1989 V6 - Servicing your Hydraulic Lash Adjusters.

Jay Ayala

Explorer
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mapper

Explorer
This is an awesome write-up. Thanks Jay. I highly recommend anyone replacing their valve stem seals (or valve guide seals I get confused about what is the proper name) to do this at the same time.

I just had my seals done by a mechanic. My lifters/lash adjusters were silent before the job but were ticking, loudly, after the job. Mechanic was hopeful he could bleed them and get them quieted down. Unfortunately he had to pull everything apart again and replace (or bleed) the adjusters.

Point being, save yourself the hassle and just plan to do this at the same time.

Edit: my motor was the 3.5 SOHC. Not sure the procedure is exactly the same as my mechanic told me he needed to replace the lifters/lash adjusters but from my research on the job, the parts are similar throughout these V6s. Based on memory, there is an updated lash adjuster part that apparently has a better bleed hole than those originally fitted to the early 3.5 motors.
 

Jay Ayala

Explorer
Results are in.

I just wanted to give everyone an update on the results of servicing the lash adjusters. This job was performed whilst I was doing the Valve Stem Seal replacement. It took me only a few minutes but the results I got was actually pretty astonishing. I just overhauled the entire engine including getting new Cylinder heads. The Cylinder heads sat on my shelf in the garage for a while, over four years to be exact. With time, I think the fluid inside some of my lash adjusters leaked out or just wasn't working well. After firing up the engine for the first time, I realized I had a lot of valve ticking noise. The noise eventually went away and over the course of the last month or so I was then left with a slight ticking noise immediately after starting the engine and it would gradually go away after a minute or two.

This job did two noticeable things.
  • It made the engine feel very, very smooth.
  • The valve ticking noise is gone altogether.
Its kind of hard to put in writing the difference this little job made in the feel of the engine. I am very happy to say that I am extremely satisfied after having done this part of the valve job.
 

Jay Ayala

Explorer
Hey there MontyPower, it's been a long time bro. How have you been? We should get together sometime soon. Yes, same Raider from '03. I've owned this one since '02 and slowly have been working on it over the years.

Sent from my HTC6500LVW using Tapatalk
 

montypower

Adventure Time!
That's awesome! I was looking through some pictures of your rig from years ago. It's looking much more capable now. Yes, let's get out on the trail soon. :)
 

Jay Ayala

Explorer
That's awesome! I was looking through some pictures of your rig from years ago. It's looking much more capable now. Yes, let's get out on the trail soon. :)

Old pictures??? I want to see them too. Can you post them somewhere I can access them please?


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tin

Observer
Mitsubishi recommends doing this with diesel fuel. I would pump them clean using three tubs, one for the initial clean, one for a secondary and one for filling. Be vary careful when compressing the piston inside the lash adjuster, the spring that you are compressing is very fragile and can break is compressed to quickly or too many times. I like to use a small allan key or wire, something that you can feel the spring's resistance very well. Once the lash adjusters are filled again they should have less than or equal to 1/32" of compressible movement. And test using your fingers not any kind of pliers! In fact be very careful not to score or scratch them at all, a scratch can cause premature wear on engine components!
 

Jay Ayala

Explorer
Mitsubishi recommends doing this with diesel fuel...

No, not diesel fuel, diesel oil. I know we are talking semantics here but it makes a difference. Kerosene and diesel oil are often interchangeable but should not be "mixed". From all that I can tell, the viscosity and the flash points and burning temperatures are the difference between the two. Kerosene has a lower flash point 100° vs diesel oil at 125°. Kerosene also burns hotter.

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nckwltn

Explorer
I did the job when replacing valve seals as well in Jan/Feb 2013. I ended up going to a gas station that had diesel, and pumped a few cents worth of diesel into a container.

When I popped my rocker arms, 2 of my lash adjusters fell apart, so if you plan on doing this job, expect to need to replace a few of the adjusters. it isn't too expensive to replace them all.

I used a paperclip to trigger the thing inside the adjuster to allow me to fill it with diesel. When I did fire the engine up, it sounded REALLY bad, but quickly the ticking went away and turned into a smooth 3.5L purr
 

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