silvertaco4X4

hello all. ive searched on this topic and have read everything i can find on this forum that seemed like it might help my problem. im hoping for some new or different ideas because this just drives me crazy. i have a 2000 tacoma with the 2.7L engine and my problem is this - when i start up my truck on a cold morning, say, freezing or below, my engine will knock for a minute or two and then the noise disappears as it warms up. sometimes it is pretty noticable even if you just start it and let it sit, but much much worse if you actually try to take off in it right away. this is the second winter ive had this truck, and it did it (for at least part of) last winter too. i dont think it started until one really seriously cold day last year, i could be wrong, but i dont always have the stereo up that loud and im not completely oblivious to things like that. i started to drive off that morning and it sounded like the truck was going to fall apart right where it was. it was cold before that day but i dont ever remember hearing anything until then...

i know many people would be quick to say "piston slap" when they hear stuff like this, and in fact, thats what the local dealer told me. i guess maybe im just in denial and dont want to believe it. i consider myself a novice when it comes to car repair but i am learning a lot about my truck thanks to this. ive tried everything from changing brands of oil and oil filter to replacing the spark plugs, pcv valve, cleaning the egr valve - anything i feel comfortable that i wont screw up. the noise doesnt seem like it comes from the top of the engine, it seems lower down and possibly more on the passenger side of the truck. my biggest question is - if my knock sensors are functional, why isn't the timing retarded when this happens? this is definitely knocking, not ticking, not anything else. could it be my timing chain instead?

i love this truck in the summer, but im really starting to hate it in the winter. this is really a horrible way to start the day. how can a vehicle make such a loud knocking sound and it be normal and not do harm? i just cant seem to accept it. TIA for any ideas or input, sorry for the long post.

oh, and if anyone could recommend a reputable shop in northern va so i can get another opinion, id really appreciate that too...

kevin444

I kinda have this problem with my 4runner. Its the 5VZ. My car is parked on my driveway. Usually when i back up for a little and shift it back into drive it makes this knudge sound like faint dunk sound and it goes away.. The sound only happens for about 1.5 secs... soo yeah.

joegee1773

I'm going to put my two cents in here, but let it be known that I don't know all the spacifics of the situation. I have a 1997 Tacoma with a 2.7L and it does the same thing.

I read somewhere that these engines have some kind of time chain(or something) tensioner, that is controlled by oil pressure. Therefore when you first start your vehicle it takes a couple minutes to build oil pressure so the tensioner works properly. So until the oil pressure builds, the timing chain(or whatever it is) makes the noise you hear.

Now remember I only kinda understand what's going on, so hopefully somebody can chime in and correct me. So basically, from what i understand, it's not really a problem you can do anything about.

ejr

ewarnerusa

My '01 2.7L did it. I took it in to a mechanic and he thought it was fine. His reply was "all these new engines seem to do it". I didn't read that you tried switching to synthetic oil, maybe try that next. Otherwise, the consensus seems to be that piston slap is OK in the 2.7L engine. Good luck.

TacomaTRD

My 98 2.7 taco does it on the very cold mornings, but only for about 10secs, it has 140K on it...

ewarnerusa

if you haven't already, read this article,
http://www.canadiandriver.com/articles/jk/020320.htm

from the article so the piston slap is not knocking in the sense of the engine timing. Your diagnosis sounds exactly like my 2.7L behaved, and my 4-banger was going strong still on the day I traded it in.

silvertaco4X4

thanks all for your input. i did already try mobil1 synthetic, in fact i think that was the very first change i made and unfortunately it didn't seem to make a bit of difference. i used to use fram oil filters and then after reading so many bad things about them i switched to a mobil1. no difference with that either, so now im using a toyota filter. still no change. ive always had the recommended 5w30 oil in the truck but ive thought about experimenting with an even thinner oil and see if that makes any difference, although from what ive read thats probably not the greatest idea either. oh, and i appreciate the link but ive already read that canadian driver article, probably 5 times over. believe me i have spent many an exciting night reading everything i can find on the internet about piston slap, etc. lol.

one other thing i checked was my exhaust manifold, i read some things people have written about those cracking and making noise at startup until everything expands, mine seems okay though. on the bright side, i got a remote start for christmas so i guess that might take a little bit of this pain away once my brother finally has time to help get it in there...

again, thanks all for taking time to reply. much appreciated!

Unhappy99

Does it make noise during warm start? i.e. get it warm, then shut it off for 30 minutes and restart. What's the noise like then?

If you have any oil pressure related noise which doesn't go away within 10 seconds after startup, you have serious problems.

Piston slap and bad bearings get worse with temperature, not better.

