At wit's end with a coolant issue

[Ian_E_UK]

My Superb TDi 190 4x4 L&K has developed a persistent issue with coolant leakage that is driving me mad (and poorer). The car has 110k miles on it.    

About four months ago the coolant warning light came on so I topped up the header tank (between the min and max mark).  After a 400 mile round trip later in the week it was almost empty again.  This cycle carried on for a few weeks when I managed to get it into the local Skoda main dealer.  

They replaced the coolant header tank and water pump...I also took the opportunity to have the timing belt changed (£800 total) .  After 2 weeks the coolant tank was empty again.    

The car went back into the main dealer who pressure tested it overnight and found no leak but said there was a little moisture visible in the charge air cooler.  

 

I took the car to an independent garage a few of weeks ago who pressure tested it again but found no leak so we initially tried fitting a new cap on the coolant header tank.....but no joy.   It only seems to lose coolant when driven. 

The garage then replaced the charge air cooler a couple of weeks ago (£1100) and I topped up the header tank during the next few days as the engineer said the level would go down immediately after the work.  They also showed me a video of the old part in a water tank with bubbles clearly escaping near one of the connections.    

It's now 10 days later and it's been through a further litre of coolant and the warning indicator came on again this evening....tank almost empty.  I now also have an amber engine warning light on constantly (emissions issue ?).  It'll be going back in to the garage this week. 

  

I really do like the car so am willing to take one more punt on repair but thought I'd see if anyone here has experienced similar issues and found a solution before I risk throwing more money at it.  

The Skoda main dealer did mention that if the charge cooler replacement didn't work it is probably the EGR, which would involve a further outlay of several hundred £. I really need to be sure this time.     

 

The car was registered at the beginning of 2019 so is now out of warranty.  I'm in the Liverpool area so if you know any garages that are solid and could help then please let me know.

 

    

[J.R.]

I might be having a senior moment but I thought the turbo intercooler was an air to air heat exchanger so even if it had a tiny leak I cant see how that would pressurise the cooling system.

 

I do hope that they havnt been playing parts bingo with you.

 

A leaking EGR cooler is a possibility but that should have shown up on the pressure test, the thing that may not would be a combustion leak from the head gasket and I would have expected them to have done a gas sniff test before emptying your wallet on things which were not causing the problem.

[ApertureS]

8 hours ago, J.R. said:

I might be having a senior moment but I thought the turbo intercooler was an air to air heat exchanger so even if it had a tiny leak I cant see how that would pressurise the cooling system.

 

I do hope that they havnt been playing parts bingo with you.

 

A leaking EGR cooler is a possibility but that should have shown up on the pressure test, the thing that may not would be a combustion leak from the head gasket and I would have expected them to have done a gas sniff test before emptying your wallet on things which were not causing the problem.

On the newer tdi they are often air to water coolers.

 

that is a crazy case of loading the parts canon and seeing what sticks!

 

sounds like your only possible options are;

 

dsg cooler

oil cooler

heater core 

EGR valve 

head gasket

 

all of which can be gone through and eliminated or require further investigation like J.R said, a sniff test will eliminate egr and certain types of head gasket failure.

[Breezy_Pete]

Could potentially rule in/out the EGR cooler by bypassing it temporarily so coolant flow doesn't go through it.

[J.R.]

I am always suspicious of garages that say they did a pressure test and there was (they found) no leak, I dont think most of them understand the principles of aerostatics and fluid statics, if there is a pressure drop over time then there has been a leak of fluid or air from the system or tester, many think that if they cannot see fluid then there is not a leak.

4 hours ago, ApertureS said:

On the newer tdi they are often air to water coolers.

More compact?

[Kevinmaj]

Really sorry to hear about your issues Ian and hope they get resolved soon.  From experience you would hope a main dealer would be able to diagnose the issue and fix it, especially if they are charging you top dollar for the works.  I had a similar issue initially with my last 2016 L&K, it was leaking coolant whenever it felt like and was having to continually top up for many weeks, but some days it would be fine driving and others were not and it would just leak the coolant.  This was in 2020 when Covid hit so dealer would not take the car in.  Luckily the car went in eventually as it needed a new cam belt/water pump @100K miles and they found an issue I believe with coolant tank and just replaced it at no cost to me (just the cam belt/water pump) , perhaps because it took a long time to get the car booked in.   

