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coolant leak 05 v6

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33K views 101 replies 12 participants last post by  TRespect  
S
#1 ·
Hi,

I have a coolant leak that i am having trouble locating on my 05 v6. shortly after my coolant light came on, i replaced the water pump, which was the source of an obvious leak. now, it is still leaking slowly, with no obvious source. i think that it is somewhere on the passenger side, but the only place i have seen any liquid coming out is on the firewall. there is some kind of a weep-type fitting down low on the passenger side firewall and that was dripping when i ran it hot for a couple of hours yesterday. climate control is gurgling pretty loudly when i stop the vehicle hot as well.

any ideas??
 
S
#2 ·
On the 07 the AC condensate hose is on the passenger side, low down near the engine cradle. It also has a flap in front of the rubber hose sticking out the firewall. Mine stuck frequently and caused water to go into the cabin, so I tied the flap open slightly.

Do the radiator hoses feel full of coolant when you squeeze them when cold (no air gurgling). Are the radiator hoses pressurized when the cooling system is hot? A radiator shop may be able to test for combustion gas in the cooling system for you. Another thing might be that you still have air in the system, and it is slowly working its way out. Did you change the thermostat as well?
 
S
#3 ·
I was wondering if it might be ac condensate. that sounds pretty likely, but was the only liquid of any kind i could find.

the hoses do pressurize when the system is hot.
did not change the thermostat, it is not heating up always runs at 200.
i will squeeze the cold hose when i get home.

everything is functioning fine, it is just that i am losing coolant somewhere and cannot find where it is going. prior vehicle experiences make me think head gasket right away, but i am not sure if there is some other thing i should investigate.
 
#4 ·
Have you looked under the oil filler cap for the dreaded "mayonnaise"?

Or, when the engine is completely cold, have you looked in the coolant bottle for signs of oil?
 
D
#5 ·
I would check your coolant flange on the back of the engine. If you remove the belly pan and slide underneath the car and look up on the back side of the engine (drivers side) near the top of the engine, that is where the flange is (also houses the thermostat and coolant temp sensor). My flange currently has a small leak coming from this flange. Big repair cost (10 hours labor: have to remove tranny and drop engine per dealer). Hope yours isnt leaking but eventually it will.
 
N
#7 ·
Check the area referred to by dstiedeman.

It could be a slow leak on the new water pump, it happens sometimes. I would watch it both when cold and when hot, looking for any possible condensate. Have someone rev the engine somewhat while both cold and hot also while you are watching the pump. Or, modern way, put a camera on the pump and do it as a one person job.

It could be a slow leak near the heater core, which would put the few lost drops on the inside of the vehicle. Do you ever smell any coolant?

It could be a small leak thru any of the many many hoses. I once chased a small radiator leak for three years before I lucked into finding it. That one I could smell sometimes, and then it would not smell. Tiny pin-hole in a hose that only dribbled a drop when the engine hit high revs and the drop fell on the hot exhaust, disappearing completely without a trace.

Later models can suffer from coolant lost thru the water heated EGR system. I know the V8 AXQ is immune and I "think" that the early V6 you have is also.
 
B
#8 ·
Hi, I 've been finding the puddles for last month. Started with few drops, but last few days morning I found a bigger ones (under the vehicle). The coolant level is ok. I can see the that there is a coolant leak from the LH side of the engine block and this had been leaking for some time as the coolant has formed a large crusty stain on the LH side of the transmission bell housing.
I used the mirror and I detected some coolant stains on the thermostat housing. It looks that leaks is caused by bad seal on thermostat housing. I got the genuine thermostat with housing, but to install it need to take off the manifold. While doing this, was thinking maybe it wouldn't be a bad idea to change the hoses behind the engine, but to save a time, was thinking to order the hoses in advance. I can't smell coolant inside the vehicle, just found a puddles beneath. Thanks
 
N
#9 ·
It wounds like dstiedeman nailed the problem with the leak at the back of the engine description.

The hoses are probably OK at this point. It would be good insurance to change them, but for my personal vehicle I would visually verify they look good and reuse the old ones. If I ran a shop or if you were my mother, I would tell you to change the hoses just to sure. Better safe than sorry.

Just so there is not misunderstanding. If the hoses even look slightly wrong, then order the replacements. Don't keep using any hose that looks less then perfect. A used hose that looks wrong will be a hose that will find the worst possible time to bust and usually leave you stranded.

Even a perfect hose with that age might strand you, but a damaged hose WILL strand you at some point.
 
T
#10 ·
I decided to bring this back from the dead than to start another one.
I have a slow leak on my V6 3.2 and have replaced some parts. Next is a check of the thermostat housing and the coolant pipe on the driver side. What they call the crack pipe on the vr6 forums. Gruvenparts sell a cast aluminum one. They even sell the a cast aluminum thermostat housing. I will uplaod some pics of what I found wrong with my cooling system. I repaired some parts and ordered some other parts to go,on with chasing the leak.
I also have an AC leak but that will be on another thread when I start working on it.
 
T
#12 · (Edited)
More pics and a bare VR6 3.2 bonus :)
You can see the coolant temperature sensor, the coolant pipe on the driver side. The auxiliary coolant pump on the passenger side and a leaking hose near the auxiliary coolant pump. That hose has a Y connection on it that's brittle and was cracked/leaking too. VW does not sell the part separately for the Touareg (you have to buy the full hose for around 180€) but you can get it for 6 € if you provide the part number (I'll put it here later).
I bought a Porsche Cayenne auxiliary water pump with the all the complete hoses so I'm gonna swap the gunked coolant hose. Above the gunked hose sits the combi (egr) valve for the 3.2. I removed it to have access to the hoses and repair the leaking Y piece. I'll be replacing all the spring clamps and all.
 

