As the title really, which is the best eay to park on my steeply sloping driveway, to allow rain wwater to drain?
Nose downhill allows water to pool around the boot lip but how about draining through the doors?
Nose uphill allows water to pool around the bulkhead but how about draining through the doors?
Is there a definitive “best” way to point the car, when parked for long periods on a slope? And why?
Thanks
I also have to park my MX5 (MK2.5) on a sloping driveway.
I park nose down, my reasoning and understanding being -
Rain from the hood is collected by the rain rail at the the back of the hood
From there it is directed toward the hood drains at each side of the hood (just behind where the doors open)
It then drains out underneath the car (providing the hood drains are kept clear) and prevents ingress to the interior
Any rain falling toward the front is directed into the small drains which run down the front side of each door
I have found it essential though to keep the hood drains clear as well as the front side door drains and sill drains
Parking nose up would, in my opinion, have the effect of rain collecting in the rain rail and needing a considerable amount to accumulate before it was able to drain away.
I have not seen a definitive “best” way but I have parked my MX5 like this way for 7 years with no problems with water ingress, but definitely make sure all the drains are clear - I’m sure they were put there for a reason!
Makes sense Terry.
Where are the “sill drains” that you mention?
Not heard of those ones.
Thanks
I agree with Terry.
[quote=Fraz;788200
Where are the “sill drains” that you mention?
Not heard of those ones.
Thanks
[/quote]
The bottom flange of the outer sill and the bottom flange of the inner sill meet and are spot welded together.
At a place near the front and another near the back there’s and area of 20mm or so long where one plate has a step so for that 20mm the two metal sheets don’t touch,
in fact a 20mm long gap. If you park uphill or downhill one of these slots will drain the sill.
Trouble is that they get clogged with rust scale and block. Needs a poke with a thin screwdriver every now and then. Even a wider blade and prize them open a bid more
and then a blast with an air gun, after the water has drained out.
Then theirs the “I filled my sills with goo. They won’t rust now.” Smug look. I’m smarter than you.
There’s also the “I welded my sills up. I did a continuous seam weld like those MOT men tell you to.” (Right over the drains)
There’s a few more involving filler (bondo), underseal with a brush, ripple anti chip sill paint … I could go on.
Paul G
The bottom flange of the outer sill and the bottom flange of the inner sill meet and are spot welded together.
At a place near the front and another near the back there’s and area of 20mm or so long where one plate has a step so for that 20mm the two metal sheets don’t touch,
in fact a 20mm long gap. If you park uphill or downhill one of these slots will drain the sill.
Trouble is that they get clogged with rust scale and block. Needs a poke with a thin screwdriver every now and then. Even a wider blade and prize them open a bid more
and then a blast with an air gun, after the water has drained out.
Then theirs the “I filled my sills with goo. They won’t rust now.” Smug look. I’m smarter than you.
There’s also the “I welded my sills up. I did a continuous seam weld like those MOT men tell you to.” (Right over the drains)
There’s a few more involving filler (bondo), underseal with a brush, ripple anti chip sill paint … I could go on.
Paul G
[/quote]
Thanks Paul.
I’ll have a crawl about and see if mine are detectable.
Do you know roughly how far from each “end” the sill drains are please? (Just so I don’t start digging for holes where holes don’t belong)
Consider putting a half cover on it. It will keep the rain out of the drains along with all the detritus that washes down there and blocks them.
The Mazda ones are best IME. The elastic on the chinstrap type doesn’t last.
Have you thought about getting a hardtop for it? Should stop the water getting anywhere near the inside if parked up for long periods.
Regards
Phil
The slits on the sills are not drains for the hood. Water off the hood drains into the rain rail, a sort of gutter. Rain water is then conduction to collection cups which are just behind the seatbelt towers. Water than drains out via approx. 2cm diameter tubes.
These are the drain tubes through which all the rainwater off the hood should be flowing through (Mk1 and Mk2 only):
See this video of the drain in action:
https://www.youtube.com/watch?v=1VHvtX0Z1SM
The sill slits, two per side are (straddling the jacking points), I suppose, about 1cm by 2-3mm. A calculation of cross sectional area will show these are incapable of flowing as much water as the drain tubes.
Occasionally owners may find the sill full of water, and clearing these slits helps clear. Water is not supposed to get into these sill sections. Annoyingly, water will tend to flow down the outer surfaces of the inner sills/inner wings, and will first pool in the non-draining area, before overflowing into the main sill.
The non-draining area ALWAYS rots out faster
And here is how water gets in these; a welded seam failing
The slits, they are tiny:
And if these are designed to relieve flooding in the sill, why do they straddle the easily, and often damaged jacking point, and why not place more?
Water gets into the sill because:
My view is that although these slits are useful for relieving pooled water in the sills, their major junction is the ventilation of sills. Most cars built during the last 40 years have had some kind of system to ventilate sills (tin top cars still manage to get sills rotting from the inside out), with varying degrees of sophistication. Some Rovers and Saabs, for instance, used to conduit hot air from the engine bay into the sills.
The confusion is exacerbated by Mazda North America (only) referring to drain holes in a 1994 TSB. I suspect there was a realisation that the rain rail was an inadequate design (the Mk2 has a revised design, using different construction and attachment).
Drainage at the front is achieved by collection cups moulded into the windscreen rubber seal. On the Mk2, the size of this cup was enlarged. Small amounts of water are supposed to collect here, and drain through a soft rubber tube, and over the sill threshold. But there is an obvious flow; the tube becomes compressed by the door (and on the passenger side, this might become permanent because that door isn’t used so much), and the vinyl hood ages, allowing more water to collect. Flaws here allow water to soak the front footwell carpet. If water gets under the backing membrane of the carpet, it has the potential to ruin the ECU located in the passenger footwell.
Perking uphill or downhill has bedeviled the MX5 community for 30 years. Park facing downhill, and there is increased chance water will collect in the foot wells. Park uphill and the water collects behind the seats, or just drains out of the boot.
Cars with aircon can have additional drain problems; this probably why Americans are reporting rotted footwells:
https://www.youtube.com/watch?v=iHhwXRzRraM
If water is regularly pooling in your sills, you have bigger problems that just keeping some slits clear.
Mine leaks more nose down on our steep drive, so regardless of anything else longer term I park it nose up.
Wouldn’t that just retain the water that is draining out within the car’s structure?
Possibly, but nose down the interior is as wet as old fish so it’s horses for courses…
Or park sideways on a slope.
Not sure about this but is the oil pick up at front of sump on MK3, so
needs to be nose down on slope?
Could be a choice damp car or oil starvation on tick over on sloping drive?
Discussion is about NA/NB. Drainage issues on later models are completely different.
oops sorry