Will i damage the stereo in my 2001 toyota sienna if i replace the stock 8 ohm speakers with 4 ohm speakers? the rear speakers are blown. if i can should i do all four? i happen to have four 4 ohm speakers

Yes, they will be a little louder..

Get a known good speaker an hook it up in place of the old ones an see if it works , if it does the old one is no good . Now if it doesn't work the radio isn't set correctly or that channel of the radio is blown .

If all speakers quit at once i would suspect the amplifier has quit. Depending on the specific stereo system it may be inside the radio or an external amp.

OLDSMOBILE ALERO 2000 speakers - Sonic Electronix

www.sonicelectronix.com/oldsmobile-alero-2000-car-speakers.html

OLDSMOBILE ALERO 2000 speakers - find speakers that fit your ... sound. This size is capable of delivering exceptional mid-bass that can't be found in smaller ...

2001 Oldsmobile Alero Car Radio Stereo Audio Wiring ...

www.modifiedlife.com/2001-oldsmobile-alero-car-radio-stereo-audio-wi...

Easy Plug and Play Wiring Adapter. ... 2001 Oldsmobile Alero Car Radio Stereo Audio Wiring Diagram ... If you can't find your car audio wire diagram, car stereo wire diagram or car radio ... Right Rear Speaker Positive Wire (+): Dark Blue ... olds alero and I have replace the stock stereo and have found that the sound out put ...

Request a Oldsmobile Car Radio Stereo Wiring Diagram

Radio Battery Constant 12v+ Wire: Blue/Yellow
Radio Accessory Switched 12v+ Wire: Gray
Radio Ground Wire: Brown
Radio Illumination Wire: Green
Stereo Antenna Trigger Wire: Black/Red
Left Front Speaker Positive Wire (+): Pink
Left Front Speaker Negative Wire (-): Violet
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Blue
Left Rear Speaker Positive Wire (+): Black
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Red
Right Rear Speaker Negative Wire (-): White

Do not use factory speakers with a aftermarket radio the ohm rating will not match and you will never get any kind of good volume out of them.
New aftermarket stereo's are set for 4 ohm load. consult ohms law when purchasing new speakers. ALWAYS run new speaker wire to your speakers. If problem still persists then you have to install a choke (noise suppressor) on the positive side wire of you stereo or relocate it to another source of power.
Resistor spark plugs never hurt as well.

2007 Toyota Sienna Car Audio Wiring Color Codes
Car Radio Battery Constant 12v+ Wire: Blue/Yellow
Car Radio Accessory Switched 12v+ Wire: Gray
Car Radio Ground Wire: Brown
Car Radio Illumination Wire: Green
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: Black/Red
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Pink
Left Front Speaker Negative Wire (-): Violet
Right Front Speaker Positive Wire (+): Green
Right Front Speaker Negative Wire (-): Blue
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Black
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Red
Right Rear Speaker Negative Wire (-): White

I just replaced my blown sub in my Avalon xls with a Kicker 07C84 and it works great. For the same price of a repair kit, you can just buy this new speaker. Why go through the hassle of repairing a 9 year old speaker. This speaker fits into the same cutout of the old speaker. All I did was splice the red and black wires within the factory plastic housing so I could still use the factory connector.

I would be very proud of that truck as the sub that came with the truck was only a 8". The only one that works is the factory model as it is a 1 1/2 - 2 ohm speaker; replacements are 4ohm. You will have to replace the amp as well if you put in an aftermarket sub. Oh and apparently the amp will have to have "speaker level" inputs as opposed to pre-amp inputs. I have a 1999 Eddie Bauer wih a blown sub and I'm trying to decide what to do as well. The speaker is $400 with tax in Canada! Good luck.

Constant 12V+                 Blue/Yellow  Switched 12V+                             Gray  Ground                                         Brown  Illumination +                                Green  Dimmer n/a  Antenna Trigger                             Black/Red  Antenna Driver's Pillar  Front Speakers                             3 1/2" Dash Left Front (+)                                 Pink  Left Front (-)                                  Purple  Right Front (+)                               Light Green  Right Front (-)                                Blue  Rear Speakers                               5 1/4" Rear Deck Left Rear (+)                                  Black  Left Rear (-)                                   Yellow  Right Rear (+)                                Red  Right Rear (-)                                 White