Underbody protection for winter driving - Page 3 - Porsche General - PistonHeads UK

I took delivery of my new 718 Cayman back in March this year with the express intention of keeping it very long term and using it as my daily driver. So far, so good, it's bloody marvellous and everything I hoped it would be. I'm pretty OCD when it comes to condition, so it's ceramic coated, has RGS front mesh radiator grills and subtle arch guards to protect from stone chips, which I designed, 3d printed and fitted as I couldn't find anything up to the right standards. With autumn and winter fast approaching, thoughts are turning to keeping underneath in good order. Whilst I won't drive it when the roads are heavily salted, it will get used throughout the winter months, so it needs protecting. It's booked in to my go-to Porsche Indy for a thorough job on the ramp, with the undertrays removed etc. at the end of October but I'm open to what we use to protect it. I've had good results with ACF50 in the past on my Caterham, but interested to hear about any other experiences eg Lanoguard or any other treatments that would do the job. I'm not necessarily looking for a once only solution, doing it every year in the autumn would be fine if that's what's required. Edited by AndrewGP on Wednesday 17th September 17:12

My mate has just done his car with Lanoguard and he's very impressed although he did say it smells a bit, he also considered Bilt Hamber underbody protection which apparently gets good reviews too. I am a bit old school, I like Waxoyl its proven and very easy to apply (thin down with white spirit and warm it up in a bucket of hot water) buy a proper air application tool and its not even very messy to apply with the correct kit. Check every year and apply more if required. When I bought my GR-Yaris Waxoyl was what I used.

Bilt Hamber every time for me-their cavity spray is fantastic-I use it on my classic mini, I wouldn’t use anything else now

My cayman was recently coated in waxoyl and previous Vantage was treated with lanoguard. Seems to be what each specialist favours does the job. I’m sure there are strengths and weakness of both if I dug a little deeper.

I’d go dinitrol

Bilt Hamber, sprayed on with a garden sprayer, with a bit of thinners in and then I get down and dirty underneath and wipes it around with a piece of cloth.. Leave it a week or so then a fine spray on top with Bilt using the compressor.

Is this there any evidence to suggest this is needed?

If you have or have access to an air compressor this bit of kit is superb, it has a lance with a 360deg sprayer for the box sections and a little right angled sprayer for everything else...its very precise and makes little mess.

SkinnyPete said: Is this there any evidence to suggest this is needed? Probably not, but it is a personal thing and does help in the long run, and the OP says he is OCD and in it for the long term.

SkinnyPete said: Is this there any evidence to suggest this is needed? Yes

I think putting the effort in to use one of the options is the main thing. I’ve had lanoguard under my 911 as everything is so exposed. It seems to still look good under there, whereas mechanics always seem to complain that waxoyl looks black and gunky. Maybe that’s just Defenders who’s owners have the rust covered up with a thick layer of the stuff?

Billy_Whizzzz said: SkinnyPete said: Is this there any evidence to suggest this is needed? Yes Tell me about it, viewed a few 997 GT3s recently-extremely crusty underneath-OK, they're now approaching 20 years old but the rot so to speak, sets in early. I think a lot of problems with Porsche is the cheap bolts and fastenings they use-before protection I'd be wanting to swap some of those out first if I was really going to be keeping long term.

Thanks all for the suggestions, it’s probably not worth over thinking it, as all of them sound like they’ll do the job. PRO5T said: Billy_Whizzzz said: SkinnyPete said: Is this there any evidence to suggest this is needed? Yes Tell me about it, viewed a few 997 GT3s recently-extremely crusty underneath-OK, they're now approaching 20 years old but the rot so to speak, sets in early. I think a lot of problems with Porsche is the cheap bolts and fastenings they use-before protection I'd be wanting to swap some of those out first if I was really going to be keeping long term. OCD aside, I’d agree it’s definitely worth doing, my 987.2 had been protected underneath and all the fastenings and fixings were easy to work on when required. My 981 on the other hand had had nothing and all the clamps and bolts were rusty and several had to be cut off with an angle grinder.