Anything which is knocking when cold, but slowly gets quieter as it warms up is usually a crack or seam in the exhaust which seals as the metal expands. I would suspect your problem is a loose or cracked exhaust manifold, gasket, pipe, etc., or a loose spark plug.

silvertaco4X4

no, its only on a cold start. if the trucks warmed up and then been shut off for a short time or a few hours and you start it, its fine. after sitting overnight in the winter it is loudest, if i let it sit all day at work for 8+ hours sometimes it will do it then too, if its still cold enough outside. the colder it is outside and the longer the truck sits there, the louder it is if it happens. if i start it and just let if warm up, usually it isnt very audible, so thats what i do. however, if i rev it or try to drive it off right away then you can hear it. during the warmer months, the truck runs and sounds like a champ everyday, no exception. like i said, i removed the heat shield and inspected the exhaust manifold but didnt find anything, maybe i will take another look though. thanks for the response, hope all this made sense...

silvertaco4X4

found this on ttora:

2.7 piston slap

the more people i find that are experiencing the same thing, the better i feel about it. but still, i dont think ill ever stop hoping to find a cure for it. ive worked hard for this truck, and i want to be proud of it, not embarrassed by it.

CynicX

I had a similar problem with my S-10....This was my first new vehicle so I did a ton of research on it...Basically what I found out is basically engines built for cheaply (by cheaply I mean not a ferrari or BMW etc) usually do this. My toyota does it a little too....it has alot to do with the metals expanding at different rates due too there different densities. Also oil flow needs to reach the valves to quiet them down.....

Some S-10's did this because the block was manufactors at company "a" with grade "3" metal (this is just for comparison by the way) and the pistons were made at company "b" with grade "1" metal.....They were designed to run at operating temps, so starting it up on a cold day it would tap pretty bad (for a new car and being a picky person it was pretty bad, most people couldnt hear it) until it was nice and warmed up, then it would sound normal...

And another thing...not to knock toyota...but IMO all tacomas sound like crap at idle.....just the engine design I guess....

silvertaco4X4

i hear what youre sayin. i guess ive just always heard so many great things about toyota trucks - how they are virtually indestructible and last forever, etc etc. this just doesnt make me feel that way ya know? but i guess if the truck keeps going strong and has no other problems ill just have to learn to live with it like so many other people apparently are. thanks for chiming in man, i appreciate it.

oh and yeah.. everyone else that hears it seems to go "ah, thats nothing", while i sit there and cringe.. lol.

CynicX

Well take it too a mechanic if its real bad....I do the same thing though...I want to here an awesome idle like a porsche....but its not like that with the any 3.4 i've heard.....

silvertaco4X4

i wouldnt mind doing that, i wish i had a good place to take it that i trusted though. its already been checked out 3 times, once by the dealer, once by another place, and then again at the dealer. the first 2 times both places claimed to not hear anything (this was in the winter but maybe just not cold enough for it to occur) and say that the truck seemed to run fine and be well taken care of. the last time i took it in, the dealer did hear it, and it was diagnosed with "normal piston slap". they basically told me that if it goes away when warmed up i have nothing to worry about.

soooo, if anyone knows of a good shop in this area, that would be a big help..

04Tacoma4x4

man my 2004 does it and has since i noticed it shortly after i bought it, i go to school an dwork hard to pay for it so i know what you mean. i tried to research it and found nothing, when its realy cold out side and i get in it and turn it on it like seems like its struggling to turn over but cranks right up and then makes the noise for about 10-15 secs but then if i cut it off it has no trouble turning over of makes no noise for the rest of the day, but after it is warm and i am like sitting talkin to some of my friends and its just idleing it idles kinda loud like alot of noise coming from the motor but if you just barely touch the gas and get the rpms up like 50 more rpm's from idle then its smooth. i dont know what it is and its weird but i have come to the conclusion that its the norm with 2.7's

Duc Hunter

My 04 4.7 does it too. I was just beginning to get curious about it and then saw this thread. I will have to check it out more. As for the oil pressure thing, I run Redline 5-30 so there is almost no change from a 30 degree morning to a 60 degree morning (the latter it does not knock).

deerslayer

My '98 2.7 has had the same knock since I bought in 2000. I bought it in August, so I never heard the knock 'till winter. I'm convinced from all I've read that this characteristic of the 2.7. And from what I've read here, the same goes for other Toyota engines too.

Mohamed

All Tundra/Sequioas do this at cold startup. It's not till expansion occurs that the noise goes away. Technically, it's not good, but it's normal for these trucks and I'll have to live with it.

Now I just need to get rid of that annoying brake squeak, apparently I didn't clean the drums well enough a week ago to stop the brake squeak, so once again, I'll try it this weekend.