What shall I do with rusts underbody?

The manufacturer really cares only about the outside appearance of the vehicle and penetration that starts to appear on the outside of the car. The majority of car owners and buyers buy cars on account of appearance. Very few buyers look under the car before buying it, NEW or USED.

 

I do notice HV orange cable/electrical connections going under the car (which I think is a hazardous design). So caution if spraying any chemical under the car. I think for that reason Toyota will not encourage undercoating and can void certain warranties.

Regular warranty for sheet metal protection is 5 years. A Tacoma / Sequoia lawsuit brought their warranty protection to 12 years.

Average lifespan of a car is 11 years. Most just die off in collisions. Those that make it longer will have to face corrosion issues if exposed to the elements a lot. If there is a known safe way to protect the under belly I would consider it.

 

Different grades of steel are used in different parts of the car. A lot of them have high chromium content which is good at preventing rust somewhat. A lot of the steel has rust preventative coating applied but when they are spot welded together get burnt off and can lead to rust.

I have heard of the ungodly amounts of salt they use on the roads in upstate New York.

This guy is in New York, enough said.

 

In the middle of this snip from OP's posted image, is the rear/center jacking point, hopelessly rusted. I'm thinking that car must have regularly driven through a brine bath.

Couple of shots of ours, don't know what I'm whinging about. The sheen on the suspension components is that linseed oil, put on maybe 6 months back.

 

This same guy basically says " Upstate New York is a Brine Bath". I'm sure someone will confirm it.
In some of his other videos he says they salt county roads even in the summer.

 

Yeah around here they go nuts too. Mall parking lots are particularly overzealous: page 2, post #23 in this thread has a local example:

Road salt | PriusChat

 

Rustproofing is NOT undercoating, Just review his next video. Fluid Film, Noxudol and Transtar 4423 are thin oil filn\ms that flow in the cracks between metal pieces where water vapor (a gas) penetrates and when mixed with any form of salt, acts as an electrolyte in a battery to enhance corrosion.

I use undercoating as additional mechanical protection from flying gravel. I'd only apply it only on top of rustproofing. Applying undercoating to bare or painted metal is obviously foolish and provides no protection.

Unfortunately commercial aftermarket rustproofing sells the warranty - an insurance policy, while the quality of the rustproofing will only depend on the skill and the care of the applicator.

 

Best solution is to move to a jurisdiction that does not squander your tax money buying salt with which to sabotage your vehicle. However, those are increasingly rare.

 

After review many YouTube videos on rust abatement, I'd rate NHUO and Krown and the best alternatives. Even in the South, my husband and I both rustproof both of our cars.

My retired engineer friend has always believed in well done rustproofing, not just the once and forever stuff that Ziebart and Rusty Jones promoted. They advocated selling the warranty on every job, without regard to how carefully the job is done.

I saw his 20 year old car with no rust on it. Every part worked on came off as if the car was new. I was surprised that no critters ever chewed anything under the hood.

Neither Krown, NHUO, or Fluid Film provides such sham warranties.

While the uninformed customer concentrates on warrantied, the well informed believe, "The best warranty is a well done job in the first place." Warranties are worthless, if you try to make a claim after your car is rusted out. Warranties are to protect the vendor. Many are not worth the paper they are written on. So many are written for the company's advantage. I've seen Lifetime powertrain warranties that require the owner to do all the scheduled maintenance at the dealer at the owner's cost at their inflated prices.

 

What rust delaying oils would you recommend ? do you use multiple oils using multi coats after a few days or do you do that on a same day ? I like fluid film as PriusV17 showed an example here (Thank you for reminding about fluid film) and was going to go with just that all over underbody or get it sprayed at rust check or some other place (but I do not know if they know how to oil spray a hybrid car and where to avoid)

I do not know what areas to avoid to not hurt hybrid systems under the car as its our first hybrid ?

 

This is a warning for those who do not believe or get rustproofing in northern climes where roads are treated with salts.

Should You Rust Proof Your New Car? » AutoGuide.com News

 

AutoGuide is NOT a consumer organization.

And it has been proven over and over that what is commonly sold as "rustproofing" isn't.......and is indeed worse than doing nothing.

 

My boiled linseed oil* coating seems to be holding up good.

You really need to invest some sweat equity, it's not economical to pay someone to do this. Besides the wholesale coating of suspension pieces, I also back out any small bolts/screws that are readily accessible, especially the ones that are down low, and put a drop or two of whatever I've got cluttering the shelf, currently an old can of 3-in-1 oil.

* This was a tip I heard here from @tvpierce btw.

 

Spoken like, "Ignorance is bliss." Cars rust from the inside out. It occurs where water and debris collect - at the bottom of doors, internal fender "dog legs," between plastic and steel panels and at bolt and screw fastener points. Bottom corners of door and fenders behind wheel wells often show rust "bubbling" through the paint.

 

Yes....and.....what's your point ??

The most commonly sold "rust proofing" or "undercoating" tends to plug up the drain holes to those areas that you mentioned causing water and corrosive salts to remain.......and sometimes creates a problem where none would exist.

 

doesnt all prius have metal covered with plastic under the car ? Do you have to remove the plastic parts to oil spray under those ?

In that case doesnt krown or rust check oil spray would sag that plastic ?

 

I did some strategic removal of plastic panels when I was doing ours. In particular I took off panel that covered portions of the main suspension components. At the rear suspension the trailing link members go into a joint that's half covered. Taking those off, I found the small diameter bolts in some case holding them on were nearly seized. It's a very good idea to remove those sooner than later, and soak them in oil before reinstall. I also remove the wheels.

Then there's plastic panel covering sheet metal underbody. I found little or no corrosion there, it's quite sheltered, so just left them alone.

 

great, thanks for the hints Mendel

 

I believe Eric says they salt the dirt roads in the summer to keep the dust down. He's lucky enough to live on one of them, so his personal vehicles get salted year round.

This document shows only Mass and Vermont hitting it any harder. Of note, Maine does it on half the salt of 4 neighboring states which lead the nation:

 

Where’s Pennsylvania on that list?

That may take the cake for salt conditions .