This guide will help you disassemble and reassemble the HLAs which are found in most Mazda engines of the nineties. Do this as a last resort, most HLA rattle can be solved by an oil change. If an oil change works but only for a short period then you can try this guide. If this guide doesn’t work then you can diagnose which HLA is at fault.

A HLA is the same as a solid lifter but doesn’t need any adjustment. When you remove the cam shafts, the HLAs must be kept in their original positions. If you have a constant tapping noise then you should try this guide to clean the HLAs.

The HLA is a bucket, and self expanding piston within. The piston expands under oil pressure and is locked in the piston via a ball bearing one way valve so that the piston never compresses under load.

Remove each HLA and keep them in some sort of order
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The first thing you need to do is remove the piston, using pliers. They are only held in by a circlip.
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The piston can be pulled apart, within is the one way valve a spring and the piston.
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Now what you want to do is clean all the old engine oil out of the lifter and the piston.
Reassemble the piston with spring inside, and place the piston back in the bucket. If the piston gets stuck then take it back out and check nothings trapped.

Now, the piston should stay in the bucket once you’ve clicked it in place. The piston should spring when you push it, this is normal.
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Lubricate the bucket and slide back in the cylinder head. Once you start the engine it will be very clattery for maybe 30 minutes or so. Eventually the oil will pressurise the lifters until the buckets, and pistons are full of oil. Once this has occurred on all HLAs you should have smooth running.

If you still hear rattling you can check which HLA is at fault by pressing on them, a bad HLA will spring and a good one won’t budge.

The torque settings for the camshaft bearing cap bolts is 15Nm, tightening from each end inwards.

Fantastic guide

This needs to be made a sticky

2x

hi!i just want to ask if BPT engine is also equipped with HLA? i have a BPT engine and i already changed my engine oil and add oil additives... at first the sound disappears but once in a while the sound returns... im guessing that this is the problem.hope anyone can help me.

Ive been wanting to do this for quite sometime....but never had the confidence..but my engine starting to sound like an old lorry nowadays..huh! Thx for the guide,definitely will try next weekend..