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#99 ·
TRespect said:
More pics and a bare VR6 3.2 bonus :)
You can see the coolant temperature sensor, the coolant pipe on the driver side. The auxiliary coolant pump on the passenger side and a leaking hose near the auxiliary coolant pump. That hose has a Y connection on it that's brittle and was cracked/leaking too. VW does not sell the part separately for the Touareg (you have to buy the full hose for around 180€) but you can get it for 6 € if you provide the part number (I'll put it here later).
Click to expand...
Any chance of the part number for the y piece you mention (€6 vs €180!?)
 
#17 ·
Hello again TRespect,
Isn't there something strange about these pictures?
The outlet on the thermostat housing (upper one) points towards the bottom side of the radiator as for the inlet (thermostat side, lower one) points to the upper side.
In reality on a VR6 it is the other way round, isn't?
Au revoir :),
Pat
 
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T
#15 ·
Here is the Porsche part I bought to get both hoses and the pump for lest than 30€. So I have a spare pump and some spare hoses just in case. I didn't want to touch that gunked hose on the passenger side of the engine unless I have a replacement. I'm also getting heat/insulation material from aliexpress to protect the hoses. The pump sites behind the engine by the way.

237062
 
#19 ·
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#20 ·
Is the o-ring on the temperature sensor, located on the thermostat housing know to fail?
I have a small coolant leak and after hours of searching (even with an endoscope) i found that it is originating in the location of the temperature sensor: so sensor o-ring leaking, a little crack in the thermostat housing or a leak between engine and housing i think ...
 
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T
#21 ·
Not the temperature sensor but the second temperature sensor slot is.
There are two sensor ports on the thermostat housing. The right one is blocked by a plastic piece and an o-ring, same size as the one in the sensor. Mine was leaking from there. I replaced it and now all is good. But it might be the thermostat housing or what is called the crackpipe, the coolant pipe which goes from the thermostat to the water pump. Check my pics for more details.


Sent from my iPhone using Tapatalk
 
#24 ·
TRespect said:
Not the temperature sensor but the second temperature sensor slot is.
There are two sensor ports on the thermostat housing. The right one is blocked by a plastic piece and an o-ring, same size as the one in the sensor. Mine was leaking from there. I replaced it and now all is good. But it might be the thermostat housing or what is called the crackpipe, the coolant pipe which goes from the thermostat to the water pump. Check my pics for more details.
Sent from my iPhone using Tapatalk
Click to expand...
Crack pipe is completely dry and i'm happy for that as in my case it is also used to heat my LPG reducer ...
No: leakage certainly originates from around temperature sensor, so today i ordered a new sensor, a new plug and new o-rings: will be replacing those asap
If that does not solve the leaking, then i will have to replace thermostat housing ...
Difficult to reach, but i will try to do so without taking intake manifold off (luckely i am of the slender tipe hahaha, only my chest hurts from lying on the engine after surching for the leak from the connector on coil n° 1 poking me LOL) since i have just had it off to replace all 6 petrol and LPG injectors, solving my hot start problem.
At that time there was no leakeage o_O
Perhaps o-rings became brittle and perhaps i somehow manipulated the sensor or the plug a little allthough they are situated lower ...
 
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T
#22 ·
Here is something I’m working on which might interest you:


www.clubtouareg.com

Upgrading the 3.2 thermostat housing to a 3.6 one !

I started thinking about modding the thermostat housing on my V6 3.2 to make the thermostat easily accessible and serviceable and also make it bullet proof by upgrading it to a cast aluminum housing when I had an idea: My idea was to re-locate the thermostat housing by using a custom housing and...
www.clubtouareg.com www.clubtouareg.com


Sent from my iPhone using Tapatalk
 
#23 · (Edited)
TRespect said:
Here is something I’m working on which might interest you:
www.clubtouareg.com

Upgrading the 3.2 thermostat housing to a 3.6 one !

I started thinking about modding the thermostat housing on my V6 3.2 to make the thermostat easily accessible and serviceable and also make it bullet proof by upgrading it to a cast aluminum housing when I had an idea: My idea was to re-locate the thermostat housing by using a custom housing and...
www.clubtouareg.com www.clubtouareg.com
Sent from my iPhone using Tapatalk
Click to expand...
I'm following your thread :)
Problem is that i do not have as much space as you have in the engine bay: it's filled with my LPG equipment ...
I'm interested though in an aluminium thermostat housing (preferrable one without detachable thermostat cover) and crackpipe, combined with an inline thermostat :)
 
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T
#25 ·
According to Elsawin you don’t have to drop the engine to replace the thermostat. But I don’t think you will be able to do it without removing the intake manifold. Even the sensor is a pain if you don’t remove the intake. It’s not that difficult to remove unless you have your lpg setup in the way.


Sent from my iPhone using Tapatalk
 
#27 ·
TRespect said:
According to Elsawin you don’t have to drop the engine to replace the thermostat. But I don’t think you will be able to do it without removing the intake manifold. Even the sensor is a pain if you don’t remove the intake. It’s not that difficult to remove unless you have your lpg setup in the way.
Sent from my iPhone using Tapatalk
Click to expand...
I had the manifold and the lpg setup out twice allready so idd.: it is possible but i'm gonna at least try to not do it a third time right now, at least not for replacing the o-rings on sensor and plug: wish me luck haha
 
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#31 ·
Coolant leaking seems to be intermittant so together with replacing sensor, plug and o-rings once i receive them, i will be replacing overflow tank cap also (very low price) allthough pressure in radiator hoses doesn't seem a problem ...
 
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