Coolant leak behind the engine 5.2 V10

A6 All/ S6 All
#1

Hello
I m new in this forum
I have a S6 2007 5.2 V10, sins a year ago i considered a coolant leak from the right side of the engine.
i have checked everything from radiator , hoses and changed the coolant reservoire and cap aswel

last weekend i finished the carbon clean and i couldnt see any leak from the coolant pipe behaind the engine

now is still leaking and i think it is the O ring for the coolant pipe .

my question is it possible to change them with engine in car or it is engine drop job

thanks :slight_smile:

#2

I’d say possibly doable, but tough with a lot of tear down

#3

So its possible to do ?
I know i need to tear down a lot of hoses and stuff, but i wonder if i need to take out the intake manifold again or only all vaccum and other hoses and stuff…

i think i have a leak on the left side behind the engine :roll_eyes:

#4

Check this, can be cracked
Collant plastic line

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#5

For the transfer pipe - yes, you would need to take the IM off again. However, before any teardown you should do a leak pressure test, to locate the leak and not go blind.

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#6

I already did a pressure test amd it drops about 0.5 bar on maybe 30 min.
But I coud not found the leak anywhere. The coolant leak under the car about the right driveshaft !
So the next think is that pipe.
Hoses connected to that pipe is not leaking eather. So the only one i could not see is the O ring to the rear pipe!

#7

I’ve already changed that plastic Y fitting last year.

#8

A couple of months ago, i had collant leak. If the car was driven “normally” without fast acceleration and on the highway for around 200km, it lost around 1l. But, if driving rough and high revs/speed, it is almost empty coolant tank in 30km.
The problem was some small rubber hose somewhere behind the alternator, thats connecting two metal pipes. On high temp and pressure, it expands and leaks more than on standard specs

Not shure anymore it was part 23 or 36

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Edit: dont reuse original spring band clamp, put new ones with bolt so it can be tight

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#9

Those hoses around alternator is not leaking att all. I ve checked them servel Times and they are good.
The leak is behind the engine i’m 90% sure of that and I think it is the O ring to the pipe behind the engine.
But I need to know if its possible to fix it without engine drop before i start to take out the intake again!
The o ring number 13 on the pipe number 12 in the picture.

Thank you

#10

Not shure, anyone know if gearbox is removed then it can be accessed to avoid all engine drop?

Edit: yes, if gearbox is removed it can be accessed, but maybe by removing only exhaus it can be accessed?

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#11

thanks
I will lift up the car and check if its possible to check it from under

because i need to see where the leak is, but i think its the last part is maybe have a leak after att checked everything arund the engine bay

thank you man

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#12

I bet I know! A lil hose

#13

Ya fix it? I pulled my engine. Went over everything. Back in. Rear engine coolant leak. Right side little black line going to posvalve thing that’s called…pcvp

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That I have called it the pos valve for so long I can’t remember the parts name. I know everything it does. Cause problems and cost money. Need a waste gate for this beast .It’s the line of that going to the Coolant line behind the Right timing chain.