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Post-oil change hissing sound

Immediately after my last Jiffy Lube oil change, my 2006 Toyota Matrix now has a faint hissing sound on acceleration. The sound seems to be coming from the engine compartment, kind of near where the glove compartment is. My first thought was that a leaf or piece of paper had gotten in with the cabin air filter when they checked it, but that’s not it. The sound is there even with the fan off. There is no noticeable change in performance and no loss of air conditioning. Did they bump into a vacuum hose or something when they changed the oil? What could it be?

A vacuum hose is a possibility, but usually if a vacuum hose is disturbed, you will wind up with a rough idle and/or other engine issues. But, in addition to having a REAL mechanic check for a disconnected vacuum hose, you should also check for improper closure of the plastic box that holds the air filter. Even if you don’t tell the Jiffy Lube kiddies that you want a new air filter, they will almost always open up the air cleaner box in order to “check” it and try to upsell you. My theory is that they did not secure the clips on the air cleaner box properly.

When you go to a REAL mechanic in order for him to check under the above items, be sure to ask him how much he charges for an oil change. Chances are it will be no more expensive, and may actually be cheaper than what Jiffy Lube charges. Even if it is more expensive, it is worth a few dollars to have someone competent working on your car.

If it sounds like I am biased against J-Lube and their clones, you are correct.
If you want to know why, try using the search function on this site to see the HUGE number of posts from folks whose (pick one or more): engine/transmission/differential/power steering/brake hydraulic system was destroyed by these folks. You couldn’t pay me to have my car serviced at one of those places.

I’m with VDC on this. The quickie lube places now have their kids check a lenghty list of things looking for an additional “need”…even if you order them not to. I had to use one once (long story) and even though I ordered them with emphasis and vis the manager that I did not want them to do ANYTHING but change the oil, they still walked up to me with a white rag with a drop of my differential oil teling me my differential was about to fall apart if I didn’t get it flushed & refilled. It was a 2WD Toyota pickup. Ironically I’m probably the only person in the history of the world that actually DID drain and refill my differential (I was lying under the truck after changing the shochs and figured aw, why not…). ALL fluids look excessively dirty on a clean white cloth…don’t ever fall for the “white cloth scam”.

I’ve learned my lesson about the Jiffy Lube. But I guess what I need to know is, given that they check a finite number of things, what could they have unintentionally done to cause this noise? I think I’m going to replace the PCV valve and see if that helps. It should probably be done anyway, after 50k without a new one.

It could be anything in the induction system that they left loose. The air cleaner box is a good guess. Or, conversely, they could have left a rag by the intake snorkle to the air filter box. Pop the hood and see what you can find.

Just supporting the air cleaner box theory (and seconding mountainbike’s experience)…

I do sometimes use Quicky Lube, but I always make sure that they actually put in oil* and I never let them upsell me (or my children). And I always tell them not to do anything but change the oil and filter. And they always check the air filter and cabin air filter anyway. And on my Camrys (2000 and 2004) they almost alway leave the air filter cover cover ajar.

(* I do realize that I am still increasing the risk that they will mung up the oil drain threads. And I don’t ask them for directions.)

"But I guess what I need to know is, given that they check a finite number of things, what could they have unintentionally done to cause this noise? "

Ummmm…That is just what I did, and my theories have now been seconded by two other forum members. My friend, mountainbike gave you some other, closely-related possibilities.

I’m sorry, but from cyberspace, nobody can tell you exactly what the cause of the problem is.
All we can do is give you the most likely scenarios–and now it is up to you to take the car to a REAL mechanic who can see, hear, and examine the engine.

Good luck!