Mark My Words – Tires, Antifreeze and Spark Plugs

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September 16, 2015

Close up of tire on truck or RV

Hi Folks! Some great questions this month: Tires, antifreeze, spark plugs, and a possible solution to last month’s question about an inside actuator for that pesky range hood vent! Enjoy the read, and send your RVing questions to [email protected].


Mark, I just read that in tires there is 21% oxygen and 78% nitrogen, the rest mixed gases. It was suggested that one should put mostly nitrogen in the tires, both trucks and RV’s. Where would one get

Nitrogen in enough quantities to top off or even fill tires on and RV? I know this, from being in the compressed gas business, that nitrogen is a little on the pricy  side and where would one get it on the open market.  Thanks, Bill

Hi, Bill,

Most tire shops have nitrogen available, and a few gas stations, but it is not very easy to find for the average RVer on the road. The primary advantage advocates claim for pure nitrogen is that it is a larger molecule, and that slows down the normal loss of pressure through the permeable rubber of the tire. The most important thing you can do for your tires is to keep them at the proper inflation pressure at all times for best fuel economy and tread life. Nitrogen is supposed to make this easier by not leaking down as fast, but there is no scientific evidence that a tire properly inflated with nitrogen lasts any longer or provides any better gas mileage than one that is properly inflated with air. There may be some advantages to using pure nitrogen in tires, but it is impractical for most RVers. Just fill them to the correct cold inflation pressure with good old air, and you’ll do fine.


Mark: Is there a difference between RV antifreeze & plumber’s antifreeze?  We have had problems with lines and our filter freezing and even the antifreeze freezing in the toilet of our RV. Rhena

Hi, Rhena,

RV antifreeze is formulated to be non-toxic and safe for use in potable water systems. Plumber’s antifreeze is essentially the same stuff as RV antifreeze, and can be used in your RV, but I am unable to find any that offers any better protection. Automotive antifreeze is very toxic, and should never be used in plumbing systems. Most RV antifreeze must be used undiluted, so it is necessary to get as much water as possible out of your plumbing system before you pump in the antifreeze. RV antifreeze is designed to protect down to -50F, so it is very unusual to have a freeze problem with it unless it has been diluted with water. If you live somewhere that routinely gets colder than that, I’m not sure what else to suggest, except maybe it’s time to move your RV to indoor storage or move yourself somewhere warmer?


Hi Mark,

I’d love to get your opinion on changing spark plugs in a Ford 6.8 liter V10 engine, especially a 15 year old (55,000 miles) one like mine.  I have heard that the head has only 2 or 3 threads and is made of aluminum, so a spark plug replacement is risky, as the threads might strip-out and fail (requiring the installation of an insert).  On the other hand, I have heard that the plugs sometimes “weld” themselves into place if you wait too long to replace them. What’s your opinion? Jeremy

Hi, Jeremy,

I have only owned one aluminum-head engine, and I have always been very careful with spark plugs on it. I never try to remove a plug from a warm engine. I only wrench on a cold engine that has not been run for 8 hours or more. Turning the plug back and forth a little bit after you initially break it loose can help get it out safely, and I always break the plugs loose from the head and immediately spray some penetrating oil at the base of the plug to help lubricate the threads before removing it. If it drags significantly on removal, use more oil and loosen/tighten/loosen back and forth gently until it comes out freely. If you do bung up the threads, you can usually install a HeliCoil, provided you can see/reach the plug hole. Before you install the new plugs, put a dab of anti-seize compound on the threads… this will ensure that the plugs can be removed easily next time. Anti-seize can be found at all auto parts stores. I have read that many folks with V-10s wait till either the 100K mile mark to do a plug change, or until they are experiencing a rough idle or loss of fuel economy. I would be itching to pull them sooner than that, but that’s me….


Hi, Mark,

I have a 2008 27′ Dutchman travel trailer my auto mechanic told me his dad use to put wipe brake fluid on his trailer tires to extend the life. I do keep tire covers on all the wheels and have my wheels on top of my plastic leveling blocks to keep the tires of the pavement or ground during the off season. Would wiping brake fluid on the tires extend the tire life or is this not a good idea? Also if it is not a good idea, are there any products out there that would extend tire life? Thank you… some excellent comments on your site, always great. Happy Camping, Gary

Hi, Gary,

Don’t put brake fluid (or any other petroleum product) on your tires! It collects dirt, and can damage the rubber and lead to tire failure or early sidewall deterioration. All the major tire manufacturers recommend that you use nothing on your tires except soap and water. No tire dressing product currently on the market will extend the life of your tires. They just make them look shiny. Great for show cars, not so great for RVs.



In your recent “Mark my Words” one of your readers inquired about a device that can open and close the stove vent flapper door from inside the RV. There is an RV repair shop in Louisiana; owner’s name is Dick Albritton. They make a custom device for around $50 for the Alfa Motorhome.  Whether or not they work on other brands of motorhomes, you would have to inquire with Mr. Albritton.  I’ve attached a do-it-yourself installation guide for his stove vent flapper door kit and it includes the contact info for Mr. Albritton. Good Luck, Steve.

Wow, Steve, that looks like just the thing! I uploaded the PDF you sent me to my site, readers can access it at’s%20Stove%20Vent%20Installation%20Kit.pdf  Thank you for sharing!


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