We generally don't drive the Miata when the roads are snow- or slush-covered or excessively salt-covered, Dave.  But, if we do go on the roads when they are somewhat sloppy (sometimes the annual LVMOC Polar Bear drive gets a little messy 🙄), we're fortunate to live about a block from a "Laser Wash"-style car wash.  It's a brushless system, using multiple passes of high-pressure spray with detergent, etc.  It also blasts the wheels and undercarriage.  It does a decent job, and we follow up by toweling off at home.  When the crappy-road season ends, I give our cars a good underside rinsing with the hose in our driveway.  I also check under the hood, to see if any salty spray left deposits there, and wash that area as needed.

David

Thanks, Dave.

DH

I've driven my Miata several times recently, through all the snow-melt and resulting wet roads, and it's currently really dirty.  Wait, let's make that "REALLY DIRTY!"

When the weather warms sufficiently, perhaps tomorrow, I will get my bucket, hose, and car-wash stuff and I will hand wash the car.  While I'm doing that I will also carefully rinse the wheel wells to remove as much gunk as I can.

I could visit a commercial car wash, but the above-mentioned snow melt would have my Miata dirty again before I got home.  So I won't.

As spring progresses the car will, no doubt, be driven through the usual spring showers, which will give the bottom of the car a good rinse.  Nothing like a rainy day to clean the underside!

I do not believe in using high-pressure spray under the car or under the hood.  It has a way of pushing water into places where it should not go.  Low pressure water only - that's my theory.

Others may disagree.  Let the games begin!

I agree with Mike... never use high pressure spray under the hood.  I spray a little Simple Green or similar cleaner on the dirtiest areas, then go over those areas with a soft parts brush or old paint brush (I seem to have an abundance of these) before they dry and finish with a careful, very low pressure rinse with a garden hose.  I avoid direct spray of cleaner or rinse water on areas that might not be happy if they got very wet.  I've occasionally covered components with plastic bags, secured with rubber bands (carburetors and distributors in the "old" days 😉).

Posted by: @mike-c

I've driven my Miata several times recently, through all the snow-melt and resulting wet roads, and it's currently really dirty.  Wait, let's make that "REALLY DIRTY!"

When the weather warms sufficiently, perhaps tomorrow, I will get my bucket, hose, and car-wash stuff and I will hand wash the car.  While I'm doing that I will also carefully rinse the wheel wells to remove as much gunk as I can.

I could visit a commercial car wash, but the above-mentioned snow melt would have my Miata dirty again before I got home.  So I won't.

As spring progresses the car will, no doubt, be driven through the usual spring showers, which will give the bottom of the car a good rinse.  Nothing like a rainy day to clean the underside!

I do not believe in using high-pressure spray under the car or under the hood.  It has a way of pushing water into places where it should not go.  Low pressure water only - that's my theory.

Others may disagree.  Let the games begin!

I disagree - your car isn't dirty...it's just a different shade of white 😛

Its worth mentioning too that "warmer" days much worse for the car than freezing cold days since the cold temps slow the chemical reactions down.  Driving through snow and salt when it's 20Degrees is a lot less damaging than the slush (often now mixed with salt) that gets caked onto the cars when its 45.   So I always try to at least pop by a car wash when it gets warmer to give it a good rinse. 

I drive my '09 NC all year long (with snow tires in the winter, of course). I've been using the Shammy Shine on Rt 12 in Flemington this winter. With the undercarriage wash it get's off the salt that is so dangerous. I can attest that after multiple washes, there have been no water leaks into my NC. I used to use the self car washes but they all closed by me so it's auto wash or nothing.

I should add, with regard to running our Miata thru the "Laser" pressure car wash, that ours is a 2011 NC PRHT (hard top).  I can't speak to the effect of the pressure wash on a soft top.  We had a 1993 NA (soft top, of course) for 17 years, but "mothballed" and stored it inside every winter (it was a 3rd car), so I never needed to use a car wash then.  The 2011 is Janice's daily driver all year.

The accumulated "dirt" on my white RF was primarily black/grey, so I suppose it remained within the official Mazda color palette.  But I washed it today, so now the car is white again.

Until the next time I drive it, of course! 🤣 

@mike-c

I washed my OTM today... turns out that it's white, too.  It's been so bad for so long that I had forgotten the color 🙄.

I too drive my Miata year round and try to wash it periodically when temps allow.  I use the self-serve bays at the local Shammy Shine.  My luck, I'd take it through the auto wash and "spring a leak".  I make sure to rinse off the undercarriage very well to get the salt off.

For the OTMs in the household, I run them through the auto wash and upgrade for the undercarriage wash.

My ‘02 SE has been a daily driver since 2008, and has seen many rugged winters here in Pennsylvania since then. Unfortunately, I recently received some unexpected news that rust had broken through from the inside out on the frame rails, near the front wheel wells. I did not have much warning the rust was that bad, and I’ve been told by reputable shops/inspection garages that it will not pass inspection as is.  

Body shop folks have told me the real culprit is the liquid brine sprayed onto road surfaces, which when dry is powdery and that brine dust can get up into the undercarriage much more pervasively than water/salt does. According to them, the problem of undercarriage rust-out has been growing exponentially in the northeast especially since brine has become the “go-to“ method of road treatment. 

So, short of a very expensive frame rail replacement job (worth far more than the car is at this point!) I’m wondering if anyone knows of a good, reputable (Miata) body shop/welder who can do some repair without totally replacing the frame rails?

Thanks,

Jim

@jim-turner

Wow... sorry to hear this, Jim.  The dust remaining on the roads from brine seems very tenacious.  Even after a substantial rain, I still see dust rising from the roads, most noticeable when following trucks.

Unfortunately, I can't provide any helpful information about shops for the needed repairs.  Sorry ☹️.

David

@jim-turner

well that really sucks.

I hope when going to the laser washes after snow treatments and driving does the job of stopping this problem.