Undercoating

[Garcia]

I've got a 20 year old truck that runs great but the frame is rotten and can't be repaired. It made me start thinking about my current cars, 2017 and newer. Is undercoating a worthwhile investment? For older cars, like the truck, I would think yes (mine was not undercoated) but for newer cars I'm told it's a waste of money as there are far fewer parts to corrode.

Thoughts?

[Biggd]

I've got a 20 year old truck that runs great but the frame is rotten and can't be repaired. It made me start thinking about my current cars, 2017 and newer. Is undercoating a worthwhile investment? For older cars, like the truck, I would think yes (mine was not undercoated) but for newer cars I'm told it's a waste of money as there are far fewer parts to corrode.

Thoughts? It's the salt that eats away at everything, so I personally think if you religiously wash the undercarriage in the winter, it will extend it's life as much as undercoating will.
Another thing that corrodes frames is leaving a vehicle, that doesn't get much use, parked on dirt. It just sucks up the moisture from the ground leaving it perpetually damp. I saw a lot of trucks over my 50 years of vehicle repair, that were rarely used for everyday traveling. They left them parked and just used them for plowing or going to the dump and Home Depot. Those are the trucks that rusted the most.
I just bought a new truck last year and I hope to keep it a long time. I bought a monthly pass to my local car wash rather than undercoating it.
If you got 20 years out of the truck you got your money's worth, JMO.

[SAB1]

What are you defining undercoating as, something applied to the undercarriage on a brand new car at the dealership or are you talking about the oil spray many places apply once or twice year. I think there is some benefit when applied to a brand new car though I don’t know if it is worth the cost. The spray on oil I believe is just a gimmic. Once you have rust that oil isn’t stopping it. Rust is cancer to metal.

[Descant]

Undercoating, Rustyu Jones, TufKoat-Dinol etc is for new cars, and mostly superceded by manufacturers nowadays.
Waste of money on a car that already has been exposed to road salt, etc. Undercarriage wash may help. Does your cart wash use fresh water or recycle water that has salt etc in it?

[jeffk]

The last three cars I had all died from rust in one form or another. I could keep them going mechanically but once significant rust damage sets in there's really nothing you can do about it. It reaches a point where they won't pass inspection.

I have my 3 new cars undercoated with NEOU. The actual undercoat is a wax/oil combination that dries hard. I bring them in every 2 years for a steam wash and a touch up application for $100; $1000 per car over 20 years. I think of it as relatively cheap body "maintenance". I figure that, while it might not stop ALL rust it will probably limit damage to something that is more manageable/treatable.

I'll let you know in 20 years how it works out. :D

[MeredithMan]

I've got a 20 year old truck that runs great but the frame is rotten and can't be repaired. It made me start thinking about my current cars, 2017 and newer. Is undercoating a worthwhile investment? For older cars, like the truck, I would think yes (mine was not undercoated) but for newer cars I'm told it's a waste of money as there are far fewer parts to corrode.

Thoughts?

My wife and I have driven separate vehicles for 30 yrs. We each keep our cars 7-10 yrs and well over 100K miles. We've never purchased undercoating and have never had an issue with rust or corrosion. I would say the cars built today are much better in terms of anti-corrosion than when a lot of folks on this Forum were kids, (60's/70's). I remember seeing a lot of rusty cars back then. So I would agree that for a new car today, it is an un-necessary add-on.

Keeping a vehicle 20+ years may be a different story...

[Garcia]

Thanks for the replies. Seems like with hindsight, had the truck been undercoated early in it's life the frame might have been salvaged - likewise, had the rot been discovered maybe it could have been fixed. It was given to me a few years ago and remains inspected through the year so I'll keep using it around town and get rid of it when the sticker expires or the frame goes.

I'm glad I declined the undercoating for my current vehicles. I'll continue going to the car wash regularly and while my driveway is gravel, they are generally parked on asphalt or in the garage.

I like to keep my cars as long as possible so am looking to do as much preventative maintenance as possible.

