Loss of Coolant from Expansion Tank and i don't know why???

YKFR

Active Member
Jul 23, 2019
51
8
Hi all,

Just seen this thread. I posted something similar on here as well but at that time I didn't know how expansion tank was getting empty. After catching it in the act i was able to see that coolant was leaking from tank.

In my case its also a Leon FR 14 plate 184 version (Diesel). What happens is that, coolant is rising it self past where I originally fill it up to. It is going past the max line and, as it keeps going up; the safety feature which is the release valve kicks in and the coolant escapes.

I monitored it twice when coolant escaped. I filled it up quite less than max second last time and it overflew by it self and escaped. And then I filled coolant back up but just at minimum. It has however not leaked yet and its been like 3 weeks.

I am having to open up the cap on the tank and letting pressure out and then closing it again. I think this is helping the cause and preventing it from over flowing.

But aside from that when I go anywhere more than 15-20 miles the coolant leaks out regardless.

I paid over £200 to get the car tested. The tank and cap have been replaced. And the tests were done by a VAG specialist. They ran tests on the EGR cooler, which came back negative.

They have ruled out EGR cooler and they have said that it wouldn't be the heating matrix with these symptoms. Also the water pump was replaced by SEAT in March this year.

Only thing they can say it most likely is, the head gasket or crack in engine block. But keeping in mind that I have had the car since end of June and it runs fine with no dashboard lights coming on.

Any words of wisdom anyone?
 
Aug 5, 2019
8
1
Hi all,

Just seen this thread. I posted something similar on here as well but at that time I didn't know how expansion tank was getting empty. After catching it in the act i was able to see that coolant was leaking from tank.

In my case its also a Leon FR 14 plate 184 version (Diesel). What happens is that, coolant is rising it self past where I originally fill it up to. It is going past the max line and, as it keeps going up; the safety feature which is the release valve kicks in and the coolant escapes.

I monitored it twice when coolant escaped. I filled it up quite less than max second last time and it overflew by it self and escaped. And then I filled coolant back up but just at minimum. It has however not leaked yet and its been like 3 weeks.

I am having to open up the cap on the tank and letting pressure out and then closing it again. I think this is helping the cause and preventing it from over flowing.

But aside from that when I go anywhere more than 15-20 miles the coolant leaks out regardless.

I paid over £200 to get the car tested. The tank and cap have been replaced. And the tests were done by a VAG specialist. They ran tests on the EGR cooler, which came back negative.

They have ruled out EGR cooler and they have said that it wouldn't be the heating matrix with these symptoms. Also the water pump was replaced by SEAT in March this year.

Only thing they can say it most likely is, the head gasket or crack in engine block. But keeping in mind that I have had the car since end of June and it runs fine with no dashboard lights coming on.

Any words of wisdom anyone?
I would try changing your heater matrix. It worked for me even though I thought it wasn't the problem.
 

YKFR

Active Member
Jul 23, 2019
51
8
I would try changing your heater matrix. It worked for me even though I thought it wasn't the problem.
Did you have same problems as I am facing? Also the heating matrix doesn't cost much but its the labor time on it which is costly, cause of taking it apart and coolant flush etc.

How did you get that done? Cause I don't know much about DIY when it comes to cars.
 
Aug 5, 2019
8
1
Did you have same problems as I am facing? Also the heating matrix doesn't cost much but its the labor time on it which is costly, cause of taking it apart and coolant flush etc.

How did you get that done? Cause I don't know much about DIY when it comes to cars.
I had the exact same problems and changed the heater Matrix myself. Total time for the job was less than two hours. The most time was spent running the flush through the system and draining out the system. If you read on the forum on what to do you only need to remove glovebox and the bottom of the heater fan to get to the heater matrix to change it.
I hope this helps and gives you confidence to have a go yourself.
 

YKFR

Active Member
Jul 23, 2019
51
8
I had the exact same problems and changed the heater Matrix myself. Total time for the job was less than two hours. The most time was spent running the flush through the system and draining out the system. If you read on the forum on what to do you only need to remove glovebox and the bottom of the heater fan to get to the heater matrix to change it.
I hope this helps and gives you confidence to have a go yourself.
Thanks for the words of confidence. I think its probably the heating matrix. Even though I was told its probably head gasket or cracked engine. But car is running fine for more than 3 weeks and its been more than 3 months since I have had it...

Where did you purchase your new heating matrix from? And how did you go about with flushing coolant until it was clear. I will look at videos on how to do it too. Thanks.

PS: did you ever get told it was something to do with the engine or did you fear that?
 

YKFR

Active Member
Jul 23, 2019
51
8
An update, my coolant was sprayed out of the expansion tank today. I caught it while it was overflowing. It had been almost 1 month since it did that. The fan was on and resting revs were 1000 since yesterday. So I am to assume that car was in dpf regen mode?

Come to think of it this has only happened when the fan was running or the car was going really fast.

Could this be related to heating matrix being blocked partially? Also the hot air coming out from my side as compared to passenger side is different in temp even though the temp setting is same. They are both warm/hot but passenger side gets hotter a lot quicker.

Any one can advice or give any ideas that my hearing matrix is blocked? Or my engine/head gasket is the problem?

Would be a lot of help, thanks...
 
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