Engine Knock

someguy · Post by **someguy** » Fri Mar 26, 2010 6:40 pm

Hi all

Over the past 4-5 months my ea82 has developed a bit of a knock on cold and warm starts.

It seems to be coming from the rear of the engine. (maybe clutch/pressure plate?) but I could be wrong or maybe piston slap?

Its not the lifters as they make a tick noise (this is more of a knock)

It only happens when I start the engine....once I have driven about 500m it dissapears but its just an annoying noise and I am concerned that it could lead to damage in the future.

Thanks

drof351 · Post by **drof351** » Fri Mar 26, 2010 8:43 pm

Gday, Have you got access to an oil pressure gauge? Check to see if your getting good oil pressure on start up?

someguy · Post by **someguy** » Fri Mar 26, 2010 8:48 pm

drof351 wrote:Gday, Have you got access to an oil pressure gauge? Check to see if your getting good oil pressure on start up?

Unfortunately I don't I only have a tacho and vacuum gauge

And most of the local parts stores want around $80 for an oil pressure gauge which I can't really afford at this moment as I just spent $70 on the tacho

drof351 · Post by **drof351** » Fri Mar 26, 2010 8:50 pm

Does your oil light go out straight away?

someguy · Post by **someguy** » Fri Mar 26, 2010 8:54 pm

drof351 wrote:Does your oil light go out straight away?

Yep it does

YouTube · Post by **El_Freddo** » Sat Mar 27, 2010 12:12 am

The oil light won't mean much if no oil is getting to the big end bearings. A knock on a cold start initially isn't anything to be worried about, but if it takes a 500m drive to get rid of it I'd be looking at putting an oil cleaner/flush through the motor. You might have to do it a couple of times to get rid of any build up in the oil galleries.

What sort of history does this motor have in terms of oil changes and the time/distance travelled between these changes? This could point to a few clues. And what sort of oil do you use in your motor?

Cheers

Bennie

someguy · Post by **someguy** » Sat Mar 27, 2010 10:14 am

El_Freddo wrote:The oil light won't mean much if no oil is getting to the big end bearings. A knock on a cold start initially isn't anything to be worried about, but if it takes a 500m drive to get rid of it I'd be looking at putting an oil cleaner/flush through the motor. You might have to do it a couple of times to get rid of any build up in the oil galleries.

What sort of history does this motor have in terms of oil changes and the time/distance travelled between these changes? This could point to a few clues. And what sort of oil do you use in your motor?

Cheers

Bennie

Thanks bennie very insightful as usual :P

I knew the previous owner quite well when I bought the car.

The engine had been rebuilt only 120,000km ago and had always been driven granny style (never exceeded 3000 rpm etc).

She always serviced it every 5000km and had it regularly maintained.

I now service it every 5000k and use Valvoline XLD 20w50 as thats the oil that keeps the lifters quiet.

Im not really bothered by the noise that much just aslong as its not doing damage.

drof351 · Post by **drof351** » Sat Mar 27, 2010 7:20 pm

But the oil light will tell you basics without a gauge. Like if the pick up is blocked, or no oil at all, or oil pump not working, or oil pressure switch not working. Just thought it was a logical place to start.

RSR 555 · Post by **RSR 555** » Sat Mar 27, 2010 9:45 pm

It does sound like oil pressure especially it the EA82 is "ticking" when you use thinner oil. I'd see if you have a friend or know a mechanic with a oil pressure gauge and have it checked out. I'd look into rebuilding the oil pump first, if the pressure turns out to be low.

someguy · Post by **someguy** » Sat Mar 27, 2010 10:20 pm

RSR 555 wrote:It does sound like oil pressure especially it the EA82 is "ticking" when you use thinner oil. I'd see if you have a friend or know a mechanic with a oil pressure gauge and have it checked out. I'd look into rebuilding the oil pump first, if the pressure turns out to be low.

Thanks, I might see if any of my mates have one.

If not I might just go to the wreckers and try and pick up another oil pump cheap and see if it makes any difference

YouTube · Post by **El_Freddo** » Sun Mar 28, 2010 12:07 am

Don't worry about getting another oil pump "cheap". Go to your subi dealer or parts joint and get a new rotor and shaft set with new seals and install that. It is just as much work as installing a second hand oil pump. The new rotor and shaft combo will be an as new oil pump but saves you money on buying a new housing which really doesn't wear out, and any wear that has occured is minimal and not worth worring about.

A second hand oil pump could be in the same (or worse) condition than your current oil pump.

It could also be that the oil pick up line is partially blocked, or your oil pump is sucking air through the shaft seal on the oil pump until you get down the road for a bit...

