VAG boffins - Audi A4 no heaters and poor circulation issue?

[Asa-James]

having had a quick google search, this appears to be a typical vag "common fault" to which the sealed community doesn't wish to help with.

i've so far clocked up 8 hours on this (including headscratching time)

thermostat checked and changed, water pump checked and changed, heater matrix flushed and reverse flushed.

basically, theres no heaters in the car, and seemingly no flow through the entire cooling system. doesnt overheat, but the customer has mentioned a "popping" sound behind the dash on longer journeys.

its a 2006 car, coolant in good condition, good service history etc so its not a victim of neglect.

any ideas? because i'm getting close to torching the damn thing.

[Southie]

Petrol or diesel and what size engine?

[Asa-James]

good point. diesel 1.9 tdi

[bazil]

One for john H or joe richardson is he is still about.
My sis in law had a 1.9tdi A3 with the same problem

[Southie]

Asa, this maybe of some help:
http://www.justanswer.com/audi/1ps36-audi-a4-1-9tdi-sport-having-trouble-heating.html

[Asa-James]

srsly? every time i work on one of these things i find a new reason to hate them. will try the heater core tomorrow. cheers for that southie :) xx

edit - must spread the love before i can give you moar

[meritlover]

Sounds like a scaled heater core. This is normally a result of neglected servicing.

[John]

Vags(??)/audis/vws/seats/skoda are all ****. I'd just torch it as they have too many "common problems" :) :thumb:

[Asa-James]

i would to be honest, but his dads a copper.

seriously tho, these heater matrix's have a mesh inside them?

[John]

lol so is the feed to the matrix is warm, and cold output? When you say "no flow through the entire cooling system" everything inc rad and all hoses are cold after a good run? Climatronic? :)

[Asa-James]

dual zone climate, and when i say no flow, there seems to be nothing at the return into the header tank. rad hoses get hot, i gave up today before checking the rad its self (but at a guess i'd say its good) bottom hose to the matrix gets warm, borderline hot, top hose not a great deal. one of the other lads at work disconnected both matrix hoses friday, ran a hosepipe through both and said the flow through was fine. engine revving there seemed to be some flow through the matrix, but zilch on idle/low engine speeds.

i know it all pointed to the matrix, but as i said someone ran water through it and said it was good, which got me thinking water pump impeller had started to come loose.

[mowgli]

does the matrix run a heater cut off valve, or an air flap shut off type setup??

i had a truck some years back with climate control & the heater was never ever warm.. we found the electronic control valve was jammed shut.

[Asa-James]

air flow flap, did think about that but got TPS to email the diagrams over

[blue_peg_16v]

Some of the cheap pumps have a plastic impeller that can break down

[mowgli]

Some of the cheap pumps have a plastic impeller that can break down

i was of the impression that all VAG 4 pot water pumps had the cheap impellor & they got changed every 2nd annual service...

[meritlover]

Heaters work in two ways. Either the matrix has an unrestricted water flow at all ti,es and the heat is controlled by directing air through it (like the nova) or there is a valve in series with the matrix water supply to control the flow be it cable/electric/vacuum operated a simple exploded diagram of the heater circuit should explain what it is. Failing that, it's a scaled core.

[John]

If it's dual zone climate asa there will be a valve in the matrix pipework that may possibly cause issues. iirc it's electrically operated. should be under the scuttle panel somewhere. easiest way to check is just to by pass it. Can you access the matrix in situ? iirc I have seen one at work that felt hot at the inlet, and as you felt across the matrix with your hand the heat would drop off and the outlet luke warm. Bypass the matrix and see what the flow is like at the top return to header tank.

[Asa-James]

theres no valve under the scuttle, just two pipes going through the bulkhead.

i've just spent ten minutes backflushing the matrix with high pressure water, definitely restricted at first (remind me to hit my work colleague tomorrow) but got a lot better. running up now, had hot air on the car in a matter of minutes. if i'm being honest, its not perfect, but it works compared to when it came in. customers on a budget, and knows i'm doing a lot of this on my own back, so i think he'll be happy for now. just needs a tyre tomorrow, then a good road test but i'm quietly confident about it.


cheers for all the pointers, tips etc (and meritlover for your brutal honesty xx) i'm gonna go have my weekend now.

[mowgli]

would a liberal dose of a cooling system cleaner help?