[FlyingScot]

Post-factory undercoating stopped being rational a couple of decades ago. As noted above, your new car or truck will last for 20 years without anything extra

[Biggd]

Post-factory undercoating stopped being rational a couple of decades ago. As noted above, your new car or truck will last for 20 years without anything extraPost-factory undercoating is like post-factory warrantees, high priced sales gimmicks.

[Garcia]

Post-factory undercoating is like post-factory warrantees, high priced sales gimmicks.

Agreed! It's one of the reasons I despise buying a car from a dealer - listening to all the talk on financing and after market add-ons. Not to mention haggling over price.

My most recent experience in buying a late model used car was for me to make what I thought was a fair, even a bit high, offer only to face the hard sell from the business manager explaining why the listed price was already exceptional and thanks to AI was totally fair. I walked away and low and behold a few days later the same car was listed for $500 LESS than what I offered. I'de already bought a similar vehicle elsewhere.

I will admit I bought an extended warranty once for my own peace of mind - what a waste of money. Live and learn!

[Biggd]

Agreed! It's one of the reasons I despise buying a car from a dealer - listening to all the talk on financing and after market add-ons. Not to mention haggling over price.

My most recent experience in buying a late model used car was for me to make what I thought was a fair, even a bit high, offer only to face the hard sell from the business manager explaining why the listed price was already exceptional and thanks to AI was totally fair. I walked away and low and behold a few days later the same car was listed for $500 LESS than what I offered. I'de already bought a similar vehicle elsewhere.

I will admit I bought an extended warranty once for my own peace of mind - what a waste of money. Live and learn!I had my own Auto repair business for over 35 years, I refused to accept aftermarket warrantees.
The time it took haggling about price, I could have fixed the car.
They have one labor rate regardless of where you are located, $45 per hour, when I was in business 5 years ago.
My labor rate was $100 at the time, $45 an hour wouldn't even pay my mortgage.

[BroadHopper]

In the past 30 years, I have stopped buying new cars. I am now searching for ultra-low-mileage used vehicles from the Southwest, i.e., Cali, AZ, NM, etc.
I have excellent luck getting 20 years and more! Carfax makes it much easier to recognize a primo vehicle.
As for maintenance, after the roads are salted and the temperature rises above freezing, I find a car wash with a bottom wash and use it. I entered the car wash slowly to wash the bottom effectively.
As for rust prevention on new cars, I think it is a waste of money.

[fatlazyless]

The under carriage wash at a drive-thru car wash is always no where near as good as using the hand held spray at the low-price do-it-yourself car wash. You know most car washes have both a drive-thru and a do-it-youself spray in different bays.

I mean the 4-minute $3.75 do-it-youself does a hell of a better job with the under spray than then $13 drive-thru that includes an underspray, plus it's $9.25 less expensive.

This is a scientifically proven fact done through extensive car wash testing at 99 different NH car washes in the last two years!

[VitaBene]

We use NH Oil Undercoating. https://nhoilundercoating.com/

I have it on my 2023 F150 and 1999 F250. It works great! We use New England Truck and Auto in Moultonborough across from the airport/ next to Independent Marine.

[FlyingScot]

We use NH Oil Undercoating. https://nhoilundercoating.com/

I have it on my 2023 F150 and 1999 F250. It works great! We use New England Truck and Auto in Moultonborough across from the airport/ next to Independent Marine.

How do you know "it works great"? When we were kids, it was easy to see rust buckets on the road. But cars and trucks like that are now few and far between. For the past few decades they've been built to last without rust

[VitaBene]

How do you know "it works great"? When we were kids, it was easy to see rust buckets on the road. But cars and trucks like that are now few and far between. For the past few decades they've been built to last without rust

Do you look at some of the cars and trucks on the road that are less than 20 years old. I know it works because I have been using it for years. Many people have scrapped good running cars because unlike MA, we cannot get a sticker on a car with a rust hole in it, therefore we see less rust buckets on the road.

