1 hour ago, TheClient said:

I'd say for anyone diy ing it without a vacuum fill it's very normal to have some air pockets.

 

If they vacuum filled and test drove it up to temp, it shouldn't really happen but i suppose it can as they are prone to some air pockets.

 

This is assuming there is no leak from their reassembly. It might be hard to spot if there is one. But you could check rad hoses and matrix hoses on the engine side. You won't be able to see under dash but could check for wet carpet. 

 

also, you shouldn't keep filling up with only water as you will dilute the coolant so may need to add half what you've added neat. Ideally you should use demineralised or distilled water as well. 

 

If you can spare time maybe worth calling them and arranging to check for leaks and add the neat coolant for the water added. 

Thanks for the response 

 

I’ve been topping the coolant up with a ready made G12 solution which is what the garage filled the system with.

 

I guess the question is how many times do you keep topping the coolant up before you come to the conclusion that the issue isn’t air pockets but a leak.

 

I will make some checks - the carpet would be an obvious one if there is a leak connecting to the heat matrix. I believe the hose connections to the matrix are on the engine side. The rad hoses shouldn’t have been touched but could have been disturbed during the work. If it’s something easy to fix it would save a lot of hassle.

 

 

13 hours ago, Moribund said:

Thanks for the response 

 

I’ve been topping the coolant up with a ready made G12 solution which is what the garage filled the system with.

 

I guess the question is how many times do you keep topping the coolant up before you come to the conclusion that the issue isn’t air pockets but a leak.

 

I will make some checks - the carpet would be an obvious one if there is a leak connecting to the heat matrix. I believe the hose connections to the matrix are on the engine side. The rad hoses shouldn’t have been touched but could have been disturbed during the work. If it’s something easy to fix it would save a lot of hassle.

 

 

It's hard to say. If it does it once or twice more I'd definitely get it checked. But there's no magic number of times. 

After topping up on Sunday I went for a drive last night and when I inspected the coolant level tonight it appeared ok

 

However I turned on the ignition and I get a low coolant warning. Doesn’t seem right. I topped up a very small amount of coolant mixture and the warning disappears. Is it possible that the sensors are faulty?

 

9 hours ago, Moribund said:

After topping up on Sunday I went for a drive last night and when I inspected the coolant level tonight it appeared ok

 

However I turned on the ignition and I get a low coolant warning. Doesn’t seem right. I topped up a very small amount of coolant mixture and the warning disappears. Is it possible that the sensors are faulty?

 

The coolant header tank sensor is very sensitive. My recommendation is that you keep it at Maximum all the time. If you do lots of runs, I found that TDI engines use a little coolant (ie keep an eye on it). It may well be that an air pocket was formed. This is why I see many techs do coolant changes and then pressure feed new coolant into the system. It means no air pockets. Don't be alarmed if you initially have a drop in coolant post doing work on the coolant system...it's just air being expelled from the system. If you are regularly loosing coolant, then that's a bigger problem and you have a leak somewhere.

On 17/01/2024 at 05:47, varaderoguy said:

The coolant header tank sensor is very sensitive. My recommendation is that you keep it at Maximum all the time. If you do lots of runs, I found that TDI engines use a little coolant (ie keep an eye on it). It may well be that an air pocket was formed. This is why I see many techs do coolant changes and then pressure feed new coolant into the system. It means no air pockets. Don't be alarmed if you initially have a drop in coolant post doing work on the coolant system...it's just air being expelled from the system. If you are regularly loosing coolant, then that's a bigger problem and you have a leak somewhere.

Thanks for the response. I’m not convinced I’m losing coolant - I’ve been checking the level every day. The picture below shows the level in the tank tonight. I turned on the ignition at lunchtime and no warning message came on - got in the car tonight and the message comes up. I removed the cap off the tank and put it back (without adding coolant) and message is gone. I drove for 20 minutes and no warning. Doesn’t make sense to me.

 

 

It might well be that there is internal resistance on the metal prongs in the header tank. A new tank isn't expensive, so maybe try that as an option.