Interested and I am going to look at it for my 991.1 which is used daily for a 60 mile commute. It still looks good at 91k miles now so I need to preserve it. Thanks OP for making me spring into action.

I'd love some advice on protecting my 981! I'm hoping to drive it more throughout the winter, but I'm a bit hesitant because of the salt and weather. What are your thoughts on taking it to a specialist? I've heard good things about dry ice cleaning there's a place in the Midlands that does it, Alternatively a well-known independent Porsche specialist (based in a farm) that offers underbody protection. Any recommendations or experiences with these?

Billy_Whizzzz said: I d go dinitrol ^ This. It's good 5h1T : https://rejel.com/din81s/

Have done this to my 997 which is now 17 years old and still immaculate underneath. Dynax UC (almost clear) applied in 2-3 fine coats is by far the best out there in my experience. Google salt bath tests to see how it compares to the likes of Lanoguard. And it doesn't cake the car in gunk. One thing I would say is that when I removed the under trays and wheel arch guards in my car it was already 12 years old and used year round, and the only rusty bits were fixings and 2 cross bars at the back. However it was clear that there are obvious mud traps (eg the inside of the lips of the wheel arches and the panel in the rear wheel arch just in front of the tyre). Indeed quite a few 997s which have not had treatment / regularly cleaning here are already showing signs of corrosion around wheel arch lips and it is very expensive to fix. Coil springs are another area worth close attention. And if you are into aesthetics then spray the damper casings too (Dynax will not cover tell tale signs of leaks). Bottom line? Remove wheel arch liners and Dynax everywhere, along with seams under sills, but probably no need to remove all the belly pans - my car still looked new under there at 12 years old.Worth spraying coolant pipe connectors too (not sure of the set up in your car) but with ACF50 which is more heat tolerant (although it doesn't last as long as Dynax). Edited by anonymous-user on Thursday 18th September 16:46 Edited by anonymous-user on Thursday 18th September 16:48

Just to say that the Dynax UC is a Bilt Hamber product. I have used this on a couple of cars ... Once cleaned and dried, a single large aerosol can goes a long way ... it double coated my car with two thin coatings which once dried was clear and almost invisible. It can easily be cleaned off if required but and the finish from new once dry is of a thin high temperature wax type coating which does not pick up the debris that wax oil type coatings do ... I don't know how this compares to Lanoguard which has also be recommended ...

Billy_Whizzzz said: SkinnyPete said: Is this there any evidence to suggest this is needed? Yes That's not a 718. Total waste of time in my view.

Had the opc offer me under body protection at the last service which I turned down as considered unnecessary. Surely any modern car is treated in order to prevent corrosion else they’d have a heap of bodywork claims?

SkinnyPete said: That's not a 718. Total waste of time in my view. Google 997/Boxster rust and the forums have plenty of examples. Albeit mostly in older cars eg 2003 and 2005. But, yes, if a new car that is NOT going to be a keeper then it is a waste of time - for the original owner anyway. Here's an example of rust above jacking point on outwardly pristine 60k mile Boxster. https://www.boxa.net/topic/99404-986-jackpointsill... GT3s are particularly prone to problems as Porsche skimp on underseal to save weight. My 996.2 GT3 was crusty in parts, albeit just surface, within 6 years.

Discombobulate said: SkinnyPete said: That's not a 718. Total waste of time in my view. Google 997/Boxster rust and the forums have plenty of examples. Albeit mostly in older cars eg 2003 and 2005. But, yes, if a new car that is NOT going to be a keeper then it is a waste of time - for the original owner anyway. Here's an example of rust above jacking point on outwardly pristine 60k mile Boxster. https://www.boxa.net/topic/99404-986-jackpointsill... GT3s are particularly prone to problems as Porsche skimp on underseal to save weight. My 996.2 GT3 was crusty in parts, albeit just surface, within 6 years. The OP asked about the 718, which is much better built than the models you’ve just listed. I’d put money on it being a total waste of time.

