Another Coolant Loss Thread.

[Simoneale1973]

I bought my Octavia SE Estate TDi 150 over a year ago, it had been stood for about 6 months, but the seller said it had no problems before He gave up driving (age and infirmity) It had only done 32k miles on a 2013 (63) plate!

 

I had my local dealership give the car a once over, checking everything, and got the car serviced. it has been doing me very well, but during the hot weather last year it started throwing up a Low Coolant warning, I topped it off and went on (thinking it was something to do with the time it was stood) but it came back about 3 weeks later again 'Low Coolant' so I had the Dealership pressure test the system etc.., No problems according to them, apart from the Header tank being a bit on the dirty side (but the Bag is still intact!!) but the system Pressurised and didn't leak! They changed the Cap as the seal was a bit gunky!

 

This went on for maybe a few more times, till the Temperature outside dropped, probly October Last year!. Things settle nicely no more Low Coolant warnings!

 

I then about 6 weeks ago took the car for it's next service which included Timing Belt and Water Pump this time (42k miles now on the clock). Que 2 weeks later the Low Coolant Light coming on again, I still had some left in the bottle in the boot and Topped it off again! No problems till yesterday when it warned me again! 

 

I can't see any puddles on my drive, or at work in the car park, There's no Smoke from the exhaust (black or white), the Oil is nice an nutty coloured (and not high or low) The Header bottle is still dirty, but the bag is intact!

 

I have a couple of questions..

 

1, Have I or the Garage missed anything!? Could there be a major problem brewing, or is it a feature!?

2, Would it be worth replacing the Tank? for maybe something like Amazon - Radiator Coolant Expansion Header Tank (or any other recommended if you could!!!)?

3, How easy is it to 'successfully' fit the Header Tank myself??

 

Any Help would be Fantastic!

 

Thanks Guys!

[Warrior193]

Hello Simon, definitely get rid of the silicate bag by replacing the expansion tank for a start - very easy and quick job - a tip, get yourself a set of the proper hose clip pliers, they make removing and refitting the clips so much easier. I'd also consider a cooling system flush - but I see that you had the water pump replaced, so that should have already been done. One thing that might have happened is that the system wasn't properly purged of air when the pump was replaced - I believe that this requires using VCDS (or similar) to avoid airlocks in the system.

[Gammyleg]

19 hours ago, Warrior193 said:

One thing that might have happened is that the system wasn't properly purged of air when the pump was replaced

 

That happened when I had a new belt, pump & idler fitted by an indy. Took about 3 weeks ( 1500 miles ) of top-ups to fully burp itself, no problems since. Suspect they didn't follow the correct procedure with the VCDS.

Edited 14 July, 2023 by Gammyleg
added mileage

[Simoneale1973]

4 hours ago, Gammyleg said:

 

That happened when I had a new belt, pump & idler fitted by an indy. Took about 3 weeks ( 1500 miles ) of top-ups to fully burp itself, no problems since. Suspect they didn't follow the correct procedure with the VCDS.

Weirdly this time round, when topping up, there's a 'Burping' (as you put it) happening!! Lots and Lots of Bubbling. Where as last year it just topped up and that was that!

 

So maybe it is an air lock! Fingers Crossed!!

[Cap44]

Check that you have the same temp coming out of the 4 vents on the dash. If not you have a blocked heater matrix that will cause all sorts of problems with the flow to other things while doing regenerations. Lots of information on TDi club including dealer's who have changed head gaskets, inlet manifolds charging £1k's at a time and not curing the problem.    All it needs is a £80 matrix  and 2 hours labour if you do it yourself.

[T07]

Egr coolers and charge coolers also fail on these which can introduce air and air locks into the matrix aswell. Hard to track down internal coolant leaks, but the matrix is probably an easy one to replace and rule out.