Review - RADHAUS 95B.1 Coolant Vent Line Bypass Kit for Porsche Macan
I recently had the misfortune of experiencing the failure of the coolant vent line on my 2015 Macan Turbo, at around 120,000km.
Sometimes also called the coolant T-pipe or Y-pipe, it runs from the reservoir tank back towards the firewall, then makes a U turn and comes forward through the centre of the engine V, past the intake and into two inlets below the throttle body.
A crude drawing to show how the pipe is routed.
This design would be acceptable if the pipe was at least silicone, but it’s a hard plastic which fatigues with repeated heat cycles.
Mine broke as I was pulling into my in-laws driveway. I noticed the engine fans were running which was unusual on a cool day, and I checked the coolant temperature which showed 105C. Normally it sits steady at 90C.
I hadn’t got a warning yet, but I immediately switched the car off and looked underneath to see a big puddle of coolant and more leaking.
At the time I wasn’t sure where the failure had occurred, but I did notice coolant on top of the engine, which seemed odd to me.
Note the puddle of red coolant on-top of the screw.
I waited a while for the engine to cool, filled the reservoir with more coolant so I could quickly move it into the street, hooked up the tow hook just in case, and left the car there.
My wonderful wife came to collect me, and was very nice to not make fun of another problem with my cars. (her Kia has never broken down, she reminds me 😁)
After some research online, I came across Santirx’ video on the problem. If you haven’t heard of his youtube channel please subscribe as he does amazing guides on maintenance for the Macan.
Santirx had collaborated with Radhaus to create a kit with sized silicone piping and proper aluminium machined fixtures, which could be installed without having to remove the intake. You can buy it here.
Another crude drawing showing how the Radhaus piping routes.
I watched Santirx video and thought it was something I could DIY, so I contacted Radhaus who were super helpful and shipped the kit out the very next day. It arrived in just 4 days to Australia from the US.
I thought the price was fair too, since an OEM pipe is only slightly cheaper, but requires pulling the intake, making for a much bigger job. Plus, it’ll just fail again in 100,000km.
In addition to the radhaus kit, I needed a vacuum coolant filler and compressor to refill the coolant.
I bought a Draper 09544 Coolant Vacuum Refill kitfrom Amazon, and got a used compressor from Facebook marketplace, a small Senco AC19308.
I packed my Z4 with my tools and set off on a rescue mission to repair the Macan.
The Radhaus kit is excellent quality, I was impressed with it. I set about following the steps for installation.
As I got access to the T-pipe, it became clear that it was well beyond its service life. The pipe crumbled and snapped with even a light touch.
This section of pipe broke away when I bumped it.
The trickiest part was removing the plastic fixtures which connect to the engine itself.
I was extremely careful and slow when removing them, taking a good 10 mins to gentle wiggle them loose. Despite this, they crumbled apart as I removed them, and left plastic behind.
This process would have been easier with some longer pick tools. I have a set but they’re only about 12cm long. A bit more reach would help a lot.
One of the plastic fixture removed. Note the rough edge.
Bits of plastic and rubber O ring left behind.
With some careful fishing, I was able to remove the remaining plastic. I was paranoid it would fall into the engine but in hindsight that seems very unlikely due to the size of the hole.
I felt like a surgeon removing a bullet from a patient!
I installed the new Radhaus pipe which went in perfectly, and then connected it up to the reservoir. I cut off the ends of the old T pipe and just left them in place.
Next I had to refill the coolant. Pelican have a great video on the process.
This turned out to be harder than I expected, because I bought the wrong sized adaptor for between the compressor and Draper tool.
It’s a two person job anyway, because getting a good seal on the coolant tank is difficult. With some help from my father in law, we managed to get it done. He held the Draper tool in the coolant tank, and I held the compressor pipes together, enough to create a vacuum of -0.7 bar.
We then used that vacuum to suck coolant into the system. It seemed to work well despite my not draining the system entirely beforehand.
Afterwards, I opened the bleed valve and started up the car. I ran the heater on max and idled the car for about 20 minutes. Then I closed the bleed valve.
When everything seemed good, I packed up and drove the Z4 home, and returned the next day to collect the Macan.
Over the next few days I carefully monitored the coolant level. I had to add about 0.5L more coolant, and since then I’ve done another 1000km with no fluid loss.
I recommend anyone with a 1st-gen Macan replace the coolant pipe with the Radhaus kit as preventative maintenance, as had mine split on the motorway, it could have resulted in engine damage.
There was no warning from the car that something was wrong. I got lucky that it failed as I was pulling into the driveway and I noticed it straight away.
Many thanks to Santirx for producing great resources for us Macan owners, and Radhaus for their product and quick action to help me out!
