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Weird leak from Tandem Pump area


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#1 Rgm36

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Posted 21 April 2021 - 12:35 AM

What a day!! Fixed a couple of things today on the Golf, many more on the to-do list, unfortunately. But it's always one step forward and at least one back with my car....

My starter was turning over really slowly and thanks to this forum I knew where to look, took the battery out, cleaned up all the contacts; earths plus positives, anyway it went well and seems to have fixed the issue. The problem is that whilst I was beavering away in that corner of the engine bay I noticed the top of the gearbox was damp. Using a mirror on a stick I can see red fluid slowly dripping from the edge of the tandem pump where it meets the head.

 

I replaced the tandem pump some while back but t hasn't done many miles on this one as it's been off the road for ages. It's a Pierberg one, like the original I believe. Thing is, I've just read the Haynes and it doesn't say to drain the cooling system when changing it, so I'm guessing there isn't coolant running through it? So where's the coolant coming from? Or am I going mad?

 

Just wanted to vent :blah: and see if anyone had any suggestions? I'll be poling around with my mirror on a stick again tomorrow, I really hope it's a simple weeping pipe and not the tandem pump!

 

Many thanks


MKIV Golf TDI130BHP, Broken!



#2 gerrywac

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Posted 21 April 2021 - 12:44 PM

What a day!! Fixed a couple of things today on the Golf, many more on the to-do list, unfortunately. But it's always one step forward and at least one back with my car....
My starter was turning over really slowly and thanks to this forum I knew where to look, took the battery out, cleaned up all the contacts; earths plus positives, anyway it went well and seems to have fixed the issue. The problem is that whilst I was beavering away in that corner of the engine bay I noticed the top of the gearbox was damp. Using a mirror on a stick I can see red fluid slowly dripping from the edge of the tandem pump where it meets the head.

I replaced the tandem pump some while back but t hasn't done many miles on this one as it's been off the road for ages. It's a Pierberg one, like the original I believe. Thing is, I've just read the Haynes and it doesn't say to drain the cooling system when changing it, so I'm guessing there isn't coolant running through it? So where's the coolant coming from? Or am I going mad?

Just wanted to vent :blah: and see if anyone had any suggestions? I'll be poling around with my mirror on a stick again tomorrow, I really hope it's a simple weeping pipe and not the tandem pump!

Many thanks

The tandem pump deals with air for the vacuum system (brake servo, turbo vanes, ERG) and fuel for the injection system and is driven off the end of the camshaft passing through the end of the head so you can potentially add oil to the mix of fluid leaks.
If your leaks pink and use the standard VW anti freeze it sounds like coolant.
Im not that famiar eith the Mk4 (I've a Mk5) but recall the coolant hoses to the cabin heater run front to back under the TP.

Sent from my HRY-LX1T using Tapatalk

#3 Evil

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Posted 21 April 2021 - 12:53 PM

Our tandem pump leaked, and only leaked diesel (pd130 engine).
Turns out there was no gasket fitted at all.

#4 Rgm36

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Posted 21 April 2021 - 03:29 PM

The tandem pump deals with air for the vacuum system (brake servo, turbo vanes, ERG) and fuel for the injection system and is driven off the end of the camshaft passing through the end of the head so you can potentially add oil to the mix of fluid leaks.
If your leaks pink and use the standard VW anti freeze it sounds like coolant.
Im not that famiar eith the Mk4 (I've a Mk5) but recall the coolant hoses to the cabin heater run front to back under the TP.

Sent from my HRY-LX1T using Tapatalk

 

 

Our tandem pump leaked, and only leaked diesel (pd130 engine).
Turns out there was no gasket fitted at all.

Yeah, as I'd thought, I couldn't remember but had wondered whether there was a coolant feed into the pump somehow via ports in the head which were leaking. That not being the case and the fact that I can't find any sign of a weeping pipe means that it's looking like it might be a head gasket problem. If it is I'm going to be properly gutted. I'm sure it's coolant, yes mine is the standard VW stuff and pink.


MKIV Golf TDI130BHP, Broken!


