MX5 Mk1 Water Sloshing Sills / Not Drain Pipes

[MattRL69]

Have a very very annoying issue with the MX5 Mk1 N-reg 1.8.

Decemeber 2011 - January 2012 both sills had a complete rebuild due to the wonderfull issue of rust from the inside out. The car had come out looking beautiful and if anyone is wondering where to take their's to be rebuilt go see Mark Lifton on isle of sheppy who has done and still does alot of work on mx-5's including my other car which is a race car with Ma5da racing last year and BRSCC this year which gets bruised alot.

The problem is in the last two months my sill on my onside has been filling up alot to the point where i had to drill a small hole to try and get rid of us much water as i can. Going by the amount of water that drained out it must of held at least 5-10 litres.

I have checked the common stuff such as the drain pipes to check if theres any blockages, any visible cracks or drainage issues and nothing seems to explain why.

Anyone got any advice on what this could be.

[Eighteeteewhy]

The sills should have some very small holes along them to let water out. I'm guessing when they were fixed/refurbed these were covered up.

[MattRL69]

Am i correct in saying that there should be no water in the sills in the first place.

During heavy rain it fills up very quick

[MX-5 Lazza]

Correct. There should be drain holes in the sills at the jacking points but water shouldn't get in there in the first place other than condensation.
You need to double check the hood drain tubes and also the hood rain rail.
Is the boot floor or the cabin under the carpets behind the seats and in the footwell dry?

[MattRL69]

i had a look for water in the carpet and not found any.

i think the next step is to take a proper look at the rain rail but i would be surprised if its this as its only going into one sill and theres alot of it.

A crack in a rain rail i thought might have a little seeping through over time.

This is 5-10 Litres

[SMGB]

Is it being driven in under the front wheel arch? Have a look around at how he was welded the sills and wheel arch in either side, if there isa big difference in how the panels slot together that may be the cause. I made some liners op for the MGB wheelarch out of DPC membrane, works better than it has right to.

[MattRL69]

That would make sense.

Looks like im spending the evening with a flash light under the wheel.

Cheers for the advice

[Conor D]

Open up the drain holes along the sill with a small screwdriver or a key. I had mine fill up a few weeks ago, opened up all the drain holes and the water just started flowing out!

I had mine cut out and repaired about a year ago too. Drain holes must just be filled with crap.