2024 CX-5 Undercoat necessary?

zhoom-zhoom

'24 CX-5
2024 CX-5 under carriage seems very well protected with plastic covers. Does anyone have issues with rust on theirs? Would the undercoat be overkill and waste of $? Thanks.
 
The rear isn't covered and starts surface rusting pretty quickly. Exhaust, suspension, etc are what you'll notice first. I have considered doing mine this fall, but I haven't decided if it's worth it yet. Open to opinions.
 
The rear isn't covered and starts surface rusting pretty quickly. Exhaust, suspension, etc are what you'll notice first. I have considered doing mine this fall, but I haven't decided if it's worth it yet. Open to opinions.
Although I’m in Texas and under-carriage rust isn’t a problem. But after I saw many reports on under-carriage rust problem on CX-5, I believe you should do it if you’re in North or Canada unless you plan to trade the CX-5 in several years.

Undercarriage Rust

Would you be concerned about this amount of rust?

Just joined the club and question on rust

Rustproofing & Undercoating...is it necessary?

The comparison pictures between @Fish1’s CX-5 and his much older Toyota Matrix from Southern New Hampshire is astonishing:

Rust like that after a few years even with heavy use of salt I believe is unacceptable with today's coatings and materials to look worse than a car that is 13 years old is not acceptable. How can Mazda get away with this? I love how this car drives and looks but also want one that will last. Also very happy with fuel economy so far getting around 30.5MPG on my 100 mile round trip commute.

2005 toyota matrix/pontiac vibe - 225K miles driving 100 miles a day
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2014 CX-5 (seen 2 winters) -28K miles
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Yes. the CX5 does rust. Sadly Opel invented the rust but Mazda perfected it :)
If living in the rust belt and plan to keep the car ..say 10 years or more you need to undercoat it.
 
Undercoats are not all equal. Rubberized undercoatings will do more harm than good because they will trap moisture against metal and actually cause more corrosion. You can see the results of this on Youtube videos:


You want an oil based film like Fluid Film or Blaster Surface Shield.
 
Undercoats are not all equal. Rubberized undercoatings will do more harm than good because they will trap moisture against metal and actually cause more corrosion. You can see the results of this on Youtube videos:


You want an oil based film like Fluid Film or Blaster Surface Shield.
Thanks for the tip
 
As stated above go with something like Fluid Film. IMO: Even in WA state which isn’t a salt state the magnesium chloride used in mountain passes doesn’t do a vehicle favors. I’ve seen some surface rust in some areas on my CX-5 I attribute to that. It’s either that or the steel used as my G35x which sees mountain pass use as well doesn’t exhibit the same.
 
Is Fluid Film the one made with lanolin from sheep and can have a strong , lingering odor. A couple years ago I read internet forums where different rustproofing ides were discussed and what I came away with was FF doesn't dry and leaves a greasy, smelly coating. I have no personal experience, just something I remember. Not trying too criticize. There's also many youtube videos where different products are tested.
I ended up using CRC Marine Heavy Duty Corrosion Inhibitor. It leaves a dry, wax-like, light amber coating. I used 2 or 3 cans right over surface rust and painted suspension parts. Definitely need respirator with cartridges (mine has organic solvent cartridges for painting etc) and cover up face and hair if possible. Cost about $11-13 a can IIRC. Seen it on Amazon for~$10 one time.
Not pushing this stuff, just mentioning what I used. There's always commercially applied also.
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@Jmaz thanks for sharing. Do you think it's a good idea to run the pressure washer under the car first or let it be? On one hand, I'm thinking let's get everything clean before sealing it up. On the other hand, I'm thinking water + air + iron equals rust...
 
