Welcome to the North American Subaru Impreza Owners Club Friday September 22, 2017
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
Go Back   NASIOC > NASIOC Subaru Models > Legacy Forum

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Thread Tools Display Modes
Old 06-30-2008, 01:17 PM   #1
Scooby Specialist
Member#: 9264
Join Date: Aug 2001
2016 BMW M235i 6MT

Default Is the 2.5 DOHC Phase I with a 4EAT just rough?

My wife has owned her 98 LGT wagon since 2000 and she loves it. The car currently has 107K miles and it's basically been flawless except for a couple very slight valve cover leaks and rear pinion seal leak, vibrating heat shields (I cut them off when they get noisy) and an AWD bind issue that has plagued the car since a month after we bought it. I maintain the car and have done the tranny fluid, diff fluids, fuel filters, plugs, wires, coil pack, struts, new half-shaft, etc. plus we've had the timing belt, water pump, and oil pump seal done. Since day one of owning the car, the motor just isn't that smooth and is rather noisy. The noise I'm sure is mostly a factor of heads and manifolds within 8" of the road, but still, it's not a sexy sound at all with the windows down. I've listened to other Outbacks/GTs and they seem to emit the same wheezy clamore of noise. The motor just feels grainy and the initial throttle input is slightly delayed when you press the pedal (throttle cable slack is good). At a stop with the car in gear, there is some decent vibration. This weekend, I messed around with the throttle position sensor to raise the idle rpm a bit, but that didn't seem to help too much plus I think the ECU would eventually compensate and dial the rpms back to spec over time (I know Nissans do this). I've checked engine vacuum and it's fine. All the vacuum lines are good. PCV valve is fine. I've checked the IAC system for carbon build up and it was clean.

When putting the car gear and the car is cold, I sometimes (70% of the time) hear a chassis clunk which makes me think a tranny or motor mount is bad which could be causing NVH problems, but when I was doing a half-shaft replacement this weekend, I inspected the motor/tranny mounts, I couldn't see any tears. I would think the damage would be obvious if there a problem. Do one of these mounts typically fail. The sound almost seems to come from near the upper mount that is attached to the fire wall, but it seems to look fine.

The car gets continues to get 22-23 in the city and 26-28mpg on the highway so I think tuning is fine, I guess. I just bought a new set of tires to replace the aging 5 y/o tires that ride like crap even though they have 50% tread left. Maybe that will help lower some of the NVH this car has.

Last week, I helped my sister in-law buy an 99 Impreza Outback hatchback (2.5 DOHC, Phase II) and that motor/tranny is so much smoother, quieter, and responsive. Granted the car is about 300lbs lighter, it just "feels" so much more refined. You can still wear that wheezy boxer sound, but it's not near as pronounced.

I really do like the car because it's been such a work horse, but I'm a car guy and can't but think there's something out of adjustment, broken, etc that is adding NVH to this car. We are keeping the car for another 1 to 2 years and will be buying another LGT (turbo this time). Any help or insight would be great. I guess the other possiblity is that I'm just use to driving newer and more refined cars like my 03 G35 and 07/08 rentals for work.
* Registered users of the site do not see these ads.
MaddMax is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 06-30-2008, 01:55 PM   #2
Scooby Specialist
Member#: 11620
Join Date: Oct 2001
Location: Ontario
1997 GF4-STiV3 clone


I tried a lot of things to cure that vibration when stopped at idle while in gear. I have read a bunch of other threads on the issue as it is a pretty common issue. Nothing really worked. I tried NEW ENGINE MOUNTS, new O2 sensor, IAC, cleaning TB, new plugs and wires, flushed tranny, different oils and a new short block after the other one failed.
It was a little better with A/C on. It was much worse in winter when cold. It was fine when in park or driving.
I think it is the torque converter getting old.

The motor is a pretty noisy bugger. Lots of valve ticking and clacking. Piston slap is pretty normal too. These are mostly just the way it is and not a sign of impending doom.

Like you, it started to really bug me after I got the Lexus. The Lexus is like budda and made the Legacy seem like a tractor. I spend a bunch of time and a few $100 trying to fix the vibration, but nothing really solved it.

Last edited by linsavy; 07-02-2008 at 10:11 AM.
linsavy is offline   Reply With Quote
Old 06-30-2008, 01:58 PM   #3
Scooby Specialist
Member#: 32503
Join Date: Feb 2003
Chapter/Region: TXIC
Location: Johnson City, TX
2011 Tribeca
1995 Legacy Wagon


After 10 years I'd expect the motor/tranny mounts to be worn out. It's not always bad enough that you can see cracks/tears - but if you grab the intake manifold and can rock the engine around a bit, or if the engine is doing a lot of moving around when revved in neutral, then you just might see a lot of NVH go away with some new mounts.
jey is offline   Reply With Quote
Old 06-30-2008, 03:23 PM   #4
Scooby Newbie
Member#: 61907
Join Date: May 2004
Chapter/Region: NESIC
Location: maine
1998 2.5 GT
spruce pearl


^^^im with jey. ive had to replace the mounts on my bd because they were really bad, but you couldnt tell by looking at them... only by prying on them with a pry bar.
gt_drifter is offline   Reply With Quote
Old 06-30-2008, 09:55 PM   #5
Scooby Newbie
Member#: 163484
Join Date: Nov 2007
Location: Harrisburg, PA
98 OB M/T
99 Miata


I remember when I first went for a test drive in a 2.5RS. It was so quiet and smooth after it was started, I asked the sales lady if it was actually running as I was about to turn the starter again. No joke. The thing is, I can't be sure of what year it was (98-00?). So I don't know if it was the DOHC or SOHC model. But I remember that it was SMOOTH. My newly purchased 98 Outback with the DOHC isn't anywhere close. It has a pretty rough idle but it also has issues. We'll see what happens after a few things are fixed.
Minjin is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
WTB old 2.5 DOHC phase 1 head madmax718 Tri-State Area Private Classifieds 1 02-13-2009 05:03 PM
Need Help! Is The 2.5 Rs Compatible With The Sti Headers? DennisAltered Normally Aspirated with bolt-on Forced Induction Powertrain 2 03-10-2005 06:46 PM
is the 2.5 rs(2002) same as the sti motor? DennisAltered Mid Atlantic Impreza Club -- MAIC 5 03-10-2005 06:27 PM
Is the 2.5 Turbo the same in the STI and Forrester? tchprivat Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 10 09-09-2004 06:28 PM
Accessory belt size for the 2.5 DOHC MaddMax Legacy Forum 1 05-21-2004 12:21 PM

All times are GMT -4. The time now is 11:04 AM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2017 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.