[TOK]

I know they pretty much all do this, but how bad does it get?
My truck has about 50,000 miles on it, and it only used to happen on the coldest days. Now it's doing it anytime the temperature is in the 30's, and also seems to be lasting a bit longer -maybe 20 seconds or so now. Using Mobil 1 0w/30 in the Winter.

 

[tacoman13]

what grade fuel are you using? it could just be preignition

 

[TOK]

Don't think it's anything related to pinging. Does it regardless of fuel, and only when it's cold (basically the opposite of when a mixture will pre-ignite). There were a lot of threads on this in the old Delphi forum.
Just want to make sure I don't have anything to worry about as the truck gets up in miles!

 

[akshunj]

Don't think it's anything related to pinging. Does it regardless of fuel, and only when it's cold (basically the opposite of when a mixture will pre-ignite). There were a lot of threads on this in the old Delphi forum.
Just want to make sure I don't have anything to worry about as the truck gets up in miles!

My truck did the same in the past. I noticed I was parking on an incline so that the nose of the truck was pitched down. I started backing in so it was a little more level and it alleviated the slap. I know it sounds weird, it surprised me too. I figure the pick up for the oil pump might not have been submerged enough.

 

[99SD]

Mine started at about 79000 miles. Only does it when cold. Emailed toyota about it at their website, and they basically said they were not aware of the problem. If everybody that had the problem would email them and ask about it, maybe they would be concerned. On mine, the thinner the oil (0w or 5w) the louder the knock. Presently using 15W 40 Rotells, and it ain't so bad. Going to sample the next few oil changes and check for anything abnormal. Best I remember from Delphi, there were several people with over 150,000 miles on their knocomas, with no problems other than the embarrassing noise.

 

[Doug 97SS]

I have a 2.7 4x4 Ext Cab and I have this slight knock on the cold days...not every day...but it does happen. My truck has over 105K on it and going strong...I do NOT rev the engine though, I let the motor warm up and THEN I let the engine rev....

 

[greenamp]

That noise is pretty common on 2.7's. I have it on cold days and my truck has just less than 30k miles on it. No one really know whether it's genuine piston slap or not, but the consensus seems to be that it is not harmful.

However if it is concerning you, the only real thing to do would be to take your truck to a toyota technician, who would be able to tell you within 15 minutes what the noise was and whether or not it is something to be worried over.

Either way, good luck

 

[KStacoma]

It is normal man, i've posted before about it and got tons of replies from people w/the same probl. on 2.7l engines. I found too when on an odd incline or off camber on a cold morning it is worse than when parked on level ground.

 

[rokbrkr]

What you guys are describing sounds more like lack of lubrication, than piston slap. I have an '85 4runner that has a piston slapping, does it every day, cold or hot, no matter what kind or weight of oil, it doesn't ever go away it just quiets down after the engine comes up to temp, due to the piston swelling with heat. It's been LOUD for 30,000 miles now, but hasn't got louder, I'm replacing soon!
My last '85 did what you are describing exactly, and the dealer told me to use a toyota oil filter with the back flow valve, as it was due to the oil filter draining after shut down, then having to fill up again, causing a momentary lack of oil pressure, that helped but didn't cure it, sold it with 185,000 on it and still going strong!
I'm not a mechanic, these are just my own personal experiences, sounds pretty common, I would be curious to know what exactly is rattling around in there at start up

 

[TOK]

I agree with your assessment, rokbrkr. When I first heard the noise, I thought it was a rod knock and the engine wasn't getting oil. Scared the heck out of me. I was already using Mobil 1 0w/30 from late November through March. Reading that many other people in cold climates had the issue (some with over 100,000 miles) calmed me down, but I'm still not real happy to hear that knocking when it gets cold.

 

[Footpounds]

What you guys are describing sounds more like lack of lubrication, than piston slap. I have an '85 4runner that has a piston slapping, does it every day, cold or hot, no matter what kind or weight of oil, it doesn't ever go away it just quiets down after the engine comes up to temp, due to the piston swelling with heat. It's been LOUD for 30,000 miles now, but hasn't got louder, I'm replacing soon!
My last '85 did what you are describing exactly, and the dealer told me to use a toyota oil filter with the back flow valve, as it was due to the oil filter draining after shut down, then having to fill up again, causing a momentary lack of oil pressure, that helped but didn't cure it, sold it with 185,000 on it and still going strong!
I'm not a mechanic, these are just my own personal experiences, sounds pretty common, I would be curious to know what exactly is rattling around in there at start up

How would the oil drain out of the filter? On the 2.7L, the filter is mounted base-end up. You don't even need an anti-drain back valve with the filter mounted in this position so I don't understand why you would be told that. The filter is always full!

 

[rokbrkr]

The engines I am speaking of are the older 2.4, it is my understanding the 2.7 is just a bored out version of this engine??? They must have changed the oil filter position, because mine sits horizontily, angled down at the base end, allowing the filter to drain almost COMPLETELY, the dealer that told me that was talking to me about a 2.4, not a 2.7, that being the case.....any idea what the noise is, and the cause, in the 2.7?

 

[tacoma200]

I put Lucas oil treatment in with the oil change and it stopped the piston slap on all but the coldest days. I have used it on two Tacoma's with 2.7 4 cylinders and it helped both of them.

 

[TOK]

I put Lucas oil treatment in with the oil change and it stopped the piston slap on all but the coldest days. I have used it on two Tacoma's with 2.7 4 cylinders and it helped both of them.

Thanks buddy. Even though I'm using Mobil 1, I might try this with my next oil change.

 

[agroal]

I know they pretty much all do this, but how bad does it get?
My truck has about 50,000 miles on it, and it only used to happen on the coldest days. Now it's doing it anytime the temperature is in the 30's, and also seems to be lasting a bit longer -maybe 20 seconds or so now. Using Mobil 1 0w/30 in the Winter.

Iv'e never had a problem w/my 2000 2.7L until this fall. (40 K Miles). I heard the knock on start-up. (Gone after 30 sec.). After much searching, I relegated it to "piston slap". With a cold snap upon the Northeast the past two weeks, it hasn't happened again. Go figure! I have faith in the 2.7L. Another Toyota: PKTCE. Translates to: Puts kids through college engine!

 

[AN1]

I know they pretty much all do this, but how bad does it get?
My truck has about 50,000 miles on it, and it only used to happen on the coldest days. Now it's doing it anytime the temperature is in the 30's, and also seems to be lasting a bit longer -maybe 20 seconds or so now. Using Mobil 1 0w/30 in the Winter.

I've had this on and off during cold weather starts for at least 150,000 miles, and it's still unclear exactly what triggers it. Sometimes it's only in the low 40s when it happens. Only at the first cold start. Unpredictable. If it had done damage by now I think I'd know, as the engine has over 280k miles with no rebuilding. Synthetic oil of various brands has always been used. 1996 2.7L 4x4 5-speed, original owner.