Car blowing cold air

Fargo Boyle wrote: »

Good evening boards,

So my fingers have just thawed out so I can now post. Driving home from work today, 125km commute, my car was blowing cold air for most of the journey , (i didn't notice it at the beginning ). I should also state that I had the fans set to off. Coolant level seemed ok, above minimum level in top-up bottle under the bonnet. Coolant temp while driving was 90°c. Oil temp was jumping between 110°c to 115°c. Any ideas what could be the issue here?

I believe there is a motor that controls a flap that opens/closes different passageways for hot/cold air through the vents, I think it's called a blend door actuator or something like that. Electrical components failing can be an expensive repair because motors are usually on the pricey side. Maybe look into getting one second hand at a car breakers if that is the issue.

Fargo Boyle wrote: »

Sorry, that info would probably help alright, it's a 2014 seat leon 1.6 tdi

Oh dear.

I'd say your another victim of the infamous silica bag issue.

Need to flush the coolant system, replace the heater matix and expansion tank.

Teabag of doom.

No, usually ok to drive once the temp is ok on the dash. It does get worse over time though, so definitely get it sorted. I've seen them having to get EGR coolers, main rads, water pumps and the whole works as things were just too blocked to flush clean. That's not unusally the case now but it can happen.

Yeah, it would have it too.

It should say "mit silikat" on the expansion tank.

Some have the teabag built into the walls of the coolant bottle.

The new bottle is only €27.

Finally got off my butt and looked at my own. It has the dreaded mit silika written on the outside it looks like a double skinned expansion bottle, the coolant doesn't look too great either, it's brownish in colour it was originally purple. Does the double skinned bottle give trouble too?

A new mechanic would be the first corrective action i would take. The issue is a known one and he went nuclear without addressing the actual fault.

I would consider the heater radiator and the heater matrix two terms for the same component so we probably need some clarity there.

The heater matrix is handy accessed in the Leon, less than an hours work.

The problem is if he has replaced the heater rad/ matrix already and you still have bad heat it's now because the new radiator is also blocked.

There is a very specific process to correctly flushing those coolant systems and often it needs to be done more than once to get the desired effect. You need to flush the system properly before fitting a new rad or it will just block up again and again.

Yeah, look, i doubt that that is the fault.

A few years ago, when this issue first started surfacing and all the affected cars were still under warranty we used to see that, particularly in Golfs, which are effectively a Leon with a different outfit on.

There would be no heat, you'd flush the system once, fit a new heater rad and you'd have good heat on the passenger side but still weak heat on the driver side. Reason being, the system is still sludged and the new rad is already blocking up and not giving full heat. We've seen cars where every single part of the cooling system had to be replaced, the sludging was that bad.

I'd guarentee if you have weak heat on the driver side now, over a period of a few weeks you will go back to a point of no heat at all.

Whatever you do, dont go spending money on flap motors behind the dash or whatever he is recommending. It won't help.

Get a garage who knows what to do on the job, trading in the car will cost money too.
Even if you financed the repair over a year or two, it would be much less money than trading up, at least your own car will have a new timing belt etc.

So is the water pump and matrix likely to be goosed now or would it be salvageable?

colm_mcm wrote: »

So is the water pump and matrix likely to be goosed now or would it be salvageable?

Matrix is ****ed, 100%. The veins are so fine, once they start blocking, there really is no return.

Unless it's really really far gone in terms of sludging the rest of the stuff like the main rad water pumps, EGR etc should be salvagable.

There are two keys to success with this IMO.

One is using the real VW cleaning agent as it allegedly has "stuff" in it to break down and dissolve the sludge. I think the kit isn't too expensive. Flushing with water or generic rad flushes is a waste of time.

The other is to follow the correct flushing and bleeding sequence. There is one mechanical water pump and 3 electronic pumps on most of the 1.6's and activating them in the right sequence and properly bleeding the system each time is key to getting the cleaning agent into every crevace and also emptying all the contents from the system. As in if you have pump 1 running but pump 2 isn't, how will you ever get the debris between the two out?

After that just keep flushing.

Have seen a handful needing a rake of stuff replaced where no amount of cleaning would do. The only upshot to the OP's predicament is that he's had two coolant changes recently so thst should have taken some amount of crud with it, which may have helped with some level of damage limitation.