SkinnyPete said: The OP asked about the 718, which is much better built than the models you ve just listed. I d put money on it being a total waste of time. I posted those images of my 997.2. Unless the fixing and bolts are stainless on a 718 I’d wager that they’d go a similar way. I’ve never seen any car not begin to corrode underneath, even my 2020 series. Can’t see how a 718 is any different. It isn’t a manner of being ‘well built’ or not - a simple matter of the harsh reality of winter roads and paints used (or not used, as on many underbody parts).

I use acf50 every year on my m3. Easy to do and effective.

SkinnyPete said: The OP asked about the 718, which is much better built than the models you ve just listed. I d put money on it being a total waste of time. More cheaply built, probably. Better? Time will tell.

Gents, please let's not let this degenerate in to an argument about whether its a waste of time or not. It may well not be needed, but as I intend to drive the car all year round and keep it long term, I'm not prepared to take the risk of doing nothing. Thanks.

Slippydiff said: Billy_Whizzzz said: I d go dinitrol ^ This. It's good 5h1T : https://rejel.com/din81s/ I can highly recommend Dinitrol and prefer to use the clear stuff. We used to use it on aircraft and I have used it on several of my own cars.

Slippydiff said: Billy_Whizzzz said: I d go dinitrol ^ This. It's good 5h1T : https://rejel.com/din81s/ I can highly recommend Dinitrol and prefer to use the clear stuff. We used to use it on aircraft and I have used it on several of my own cars.

Was there ever any truth to the concern that any treatment ended up trapping moisture which for a galvanized underbody wasn't as critical as for those earlier 80's cars? Tended to flip-flop because of this so resorted to always giving the underside a good blast with the hose.

Popolou said: Was there ever any truth to the concern that any treatment ended up trapping moisture which for a galvanized underbody wasn't as critical as for those earlier 80's cars? Tended to flip-flop because of this so resorted to always giving the underside a good blast with the hose. That is a concern with poorly applied thick underseal / schutz / ziebart / paint etc but modern waxes don't lift, split in the same way. Assuming you apply them to a clean, bone dry car, and properly deal with and treat any existing corrosion. But they do need reapplication with time to maintain full benefit. Each to their own, but I use my cars in all conditions and actually enjoy applying the stuff - and appreciate the fact that is better protected. I may need to get out more.... Just cover your hair before you use Bilt Hamber stuff. You will thank me

Another vote for Bilt Hamber Dynax UC. Used it on my then three year old BMW 4 series throughout the underside, arches, suspension components etc. This after washing, rinsing and then drying with an electric heat gun. At seven years old it looked unchanged but I went around again, this time with a lighter application. Not long before sale at nine years old, it still looked great; the black painted subframes were uncorroded and fasteners similar. I have been around my 718 with Dynax UC shortly after purchasing it.

Getting a hose under the car and in wheel wells during winter to wash off the salt helps a lot too, don't just rely on the underbody protection to do all the work.

pakora said: I'd love some advice on protecting my 981! I'm hoping to drive it more throughout the winter, but I'm a bit hesitant because of the salt and weather. What are your thoughts on taking it to a specialist? I've heard good things about dry ice cleaning there's a place in the Midlands that does it, Alternatively a well-known independent Porsche specialist (based in a farm) that offers underbody protection. Any recommendations or experiences with these? I'd be interested to hear views too from those who've had sent theirs in. I just don't have the space to do this myself sadly.

A couple of people have said to use Dinitrol. I’ve just re coated our MGA with dinitrol 4941 aerosol which does a fantastic job. Needs 12-24hrs to set but the finish and coverage is really good. Sets to a solid black coating so won’t wash off or get stones / muck etc sticking to it. Also tried the dinitrol 1000 as a cavity protection. It didn’t set and remained sticky after 3 days so there’s a risk it’ll collect dirt. It’s not a cavity protection product, but we did all the chassis / wood and suspension.

I used a variety of these products on mine but it’s 17 years old and was looking very crusty. Nothing wrong with a thin layer of protection once a year IMO.