 

They are great cars when they work and I've just bought another one after issues with the DPF but a Sportline this time.  The last car had a lot of miles on it when i bought it and despite a FSH I don't think it was well looked after.

[Awesam]

There is a coolant pipe at the back of the engine which may be lose or the seal has gone - I think the downpipe may need to be removed to get to it.

 

I had an issue of losing coolant when it was on the dyno otherwise it was fine when driving normally/steady.  Upon acceleration the coolant was dripping out.

[Ian_E_UK]

Thanks for all your comments which have given me plenty of food for thought. 

 

The car is going back in to the garage later this week for further investigations.  I'll keep you posted.

[numskull]

Where are you located, Ian? I ask as helps other members who are local to you, who can potentially recommend an indie with whom they’ve had a good experience. 

[Ian_E_UK]

11 hours ago, numskull said:

Where are you located, Ian? I ask as helps other members who are local to you, who can potentially recommend an indie with whom they’ve had a good experience. 

I'm near Huyton in Liverpool. 

[numskull]

Can anyone help Ian with the name of a decent indy in the Liverpool area??? 

[Awesam]

http://www.unit82performanceparts.co.uk/

 

Unit 82 - VW specialist - I've heard good things about them.

[Danoid]

Personally I’d get something like this https://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=230723938073&category=43998&pm=1&ds=0&t=1640273183000&ver=0&cspheader=1

 

Then one evening go out and have a look, cheap enough and easily DIY

[SuperbTWM]

On 03/10/2022 at 10:28, J.R. said:

 

More compact?

 

adds an extra electric pump and another radiator but it does save on a hell of a lot of intercooler pipework which probably helps a lot with throttle response

 

On 03/10/2022 at 08:02, Breezy_Pete said:

Could potentially rule in/out the EGR cooler by bypassing it temporarily so coolant flow doesn't go through it.

I'm not sure it could be driven like this, i'm not 100% sure where the exhaust gasses are taken off the manifold but i can imagine if its after the DPF and its doing a regen its going to be very hot and could potentially melt the egr valve or parts of the intake if there is no cooling

Edited 5 October, 2022 by SuperbTWM

[Breezy_Pete]

If the EGR was fed from post-DPF they wouldn't clog up with with soot like they do, I think?

Not sure on such a recent engine/car to be honest.

Edited 5 October, 2022 by Breezy_Pete

[J.R.]

EGR takes pre DPF exhaust gases AFAIK.

[Breezy_Pete]

I think some recent versions have two EGR systems, high and low pressure. Lucky owners...😆

[J.R.]

I will have to go out and get me one of them then without delay!

 

 

NOT!

 

Chief Brody says I'm going to need a bigger notepad for my list of reasons not to buy a newer car.

[Ian_E_UK]

Update:  The car went into the garage again last week. They found a secondary coolant leak caused by a broken clip on a hose which was replaced.  I drove 300 miles over the weekend and the coolant level appears to be holding steady. Fingers crossed it stays this way. 

 

Thanks for everyone's comments and advice!

[steevs]

On 12/10/2022 at 07:49, Ian_E_UK said:

Update:  The car went into the garage again last week. They found a secondary coolant leak caused by a broken clip on a hose which was replaced.  I drove 300 miles over the weekend and the coolant level appears to be holding steady. Fingers crossed it stays this way. 

 

Thanks for everyone's comments and advice!

 

Hi Ian, not sure if you're still around here.

 

Pretty sure I have the same engine as yours (DFHA?)

 

Was the pipe replaced in this last reply the root cause of the leak? 

 

I'm currently having a pretty slow loss of coolant, takes about 3 months to empty a tank but I've previously never had to fill a coolant tank between coolant services on any VW group vehicle. It also worries me that it may suddenly get worse when I'm not the main driver.

 

No sign of head gasket issues, car otherwise runs spot on.