black, white, small sugarlike chrystalized crap, and really bad looking coolant. The passenger side heat exchanger was probably almost blocked.

Same story on driver side, but not as bad, but 80% of it.

Blew out it with pressurzed air, flushed with garden hose like 10L (2,5gal) of water to a bucket (again same crap came out). Then put vinegar in for 30min, and let it sit. Blew it out with air again and put together. Now like 55-60c coming out from vents. Car up to requested temp in like 5min even though engine just 50-70c. Before it took like 1-2h to get it up to something like 17-20c.
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Old 01-31-2017, 08:15 PM
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Good to know...albeit unfortunate. There was the TSB saying they had changed the internal coatings on the heat exchanger/cores, but I guess it maybe still wasn't bulletproof.

You are using G12++ or G13 for the W12, correct--that is, the standard current type with silicates?

Last edited by MP4.2+6.0; 01-31-2017 at 08:20 PM.
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Old 02-02-2017, 08:41 AM
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Originally Posted by MP4.2+6.0 View Post
You are using G12++ or G13 for the W12, correct--that is, the standard current type with silicates?

Always dealer serviced car before me, so the coolant SHOULD HAVE been changed according to service schedule, but I doubt it has been ever changed. So probably factory original G12++ in it.

Will be replacing it ASAP, and doing a complete superflush on the system (coolant drained out, flush with water 2-3x, flush with cleaner, and in with G13 + de-ionized water.

Brake fluid has been swapped in last service. Tough that is also due when it needs service next time. Will be swapping tranny+diff oils at same time.

How much aren't those 1000/pc stamps worth in a service booklet at this time when things haven't been taken car of as should have. Nada.
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Old 02-04-2017, 05:02 AM
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Default Similar Issue with my 2004 Audi A8 4.2L

I was having issues with little to no heat, so I had my mechanic perform a coolant flush about 2 weeks ago. Did not need heat much where I live until recently, I turned on the heater and when the fan is on high all my vents blow cool to cold air. When fan is low(2 or 3) my outside driver vent is warm to hot, all other vents are luke warm. I took back in and found out he used coolant that is compatible with all colors and says he puts in other Audi's and has no issues. Do you think it is because he did not use 12 or 13 that I am having these issues, Or since I was getting cold air before that it is a different issue.
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Old 02-04-2017, 09:48 AM
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Originally Posted by jeffkruse View Post
I was having issues with little to no heat, so I had my mechanic perform a coolant flush about 2 weeks ago. Did not need heat much where I live until recently, I turned on the heater and when the fan is on high all my vents blow cool to cold air. When fan is low(2 or 3) my outside driver vent is warm to hot, all other vents are luke warm. I took back in and found out he used coolant that is compatible with all colors and says he puts in other Audi's and has no issues. Do you think it is because he did not use 12 or 13 that I am having these issues, Or since I was getting cold air before that it is a different issue.

Hopefully he used what would now be std. issue G13, which is backward compatible to most anything. (Or G12++). If something else, not good.

But in general, sounds like another issue. Could be bad or clogged heater valve, or clogged heater panels inside car, both of which the OP was working on.
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Old 02-04-2017, 04:33 PM
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Originally Posted by MP4.2+6.0 View Post
Hopefully he used what would now be std. issue G13, which is backward compatible to most anything. (Or G12++). If something else, not good.

But in general, sounds like another issue. Could be bad or clogged heater valve, or clogged heater panels inside car, both of which the OP was working on.
+1, the type of coolant will not effect your heat temp. The downside is that non approved coolants can cause damage in the long run by either clogging up your cooling system or accelerated internal wear.
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Old 02-05-2017, 02:39 AM
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Pentaman, my Finish friend!
So - for your old car -did you ever resolve the issue as the heater cores? Last I recall reading that you were still hunting for the problem and then time moved on?
But I likely lost an update thread in there somewhere....
Just curious, I do not have that problem yet, but ever since I bough the car it clearly heats up slower than our Volvo (esp the old V70R is crazy, barely have time to drive down the street before heat is on full!).

So - if the difference was that drastic, thinking about maybe doing this in the summer as preventative maint. How hard was it to get the heat exchanges out?

Thanks!
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Old 02-05-2017, 07:39 AM
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Default I will check the heater control value

and probably a good idea to have another coolant flush with g12 this time. Thanks
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Old 02-06-2017, 08:06 AM
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Originally Posted by carl viking View Post
Pentaman, my Finish friend!
So - for your old car -did you ever resolve the issue as the heater cores? Last I recall reading that you were still hunting for the problem and then time moved on?
But I likely lost an update thread in there somewhere....
Just curious, I do not have that problem yet, but ever since I bough the car it clearly heats up slower than our Volvo (esp the old V70R is crazy, barely have time to drive down the street before heat is on full!).

So - if the difference was that drastic, thinking about maybe doing this in the summer as preventative maint. How hard was it to get the heat exchanges out?

Thanks!
No, did NOT resolve the heat problem with the 2006 W12 I had. Symptoms exactly the same, first not so good heat first two winters, then the third winter almost inexisting heat.

You DO NOT need to take out the heat exchangers, JUST FLUSH THEM. Take off the hoses from the heater control valves on the right (LHD passenger side) under the windscreen below the ECU(s), the 4 smaller hoses. You can not connect them back in the wrong manner, so don't worry about that.

Put a smaller hose, i used 13mm OD coolant hose and put it inside the exchanger hoses, blew air by mouth in to the hose, and out came crap from the other hose. Then i flushed with garden hose water, JUST DON'T PRESSURIZE the heat exchanger with the water hose, use a funnel etc or just pour water. DON'T connect the water hose directly, you MIGHT CRACK THE HEAT EXCHANGER!

Flush BOTH WAYS BOTH EXCHAGERS with water. And I mean flush both directions, from intake hose to outgoing and vice versa, back and forth.

Then I used home vinegar, you can use "vinegar acid" also, like 10% or something like that. Just don't let it sit for too many hours, IT MIGHT corrode the heat exchangers from inside. Flush again BOTH ways preferrably. Flush again with water (I didn't do )

And ALSO FLUSH entire engine with same manner, I'm going to do that also. But YOU DON'T need to flush entie engine with vinegar(acid) Just drive around with water.

And use preferrably GENUINE G13 coolant. I'm going to use that. 14/1L. The price wont't kill you. Clogging your cooling system with crap WILL KILL YOU!!!
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Old 02-07-2017, 08:18 AM
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Aha - I do not need to remove them? Then this is a no brainer project for the summer.

Thanks!
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