Give this guy a call, done a few of my cars now, costs around £300. https://www.krown.co.uk/

Was watching a YouTube video about rebuilding a crash damaged Porsche last night… Interestingly, they mentioned that the piss poor rust protection was down to environmental credits manufactures have to use during production. Porsche simply can’t paint/protect everything as their solvent footprint would be too high per vehicle.

Garage guy I know swears by old engine oil but that’s probably not appropriate here.

Thanks everyone for all the advice, I settled on Dynax UC and the car was done a couple of days ago. Undertrays were removed, and the whole underside and arches were thoroughly cleaned, not that it was really dirty though having only done 5k miles. I used a can and a half of UC and it went on very well, you certainly can’t tell unless you look closely. I took my time and gave everything (bar the hot bits) 3 thorough coats. I’m pleased knowing it’s at least got some protection from the salt now.

Good job.

Wow - that looks really good! I am quite sure mine does not look as clean and protected as this. You have just inspired me to do something about it!

SkinnyPete said: That's not a 718. Total waste of time in my view. One does wonder. Somehow my cars have never needed it and I keep them a long time. IMO a lot of corrosion issues are less to do with how a car is used than about how it's kept. Nothing worse than parking a wet car in a poorly ventilated garage. They're better left outside than treated like that.

What’s the typical cost to get this done at a garage/detailer?

Redline88 said: What s the typical cost to get this done at a garage/detailer? I paid around £260 in 2021, which was all the undertrays off and cleaned then sprayed. Took a good few hours, I was there most of the day, but he had a customers area with coffee, tea, drinks and chocolate/crisps. Link in previous post, it's worth a look, he does a very thorough job. I bet it's closer to £300 by now.

Was offered similar by the dealer for around £270 last service. Seemed totally unnecessary to me outside of a classic perhaps. https://www.pistonheads.com/gassing/topic.asp?h=0&... Dehumidified garage probably helps…

I know someone who does a full dry ice resto for circa £1400 in the north west. That full dry ice, rust protection, restoration where needed etc That’s more for the classic Porsches than moderns though.

As a long term owner of an eight and a half year old 718, I can vouch for the fact that the underside definitely needs treating. My car is immaculate but on checking the wheel arches & removing the wheel arch liners has thrown up some corrosion forming on the inside of the wings (the rear arches are the worst with rust bubbling on the edges). I’m currently in dispute with Porsche GB regarding the corrosion and the case is with The Motor Ombudsman. If unsuccessful, I’m looking at the dry ice route, rust converter & something along the lines of Lanoguard assuming the corrosion hasn’t gone too far. It really needs a full underside inspection with the undertrays removed. The car is driven sparingly in the Winter and always garaged. I don’t remember this being an issue on any of my previous 3 Boxsters including one that was sold at 7 years old.

Boxster5 said: As a long term owner of an eight and a half year old 718, I can vouch for the fact that the underside definitely needs treating. My car is immaculate but on checking the wheel arches & removing the wheel arch liners has thrown up some corrosion forming on the inside of the wings (the rear arches are the worst with rust bubbling on the edges). I m currently in dispute with Porsche GB regarding the corrosion and the case is with The Motor Ombudsman. If unsuccessful, I m looking at the dry ice route, rust converter & something along the lines of Lanoguard assuming the corrosion hasn t gone too far. It really needs a full underside inspection with the undertrays removed. The car is driven sparingly in the Winter and always garaged. I don t remember this being an issue on any of my previous 3 Boxsters including one that was sold at 7 years old. Thanks, that’s really useful to know. I didn’t go as far as taking off the wheel arch liners on mine but I think I will do that when I renew the protection I’ve just put on. Due to the fact mine’s a daily driver and my annual mileage is 8-10k it’ll go back to Lap911 annually for a check over and an oil change so I can keep an eye on things as the years go by and I’ll treat the underside and arches accordingly. I’d much rather over protect than under. Good luck with your case, I hope you get it sorted soon.

I had my 1967 Vitesse Dinatrol treated when it had a bare metal restoration 10 yrs ago. It looks like new still. I plan to get under my 2022 Defender this next week or so and give it a treatment of something.