Hydraulic Lash Adjuster Noise on 1990-93 Mazda 1.6L DOHC - Engine Builder Magazine

Hydraulic Lash Adjuster Noise on 1990-93 Mazda 1.6L DOHC

This condition may be caused by restricted oil flow through
the hydraulic lash adjusters (HLAs).

The noise is common after cold engine starts or when returning to idle
after highway driving speeds. To correct the noise condition, HLAs have
been modified to increase oil circulation. If a customer complains of
HLA noise and the engine is within specified range, use the following
repair procedure.

If the HLAs require replacement, inform the customer that maintaining
regular oil changes will help prevent this noise from returning.

Installer Repair Procedure:

1) Check engine oil level. If oil level is low, add oil.

2) Start
the engine and verify the HLA noise. If the noise is present, change
the oil and inform the customer that regular oil changes will help
prevent the noise from returning. If noise is present, proceed to step

3) Increase engine rpm to 2,000-3,000 for 10 minutes.
Return to idle and check again for HLA noise. If noise is still
present, proceed to step 4.

4) Perform engine carbon cleaning as described in Mazda Service Manual.

5) If
noise is still present, remove the rocker arm assembly covers and check
for excessive clearance between the camshaft and the HLA. Note: HLA
must not be in compressed position. Turn the cam slowly to avoid air
entering the HLA.

6) If .006? (0.15 mm) or more can be inserted between the camshaft and the HLA, replace the HLA.

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.

You May Also Like

Shop Solutions January 2023

Next time you have set of large journal small block Chevy connecting rods to resize, consider honing the big ends of them for a +.002” outside diameter bearing that the LS engines with fracture cap rods use.

Engine and Machine Shop Tips and Tricks


For proper block cleaning, the oil bypass valves in Gen 5 and 6 big block Chevys need to be removed. We made a couple different sized “hook” tools for a slide hammer. This tool will easily pull the valves out of the block and sometimes without damaging them.

Shop Solutions December 2022

Everyone misses occasionally, and this helps avoid dents and damage.

Jesel Certified Performance Rebuilds

Engine components are serious investments for any racer and maintaining that investment could be the difference between winning a championship and losing it.

Going the Extra Mile with Cylinder Head Porting

It’s not just the port work alone that creates spectacular cylinder head performance. The most critical areas of a cylinder head are those which pass the most air at the highest speed and for the longest duration. Your bowl area, the valve job, the throat diameter, and combustion chamber are all crucial parts. 

Tight Tolerances and Building Power

As you ascend Mt. Everest, you reach an area called the death zone. Once you climb high enough, the margin of error becomes perilously thin. That death zone also applies to engines. As the horsepower per cubic inch and rpm increase, the margin of error decreases. 

Other Posts

CNC Update: Features and Automation

Precision is key when it comes to automotive parts; the complex designs of connecting rods, pistons and rings, blocks, cylinder heads, and other parts require super tight tolerances that are getting more and more difficult to be met by hand or with other machining processes outside of CNC.

All Things Media Blasting

Engine building is a segment of the automotive industry that has always been ahead of the curve in media blasting, and no matter the engine shop, cleaning equipment is a common bond.

Engine & Hub Dynos: Necessary Tools and Additional Revenue

Being able to see the horsepower and the direct correlation to what is lost in the driveline is invaluable – dynos offer a myriad of benefits for the modern engine shop.

November 2022 Shop Solutions

November tricks and tips for the shop!