Water leak underneath middle of car

[bflare]

Hello all.

I have a 2007 Leon FR & the coolant warning light came on Monday. I filled the tank up & it came on again after only a day. I could not see any visible leaks until this evening when I jacked up the car & had it running. At first, there were no leaks until I put the heater on warm & the leak started. It's difficult to see where it's coming from as it's dripping from the plastic trim underneath. The location is towards the center of the car which seems quite far back. I'm assuming its a problem with the heater system?

Has anyone had a similar problem & could offer any advice?

 

[Robbo86]

Hi,

Funnily enough I had a similar repair done on mine over the last 3 weeks. I thought it was firstly to do with the coolant flange that sits around the temp sensor as there was a build up of coolant sludge around this. That got replaced but it was still leaking, turned out to be both of the heater matrix pipes. Had them replaced and all was fine for nearly 2 weeks until I had done an 8 hours stint in the car and it happened again (big time, filling the coolant after every hour of driving). This time it was the pipe that feeds the EGR cooler. The under tray on mine was holding a considerable amount of coolant when I took it off but also, the coolant had travelled half way down the length of the car on the exhaust. The parts for this, providing yours turns out to be the same are relatively inexpensive and if you had a garage do it the labour time isn't massive.

 

[bflare]

Hi,

Funnily enough I had a similar repair done on mine over the last 3 weeks. I thought it was firstly to do with the coolant flange that sits around the temp sensor as there was a build up of coolant sludge around this. That got replaced but it was still leaking, turned out to be both of the heater matrix pipes. Had them replaced and all was fine for nearly 2 weeks until I had done an 8 hours stint in the car and it happened again (big time, filling the coolant after every hour of driving). This time it was the pipe that feeds the EGR cooler. The under tray on mine was holding a considerable amount of coolant when I took it off but also, the coolant had travelled half way down the length of the car on the exhaust. The parts for this, providing yours turns out to be the same are relatively inexpensive and if you had a garage do it the labour time isn't massive.

Thanks for your reply. It is difficult to see where the leak originates as it's dripping from the undertray as you say. I noticed this morning that the heater was blowing warm air when turned off. Not sure if this is normal? As I said previously i couldn't see the leak until I turned the heater on & it was then like niagara falls from the undertray towards the centre of the car!

 

[Robbo86]

If it isn't inside the cabin then I'd say it is likely to be one of the pipes rather than the heater matrix itself as this is located inside. After the fix, mine was blowing warm even when off (not as powerfully as it would when turned on but enough that you could feel it) I found if I turned it on and lowered the heat then turned it back off I couldn't feel the extra heat. I get the same if I've been using it on a hot day and had cold blowing out, when I turn it off cool air is still coming through but not as powerfully

 

[Rusty2k]

The heater matrix is on a permanently open circuit so the coolant flow is not affected at all by the heater controls.

Point a torch in from the top of the engine to have a look for any obvious leaks. You will need to take the under tray off to get a proper look at anything behind the engine though

 

[bflare]

The heater matrix is on a permanently open circuit so the coolant flow is not affected at all by the heater controls.

Point a torch in from the top of the engine to have a look for any obvious leaks. You will need to take the under tray off to get a proper look at anything behind the engine though

I wonder why the leak appeared to stop when I turned the heater off? Unless the water was from the AC & I have mistaken it for a leak but surely the AC unit wouldn't give off so much water? Also, I may have had the AC on for maybe 10 minutes after work but when I was inspecting the car for the leak this was at 10pm. I would assume that the AC unit would have dispersed most of the water by then?

 

[Robbo86]

@bflare what colour is the liquid that's leaking?

 

[bflare]

@bflare what colour is the liquid that's leaking?

It's clear just like water which is now making me think it's the AC & the leak must be somewhere else.

 

[Robbo86]

I wouldn't have thought it was AC as that is a gas and wouldn't leak out in vast liquid quantities .You can get condensation from the AC unit but it would be minimal. In your first post you mentioned the coolant light coming on and refilling the tank. Was the tank level low?

 

[bflare]

I wouldn't have thought it was AC as that is a gas and wouldn't leak out in vast liquid quantities .You can get condensation from the AC unit but it would be minimal. In your first post you mentioned the coolant light coming on and refilling the tank. Was the tank level low?

Yeah, the warning light came on originally a couple of weeks ago. I topped up the tank & it was ok until this Monday when the light came on again. The tank was definitely low. I topped up the tank once again & this time the light came on after only a day. I checked the level again this morning after driving to work & it's definitely losing coolant.

 

[Robbo86]

Just to check for my understanding (really not trying to imply anything about you) you are loosing coolant but what you are seeing under the car is a clear liquid. Are you using g12++ or even g13 when filling? If you are using the pink fluid to top up the coolant and loosing it bit not out the bottom have you noticed your car smoking at all?

 

[bflare]

Just to check for my understanding (really not trying to imply anything about you) you are loosing coolant but what you are seeing under the car is a clear liquid. Are you using g12++ or even g13 when filling? If you are using the pink fluid to top up the coolant and loosing it bit not out the bottom have you noticed your car smoking at all?

Your reply got me thinking. I put a bowl under where the fluid was dripping and collected it. It was just like clear water so it must be from the AC. I assumed that there must be a leak somewhere else so i had my son rev the car while I looked underneath and I noticed splashes of water which I traced back up to a split pipe shown in the pic. Off to the scrap yard in the morning for a bit of hose and a spring clip I lost taking the pipe off. Hopefully it will be sorted then.

Thanks for your help.

 

[Robbo86]

No problem. Try where I can although I am now stumped as that is the pipe from the expansion tank

 

[Robbo86]

No problem. Try where I can although I am now stumped as that is the pipe from the expansion tank

Although I don't know what colour the heated coolant would cool down as

 

[bflare]

No problem. Try where I can although I am now stumped as that is the pipe from the expansion tank

Yes but it's teed off to the engine block. It's from that end it was leaking.

 

[Robbo86]

Ahh