Amnesiac

I searched and couldn't find a specific answer. I need opinions on running 15w-40 oil in my 4runner. It's a 97 with the 3.4.

For a while now, the engine has had a tapping sound when it warms up. I don't know if it's the valves or what... I took it in to a shop and the guy recommended running a heavier oil in there to see if it would quiet it down. I've been reading that running a heavier oil might not be good in cold weather. Where I live it's around 10-25 degrees F right now.

When I started up my 4runner this morning, I thought I heard a slight knocking sound but after a few seconds it went away. I'm pretty paranoid about it, so let me know what you all think.

Thanks for the help.

claudebadly

running the 15w-40 in the 3.4 in cold weather isnt nessesarily bad for it. just takes more power to move the oil in cold weather.
i have a 3.4 and live where its normally right around 5-20 in the winter *usually colder* and run nothing but the 10w-40 in it. tried the 15w-40 for like 4 weeks and noticed that it was bogged down a little bit, switched back to the 10w-40 and the power came right back.
so dont try to "quiet" the noise with a heavier weight oil. figure out what the noise is.

Gerdo

Only use the weight oil specified by the Mfg! The tolerances in todays engines are much tighter that older engines. The weight of oil has to deal with molecule size not just temp range. If you use a higher weight oil it will not reach into those tight tolerance parts and you will have problems.

Amnesiac

Okay, thanks for the answers. I think I'm going to go change the oil today back to 5w-30.

Gerdo

If you haven't changed your oil yet, I have something to try. Having worked on quite a few niglected engines that make noises. I would put 1/2 qt of ATF into the oil and drive for 50-100 miles. This will clean out oil passages and oiling holes that get gunked up. After driving for the 50-100 miles, change the oil. My son had a Jeep that clatter tward the end of a few oil changes. I would do the ATF trick and it would be quiet for a few more changes.

dbcx

Good idea 15 is way to thick. Thick oil at startup is bad , there is no flow when you need it the most. When I got my 97 w/3.4 it had a tick , as soon as I swapped it over and started running Amsoil it went away. That was at 196k im at 213k now in less than a year.

Ironmike4x4

If it's not really cold where you live you can run 10w-30. That's what the Toyota dealer where my auto tech buddy works at runs. In the winter time I switch over to 5w-30. 150K miles and no problems yet.

Amnesiac

I changed my oil to 5w-30. I'm going to take it to a shop next week to see what they say. It doesn't seem like it's that big of a deal, but it bugs me so I want to get it fixed.