Cheers

Bennie

tony · Post by **tony** » Sun Mar 28, 2010 12:07 am

you can buy a used oil pressure gauge cheap, one of those that you install permanently in the car. get them at most wreckers. there is not much to go wrong with them so will most likely work. no need for an expensive mechanics one. or buy a new one at supercheap or wherever for about $30.

RSR 555 · Post by **RSR 555** » Sun Mar 28, 2010 10:13 am

Yeah.. I'd buy a secondhand oil pump from the wreckers, so you can rebuild it and still drive around in your car in the meantime.

someguy · Post by **someguy** » Sun Mar 28, 2010 11:26 am

RSR 555 wrote:Yeah.. I'd buy a secondhand oil pump from the wreckers, so you can rebuild it and still drive around in your car in the meantime.

Yeah, I would get my mechanic to do the job anyway (they don't charge me labour) as its my only car and I don't have the time to do it myself so I will just leave it with them and take their loan car.

Its only around $25-30 for an oil pump from the wreckers here but its a big job to get it out so next time I have a spare day or so I will go up there and pull one out

But my question is, is this doing my engine any damage or is it just an annoyance?

drof351 · Post by **drof351** » Sun Mar 28, 2010 12:34 pm

Until you know what it is you don't know what is happening and if its causing damage. Generally a knock means somethings loose or clearances are to big etc, its certainly not going to get better. Might just end up having your alternator fall off from a broken bolt or you may end up throwing a leg out on your next 4wd trip.

someguy · Post by **someguy** » Sun Mar 28, 2010 12:54 pm

drof351 wrote:Until you know what it is you don't know what is happening and if its causing damage. Generally a knock means somethings loose or clearances are to big etc, its certainly not going to get better. Might just end up having your alternator fall off from a broken bolt or you may end up throwing a leg out on your next 4wd trip.

Haha fair enough.

I meant to say if it is a pressure problem, will continuing to run it like this cause damage or should I look into getting the pump done asap

drof351 · Post by **drof351** » Sun Mar 28, 2010 1:01 pm

If it's pressure problem you're better off fixing it asap. But maybe try a little more diagnosis work first.

NightHawk · Post by **NightHawk** » Sun Apr 04, 2010 2:14 pm

I recognize the description and this noise used to happen to mine once in a while
in the start, but it hasn't for a long time now. it may be because of worn or loose
timing belt skipping a beat or the gearbox is not greased enough, in my experience
i can't think of another reason. I recently moved the engine and gearbox to another
shell so the gear oil was replaced and recently one timing belt broke so i replaced
them. Since then no knock noise in the start... actually surprisingly efficient.

tony · Post by **tony** » Sun Apr 04, 2010 6:43 pm

If it is a light tapping noise as you cruise along it is most likely big ends, if it is a thumping noise as you accelerate under load it is most likely mains.
Drive at about 50kph up a medium hill and acclerate hard, apart from the pinging if the noise is the heavy thump the mains are pretty bad.
An oil pressure gauge is unlikely to pick up one bearing on the way out, it will mainly just show low oil pressure from a number of bearings being worn.
chang the oil pump and while you have it all apart it is worth while doing the timing belts so you know you have another 80,000k wiht no surprises, if the thump is still there the mains will have to be looked at. Of course it could be thrust bearings, which can be tested with the sump off by levering the crank forward and backwards, and I think the mains can be done with the engine in, drop the sump and swap the bearings, do the big ends as well, if the mains have gone the big ends are sure to be gone. A loose main will give you fair warning and won't generally go suddenly but a big end will destroy your engine as quick as flash when it lets loose through the side of the block.

drof351 · Post by **drof351** » Mon Apr 05, 2010 1:08 am

tony wrote:If it is a light tapping noise as you cruise along it is most likely big ends, if it is a thumping noise as you accelerate under load it is most likely mains.
Drive at about 50kph up a medium hill and acclerate hard, apart from the pinging if the noise is the heavy thump the mains are pretty bad.
An oil pressure gauge is unlikely to pick up one bearing on the way out, it will mainly just show low oil pressure from a number of bearings being worn.
chang the oil pump and while you have it all apart it is worth while doing the timing belts so you know you have another 80,000k wiht no surprises, if the thump is still there the mains will have to be looked at. Of course it could be thrust bearings, which can be tested with the sump off by levering the crank forward and backwards, and I think the mains can be done with the engine in, drop the sump and swap the bearings, do the big ends as well, if the mains have gone the big ends are sure to be gone. A loose main will give you fair warning and won't generally go suddenly but a big end will destroy your engine as quick as flash when it lets loose through the side of the block.

Have you worked on a subaru before? We know an oil pressure gauge won't show individual bearing failure, but if you have oil pressure and its still knocking its not going to be an easy fix and no point putting a pump and t belts on etc. And as far as dropping the sump and replacing the mains and big ends?