HLA noise after leaving car for 4 weeks

  1. My model of MX-5 is: NA
  2. I’m based near: Berkshire
  3. I’m looking for technical help or recommendations on:

Took my car for a quick spin today after it had been sat in the garage for around 4 weeks, noticed I had horrendous HLA rattle until I’d driven about 4-5 miles and got everything warmed up.

I replaced the oil at the start of August and hadn’t noticed anything up until today (well from oil change to when I last used it).

Am I right to assume that the fact it’s been left for a little while is likely the cause for them to get a bit noisy and then after giving it a bit of a run it’s been able to get the oil sloshed around nicely to stop the noise?

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I don’t know the answer but having an NA sitting on my drive that’s not been on the road now for about 2 years my experience of HLA clatter is very random. I start the car up every week or so and as of late its not clattered at all, its starts and runs as smooth as anything, but a few months ago it was terrible every time. Other experiences with another NA and oil changes, oil flush etc. I can’t honestly say anything every made a huge difference. Sometimes it did it, other times it didn’t, so much. i think you need to remember the standard salesman’s reply, “they all do the sir”.


Had the feeling that might be the case, before the oil change it would do it intermittently on start up but this wasn’t going after a few starts.

In my mind it made sense that it sitting would make it more likely as the oil would have had however many days time to completely drain to the pan.

Bit of a spirited run once it had warmed up got it sorted though :smiley:

That HLA rattle can be disconcerting. I’ve owned my 1997 MK1 1.6 for nearly 19 years now and still worry it is something major. Usually gets me after 3 or 4 months of winter layup.
Sometimes it clears very quickly and other times there appears to be a secondary affect that can take at least 10 minutes driving to clear.
This is the price paid for irregular use of a MK1. From my experience; 2 - 4 weeks of non use is enough to initiate this HLA rattle.

Is it not strange?
I just fired up my Mk1 1840cc two days back Rob…it’s only done around 50 miles with your new CAT…but thanks to the slushbox fail.
Anyhow, popped the battery in which was on Bench Conditioner after 3 months to get it up to the workshop, and 1st turn of the key as usual…with zero HLA pump up…as usual. Indeed, I cannot recall the last time I had HLA pump up…but then…I started using Mobil Full Synth which the engine seems to love. Zero burn off, and it’s still kinda honey brown when it gets drained…although I skipped it this year as it’s only 1800 miles “old” and 2 years, but still up to Full on the stick.
I’ve wondered in the past if oil specs have a bearing…no pun.


Excuse my slight thread jack, but having never come across the term, what is an HLA?

According to Google it’s Mazda’s Hill Launch Assist though wikipedia might make more sense by describing it as a Hydraulic Tappet (Hydraulic tappet - Wikipedia)?

Yeah it gets me whenever it does it, always instantly think it’s about to blow up!