@Jmaz thanks for sharing. Do you think it's a good idea to run the pressure washer under the car first or let it be? On one hand, I'm thinking let's get everything clean before sealing it up. On the other hand, I'm thinking water + air + iron equals rust...
I'd pressure wash it first and apply rustproofing after it's dry. You're not going to cause any rust if it dries. Not having a pressure washer I used the self serve car wash high pressure spray. Naturally I couldn't get into all areas very good but it was OK. I did mine in the fall when the air was dry so as to not trap moisture.
I concentrated first on any bolts or items that would be good to protect especially if later need loosening/removed. Sway bar end links(F&R), sway bar bushing brackets, front and rear knuckles, ABS sensors, ball joints & pinch bolts, tie rod ends, strut bolts especially (aluminum casting) rear strut upper mount, rear camber "adjustment wheels", lateral and trailing links etc. The list goes on.

ETA--- After applying this I could detect a smell inside the car but it wasn't overpowering and nasty (drop the windows when getting in) and was gone within about a day.
AND to reiterate, a bonafide respirator with appropriate cartridges is needed. Using a dust mask or respirator with just filters (P100 for example) is risking lung damage assuming you can even continue without gagging. It really wasn't bad with using protection.
Finally, I wish I would have taken the time to do it when the car was new. Even though the rust wasn't (and isn't) horrible, I shouldn't have waited 8 years to do it.
 
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I've heard the smell goes away and don't believe it completely dries but many swear by it.


"FLUID FILM® is formulated from specially processed wool-wax, highly refined petroleum oils and selected agents to provide corrosion control, penetration, metal wetting and water displacement. These long lasting products contain no solvents, will not dry out and will penetrate to the base of all metals, providing corrosion protection from both natural and industrial atmospheres. Heavily corroded and/or frozen parts such as nuts, bolts, shafts, etc. that would normally be damaged during maintenance, can be salvaged by applying FLUID FILM®."

Amsoil has a product out now as well


IMO.. they probably all work.. it will then come down to cost and how often you have to re-apply

 
So...cosmoline vs lanolin? One dries matte black, one stays wet. Will need to research further. Thanks.
 
Here's a couple of pics to show what the CRC looks like when applied. The first pic shows the amber color on the white plastic piece where too much was applied and it has a few runs.
The second pic shows a little better that the coating leaves a semi gloss sheen for instance on the lateral link behind the rotor. Also coated the brake line fittings and bracket. The pics give an idea of the thickness of the coating and the degree of it's transparency, so it's not like painting the parts. After seeing cosmoline coated parts in the military, I'd call this stuff "cosmoline lite".
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Here's a couple of pics to show what the CRC looks like when applied. The first pic shows the amber color on the white plastic piece where too much was applied and it has a few runs.
The second pic shows a little better that the coating leaves a semi gloss sheen for instance on the lateral link behind the rotor. Also coated the brake line fittings and bracket. The pics give an idea of the thickness of the coating and the degree of it's transparency, so it's not like painting the parts. After seeing cosmoline coated parts in the military, I'd call this stuff "cosmoline lite".
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Do you know if CRC Marine Heavy Duty Corrosion Inhibitor rubber friendly? Did you protect the ball joint rubber boots and brake lines when you’re spraying it?
 
⋯ I’ve seen some surface rust in some areas on my CX-5 I attribute to that. It’s either that or the steel used as my G35x which sees mountain pass use as well doesn’t exhibit the same.
Same here. I can see some surface rust under chassis on my 2016 CX-5 which is seldom seeing salt road in Dallas area, but my 26 year old 1998 Honda CR-V and 24 year old 2000 BMW 528i suffer very minimum or almost no surface rust under chassis. Some say surface rust is no big deal, but it eventually will develop into deep rust making it difficult to loose the nuts and bolts. This just shows Mazda has failed on rust proofing process under chassis comparing to other car manufactures on my book.
 
Do you know if CRC Marine Heavy Duty Corrosion Inhibitor rubber friendly? Did you protect the ball joint rubber boots and brake lines when you’re spraying it?
As far as I know--- yes. It's one thing I looked at before choosing. Here's the manufacturers website. It lists what it can be applied to and check out the video there. In the video you can see the color on a white background when it's applied to electrical terminal strip. There's also youtube videos of different products being tested. It's on some of those too. I sprayed directly on the boots, no masking, but I didn't soak them either, just a light coat. I did spray heavier on on metal parts and fasteners that do corrode.

 

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