First convertible - cleaning and sealing

Nathanio · Post by **Nathanio** » Thu Nov 11, 2021 10:55 pm

Evening folks.

Will be cleaning the Z4 at the weekend as it's not got any beading action going on.

I typically use the AutoGlym Polar series on the Skoda's and works really well for me.

I'm cognisant of the fact I don't know whether I should use the Polar Seal on the roof or not.

I've got aquapel for the windows as well.

Thanks

Southwestz4 · Post by **Southwestz4** » Fri Nov 12, 2021 1:10 pm

I only use Renovo products on a soft top as this is what they are designed for ...they do a cleaner, re colouring dye and a waterproofer ...very good stuff

Chris_D · Post by **Chris_D** » Fri Nov 12, 2021 1:15 pm

Don't use any form of waterproofer on your roof.
The outer fabric layer is NOT the waterproofing layer.
Constantly amazed by how many think they should 'seal' or waterproof the roof!

Ian J · Post by **Ian J** » Fri Nov 12, 2021 2:16 pm

Chris_D wrote: ↑Fri Nov 12, 2021 1:15 pm Don't use any form of waterproofer on your roof.
The outer fabric layer is NOT the waterproofing layer.
Constantly amazed by how many think they should 'seal' or waterproof the roof!

BMW disagree with you as the handbook states "After three to five washes, treat the convertible top with impregnating agent."

q96169we · Post by **q96169we** » Fri Nov 12, 2021 3:14 pm

Nathanio wrote: ↑Thu Nov 11, 2021 10:55 pm I don't know whether I should use the Polar Seal on the roof or not.

Don't use Polar Seal on the fabric roof unless your car is hard-top (you didn't mention which version of z4 is yours). The Polar Seal is for use on lacquered paint. For fabric roof, Renovo is good but take long time to dry. I used fabsil gold a week ago and it's good as well. BMW also has soft top care kit which is also good. GTechnique smart fabric is also good.

Chris_D wrote: ↑Fri Nov 12, 2021 1:15 pm Don't use any form of waterproofer on your roof.
The outer fabric layer is NOT the waterproofing layer.

No and yes. The car doesn't rely on the outer fabric to stop the water getting into the car. There is a waterproof layer in the roof sandwich and the outer fabric layer is to protect the waterproof layer plus it looks much better than the waterproof layer. The outer fabric impregnating agent (or, usually being called waterproofer) is to help the outer fabric itself to stay dry for longer and easier to dry if it gets wet, just as your outdoor jacket. Wet fabric will encourge mold etc. to grow and deteriorate the roof faster than it should. It also has some anti-uv agent as well. Overall, it's purpose is to protect the fabric roof. However, you don't have to apply the impregnating agent to stop water getting into the car.

Special Kay · Post by **Special Kay** » Tue Dec 28, 2021 5:51 pm

I've had a couple of Bmw convertibles over the last decade and have always used fabsil. I've always found it easy to easy to apply with a new brush, and have always trusted it to work even in the heaviest of winters and rain. The water repellency of fabsil once cured is praiseworthy by my standards. Over the last decade it's never let me down. I always apply it once every summer. For me personally, if it ain't broke don't fix it!

DMike · Post by **DMike** » Tue Dec 28, 2021 8:15 pm

I’ve used Autoglym’s and lately BMW’s convertible roof kits, both last easily two to three years. I garage my zed wintertime.

tomjonesBT33 · Post by **tomjonesBT33** » Wed Dec 29, 2021 1:16 am

I use 303 cleaner and sealer on both my Z4s. Works great to keep the water beading on the outer fabric layer and also restore the black color.

Tango22 · Post by **Tango22** » Wed Dec 29, 2021 11:47 am

I used Meguires Convertible Top cleaner on my hood when I got my first Z4 a few months ago. Car had been sat on the previous owners driv e for a good while and had green algae and a few other stains on it. The Meguires stuff shifted it after one application and left it looking like new. Highly recommended.

Have not bothered with a sealer, it's not needed.

Ewazix · Post by **Ewazix** » Wed Dec 29, 2021 12:14 pm

Special Kay wrote: ↑Tue Dec 28, 2021 5:51 pm I've had a couple of Bmw convertibles over the last decade and have always used fabsil. I've always found it easy to easy to apply with a new brush, and have always trusted it to work even in the heaviest of winters and rain. The water repellency of fabsil once cured is praiseworthy by my standards. Over the last decade it's never let me down. I always apply it once every summer. For me personally, if it ain't broke don't fix it!

You might want to check out the chemistry in Fabsil and make up of the BMW triple layer roof. Fabsil is nearly 100% Heavy Petrolium Naptha. The actual waterproof layer underneath is made of Butyl. According to freely available technical data the resistance of Butyl to Naptha is the lowest rating at 'unsatisfactory' i.e. may be damaged by Naptha products.

Fabsil data sheet http://www.farnell.com/datasheets/1536436.pdf

Rubber resistance to chemicals http://mykin.com/rubber-chemical-resistance-chart-4

I have stuck to BMW cleaner and treatments for the last 11 years and the roof still looks good, but other members get good results with other brands (which are probably cheaper and made by the same people

) but Fabsil is not ideal because of potential damage to the butyl.

BTW I use Fabsil gold on outdoor kit and really works

craig3.2 · Post by **craig3.2** » Wed Dec 29, 2021 3:48 pm

On both my zeds, past and present, tried Autoglym kit, Turttle wax, Renovo,Meguirs, BMW and Gtechniq

Found all to be good, but Renovo, Meguirs and Gtechniq have been my favourites, currently use Gtechniq.

Basically, all work well, while some clean slightly better and others ast a bit longer, but not found a massive difference between any of those mentioned above.
You can't go wrong with any of those, imo

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