Coolant Leak 1.4 BBY Petrol

Tomscar

Member
I was going to reassemble the rear suspension today on Project Resurgam ... but ... :eek:
After discovering a small pool of coolant on the garage floor I went in from underneath and think it is leaking from here ... it's the junction at the back of the engine where the coolant pipe from the water pump meets the thermostat housing ... according to the drawing below it is sealed with an 'O' ring.
It's not too bad at the minute but I might as well get it done as it's on axle stands over winter.
Has anybody come across this or attempted to fix it?
I'm guessing the thermostat housing will have to come off to gain access ...

Waterpipe Junction Leak.jpg


Part 15 is the thermostat housing and bolts onto the engine above the gearbox linkage cables and part 14 fits into the casting at the back of the water pump, hopefully it is only the 'O' ring, part 5 that has failed.

Coolant Regulator.jpg


Any advice greatfully received and thanks for reading ...
Slight edit and another question ... is pipe 14 what others are calling the 'pipe of death?'
 
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The coolant system on the 1.4 petrol is normally quite reliable Tom. The commonly referred to "pipe of death" is unique to the 1.6 FSI engine.
 
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The coolant system on the 1.4 petrol is normally quite reliable Tom. The commonly referred to "pipe of death" is unique to the 1.6 FSI engine.
I looked at the picture and thought that looks like the (overly dramatic named) death pipe on a 1.6 FSI, looked at the diagram and the pipe exactly the same position between pump and thermostat but not FSI diagram and checked in title, BBY. It does look like the FSI, best check part number on 7zap between FSI and BBY. Guess what?

Andy
 
Hi Andy and Dave ... thanks for replying :)
The drawing posted is of a BBY engine from a Fabia Repair Manual ... the picture was taken looking from behind the Subframe to the back of the engine, the pipe is made from a hard plastic running between the water pump and joining the back of the thermostat housing ... the layout looks similar to the drawing.
Can't remember ever having to top up the coolant at any point before, I think the last time was around four years ago when the belts and water pump were replaced and as Dave said the 1.4 has always been reliable.
I've just been having another look and think it might be possible to do the following:

Drain the system
Undo the 13mm nut and remove the gear shift mechanism off the spline for access to the thermostat housing bolts
Remove thermostat (and replace, it's still the original) and maybe remove all the pipes
Undo three Torx bolts that hold the thermostat housing to the engine block
Remove the U clamp from the 'pipe of death' and move the thermostat housing off the engine block ... it should separate and give access to the 'O' ring

Does that sound like a feasible plan or am I over simplifying it?
Thanks again for your input, it's great that you are taking the time to help a newbie.
 
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Doing a bit more investigating, maybe my cars been built from the spare parts bin :D
Had a look on the 7Zap drawings and mine appears to have the 'correct' thermostat housing installed for a 1.4 Petrol BBY and also shares the 'death pipe' part number with the 1.6FSI.
The curious thing is my lower radiator pipe has a part number corresponding to the 1.6FSI and has another temperature sensor in the housing where it joins the radiator (as in the 1.6 FSI) ... the BBY drawing shows a plain pipe without this sensor ... :confused:
It doesn't seem to have effected the running of the car, just curious if this is normal or if 7Zap isn't so accurate?

Lower Radiator Pipe - Part Number 8Z0 121 049P
IMG_0601.JPG
 
Hi Tom,

Strange indeed. The 'extra sensor' you have does indeed match the FSI. From memory it is the G83 sensor that is part of the radiator fan control system. Unless 7zap is wrong (any BBY owner comment??) I can only surmise your car had a bump in the past requiring a radiator replacement that was sourced from a FSI that came with the sensor so it was installed. It seems wired in and a joins a larger loom but how it could be made to work on a BBY is beyond my pay grade.

Andy
 
Hi Andy ... thanks for commenting ... still has the original radiator, I've owned the car from new and put all 190 000 miles on the clock.
Maybe next time somebody has their under tray off on a BBY they can take a quick look?
I'm ordering some gaskets and seals from Belfast Audi and will try to tackle the leak, I'll take plenty of pictures and post the adventure :D
Maybe the Audi service manager can throw some light on it.
Cheers ... Tom
 
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Hi Tom,

Thought my FSI sourced radiator was a bit far fetched. Came across evidence that the radiator bottom hose sensor is perfectly normal on your BBY and 7zap is wrong.

https://workshop-manuals.com/audi/a...adiator_outlet_coolant_temperature_senderg83/

While there noticed the thermostat housing removal procedure, similar to what you outlined but extras to create more/easier access. This should help a lot.

https://workshop-manuals.com/audi/a...g_thermostat_housing_and_coolant_pipe_(rear)/

Look forward to reading your adventure.

Andy
 
Hi Tom,

Thought my FSI sourced radiator was a bit far fetched. Came across evidence that the radiator bottom hose sensor is perfectly normal on your BBY and 7zap is wrong.

https://workshop-manuals.com/audi/a...adiator_outlet_coolant_temperature_senderg83/

While there noticed the thermostat housing removal procedure, similar to what you outlined but extras to create more/easier access. This should help a lot.

https://workshop-manuals.com/audi/a...g_thermostat_housing_and_coolant_pipe_(rear)/

Look forward to reading your adventure.

Andy

Thanks Andy, you're a gent, this info is a big help and I will study it in detail ... I love this site and I'm learning so much ... and great to be part of the A2 community :D:D:D
 
Hi Kleynie, no not yet but making some headway, I'm putting a list together for all the gaskets and seals that will be disturbed during the process ... it seems overly complicated on Elsawin but hopefully easier to follow when the spanners are in hand. I'm going to change the thermostat while it's apart and the gearbox oil ... not to mention new brake drums ... VCDS still to buy and then should be all set to proceed, at this rate you will be finished first :D
 
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