Coolant Woes..

[LukeyP_]

Hi All,

Just some help if I may....Mk1 Octavia 1.9 TDI 110 (ASV)

OK, so since having my timing belt replaced (really wish I had not bothered) I have had a few issues with the car. I'd really like peoples thoughts around this if possible...

1. Fuel pump was slightly out but this was fixed.
2. Coolant issues
3. Turbo pipe came off

Items 1 and 3 are now fixed, can't fault that.

On Saturday morning, after leaving the car stood for a couple of days - I checked coolant to find it had dropped again (2nd time in 3 weeks). Started it up and the coolant light started flashing, which I expected.

Now I am trying to narrow down what the issue could be and I'm thinking it could be air in the system, although the header tank is the highest point of the system. So I did the following;

1. Started it up, with coolant cap off.
2. Let the car get upto temperature, with the air vents/heating on full and varied the revs.
3. After 25 minutes, the car was at 90 degrees and coolant had risen.
4. The heater inside was FLAT COLD though, no heat coming through.
5. I started to squeeze the pipes into the car - flow and return and the pipe did start to get warmer.
6. Topped up the coolant and left the engine running

The car then was getting nice and toasty again, left it for a good 10 minutes and remained warm throughout. Yesterday, I took it for a run and left the car running whilst i nipped into B&Q (wife was in the car!) and the heaters remained warm - usually when stopping, they went cold.

Have I fixed the issue? Was it just an airlock that causing me to loose coolant?

I am not a mechanic, nor technically minded but I am trying my best to teach myself and learn it as I go along. One person on a Skoda group said it sounds like early signs of a head gasket, but not sure I am fully on-board with that given these issues have only started since the belt was changed.

Any advice appreciated. I will obviously keep eye on the coolant in the meantime, garage are aware but given my not so great experience - I'd rather fix it myself first.

Cheers

[Demelitia]

If it’s anything like a similar era Passat (probably will be) they the highest point of the system is often the heater hoses where they go through the bulkhead/firewall under the windscreen.
On my Passat after doing the cambelt and pump I had a bit of a faff bleeding it, ended up taking the return hose (?) off the heater matrix so the system filled the matrix, pushing the air out. You basically wait until it starts to come out of the bleed hole and then put the hose back on.
After that it’s just a case of making sure you’ve squeezed the hoses and your thermostat has opened to allow the full circuit to be purged.
If you still struggle, you can sometimes have results by either removing the expansion vessel off its brackets and holding it in the air, or getting the front of the car higher than the back, either on ramps or a hill and some blocks.
A decent drive out with a bottle of coolant in the boot is another option. Just keep topping up every so often until hopefuly, the level settles and stays correct.

[LukeyP_]

Demelitia said:

If it’s anything like a similar era Passat (probably will be) they the highest point of the system is often the heater hoses where they go through the bulkhead/firewall under the windscreen.
On my Passat after doing the cambelt and pump I had a bit of a faff bleeding it, ended up taking the return hose (?) off the heater matrix so the system filled the matrix, pushing the air out. You basically wait until it starts to come out of the bleed hole and then put the hose back on.
After that it’s just a case of making sure you’ve squeezed the hoses and your thermostat has opened to allow the full circuit to be purged.
If you still struggle, you can sometimes have results by either removing the expansion vessel off its brackets and holding it in the air, or getting the front of the car higher than the back, either on ramps or a hill and some blocks.
A decent drive out with a bottle of coolant in the boot is another option. Just keep topping up every so often until hopefuly, the level settles and stays correct.

Thanks for this, that is useful.

Just been to drop my daughter at nursery - car only got to 80 degrees (short trip) but was pushing nice warm air out. Pulled on drive and it did drop a bit, so revved it slightly and it got warmer so something is not quite right.

[paintman]

I wouldn't worry about the short journey.
Likely the system hasn't fully warmed & the thermostat is doing its job & allowing cold water from the radiator into the system.

As said, your first issue was almost certainly an airlock.
Keep an eye on the level over a few days.

[Demelitia]

LukeyP_ said:

Demelitia said:

If it’s anything like a similar era Passat (probably will be) they the highest point of the system is often the heater hoses where they go through the bulkhead/firewall under the windscreen.
On my Passat after doing the cambelt and pump I had a bit of a faff bleeding it, ended up taking the return hose (?) off the heater matrix so the system filled the matrix, pushing the air out. You basically wait until it starts to come out of the bleed hole and then put the hose back on.
After that it’s just a case of making sure you’ve squeezed the hoses and your thermostat has opened to allow the full circuit to be purged.
If you still struggle, you can sometimes have results by either removing the expansion vessel off its brackets and holding it in the air, or getting the front of the car higher than the back, either on ramps or a hill and some blocks.
A decent drive out with a bottle of coolant in the boot is another option. Just keep topping up every so often until hopefuly, the level settles and stays correct.

Thanks for this, that is useful.

Just been to drop my daughter at nursery - car only got to 80 degrees (short trip) but was pushing nice warm air out. Pulled on drive and it did drop a bit, so revved it slightly and it got warmer so something is not quite right.

When the blower motor is running on mine, one of the radiator fans comes on slowly, whether this is normal, or the same as yours I don’t know. If it is, it might explain your loss of temperature when sat on the drive.
The reading on the temp gauge is often not accurate; it’s normalised to a certain degree to stop it jumping about when the car is doing its thing with the thermostat and radiators.
If you’re concerned, you can buy cheap code readers that will tell you info direct from the ecu. I’ve got an autool x60 which is a handy little gauge doofer.

[LukeyP_]

Dropped car back in the garage again this morning, as I got the coolant light (although coolant doesn't seem to have been lost as much this time around) but still - something isn't quite right.

[LukeyP_]

Just spoke to the mechanic.

He has put a new thermostat on it and flushed the matrix, no obvious leaks so hopefully the thermostat was causing the loss.

[LukeyP_]

And the issues continue - this time coolant over the engine bay where it’s escaped.

Head has been tested and told it was okay. The coolant is over the max line so hopefully it’s just escaped and that’s it.

[Mave]

Where has it escaped from? Leaking hose? Dodgy pressure cap? If there's evidence of coolant over the engine bay then it's leaking somewhere...

[LukeyP_]

Mave said:

Where has it escaped from? Leaking hose? Dodgy pressure cap? If there's evidence of coolant over the engine bay then it's leaking somewhere...

Trying to establish where it is, the expansion bottle is now an inch over the max marker! I think it is still full of air