hearing a knock when engine is revved upto 2500 rpms

kfcmgr
0

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

Question type: Maintenance & Repair

11 Answers

tenspeed
85,855

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

1 out of 1 people think this is helpful.
Derek Dilts
165

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.

3 out of 3 people think this is helpful.
Jeff Smith
2,425

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

6 out of 6 people think this is helpful.
John Sturman
2,015

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

Jeff Smith
2,425

John, what 'shells' are you talking about?

John Sturman
2,015

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

1 out of 1 people think this is helpful.
Jeff Smith
2,425

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

1 out of 1 people think this is helpful.
John Sturman
2,015

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

1 out of 1 people think this is helpful.
tenspeed
85,855

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.

Jeff Smith
2,425

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

DrWentz
0

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*****

Your Answer

Add photo

Related Questions

  • Sound coming from the engine when revving 3 answers

    95 Legacy 250t Stock ej25d engine There is a knocking/tapping sound coming from the engine when revving. The sound only occurs between 1500-2000 rpms. Most noticeble when taking off. This does not ...

    1995 Subaru Legacy 4 Dr L AWD Wagon

    -

    Maintenance & Repair

  • High rpms low speed spitting and sputtering 1 answer

    After I shift gears rpms rise like it wants me in 3 gear @ 20 mph spits and sputters or stalls out

    1992 Subaru Legacy 4 Dr L Sedan

    -

    Maintenance & Repair

  • How can I fix the sputtering that occurs when accelerating at low rpms? 5 answers

    My 1999 Subaru Legacy 2.5 l with 200 000 km sputters when accelerating at low rpms since a few weeks. This does not occur always, but about 99% of the time. On one occasion the sputtering was comple...

    1999 Subaru Legacy 4 Dr L AWD Wagon

    -

    Maintenance & Repair

  • What's the problem with my car's acceleration? 8 answers

    Okay I have a sever problem and I am unsure what to do about it. So I own a 1995 Subaru Legacy LSI 4 Door Sedan. As of the last yearish when I go to start my car it starts up fine and the RPM's go to ...

    1995 Subaru Legacy 4 Dr LSi AWD Sedan

    -

    Maintenance & Repair

  • How long do Subaru Legacys last? 57 answers

    What is a typical lifespan for Subaru Legacy wagons? I have a 1996 Subaru Legacy Brighton with 132,000 miles (bought it used, with 18k already on it). I've kept it maintained over the years. Two di...

    1996 Subaru Legacy 4 Dr Brighton AWD Wagon

    -

    General

Legacy

Looking for a Used Legacy in your area?

CarGurus has 14,209 nationwide Legacy listings starting at $1,295.

ZIP:

Search Subaru Legacy Questions

Subaru Legacy Experts

#1 Anthony_60
Anthony_60
Reputation 900
#2 Nick Eidemiller
Nick Eidemiller
Reputation 650
#3 dandyoun
dandyoun
Reputation 570
View All

Related Models For Sale

Used Subaru Impreza"
190 Great Deals out of 10,818 listings starting at $1,800
Used Honda Accord"
1,087 Great Deals out of 72,219 listings starting at $500
Used Toyota Camry"
1,459 Great Deals out of 86,641 listings starting at $999
Used Honda Civic"
826 Great Deals out of 52,661 listings starting at $995
Used BMW 3 Series"
1,144 Great Deals out of 38,078 listings starting at $1,450
Used Toyota Corolla"
1,116 Great Deals out of 65,486 listings starting at $1,295
Used Nissan Altima"
1,312 Great Deals out of 84,123 listings starting at $1,100

Used Cars For Sale

2017 Subaru Legacy For Sale
6,429 listings starting at $20,165
2016 Subaru Legacy For Sale
23 Great Deals out of 1,937 listings starting at $17,912
2015 Subaru Legacy For Sale
49 Great Deals out of 837 listings starting at $14,900
2014 Subaru Legacy For Sale
40 Great Deals out of 1,153 listings starting at $9,799
2013 Subaru Legacy For Sale
61 Great Deals out of 1,076 listings starting at $9,495