Alphard Undersealing

[eric140253]

We have had our 56 plate Alphard 3L MZ-G for for some 4 years from an importer in the shadow of Heathrow Airport (?). We didn't consider the underneath at that time and have only just got around to sorting it. Living in North Somerset there are not a lot of options so eventually we went to Moore's Motorcars in Clevedon. They confirmed that the van had NEVER been treated with underseal from new! Understand that the roads are treated differently in Japan but my vehicle had not received any preservative treatment from the factory (or since). NO underseal AT ALL! So beware, Alphardians, get that underneath done pronto!!!! I had the full works, with cleaning, preping, 2 / 3 different Dinitrol layers, inside the open box sections (a lot of them in the Alphard!), inside all the doors, and the engine bay. It wasn't cheap but we now have confidence that the underneath and cavities are thoroughly sorted. For details of the work done, message me and I will give you the details.

[Rojie]

Hello,

 

Welcome to the Forum.

 

Any issues to report during your 4 years of ownership ?

 

Most of us have had ours for far less time than that.

Your experiences would be interesting to many Forum users.

 

Japanese MPV Specialist is very near Heathrow.

 

I bought mine from them, and they had undersealed it during lockdown.

Yours looks great underneath. Your undersealer did a great job.

[Curiousgeorge]

On 10/14/2021 at 11:12 AM, eric140253 said:

We have had our 56 plate Alphard 3L MZ-G for for some 4 years from an importer in the shadow of Heathrow Airport (?). We didn't consider the underneath at that time and have only just got around to sorting it. Living in North Somerset there are not a lot of options so eventually we went to Moore's Motorcars in Clevedon. They confirmed that the van had NEVER been treated with underseal from new! Understand that the roads are treated differently in Japan but my vehicle had not received any preservative treatment from the factory (or since). NO underseal AT ALL! So beware, Alphardians, get that underneath done pronto!!!! I had the full works, with cleaning, preping, 2 / 3 different Dinitrol layers, inside the open box sections (a lot of them in the Alphard!), inside all the doors, and the engine bay. It wasn't cheap but we now have confidence that the underneath and cavities are thoroughly sorted. For details of the work done, message me and I will give you the details.

Hi Eric,

 

Would you mind sharing how much the treatment has cost you? I am considering making the investment myself, but I seem to be getting a broad range of quotes in regards of what it will cost. 

[pcous]

Hi eric140253,

 

We've had our Alphard for 3 years and were planning to underseal this season, but your post just spurred us on.... The treatment was upol with added waxoyl, our sprayer said the underside was clean enough to avoid prior steam cleaning, so it wasn't too pricey.

 

Regards,

pcous

[Teekay]

On 10/14/2021 at 11:12 AM, eric140253 said:

We have had our 56 plate Alphard 3L MZ-G for for some 4 years from an importer in the shadow of Heathrow Airport (?). We didn't consider the underneath at that time and have only just got around to sorting it. Living in North Somerset there are not a lot of options so eventually we went to Moore's Motorcars in Clevedon. They confirmed that the van had NEVER been treated with underseal from new! Understand that the roads are treated differently in Japan but my vehicle had not received any preservative treatment from the factory (or since). NO underseal AT ALL! So beware, Alphardians, get that underneath done pronto!!!! I had the full works, with cleaning, preping, 2 / 3 different Dinitrol layers, inside the open box sections (a lot of them in the Alphard!), inside all the doors, and the engine bay. It wasn't cheap but we now have confidence that the underneath and cavities are thoroughly sorted. For details of the work done, message me and I will give you the details.

Can you please share details as to what the process was like? How much it cost? How much time it took? Etc thanks 

[eric140253]

Hia.

 

The people I use have developed a reputation for waxing other makes of vehicles, apart from the VWs they specialise in, to a higher standard than the 'drive in' waxing centres. They also offer varying levels of surface preparation from just intense surface cleaning to de-clinker, sealant replacement and rust converting pre-treatment (welding and fabrication works if required). I opted for the full monty!

 

With this type of work preparation is the most important part, so often you need to try and rectify wax sprayed over the top of unprepared surfaces where people are expecting the wax to be some kind of miracle cure. I believe that unless you wish to sell a car and your aim is to simply cover up a corroded vehicle, either do it to a good standard or leave well alone. I initially had an inspection done of the underneath to assess any initial de-rust treatment / repairs required. Mine was in excellent condition and didn’t need anything. So, the work done on my vehicle was as follows:

 

Basic underbody treatment consists of: Underside intensive pressure wash. Masking of upper body, exhaust, brakes, radiator etc. Drilling of any holes as necessary for access for cleaning and waxing box sections. Surface preparation (scraping, wire brushing, removal of old coatings, loose and flakey corrosion)

Dinitrol 3642w cavity wax applied to chassis inner cavities and box sections. Dinitrol 4941 black protective wax applied to all underbody areas under body, chassis and mechanical components.

 

A masked line is taken around the lower outer sections of sills, wheel arches and front and rear valances to allow the black wax to protect the vulnerable edges. This can be kept to return onto the outer surface by just a couple of millimetres or for vehicles requiring the highest level of protection, as far as will look acceptable. This can be removed in the future using a solvent. Final inspection, bungs inserted to access holes. test drive/brake test. Price around £700.

 

The clean-up allowance in this example is for vehicles that have a modest amount of surface corrosion and failing coatings. This is where careful inspection is essential; some very old cars, 50+ years old, need minimal preparation whereas some cars barely 10 years old can be horrendous. For this aspect of the task, Rust converter and epoxy coating (Dinitrol RC900) are sprayed onto all areas of corrosion to chemically neutralise the rust and provide a good key for the subsequent waxes. Where necessary, this costs around £130.

 

Where the underbody warrants, and to further enhance protection, a pre-treatment of 3125 ML wax is given. This is a thin penetrating wax which has very high corrosion inhibiting properties that penetrated seams and soaks into areas of inaccessible corrosion etc. This acts as an excellent key coat for subsequent waxes. This is applied to all accessible underside areas and left to flash off before application of the cavity and black waxes. Price £220.

 

Upper body: For the highest level of protection; the front grill/radiator surrounds, headlights, trim panel etc are stripped down for access and treating of metal frames and sections. The returned seams on the body shell have a thin wax injected in to the outer gap penetrating the seam and excess cleaned off, front bulkhead cavity (bellow screen treated). Clear high-performance wax is sued which is heatproof. All removed parts refitted and the body shell cleaned to remove excess wax.  Price £175.

 

For a higher level of protection Epoxy paints can also be used before wax if accessibility allows, for example in the engine bay, and includes a good level of surface degreasing and preparation. The end result will be a clear wax over a freshly painted surface.

 

I decided to have the lot done after the initial inspection revealed that the underneath was in excellent nick. So, my total outlay was around £1225. Yes, I know the cost looks high everything is (literally) covered and it includes a full warranty. Overall it took 10 days. I can supply pics if you like.

Edited May 16, 2022 by eric140253