Spew sound when starting 08

Started my truck today and made a spewing/blow off valve kinda sound. Had been sitting in 100 degree heat all day. Any idea what this is? Major issue?

 

Coolant spilling into the overflow tank when the water pump started up??

 

I get the same thing with my 08' SR5 4X4 2.7, it's been like that since I got it early last year. Doesn't matter whether it's hot or cold outside. Sounds like a little 'pop' from the tail pipe when starting it up after it sits overnight or all day. Have no idea what causes the noise (maybe a little residual gas left in the cylinders), but it doesn't seem to affect how it runs...like a top.

 

Is your AC turned on?
If mine is on when I start, or if I hit the button before the engine idles down, I'll get an "odd" noise.

 

Yes ac was on. Drove it around 100 miles since yesterday. No issues and hasnt happened again.

 

just set your waste gate higher on your turbo

 

The air pump for the emissions system makes some noise at first start up??????

 

Yes it does, it blows hot exhaust into the cat to heat it up at cold start, but if he hasn't noticed it until now, and especially on a hot day, I kinda ruled that out.

 

Just bought the truck a month ago. I've know Chevy "noises" all my life. New to the Tacoma world but love it so far.

 

mine does the same thing. usually when I start backing up. emissions system.

 

I could be mistaken, but I believe the air pumps are only on the 2012+ V6.

You are likely hearing what Rich described. The refrigerant in your a/c system condensed and when your compressor started up the condensed refrigerant rams into the compressor. This usually only happens on hot days. Best way to avoid this is to leave your a/c off until the first minute or two of engine operation.

 

Thanks for all the help guys!

 

I'd be surprised if it's the a/c system since I never use my a/c and it still happens most of the time, summer or winter, when starting up after a long sit. Maybe a good question for the dealer.

 

Your 2.7 does have the air injector blower that would make a noise on startup.

 

Thanks for the tip. That's interesting, I wouldn't have guessed that the blower would be an issue unless the a/c was actually being used. Mine probably has cobwebs on it...not too many hot days here. Short of removing the a/c, is there a fix for the noise?

 

Two different systems creating two different noises. The noise on startup with the blower is an emissions thing and it blows air into the exhaust manifolds before the catalytic converters to help give a more complete combustion. It will do this regardless of outside air temp (I think).

The noise from the a/c system is entirely independent of the emissions blower.

 

Learned something new, I appreciate the explanation. Truck runs great so not a worry, but at least the minor mystery on the 'poof' noise seems to have been solved.