The salt brine they use to pretreat is meant to stick to the road well, but it also sticks to the frames and wheel wells even better. This is my 99 F250 with 230K miles on it. Ill spend 250 every other year to keep it as good as it can! It has 2700 pounds of bluestone in the back- it is usually level.

[SAB1]

2700 lbs of blue stone in 3/4 ton hmmmm?

[Biggd]

2700 lbs of blue stone in 3/4 ton hmmmm?If the frame was rotted that would finish it!

[VitaBene]

2700 lbs of blue stone in 3/4 ton hmmmm?
1 ton rear springs- the helper springs were not even engaged

[TheProfessor]

I'm glad I declined the undercoating for my current vehicles.

Post-factory undercoating stopped being rational a couple of decades ago.

Post-factory undercoating is like post-factory warrantees

How do you know "it works great"?

Some just don't get it. And probably never will. As an ostrich. With head in a dark hole. Missing all that is going on around them.

https://www.youtube.com/watch?v=c-Kfb6-eD98

I'd hazard to guess that 90% of posters here have never viewed or seen the bottom of their vehicle. Up on a lift.
Most go to dealer. Get vehicle serviced. And sit in the comfy waiting room. Never to view the destructive rust on the bottom of their vehicle.
New vehicles begin to rust right on the new car dealers lot. Take a look at the rusting nuts, bolts, clamps made out of steel that rusts.

If you trade every 5-7 years - you probably will not see any body panel rust thru. But the bottom is surely rusting. Of course, you now have another new car for the next 5-7 years. So who cares.

Traditional undercoating is a misnomer. From the 1950'a Undercoating was done to add to sound deadening - not for rust inhibitors.

Oil undercoating is done annually. If one plans to keep vehicle for a long time. The oil will prevent rust. Even if there is some undercarriage rust on an older vehicle. The oil will restrict it. It is never too late to begin oil undercoating.

Thanks to the ostriches reading here. They keep the new car sales going.

[Biggd]

Some just don't get it. And probably never will. As an ostrich. With head in a dark hole. Missing all that is going on around them.

https://www.youtube.com/watch?v=c-Kfb6-eD98

I'd hazard to guess that 90% of posters here have never viewed or seen the bottom of their vehicle. Up on a lift.
Most go to dealer. Get vehicle serviced. And sit in the comfy waiting room. Never to view the destructive rust on the bottom of their vehicle.
New vehicles begin to rust right on the new car dealers lot. Take a look at the rusting nuts, bolts, clamps made out of steel that rusts.

If you trade every 5-7 years - you probably will not see any body panel rust thru. But the bottom is surely rusting. Of course, you now have another new car for the next 5-7 years. So who cares.

Traditional undercoating is a misnomer. From the 1950'a Undercoating was done to add to sound deadening - not for rust inhibitors.

Oil undercoating is done annually. If one plans to keep vehicle for a long time. The oil will prevent rust. Even if there is some undercarriage rust on an older vehicle. The oil will restrict it. It is never too late to begin oil undercoating.

Thanks to the ostriches reading here. They keep the new car sales going.I was an auto mechanic for 50 years and had my own business for 35 of those 50 years, just retired 5 years ago. I've seen plenty undercarriages of almost every kind of car and truck.
You are right, they will start rusting as soon as water hits the vehicle. But is undercoating worth the price, I say no. Just like I say no to extended warrantees. It's the salt that eats away at the metal, wash that off religiously and it will last a long time.
Most people don't keep their vehicle for 20 years. If you take care of it, wash it regularly including the undercarriage it will last.
And of course, as a mechanic, we all hate working on a car or truck with any kind of messy undercoating.
If you're happy paying for it, great. I'm 70 and I have never undercoated a vehicle, and I tend to keep my vehicles a long time.
I just bought a new truck, no undercoating for me, and I'm planning on it being my last vehicle purchase.
I have the unlimited monthly car wash including undercarriage for $40 per month and I go once a week during the winter.

