Hi, 

 

We have a my17 Octavia 2.0tdi 150 DSG with 60000km on it. 

 

I was having a check under the hood and noticed that the coolant is dark brown instead of red and have a lot of oxide or other contaminations in it. 

 

I stuck my fingers in it and it feels mor or less like normal water, and not quite as slippery as antifreeze usually feels. 

 

The car was serviced 4 month ago so I went back to the stealership who said this happens easily on diesel engines, but he couldn't tell me why when I questioned that as it's a closed watersystem and not like the oil that usually get sot in it. 

He continued to tell me that the only check in the service is checking the freezing temperature of it.. 

 

He told me that I can let them change it if I would like, but I don't think that's gonna happen. I'll go somewhere else in that case. 

 

Any how..

Have anyone had the same issue? 

Don't know if they have mixed different coolant types or if it might be oil in it? 

The oil is normal and no trace of water in it. 

No smoke from exhaust and it runs fine. 

 

I have never experienced coolant going bad so to say and changing color.

 

The car is going to another stealer In a month as there is no hot air on the passenger side.

 

Hi 

I’ve a vrs diesel and have seen the same discolouration in the coolant, I replaced the expansion bottle and topped up with new coolant. The sediment in the old expansion bottle looks kinda like rust.

I think its to do with the failure of the silly silicate bag in the header tank, releasing the silicate which is a sand like substance. Eventually making its way into the heater matrix and blocking it, very difficult and expensive to remedy.

 

Search for "mit silikat" and do something NOW.

If they took some of that out to check the freezing temp, they should have seen a problem!

 

As above, sounds like the bags gone and messed things up. Certainly sounds like it if you've lost heating. It's a common fault if that happens.

Having suffered this common issue too at 67000 miles, 2016 2.0 tdi there is absolutely no doubt that @51MM3 has 

 

1. Has a blocked heater matrix as in the UK, the driver's side has little or no heat when it happened to me, so as the OP is in Sweden they say "passenger" side as left hand drive. 

2. Needs all the coolant draining and the system flushed several times. 

3. Expansion tank replaced with one without silica bag. 

4. Heater matrix replacing. It can be done without removing the whole dashboard which is what the dealer is likely to say and costs a fortune. 

however there is room with the fan removed and a few other parts around it,

 

YouTube has video of some one doing this. 

 

 

I was lucky and my garage flushed my system twice and some heat was recovered and I'm living with it for now. 

 

 

 

Edited 19 January, 20224 yr by paulski

Is the cooling system silicate bag only fitted to diesels or on all models?

 

I have a 2014 1.4tsi and wondering, if fitted, whether it should be removed at the next service.

Edited 20 January, 20224 yr by Gerrycan

I had one in my 2.0tsi.

I went to remove it, but it's been done by a garage already.

 

My concern now is, if I have G13, do I need to drain a bit and plop a bit of fresh G13 in, to top up the silicates?

Can you just change the whole lot to G12, are G13 and G12 compatible, as I wouldn't get all the G13 out.

 

13 hours ago, Gerrycan said:

Is the cooling system silicate bag only fitted to diesels or on all models?

 

I have a 2014 1.4tsi and wondering, if fitted, whether it should be removed at the next service.

See if the expansion tank has the wording "mat silikat" on it. If it has then your car is fitted with it

@ords  I went down the garage with my torch and checked it out straight away.

No 'mit Silikat' on it at all. Just the G13 for refilling.

Phew!

16 hours ago, RoddersUK said:

I had one in my 2.0tsi.

I went to remove it, but it's been done by a garage already.

 

My concern now is, if I have G13, do I need to drain a bit and plop a bit of fresh G13 in, to top up the silicates?

Can you just change the whole lot to G12, are G13 and G12 compatible, as I wouldn't get all the G13 out.

 

 

See post by varaderoguy here page 9 to show interchangeability of coolants