Under Carriage Rust Protection

[Pattaya Spotter]

We all know that anti-corrosion treatments sold for new cars by dealers is unnecessary and just a profit center. I recently had my car serviced by a dealer in Phuket who tried to sell me such a service for the bottom of the vehicle, explaining that the air and road surface in Phuket is saltier due to it being an island and thus vehicles are more prone rust. I declined. Is there any truth to this contention?

[Liverpool Lou]

On 3/1/2022 at 2:54 PM, Pattaya Spotter said:

a dealer in Phuket who tried to sell me such a service for the bottom of the vehicle, explaining that the air and road surface in Phuket is saltier due to it being an island and thus vehicles are more prone rust. I declined. Is there any truth to this contention?

His contention was correct about the effects of salt on unprotected vehicles near the coast. 

 

Whether your vehicle would benefit from any "extra protection" he wants to sell you is debatable.  I would have declined his kind offer, also.

Edited March 4, 2022 by Liverpool Lou

[petermik]

Get it done ASAP....it will improve the value of the vehicle no end....

[Longwood50]

36 minutes ago, petermik said:

Get it done ASAP....it will improve the value of the vehicle no end

Perhaps there is some credence to vehicles close to the ocean being subjected to salt and therefore more prone to rust.  With that said, I am from Michigan where the roads are continually salted during the winter to prevent icing.  Factory protection appears to be more than adequate to prevent them from rusting so I doubt the salt air is more corrosive.  

Though I don't live on the coastal areas I see many older cars here in Thailand all with their bodies still in good shape.  I have yet to see one with the rusted body panels that I got use to seeing in the USA before the companies started corrosion protection 

[Liverpool Lou]

22 hours ago, Longwood50 said:

Factory protection appears to be more than adequate to prevent them from rusting so I doubt the salt air is more corrosive.  

"I doubt the salt air is more corrosive".  

Hahahahahahahaa..!    Be careful that you don't fall off the edge of the earth!

[Rimmer]

A post having an  altered quote to change its meaning has been removed also a reply

[HauptmannUK]

Salt, or more specifically salt solution, massively accelerates corrosion because it acts as an electrolyte which promotes oxidation.  Cars/structures in coastal areas usually suffer due to the humid salty air.

 

By way of context I should say that my family back in the UK have been in the motor trade for over 100 years. My grandfather started the business in 1921. Sales, service, MoT tests - (and accident repairs until about 15 years ago). I was always involved in the business (although it was not my main career) and was qualified as an MoT tester until about 7 years ago. Been back involved in the business again March 2020 - Dec 2021 thanks to Covid 'grounding' me.

 

The business is located in central England but we would sometimes buy-in cars that had spent their lives in coastal locations - these always had more corrosion. Moreover cars from the north of England and Scotland usually had more corrosion due to greater use of road salt. In fact Scottish traders often travel south to buy cars for this reason.  Often its not the floorpan and upper panels that show corrosion, but rather suspension arms and heatshields etc that rot through.

Moreover the situation varies greatly depending on the particular vehicle. For example, as an MoT inspector I can't remember ever failing the 2005-on Mitsubishi Colt on corrosion, they were really protected - however the Shoguns (Pajero) rot like fury in the UK and a used Shogun needs checking carefully underneath if its more than 3 years old. Similary Nissan Micra and Toyota Yaris were also bad, but the larger Avensis was very well protected. Some of Hyundai and Kia were bad but they have upped their game recently. Incidentally, certain models of Mercedes were also surprisingly poor.

In the last couple of years we've come across quite a few newish Mazdas with significant corrosion, so they clearly have a problem. This is UK market of course.

I see many older cars in SE Asia that have very little corrosion and I'm sure that this is due to the lack of road salt.

 

When we've been asked to apply corrosion protection to older/classic cars we refer customers to a nearby company who use Dinitrol products. Don't know if Dinitrol is available in Thailand but they make really excellent products.

If you live in a coastal area then regular washing with fresh water (on top and underneath) will help remove salt accumulation.