Hi all
I own a 2007 VW Golf 5, 1.9TDI diesel.
Car is very nice to drive and has enough power when needed.

I do have one irritating problem with it. It looses coolant. There is no leaks and pressure test and block test came back positive.
I suspect the water pushes back into the reservoir and escapes via the overflow. This happens even overnight when the car is stationary. When I remove the cap of the reservoir and let it stand like that overnight, no coolant is lost.

Remedies thus far:
Flushed system (done by mechanic so does not know if it was done properly)
Replaced thermostat.
Replaced cap of resevoir.

The guys at radiator King in Maitland did some testing and no leaks could be traced.

Found some info about the EGR (Exhaust Gas Recirculation) on the web and it looks like this is where the problem is. I have no idea where the EGR valve is or what can be done about is.

Mechanical experts are dumbfounded on this one. Dealers want to replace radiator, waterpump and what else ($$$$$$$). I just do not have the money to fund someone's experiments.

Update:
Replaced EGR cooler (5K+). Still loosing coolant

could it not be leaking into the heater matrix

Coolant ends up under the car, driver side (right).
Checked for wetness inside car (passenger side), nothing.

Strange is that most of the loss occur only when there is pressure in the cooling system. If I leave the reservoir cap off, there seems to be no loss, cos I see nothing under the car.

Only thing drivers side is the water pump. Did u strip the covers over cambelt and water pump.

mine has that fault. I have to top up every week. I found that the pipe from the top of the reservoir that runs somewhere near the engin has a leak where the rubber gromet covers it. will post a pic up soon.

keval wrote:mine has that fault. I have to top up every week. I found that the pipe from the top of the reservoir that runs somewhere near the engin has a leak where the rubber gromet covers it. will post a pic up soon.

That would be the pipe that returns the coolant to the reservoir.

Mine looses coolant while the car is standing overnight, or maybe it accumulates on the cover and runs out when car is stationary.
Still don't make sense as it does not loose the coolant when I remove the cap to release the pressure. Only with pressure in the system it looses the coolant.
Maybe a very small leak in a pipe or the radiator.

I am tempted to put Radweld or something similar in the coolant to see if it solves the problem.

TDIKop wrote:

keval wrote:mine has that fault. I have to top up every week. I found that the pipe from the top of the reservoir that runs somewhere near the engin has a leak where the rubber gromet covers it. will post a pic up soon.

That would be the pipe that returns the coolant to the reservoir.

Mine looses coolant while the car is standing overnight, or maybe it accumulates on the cover and runs out when car is stationary.
Still don't make sense as it does not loose the coolant when I remove the cap to release the pressure. Only with pressure in the system it looses the coolant.
Maybe a very small leak in a pipe or the radiator.

I am tempted to put Radweld or something similar in the coolant to see if it solves the problem.

Please dont. Check for leak marks as g60 golf has suggested.

Ok I will stay away from those quick fixes. There has to be a small leak somewhere.
Will check those hoses at the back that goes into the body of the car. One of then broke sometime ago when a bolt that secures the mounting bracket broke and the whole engine move forward. Only noticed it when I replaced the pipe at the back and replaced broken bolt and moved engine back into position.
When EGR cooler was replaced, the two black plastic connectors on those hoses was also replaced, but some inspection there may not do any harm.

So next step.
I will take the car to mecchie on Friday. Cover underneath will be removed. He will then check in the morning. Says he may put some colouring stuff in the coolant and check with a special light. Like what the aircon guys do to check for gas leaks.

I just want to get to the bottom of this.
One thing for sure, won't buy a diesel any time soon. Maybe a BMW one.
Fuel consumption is not worth it at all in my situation. I only get about 7.4l/100km with the Golf 5 TDI, with very conservative driving on the highway. Hell I have BMW that give the same with petrol on the very same road.

Well if the egr has been worked on then it could be the problem.

Sounds like you need a new mechanic.
The proper g12 coolant that vw uses actually shows ubder a black light already so there is no need to add special dyes.

Sent from my GT-I9100 using Tapatalk 2

amstel18 wrote:Well if the egr has been worked on then it could be the problem.

Sounds like you need a new mechanic.
The proper g12 coolant that vw uses actually shows ubder a black light already so there is no need to add special dyes.

Sent from my GT-I9100 using Tapatalk 2

To be fair, I was the one who put other coolant in there. I just hate to buy overpriced stuff from the stealers.
Must find ou what that stuff cost and get it.

Try to source the leak first and fix. Then flush your coolant system out proberly before you put the G12 vw coolant in.

TDIKop wrote:

amstel18 wrote:Well if the egr has been worked on then it could be the problem.

Sounds like you need a new mechanic.
The proper g12 coolant that vw uses actually shows ubder a black light already so there is no need to add special dyes.

Sent from my GT-I9100 using Tapatalk 2

To be fair, I was the one who put other coolant in there. I just hate to buy overpriced stuff from the stealers.
Must find ou what that stuff cost and get it.

I hace read of guys having all kinds of problems when using any other coolant except for g12/13. Anything from seals getting hard to head gaskets. It cant be absolutely confirmed that it was the coolant but im sure vw uses a certain coolant for a reason.

Same with the oil. Use only proper spec oil. You may have done more damage by using other coolant.
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It is not like G12 is uber expensive at around R70 per bottle...

Ok will get me 2 bottles of that coolant next time. What about mixing it, like what ratio and do you need to use distilled water?
Think distilled water is about R20 per bottle

No you don't need distilled water.

Itsa 60 40 split.
40 coolant. If u can pressure test thesystem overnight also do a leak test at silvertens maybe thehead cracked or gascket leaking.

