Knocking when cold...

Im not much of a mechanic but mine does it too. This might be a good laugh for some but I think it might be cold condensation in the headers trying to get out or the sound of hot exhaust traveling through a cold header. Just trying to pretty up the picture

 

you should never spray any liquids at your serpentine belt

 

Hey guys, maybe this may help explain - dont know if its for only v6, but maybe it may help:

http://www.tacomaworld.com/forum/2nd-gen-tacomas/57893-rattling-noise-when-cold.html

 

Add mine to the list. 2.7L 2002. It definitely seems to only happen on cold days. Mine also does it when I leave work in the afternoon. I have noticed that if I accelerat gently it seems quieter or nonexistent. To me it sounds like something like exhaust shielding. Its not really a very solid sound, if that makes sense.

 

I dont think its the intake on the 1st gens. I think its more of a problem on the 2nd gens. from what Iv seen. When I had my stock intake on it knocked, and now that I have a K@N cai it still knocks so in my case its not the intake. Im begining to accept this as a common problem that a lot of people have and I dont think, "HOPE" it will not have any detramential effects on the engine.

 

LUCAS HEAVY DUTY OIL STABILIZER

Should fix it right up. Mine was doing the same thing. Had a mechanic tell me i needed new lifters and it was gonna cost me $500 to fix the knock, I told him to F off.

Sounds like you guys have some good ideas, but if your changing your oil anytime soon, try out some Lucas. THE STUFF IS AMAZING.

 

^^^Good to Know^^^^ No one has had said a cure yet.

 

but then I find this. WOW!, It even makes a good motor oil foam up! I know, there's no gears in a motor... Really? what about the oil pump? It's gear driven, also pumps with gears. Ok, Toyota's have gears, boy wouldn't that be a mess?, Alright, here's the biggy.. What about the Ford PSD's? The high pressure pump on a PSD (95-97) is
500psi @idle 1200psi@3300 RPM 3600psi @full load acceleration. The HP oil pump is only used to control the HEUI injectors. It does not lube the engine, But at these pressures, it foams like a devil. It is then returned to the sump. So, think the oil is being whipped up any in that? On a PSD, This runs the injectors and add a little air to that system, Now you really have problems.



http://www.bobistheoilguy.com/images/lucas/lucas.htm

 

Add me to the list too. I have the same thing on my 2001 2.7. It does it on semi-cold morning and really cold mornings. It goes away after like 20-30 seconds but it has been happening every morning lately. I have 129,000 miles on mine and it didnt happen last winter.

 

I tried lucas with no luck. I run 10w30 and it still knocks.

 

I just put put some stp oil treatment in mine and Ill find out if it works in the morning, mine is definetly in the engine, I wish I could say it could be something rattling.

 

Well the STP made no difference...

 

Mine didn't do it at all this week... Below 20 every morning. I guess it was just one of those cases of Tacomas fixing themselves. (Mine has a good habit of doing that)

 

Well I e-mailed Toyota about this problem and they basically said that they are not aware of a problem and theres nothing they can do about it... Not a surprise.

 

A possibility to your problem might be from your piston getting cold, which makes it look kinda like an egg also known as cam ground. Could very well be your piston actually knocking on your cylinder walls till it expands properly. Another idea your oil pump from it being so cold makes it harder to pump the think oil.

 

Well Im not sure if it will help or not but I am going to change my oil to 10w-30 high mileage. I run 5w-30 now and Im thinking that at cold temp when the oil is at 5w it may be too thin for good lubrication and coating the metal. It never gets below 20 or so here any ways.

 

u all can add me to the list also, i just noticed mine this winter. i have right at 192k on mine. just put up a thread in the 4 cyl section about marvel mystery oil. im going to try it in my taco next oil change, & more then likely put a few ounces in the fuel tomorrow! ive been using 10w40 pennzoil with a puralator pure one filter or a puraltor classic. should i try a different weight of oil? im thinking about going back to the OEM filter too!

 

Ok it's been below zero every morning this week and mine hasn't done it at all. I just get an intermittent squeak from I'm assuming a belt when I first start it in the morning.

 

Here is what I can say, I run Mobil 1 5W-30 synthetic it flows better in cold enviorments, and I use OEM toyota filters. When the vehicle starts after being cold soaked I can here the noise at about engine speed (accelerate and the noise changes tone). Anywhere from 30secs to 1 minute it disappears, but depends on how cold soaked the engine is. I also notice that when it makes the noise that if you shift the auto trans into gear it will change the tone of the noise (RPM or load related). My guess is piston slap, and if it is piston slap then eventially the walls of the cylinders will be scored. It never happens for me if the truck has some type of heat built up in it. I will be having toyota diagnose the issue over these winter months and will keep pushing them until I hear an answer that makes sense to me.

 

Add me to the list as well, 02 2.7, only when cold, goes away after a minute or two. I have 220,000 miles, and this has been happening for 3 winters now. Here's hoping I get to hear it for at least another 3...