Partially blocked heater matrix - advice wanted

[GrahamP]

1999 Passat - oil cooler replaced due to oil in coolant- lukewarm airflow ever since.
Water pump, heater blower, flaps and thermostat ok, good coolant flow.

Have come to the conclusion that heater matrix is partially blocked.
Have tried degreaser and "rad flush" treatments and gentle back flushing with hose, but I'm wary of causing a leak.

Has anyone any experience of what else can be done? I am hoping to avoid an expensive dash out job to simply replace the matrix.

(Please excuse the non-boat nature of this post but I'm convinced that experts are more likely to be found here!)

Thanks,
Graham

 

[bikedaft]

sure its not an airlock? tru cracking the hoses as they go thru the bulkhead between engine and interior. then try blowing thru same hose, to see if blocked etc. tho you've probably done that already after rereading your post! and pretty sure these engines are supposed to bleed themselves.

is there a difference between the air temp coming out the blowers on each side of the car? (linkage fallen off under dash etc)

can you get fault codes, that will tell you if main flap (hot/cold) is operating fully. can you see it from foot well that its working ok?

might not be a dash off job for heater matrix, at least i hope not (i need to do mine a6, '99)

 

[vyv_cox]

Try forcing it through with the full flow from the pump. With everything up to temperature, heater fully open, squeeze the top hose to the radiator closed with a Mole wrench or clamp of some sort. Increase revs on the engine.

 

[Martin_J]

I replaced mine on a 97 Passat 1.8T...

and it's not a quick job... although it is manageable in a weekend.

1) Steering wheel off (inc internal airbag)... heater controls out... center console out... gear stick surround out... Glovebox out... Airbag cover removed... Instrument panel out...

2) Dash just slides towards you and out leaving a big space...

3) Remove passenger airbag... disconnect and lower all heater ducting...

4) Finally the matrix is visible... Note - there are two different style tops with the hoses leading off at slightly different angles - note which before you buy!

Put all back together... using up all the envelopes in turn that you labelled and stored the fixings in.

Are you really thinking of DIY... if you've any questions just ask!!


PS - Just a thought. I assume you have bled the upper hoses of air where they pass through the bulkhead. One of the hoses has a 2mm hole in it that lets the air out. You just have to pull the hose half way off the fitting. It's marked with a white line/dot.

 

[bikedaft]

don't panic, its hopefully not a dash off job, if it is indeed the matrix, tho struggling to think what would have got in to block it. audi a6 b5's from '98 you can do matrix without dash off.

edit; so hopefully passats are the same!

 

[GrahamP]

Thanks for your responses Bikedaft, Martin and Viv Cox.

I haven't got the confidence/expertise, location or tools to attempt a major DIY replacement job on the car so I'm looking for low tech ways of clearing the matrix.

A mechanic replaced the thermostat while doing the timing belt this week. He had expected that to solve the problem. He checked the coolant flow and linked up to a device to test the flaps/motors and sensors on the climatronic unit - all OK.

Bikedaft - Found this link when browsing the net.. It's for an A4 though
http://www.youtube.com/watch?v=ngi2cNWyWTk&feature=related

Martin - I have bled the system, lifting the reservoir with a bungee cord helps

Vyv Cox - Like your idea - makes sense to me. Will try ASAP

Thanks again,

Graham