Done extensive tests at Radiator King Maitland (Arrogant guy at Silvertons in Parow piss me off). No leaks found.
It looses most of the coolant overnight, when the car stands in the garage. If I open the reservoir cap to release the pressure, then it does not loose any coolant. Some are lost while driving but it take a couple of days.
I noticed that the mecchie did put in G12 coolant and gave me the left overs, so I just fill up when needed.
Now I just feel like driving the car until the leak/problem is in my face.

I am driving a Golf5TDi 2.0 and I experience sort of the same problem by loosing coolant. However, I had an accident with the vehicle over a year ago and the panelbeaters (in fact VW Hatfield) replaced both radiators but it took me actually some time to notice that there is no coolant (G12) in the water. I decided to do the job myself and purchased three bottles (litres) but could not find the drain plug to flush the system first though I removed the bumper and everything I found to be in the way to get to the drain plug. Eventually I removed the lower intercooler pipe (driver's side) to get to the outlet hose from the radiator coz I could not also remove the top hose (inlet) to the radiator, passenger side, plastic coupling. I could also not remove the lower hose (plastic coupling) from the radiator and after a very long struggle "twisting" and "turning" and pulling back and forth, I managed to uncouple the rubber connection and drain the water from the radiator. After closing up the connection, I filled the cooling system with the required G12/water mix. To my surprise and after a couple of days, I noticed that I am loosing coolant and it seems like from the radiator (in the area underneath the car's front bumper, and to more or less the middle of the said area) and not only coolant but oil leaking from the intercooler pipe (joint). I took a Saturday again and stripped but could not establish exactly where the water leak comes from but its like I need to top up every third day or so. I removed the intercooler pipes and reinstalled but it is still dripping oil, should I put cover the joint with RTV or something before I reconnect? But coming to the coolant leak, I don't know what to do anymore but the leak is frustrating, it could have helped if I could remove the radiator but I struggle to figure that out. I saw a remedy of Radweld and I also know that Cayenne pepper or White pepper can do the trick but how do I get it straight in the radiator. is it wise to use Radweld? PLEASE HELP

BazzyB wrote:I am driving a Golf5TDi 2.0 and I experience sort of the same problem by loosing coolant. However, I had an accident with the vehicle over a year ago and the panelbeaters (in fact VW Hatfield) replaced both radiators but it took me actually some time to notice that there is no coolant (G12) in the water. I decided to do the job myself and purchased three bottles (litres) but could not find the drain plug to flush the system first though I removed the bumper and everything I found to be in the way to get to the drain plug. Eventually I removed the lower intercooler pipe (driver's side) to get to the outlet hose from the radiator coz I could not also remove the top hose (inlet) to the radiator, passenger side, plastic coupling. I could also not remove the lower hose (plastic coupling) from the radiator and after a very long struggle "twisting" and "turning" and pulling back and forth, I managed to uncouple the rubber connection and drain the water from the radiator. After closing up the connection, I filled the cooling system with the required G12/water mix. To my surprise and after a couple of days, I noticed that I am loosing coolant and it seems like from the radiator (in the area underneath the car's front bumper, and to more or less the middle of the said area) and not only coolant but oil leaking from the intercooler pipe (joint). I took a Saturday again and stripped but could not establish exactly where the water leak comes from but its like I need to top up every third day or so. I removed the intercooler pipes and reinstalled but it is still dripping oil, should I put cover the joint with RTV or something before I reconnect? But coming to the coolant leak, I don't know what to do anymore but the leak is frustrating, it could have helped if I could remove the radiator but I struggle to figure that out. I saw a remedy of Radweld and I also know that Cayenne pepper or White pepper can do the trick but how do I get it straight in the radiator. is it wise to use Radweld? PLEASE HELP

No, its not wise, please dont do it!

It could be the radiator core thats leaking. Best would be to remove all and check.
Oil will always seap out the boost pipes.

The first tdi is it dsg or manual. If dsg has the dsg oil been checked for ingress of water?

Thx for ur response guyz. I think i ll strip and remove to check out the leak. In response, it is not a DSG. Worst case scenario, where can i get a new radiator for a good price or once radiator removed what can i use to seal the leaks? Anybody have a step by step guide to remove the radiator.

Been driving around and occasionally topup the coolant as needed.
So took a long trip and had to stop a couple of times to top up the coolant.
This car is really making me angry .
Checked the coolant the other day and it is now turning black. No water in the oil and I cannot detect any oil in the water either.
My guess is this is from the exhaust.
The new EGR I had fitted ($$$$) made no difference.
Is it a good idea to have the entire intake cleaned out?

TDiKOP, this is one strange problem that you experience which i have never heard of before. Maybe some of the other guys might be of assistance . But in my case i manage to remove the radiator myself, found the leak (on the radiator) and sealed the leak with QBond. Quite honestly, it took me about 30 minutes to remove the radiator completely after i haven't had a clue ow to

Howzit Guys,

I had the same issue with my jetta 4 tdi. was doing the exact same thing at first where it should lose water over nyt. started off with just about a cup full lose and then after a while the water bottle used to be totally empty in the morning. I have checked every possible thing to check for leaks with no luck. also check the heater radiator as the drivers side carpet used to be wet. I eventually blocked that off which helped for a day or two but started again. Had to replace the headgasket and all sorted. no more water lose.

Ok still struggling.
Replaced waterpump as suggested by another expert. Cost me over a grand (parts and labour).
No joy.
Water still pushes out through overflow in reservoir.

Note to self. NEVER EVER buy VW crap again.