to oil or not to oil

[Robertslowpoke]

good morning!

briefly, one guy at work puts his Escalade on a lift every fall, and sprays used oil on the undercarriage.

two mechanics here say not to do that.

should I?

my 2008 caddy DTS already had rust on the doors, one week and $900 to fix.

simply, should I spray oil underneath every year?
bob and THANK YOU

 

[Olas]

Not used oil, but underseal or bedliner is good. And Schultz the inside of the doors/sills/anywhere moisture might accumulate.

Basically do all e finishing work that Caddillac didn't do before they sold the car to you.

 

[The motor guy]

Don't vehicles up north already have some kind of rubber coating on the frame and everything? I find it hard to believe they actually let vehicles go without it.

 

[Robertslowpoke]

morning madman!

vehicles here rust like crazy. they use SO much salt on the roads. as far as I know, no extra rubber coating.

we have one inch of snow and one inch of salt on the road. absurd.

thanks
bob

 

[Bgallagher]

Originally Posted By: motor_oil_madman
Don't vehicles up north already have some kind of rubber coating on the frame and everything? I find it hard to believe they actually let vehicles go without it.


nah, same cars that go to TX go to New England and snowy areas.

I have heard people using fluid film in their undercarriage but not used oil. I wouldn't bother with used oil. I usually hose the undercarriage when I have a warmer day in the winter. Never seem to have any rust issues.

 

[GenesisGuy70]

Originally Posted By: motor_oil_madman
Don't vehicles up north already have some kind of rubber coating on the frame and everything? I find it hard to believe they actually let vehicles go without it.


I wish!

I've owned 3 cars in Ohio and worked on many more and not a one has ever come with undercoating.

However, the 2017 Elantra I picked up on New Year's Eve does have rubber coated brake lines, which I have never seen before and I'm thankful it has that...for the next owner more than myself I guess.

 

[ARCOgraphite]

No. Zinc slugs attached at critical points. Most doors rust due to water IN the door cavity.

Runner undercoat is for sound deadening. Most quality cars are zinc primer submerged prior to body paint.

 

[HerrStig]

"Undecoating" can block drains and create little pockets where salty sand collects. Some states pretreat their roads before a snowstorm storm with a liquid worse than salt.

 

[GenesisGuy70]

Originally Posted By: HerrStig
"Undecoating" can block drains and create little pockets where salty sand collects. Some states pretreat their roads before a snowstorm storm with a liquid worse than salt.


I got stuck behind one of these tankers and by the time I could get around him my entire car was covered in that stuff.

Immediately went and had it washed. With a good under-body rinse!

 

[RISUPERCREWMAN]

I take my plow truck every fall to a big place in NH and they coat the entire undercarriage & inside of body panels & doors with their special clear oil. Not a spec of rust on my 2014 Ram 2500 HD yet.

 

[LeakySeals]

Thats old school when frames had no protection. He has a black factory wax coating over his frame, any oil will soften and make the wax scrape or fall off to bare metal. I spray fluid film which also softens the wax, but leaves behind a wax of its own. Oil and the Fluid film attracts too much dirt and makes turning a wrench a huge mess. Not to mention it can be dangerous to put an oil framed truck up on a lift. I had the jack slip on the frame when I was under changing oil. Got out in time but that spooked me into trying a dry solution. This summer going to clean everything, scrape off the wax and use Chassis saver and a paint brush.

 

[Alex_V]

Not sure what the best product to put on an undercarriage is (though there has to be something better than used oil) but extra undercoating isn't it. I've never seen a vehicle that had more undercoat applied after it left the assembly line that it seemed to have done any good on, if not accelerate the process.

 

[Wolf359]

If you're in MA, just go to Scruadub or other car wash that has an undercarriage wash as an option and that has a rust inhibitor. Last car I had I didn't end up with much rust, I noticed other cars of the same/newer vintage with rust in the wheel wheels, but mine never had it. I usually go at least 4-5 times in the winter. They offer a free rewash after 4 days so that's why I like going there, usually a wash right after the roads are dry and then another wash 4 days later. Probably cost you $40-$60 for the winter, but I'd rather have a clean car than spend $100+ on rustproofing every few years.

 

[SirTanon]

I could be wrong here, but it seems to me that most used oil has a TAN value that makes it potentially problematic on exposed metal, especially if you add other road chemicals to it, like salt etc..

That high TAN value could potentially cause more harm than good. Never mind the fact that it makes working on anything underneath the vehicle a nasty mess.

Do as others have suggested - Get a proper undercoating done, either using bedliner, or some other more permanent and 'clean' material.

 

[Donald]

Use the right product. CarWell or Fluid Film or Krown.

Do the environment a favor and don't spray used/new motor on the vehicle undercarriage. It will be washed off onto the roadways and then streams.

 

[Robertslowpoke]

thanks guys! will NOT spray oil. will do the undercarriage wash and hope to find rust inhibitor.

best

bob

 

[SwampSurvivor]

I have been doing this on my vehicles since I got them in 2010/2011. Due to some other issues, this was the first year I have not been able to do it.

It's amazing how much the Focus rusted underneath this winter. The Cherokee was starting to rust since it's 17 years old , but it just rusted way worse.

 

[Wolf359]

Originally Posted By: Robertslowpoke
thanks guys! will NOT spray oil. will do the undercarriage wash and hope to find rust inhibitor.

best

bob


The rust inhibitor is part of the undercarriage wash. It's an extra cost option on top of the regular wash.

 

[mjoekingz28]

Originally Posted By: Robertslowpoke
morning madman!

vehicles here rust like crazy. they use SO much salt on the roads. as far as I know, no extra rubber coating.

we have one inch of snow and one inch of salt on the road. absurd.

thanks
bob




So, maybe the undercoat that the dealer 'upsells' on new cars isnt hogwash.

 

[Wolf359]

Originally Posted By: mjoekingz28
Originally Posted By: Robertslowpoke
morning madman!
vehicles here rust like crazy. they use SO much salt on the roads. as far as I know, no extra rubber coating.
we have one inch of snow and one inch of salt on the road. absurd.
thanks
bob

So, maybe the undercoat that the dealer 'upsells' on new cars isnt hogwash.


You probably don't need it if you maintain your car properly and get the salt off and not let it sit there the whole year. Just lots of people are lazy and don't do it so that's why you see the rust. Only worthwhile if the buyer is lazy and there's a huge profit profit margin in it for the dealer.