hearing a knock when engine is revved upto 2500 rpms

Asked by Feb 20, 2013 at 02:37 PM about the 1994 Subaru Legacy 4 Dr L Wagon

Question type: Maintenance & Repair

13 Answers

100,705

That's never good. Rod knock? Does the knock go away above 2.5K?

3 of 3 people found this helpful.
175

Knocking isn't a good thing. How fast is the knock, and does it get faster as RPMs increase? If the knock is more of a "tick" that's really fast, it's likely in the valve train. If it's slower and more "low pitched", it's probably rod knock.

4 of 4 people found this helpful.
3,275

It could also be piston slap on cold starts. Does it go away once the car warms up?

7 of 7 people found this helpful.
2,315

youve also forgot about the shells on the bottom end as theese wear if the car has been thrashed hard on a regular basis

3,275

John, what 'shells' are you talking about?

2,315

on the crank shaft there is a series of shell bearings normally made of phosfer bronze if theese wear you will hear a knocking sound when under load as the crank will vibrate and start causing damage to the crank itself to get access to theese you will need to drop the sump/oil pan and then undo the crankshaft this will give you access to the shells. if you can read a micromiter then mic up the shells to work out how much wear there is and replace them accordingly with new shells to correct tolerances and dont forget to replace the oil seals at the same time you will have a rebuilt bottom end which will last quite sometime you can also drop out the pistons from the bottom end if you wish and replace the rings with a set of cords piston rings which hone out the bore and clean it up but you would have to run in the engine for at least a thousand miles drop the engine oil and replace with a good quality oil after this and it would be as if it was a new engine

2 of 2 people found this helpful.
3,275

What you are recommending then is a full rebuild. The block must be split to replace those rod bearings.

1 of 1 people found this helpful.
2,315

a rebuild is the best option as a second hand motor would cost more with fitting than you rebuilding the bottom end

1 of 1 people found this helpful.
100,705

Rod knock is a result of the "shells" or rod bearings being worn out. The noise is only heard when the gas pedal is pressed. --- Sometimes engines will make noise from pistons with short skirts. They will rattle a bit until the engine warms up and the piston expands to fill the bore. Pontiac 3100 and 3400 engines do that.

1 of 1 people found this helpful.
3,275

In the Subaru world, this is referred to as piston slap. It's very common on the higher mileage EJ engines.

1 of 1 people found this helpful.

I just bought a nice used '05 Legacy GT and this happened to me after 2 months. They said it would cost $9.5k to fix which is what I payed for the car. Rod Knock messed up my lower end and turbo with shaving metal. Now im figgidy figgidy f*****

mine does not knock on acceleration,...but, when you let off

always noisy when first start up...then quiet,....when shifting, or downshifting,....it sounds like I have a marble factory under the hood...lol

Your Answer

Legacy

Looking for a Used Legacy in your area?

CarGurus has 14,774 nationwide Legacy listings starting at $2,449.

ZIP:

Subaru Legacy Experts

  • #1
    Anthony_60
    Reputation
    1,270
  • #2
    Nick Eidemiller
    Reputation
    740
  • #3
    dandyoun
    Reputation
    700
View All

Related Models For Sale

Used Subaru Impreza
181 Great Deals out of 19,845 listings starting at $2,200
Used Honda Accord
1,130 Great Deals out of 62,430 listings starting at $1,199
Used Toyota Camry
1,073 Great Deals out of 73,748 listings starting at $295
Used Honda Civic
812 Great Deals out of 73,912 listings starting at $1,400
Used Toyota Corolla
908 Great Deals out of 57,792 listings starting at $1,488
Used Nissan Altima
1,012 Great Deals out of 75,761 listings starting at $1,627

Used Cars For Sale

2018 Subaru Legacy For Sale
6,823 listings starting at $20,405
2017 Subaru Legacy For Sale
26 Great Deals out of 2,559 listings starting at $16,665
2016 Subaru Legacy For Sale
26 Great Deals out of 668 listings starting at $13,500
2015 Subaru Legacy For Sale
57 Great Deals out of 1,361 listings starting at $9,990
2014 Subaru Legacy For Sale
25 Great Deals out of 726 listings starting at $9,750

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.