#5 Evil

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Posted 21 April 2021 - 03:35 PM

Yeah, as I'd thought, I couldn't remember but had wondered whether there was a coolant feed into the pump somehow via ports in the head which were leaking. That not being the case and the fact that I can't find any sign of a weeping pipe means that it's looking like it might be a head gasket problem. If it is I'm going to be properly gutted. I'm sure it's coolant, yes mine is the standard VW stuff and pink.

 

This jogged my memory.. we also had a coolant leak, not bad but fairly constant - the area was wet underneath the tandem pump but nothing dripped onto the floor.... even the mechanic who worked on it a fair amount couldn't see where it was coming from.

It dripped onto the coolant temperature sensor, which I changed about 4 times in 3 years..



#6 Rgm36

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Posted 21 April 2021 - 03:41 PM

This jogged my memory.. we also had a coolant leak, not bad but fairly constant - the area was wet underneath the tandem pump but nothing dripped onto the floor.... even the mechanic who worked on it a fair amount couldn't see where it was coming from.

It dripped onto the coolant temperature sensor, which I changed about 4 times in 3 years..

Sounds just like my problem......


MKIV Golf TDI130BHP, Broken!


#7 Rgm36

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Posted 27 April 2021 - 08:00 PM

Update; Ok, I'm pretty sure I've found it - it's coming from the plastic "coolant junction" bolted to the head under the tandem pump. That's what Haynes calls it, it also goes by "coolant flange" when listed as a spare part. Part number 038121133. God knows why it should decide to leak....


MKIV Golf TDI130BHP, Broken!


#8 Evil

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Posted 27 April 2021 - 08:04 PM

Update; Ok, I'm pretty sure I've found it - it's coming from the plastic "coolant junction" bolted to the head under the tandem pump. That's what Haynes calls it, it also goes by "coolant flange" when listed as a spare part. Part number 038121133. God knows why it should decide to leak....

We replaced this on ours too..
Still leaked..

If your coolant temp sensor is getting wet I'd work out a way to protect it... I was going to put a plastic 'sleeve' over it.

#9 Rgm36

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Posted 27 April 2021 - 08:56 PM

We replaced this on ours too..
Still leaked..

If your coolant temp sensor is getting wet I'd work out a way to protect it... I was going to put a plastic 'sleeve' over it.

It still leaked? So how did you fix it? My sensor isn't getting wet as far as I can see but you have a damn good point and I might cover it anyway....


MKIV Golf TDI130BHP, Broken!


#10 Evil

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Posted 27 April 2021 - 09:07 PM

It still leaked? So how did you fix it? My sensor isn't getting wet as far as I can see but you have a damn good point and I might cover it anyway....

We didn't (fix it)..
Never sourced the leak.

#11 Rgm36

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Posted 28 April 2021 - 11:53 AM

I just bought the replacement part from Amazon (of all places) - a Febi Bilstein part, cost £2.45!! I'm sure it was £15 when I looked at the same part yesterday! It just made me think, I don't really have much of a handle on which aftermarket manufacturers are good and which aren't....I've bought FB several times and found the parts to be ok, just wondered what you all thought?


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MKIV Golf TDI130BHP, Broken!


#12 Evil

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Posted 28 April 2021 - 01:09 PM

Febi and Mahle are decent..
Mann for filters..
Lemforder for bushes and that..

#13 Rgm36

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Posted 28 April 2021 - 02:12 PM

Febi and Mahle are decent..
Mann for filters..
Lemforder for bushes and that..

Ok, cool, thanks


MKIV Golf TDI130BHP, Broken!


#14 Calico

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Posted 29 April 2021 - 11:17 AM

wouldnt touch mahle heard not good stories and on different vehicle manufacturers, most of my suspension parts are lemforder no movement very solid 



#15 Rgm36

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Posted 30 April 2021 - 08:00 AM

So I've replaced the "coolant flange" and I'm pretty confident that it was causing the leak - the rubber seal was compressed, so I'm sure it wasn't sealing properly against the head. On to the next issue!


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MKIV Golf TDI130BHP, Broken!






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