Is it bad to keep changing viscosities? HLAs

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Feb 12, 2014
Gold Coast, QL, Australia
Basically last year i saw some 25w60 (yikes i know!) at $10 for a 5L bottle, so I thought it would be okay being summer just to give it a short OCI (1-2000kms)
The morning after putting it in it would knock for a few seconds and it would do this every morning until I decided to drop it after a couple of weeks (around 1000Km)

I changed back to recommended 10w30 but now the lifters (Hydraulic lash adjusters in this engine) would rattle at around 1,400rpm! I have stayed with 10w30 and 10w40 ever since but i think i've clearly caused some damage to my lifters

I bought some 15w50 durablend to try over the summer to see how that turns out, but would it be worth just changing all the lifters since i've found i can get all 12 brand new ones for $78?

Thing is i don't have the tools and much experience to do it myself so would it be an expensive job for a mechanic labor wise?
Originally Posted By: Rosetta
I'd give a little more time to get the oil stabilization process in your unit. Could be just dislodged dirt that make'em loud.

I've changed the oil at least 6 or 7 times since then if that helps
^^ These are an overhead cam engine using roller rockers, with a small hydraulic lash adjuster pushing on the valve - you don't need to replace the camshaft when doing the HLA's.

I really doubt all 12 HLA's have given up the ghost, usually only 1 or 2 die at a time, and when they tap, they REALLY tap, all the time, not just at certain revs! Maybe seek the opinion of a trusted mechanic? If you do go ahead and replace them, the labour charge should only be for 60 - 90 minutes, it's a very easy job.

Like I said though, before spending any money, be sure there's actually a problem. Good luck!
Yep there is absolutely zero cam lobe wear as far as i can see thanks to the roller rockers!
And i would say somewhere between 5 and 10 of them are rattling! At certain revs it sounds like stirring a bucket of marbles with a wrench if you can imagine that hahaha but there is one or two that tap above the rest, sometimes on startup and at idle

I just changed my oil this afternoon using durablend 10w30 and a bottle of MoS2 and now i have crazy lifter noise at idle!!! Will definitely be going back up to 10w40 or even go ahead with the 15w50 next change!

And yeah i have a good mechanic i'll get him to quote it, i can get all 12 for $78 so i'll just change the lot to be safe
as long as the labour side is cheap enough
I know there'x mixed opinions about SeaFoam here, but FWIW I had a Volvo that sounded like a machine gun a few years ago.

I did the SeaFoam thing - bought two cans. Half a can went into the oil, half a can went into the fuel, and half a can got sucked into a vacuum hose (last half got set aside and went into the fuel a few tanks later).

I'm not sure what happened but the noise went away. It tapped all through the treatment. I shut it down as soon as I had finished putting some into the vacuum hose and I let it sit for about an hour. Drove it around and it was quiet. It smoked like crazy for half an hour, but the engine was quiet from then until the tranny died a couple of years later.
I've never actually seen SeaFoam in Oz, but it certainly seems to have some fans on here!

OP, yep, get a quote on the job and even if you can't afford to have it done right now, you'll know how much to save up. In the meantime, noisy lifters aren't going to hurt anything, they're just annoying. Turning the radio up works a treat at quietening them down!

It surprises me that your car is so sensitive to oil grades - every Falcon I've worked on (literally thousands of the things over the last 25 years!) couldn't care less what you put in the sump. Maybe find the "quietest" oil and stick with that from now on? Let us know how you get on with the mechanic regarding a diagnosis and price!
Could be that the extra drag in the galleries from the thicker stuff pushed some rubbish into the lifter feed gallery...maybe.
Yeah I would love to try some! And use some to try clear the carbon up in the combustion chamber
Yeah you literally can't kill these engines no matter what you do, they're just let down by very noisy lifters! My theory is that when you turn the engine off, the cam lobes will come to a stop on one or two lifters, which will have the oil squeezed out and will be under pressure all night. The cold thicker oil wouldn't have got to them fast enough when started the morning after, thus running dry for a fair few seconds!
I agree it isn't harming anything, i know someone with 418,000 on their falcon and it has had rattly lifters since forever! But noise aside are there any other downsides or side effects of tappy tappets?
I love durablend and liqui moly additive combined so maybe i'll give that 15w50 a try next change! If not they do a 10w40 at masters now

I have a very good and cheap old school mechanic, the type that uses his ears instead of a scanner for diagnosis and he is always 100% spot on and 50% cheaper than everywhere else! I'll give him a call and get a quote and let you know but he's normally booked up for weeks ahead
The only side effect is the valves may not be opening quite as far as they should, resulting in a minor decrease in engine performance.

Having said that, I had a lifter fail so badly in my AU that it literally fell in half when I lifted the rocker gear up to remove it - but I'd noticed no change in performance, smoothness, etc., nor did I when the new HLA was installed. So I think the main effect is the embarrassing noise!
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