[ApS]

1 ton rear springs- the helper springs were not even engaged

In my little truck, I installed $100 helper springs--which scarcely touch--which optimizes the ride. Load, say, a lawnmower, and the helper springs "kick-in".

Summers in NH won't affect this truck's salt damage; however, this truck is parked only 120-feet from Gulf of America saltwater during much much of NH's off-season.

While it gets rinsed on occasion, I make a point to creep through puddles of saltwater and enthusiastically drive through puddles left by tropical rains. (OK, I'm lazy and cheap).
;)

A neighbor's much newer Titan had the rear axle fall out at a gas station!

:eek:

My truck's bed has a hole in it (above the muffler) and the front valance shows rust penetration weakness, but it is a 30 year-old truck!

:eek2:

[FlyingScot]

Some just don't get it. And probably never will. As an ostrich. With head in a dark hole. Missing all that is going on around them.

https://www.youtube.com/watch?v=c-Kfb6-eD98

I'd hazard to guess that 90% of posters here have never viewed or seen the bottom of their vehicle. Up on a lift.
Most go to dealer. Get vehicle serviced. And sit in the comfy waiting room. Never to view the destructive rust on the bottom of their vehicle.
New vehicles begin to rust right on the new car dealers lot. Take a look at the rusting nuts, bolts, clamps made out of steel that rusts.

If you trade every 5-7 years - you probably will not see any body panel rust thru. But the bottom is surely rusting. Of course, you now have another new car for the next 5-7 years. So who cares.

Traditional undercoating is a misnomer. From the 1950'a Undercoating was done to add to sound deadening - not for rust inhibitors.

Oil undercoating is done annually. If one plans to keep vehicle for a long time. The oil will prevent rust. Even if there is some undercarriage rust on an older vehicle. The oil will restrict it. It is never too late to begin oil undercoating.

Thanks to the ostriches reading here. They keep the new car sales going.

That's me! I especially like the comfy waiting areas with free snacks. But it's been up to 12 years/vehicle in road-salted Mass, and I have never seen any significant rust or been told I have an issue. So I'm still thinking I've saved thousands

[thinkxingu]

That's me! I especially like the comfy waiting areas with free snacks. But it's been up to 12 years/vehicle in road-salted Mass, and I have never seen any significant rust or been told I have an issue. So I'm still thinking I've saved thousandsDitto. I'm guessing I'm younger than a lot of members here, but in 32 years of driving something like 15 different cars, many of which had over 150k miles, I've never had even a single bolt need replacing from rust.

Sent from my SM-S911U using Tapatalk

[TheProfessor]

You are right, they will start rusting as soon as water hits the vehicle. But is undercoating worth the price,

Years ago.
Neighbor No. 1
New GMC extended cab.
Stopped by with new truck. Advised him to get annual oil undercoating.
He laughed. Scoffed. That Rusty Jones does not work. Of course, oil undercoating is not Rusty Jones hard plastic coating. He did not know difference.
Years later. Neighbors nice GMC extended cab pickup truck is all rusted. Underneath. Outside rust. Rockers rusted. Cab corners rusted. Above rear wheel wells. Rusted. body paint rusted.
His next new truck - wait for it - got annual oil undercoating. In fact, he found 2 other places that do oil undercoating that I did not know about. Since then, EVERY pickup truck he has purchased gets annual oil undercoating.

Neighbor 2
Years ago.
He got a new Chevrolet extended cab pickup truck.
Advised him of annual oil undercoating.
He laughed and scoffed.
Years later same as above. Rockers, cab corners, rear wheel wells, and rust shown all over truck.

Friend 3
Got a new extended Ford pickup truck.
Advised him of annual oil undercoating.
He too laughed and scoffed. Not worth it as "new cars don't rust anymore".
Years later.
He had to junk this pickup truck as the frame was rusted along with most of the body. Could not be viable to fix.
Junked. Sent to crusher.

Again, each to their own. It's your money. Spend as you like.