Rust proof coatings, undercoatings....New Car

For the long story short, jump to the ***.

We drove from Appleton/Green Bay, WI area to Yellowstone a little over a week ago. 1100 miles/16 hour drive to get to Billings for our first stop and our 2014 Jeep Grand Cherokee was doing fine.

After a pull through the Beartooth Highway pass, 8,000ft in elevation change, an additional 800miles/30 hours of driving during the week of vacation in 8% grades and lines of tourist and bison traffic hams, the Jeep throw a cam sensor code. It throw a few codes actually, one being "Implausible Torque Demand" which has continued to be a running joke. The jeep then went into a limp home mode and would lock itself into one gear until it was restarted. Put too much load on the engine and it would do it again. 

I replaced the passenger side cam sensor in the NAPA parking lot. It still happened. My wife cried to an independent shop to have them look at the Jeep. It was Friday and the local Jeep dealership was booked out past the 4th of July. This one shop was our only real hope to get home by Monday morning to return to normal life.

The tech said he pulled the valve cover and cleaned debris off the cam where the hall effect sensor was watching the magnetic part at the end of the cam. They cleared the check engine light codes. They thought they fixed it, even test drove it.

It was as if the sensor couldnt figure our what was happening, so then the variable valve timing got lost. It was also low on oil pressure, around 20 psi when I shut it down the first time after the check engine came on.

While we waited to hear back from the shop, we started figuring out what we could do if they couldnt fix it.

All of the uhauls were out of auto transporters and the uhaul trucks that could tow a transporter only have 3 seat belts and there were four of us.

Flights, car rentals, parents/friends driving to our rescue, and towing companies were all considered. Even me sitting in a hotel waiting for the 4th of July and the Jeep dealership to look at it while sending my family home some how. Every option costs several thousands of dollars before our broken Jeep was even fixed. We felt homeless walking around with a couple of small bags and two kids with stuffed animals. We got a hotel room just to wait out the shop until it could finish it up.

Well it was still broken after the shop. We limped it, stuck in 6th gear from Livingston to Billings MT (110 miles or so) with consistent load on the engine to keep it from getting locked it even lower gear. 70mph on the flat parts, hazards flashing and 50 mph at the top of hills. Roll into the Billings Jeep dealership stuck in 6th gear.

We got $7k for the Jeep and bought a brand new 2021 Dodge Durango R/T. They saw the check engine light and heard a bit of tick at idle but when revved it went away. Since the last shop cleared the codes, when he asked what the codes were, I said I didnt know, because honestly I didnt that time.

What a stressful day!

*** I want to protect our new vehicle and we thought about some kind of undercoating or rust proofing. Whats the difference between the two? One brand better than the next? Do auto mechanics hate either?

I use Krown.  It drips a lot for a week. It gets into crevices and just works.  The application requires holes to be drilled, but in 10 cars and 30 years I have never seen rust around any of the holes.  They put in a plastic plug to seal the holes.

My 25 year old Subaru impreza has no rust,  nor does my 15 year old Mini. Nor my 7 year old X3.

Fluid film has worked really well for us, even on rust prone daily driven northeast cars (Mazda3 with 250k, 03 Suburban with 189k).   It is easy to apply and doesn't smell as bad as other options.  

Sorry to hear of the vacation drama.  Congrats on the new Durango.  

Hey Buddy how do I get this Jeep outta 6th gear?

https://www.youtube.com/watch?v=2skGMkxB6Ng 

Thanks guys.

Are those products something a shop applies or at home? I am guessing both are more like oily waxy films? Is undercoating the heavy stuff thats more like rubber/tar bed liner?

L5wolvesf said:

Hey Buddy how do I get this Jeep outta 6th gear?

https://www.youtube.com/watch?v=2skGMkxB6Ng 

Thats a new one to me! Funny!

I do the fluid film in the driveway.  You can get rattle cans or buy a gallon and a sprayer and hook to your compressor (I do the latter).  It takes 20-60 minutes we car depending on how complicated the underbody is and how big it is (like the body on frame Suburban takes a while, the Mazda is quick and easy).  I bought a kit on Amazon with everything, I don't recall how much but it was very reasonable.  

Those are all good but the best is corrosion free. 

I don’t know if you can get it in the U.S. though 

Our good friend at Project Farm has a video on this:

What I do is spray CRC Corrosion Inhibitor on the big, exposed areas on the underside of the car, and then Fluid Film in all the nooks and crannies. Especially the bottoms of the doors. There's usually a little drain with a rubber plug you can pull out, then use the flexible hose with the FF to get it all the way in there. I do this every fall.

KROWN is applied by a Krown dealer.  It's an oil- type that is sprayed everywhere from the windows down, inside doors, sills, frame holes, etc.

Krown, Fluid Film, or any other oily rust inhibitor is good.  The waxy CRC HD rust inhibitor stuff (basically cosmoline) is good too, but it needs more attention paid to it, as it doesn't flow and heal chips and such like the oily stuff does.  Stay away from anything rubberized that can potentially crack and trap stuff under it, causing severe local rust that's invisible until it gets really bad. 

Wow.  How stressful.   

Waxoly is what the Brits used....

https://www.waxoyl-usa.com/

Just to put some closure to this, we went to Ziebarts and got the rustproofing treatment. It took a few days and had a pretty strong chemical smell to it. Its better now. The cost was $600 or so and they give you a 10 year warranty if you let them clean it once a year for $44. 

Havent found any rust yet! 

As for the Durango, I am really liking it. Feels a lot like like the old Grand Cherokee, because it shares so much with it. But has an updated dash layout that feels nice and modern. The ventilated seats are great! The bump from the 3.6 V6 to the 5.7 V8 Hemi is not quite as noticeable as I would have thought since its geared differently (something like 3.45 vs 3.08)

Its still more entertaining buzzing around town, and makes great noises. We have over 7,500 miles on it. We test drove it June 11th with 60 miles, lol.

Sonic said:

Fluid film has worked really well for us, even on rust prone daily driven northeast cars (Mazda3 with 250k, 03 Suburban with 189k).   It is easy to apply and doesn't smell as bad as other options.  

Been to their site and with so many versions what do you choose?

Can't go wrong with Krown. Fluid Film is inexpensive and effective also.

Krown.  It's messy but it works . . .

I've used most of them and I think Krown would be my second choice behind Corrosion free.

Link to test of Corrosion free vs Krown and Rust check

I did Krown mostly because it was the only brand near me.  It was not expensive.  I think it was $120 for the first application because they drill holes in strategic places like door jambs, rockers, etc.  They use little fogging wands to stick in every nook and cranny.  It is a mixture of liquid paraffin and oils that creeps into places you can't otherwise reach.  When they're done, they put little rubber plugs in the holes they made and wash the outside (since the whole thing gets a film on it).  Took them a little over an hour.

Follow-ups (year or two years depending on the recommendation) are cheaper because they don't have to drill.

Honestly, for the price I just let them do it.  They have specialized equipment that makes it easy for them to do the job right, and for one Ben Franklin it sure beats me getting all lubed up with no body to take advantage of it.

All the customers in my town use Dominion sure seal dripless undercoating. May be a Canada only product though.