98 lancaster auto wagon - low mpg's

[boknows]

This is my first subaru - 98 BH9 non-turbo 2.5L Lancaster auto wagon, 250K on the clock. Drives pretty well, ticks over at approx 800rpm once started up, auto box revs a little on first few shifts and/or when cold. Has a small oil leak which i'm guessing is coming from the drivers side valve gasket and has a little squeal from drivers front which I'm thinking is brake squeal? Breezed through last two WOF's, only needing a bulb for tail number plate and steering belt.

I've had the tranny serviced, changed the oil, air filter, had new fronts and wheels balanced/aligned however I'm only returning ave 360-380kms town driving on a tank.

Any tips on potential issues causing the low mpg return? I check tires every fill up and was thinking about changing plugs/leads to see if that improved things. I don't have a heavy right foot but struggling to understand the low mpg return, unless this is normally for non-turbo 2.5's?

Any help you could offer this subaru greenhorn would be much appreciated

cheers

Paul

[Rosssub]

How's the air filter look? Plugs/Leads, make sure there's no air leaks anywhere too.

[boknows]

Filter looks ok. Was thinking plugs/leads would be the next fix. NGK's for a subaru right??

Also, air leaks, how best to scope that out? Was also thinking about fuel filter but this version seems to be in the fuel tank rather than under the hood. Armstrong Subaru on railway ave said not to stress it as they go forever?

Could the cat be an issue?

Edited July 28, 2014 by boknows

[Rosssub]

I think it's NGK:PFR6B-11 gapped to 1.1mm, but don't quote me on it.

While the engine running, spray ether (starting fluid) around any possible leaks (gaskets/hose connections etc). The idle will change if it sucks any fluid in. Just have a fire extinguisher or hose handy just in case.

The CAT could be a cause, an exhaust shop should be able to test it. How many kms has it done?

[Kiwi_Fozze]

potentially o2 sensor faulting but not bad enough to throw cel will mess up your mpg

[Stodart]

these don't like short running, mine (BH9 01 manual with 240K) fuel consumption drops significantly with city driving / short running. take it on a good trip to get a better idea what its capable of.

[boknows]

thanks for the tips re air leaks. I'll have the cat checked next, motor has done 250K

[boknows]

How would I figure out if the o2 is playing up? I'm not getting any dash lights, would I need to get the cpu scanned?

[boknows]

I've been thinking that. I took it to ureweras and back from welly and mpg was sweet as. Starting to think might need a more $$effective run about!

[Marky]

Yeah they aren't known for being frugal - to be honest they probably get better mileage in turbo form, at least up until the early 2000 sorta models

[DRFVDR]

pretty much "welcome to Early NA subaru ownership "

Largish car + AUTO + AWD = not so good on gas

[boknows]

It certainly seems that way! Can't fault the rest of the car, its sweet to drive, plenty of space in the back for the dog and tows easy as.

My current plan is change plugs and maybe leads, front o2 sensor, PCV along with air/oil filters and a new batch of oil. Being a newbie to the boxer engine, is changing the plugs the nightmare some people would have you believe?

Thanks for all the feedback, its much appreciated.

[DRFVDR]

The plugs are fairly easy

You can change them easish with the engine in place, but what I do is undo the 2 engine mounts and then jack each side up as i do them about 50-100mm makes it a piece of pie then

[boknows]

Hi guys,

further to the advice above, I swapped the old plugs out for some NGK Iridiums. Trauma to change without moving the block up but they're in now and the motor started first hit so must have done something right!

The motor seems to run much better but there is still some hesitation when accelerating. The research I've done points to a possible o2 sensor issue but I haven't had the ecu scanned. If this is the EJ254 motor, any tips on which o2 sensor I would need? Armstrong Subaru on Railway Ave are quoting $300 or so?? I'm also pondering a PCV valve change while the goings good. Any advice on whether this would be worthwhile?

[Rosssub]

Give the PCV valve a clean out with carby cleaner. Don't quote me on this part number (might be right), but partsouq.com will be near the cheapest option for an OEM O2:

https://partsouq.com/en/search/search?q=22641AA420

[boknows]

Rosssub,

Thanks for the advice. I'll give the valve a clean this weekend.

With regards to the o2 sensor, any experience with buying parts on Amazon? There are a heap of Bosch/Denso o2's on there for around USD40-80 and their parts calculator shows they fit the Ej25 DOHC engine.

[iphillipnz]

Buy from the site Ross just linked. Decent prices and OEM spec.

Aftermarket and such can be hit and miss on amazon/ebay.

[boknows]

Thanks for the advice, given the number of different makes/models on amazon/ebay that sounds like wise thinking

Any tips coolant to use? Is there an easily available OEM option or are there aftermarket products that can be used?