Amsoil 5W30 XL Oil

In my 07 Tacoma 4.0 V6 70k miles ran Amsoil 5W30 for about 1400 mi 99% Hwy at 55 MPH. Started hearing Top end engine noise at idle cold and hot. And one time drove about 30 mi to a Grandkids school program lasted about 30 min. Went to leave and engine had a vibration taking off from stop sign, like Variable valve timing was off. Yesterday I drained out Amsoil and came out like water. And at end of drain the dripping sounded exactly like a kitchen faucet dripping in a pan of water. I put in Toyota OEM 5W30 conventional oil and Toyota filter, and after about 20 mi driving around town engine top end noise is completely gone. I am done trying to be better and fix what aint broken so to speak. Tomorrow I am draining Amsoil 75W90 from rear axle probably put in John Deere 75W90 which is a top end Mobil product. I work at a Deere Dealer and can buy at Employee price.

 

A couple thoughts.

One. If you work at a Deere dealer and get employee discount on the Mobil-1 stuff why did you go with Amsoil? Seems odds to pay more for essentially the same.

Two. When the vehicle is "hot" from being driven recently the oil can run pretty fluid "water like". So that is not necessarily a concern if the vehicle had just been driven (unsure if it was?).

Three. You mention you ran Amsoil 5W-30 for around 1500 miles. Did you have conventional oil in there prior to that? If so, Amsoil states their synthetic will degrade if mixed with conventional oil. There is usually a quart+ left in the engine even after an oil change, so may need to change more frequently a few times to get it all out - or do a flush.

Four. Could be you got a bad batch? Amsoil has a good reputation and is widely used. I don't think the brand an issue here - but maybe yours was defective somehow? I've never heard of that, but I have gotten "bad gas" before even from good stations like Shell.

Five. I'd check your rear-dif fluid but why change it out (see #4 above) Amsoil is a good brand. Check the look, feel, smell, and consistency of the oil and see. Should be thick, uniformly so, without discoloration, lumps, or odd "bad" odor. It is probably fine would be my guess.

Six. Gotta say that would freak me out also. I'd probably do what you're doing and change out everything just to be safe. Hope there was no permanent damage to your timing belt, cylinders, and other parts...

 

I've been using that same exact oil for 200K at 10K intervals on the truck, and all previous cars... The only 'tic' I get is the PCV valve thing on the intake manifold, and very muted timing chain normal noise... very quiet

At 70K, it's not usually recommended to switch to full synthetic like Amsoil IF you where using regular stuff and running more than 3-4K between intervals. The detergents in Amsoil are much more powerful than all regular and most synthetics, this could result in oil leaks and initial heavy moisture absorption for all the left overs that got 'cleaned' off lubed parts.. Again, this is mostly theory, only seen this on couple of fleet crown-vics that owners switched to the Ams' stuff at around 100k, otherwise most switch-overs were normal. Some of the vics were switched to Amsoil to reduce or eliminate the oil burning and recondition valve guides where all other Synthetics failed...

 

Love Amsoil, I would run nothing but Amsoil if I could afford it

So in the mean time it's either Valvoline or Mobil 1

 

1. Not sure what you mean about Mobil-1 stuff at Deere. Deere does have 0W40 full synthetic but it is 4 bucks higher a qt than the Amsoil..

2. I did drain while engine was hot. Oil was a lot thinner than Mobil 5000 5W30. And other oil would be tacky to touch and not wipe of hands very easy.

3. Amsoil rep told me it would mix fine. But to change 1st time at 3-4k then go 7500-10000 mi. And on my Prerunner am able to change oil with truck on ground so I know there is not much oil left at all..

4. Bad batch or not. Not taken any chances and I would never 7500 or 10000 mi on oil even though Amsoil say it can. Am doing OCI at 3 to 4k period.

5. Not taken a chance or Diff fluid.

6. I believe oil and filters are cheap insurance. And will do maintenance often. These 10k Engine and 150k axle fluid changes are ridiculous. You still get contaminents in the oil. Amsoil rep say they will be suspended in oil in pan. Balony sauce. Even is oil is still good at 10k mi you still have contaminents. So for now no one can sell me again on synthetic oil unless it is in a race car or motorcycle.

 

Frequent oil changes cause added wear metals. At a minimum 5000 intervals for oil changes is recommended.

Amsoil makes excellent oils. I run Mobil 1 in my three trucks. They all get changed at 10000 miles. Synthetic oils make a slight, different, noise in the motor than conventional. No worries. You freaked out, and drained a perfectly good oil.

 

Unless the op had a sample analyzed by a lab it is showing it was "out of spec" is pure opinion, nothing more.