So I replaced the fuel filter on my '99 yesterday with a Purolater F55493. Seemed a good thing as a load of dirty residue came pouring out - the original had been on there for the 75,000 miles racked up.

Now when I switch the ignition on I get a loud humming / whine noise where I guess the pump primes or builds up pressure. This stops after about 2 seconds. Then I start and the noise begins again. It doesnt change with revs and the car runs as normal at any speed.

This is not just the normal hum of the pump, I know I had that before but it was barely noticeable.

I dont understand how changing the filter has caused this really loud whine. Could a faulty filter cause it?

I read there is a pressure regulator in some filters, could that be it?

Any help appreciated

 

The filter may have been partially clogged, like an artery. When you changed it, it now flows more and the pump possible is now running faster because of the greater flow capacity. Take the car for a spirited ride and see if you have any drive ability problem..........

 

Thanks for the idea. I had considered that and took it for a very 'sprited run'. It was only at WOT that the engine noise was louder than this damn awful whine. There is no affect on performance what so ever so fuel is obviously getting through in the right amounts.

I am concerned that the Purolater filter was $40 and the GM / AC Delco is nearer $75.

 

The regulator is built into the filter on 99's. Sounds like that may be your problem, maybe you got a bad one. Does the Purolator look like the one you took off? Since that is what you changed when the problem began thats where i would look.

 

Good point. I have asked Purolater for their opinion, and particularly whether their filter has a regulator.

I didnt realsie but they must be part of Bosch as the helpline e-mail ends with a Bosch address.

 

Just some info............... In the latest Vette magazine a reader posted that his fuel pump seems to make a lot of noise. The reply was that on the early C5s the main fuel pump that is located behind the drivers seat will emit an annoying humming noise and that is the nature of the beast.
It was suggested that there can be brought a quieter aftermarket pump or look up the GM TSB on it. The TSB is info on how to further insulate the pump to cut down on the noise. If this is your problem, then it is normal.................................. ...

 

I just dropped mine off at the garage for a little post-winter work. One of the things that I asked to be done was to change the fuel filter as I do not know if it was ever done and the car has over 75K on it. Now I am worried...

 

I would lean toward the fact that you didn't replace with an OEM (ACDelco) filter. When you switch brands the specs might not be exactly the same as the OEM. That can make a difference.

 

Yes, I have heard that before - and there is no doubt there was a small hum before change, but it is so different now.

The price difference does worry me, as it might affect the specs.

I would'nt worry, you and I are not the first and others report no probs, it may jyst be the Purolater brand, or even a dud one-off. If its like mine the crud that came out makes you realise even 'good' quality fuel is not 100% pure.

 

Hopefully this is not the case with yours!!! NOt jinxing you, but as a mechanic, in my past experiences with electric fuel pumps in general lead me to believe that after a pump has pumped so long against a clogged filter, when introduced to the new filter it pumps so freely again it burns up. 8 out of 10 vehicles I work on with a clogged filter come back a month or so later with a burnt pump. I literally check every filter I pull off by blowing into the "in" side of the filter to see how hard it is to blow through. If it's bulging my cheeks and can barely blow through , I warn the customer of future potential pump failure.
I see it as somone above kinda mentioned. If you have a clogged artery, and remove the clog, the heart (pump) can flow so easily it doesn't have to work near as hard. But after years of pumping blood against a clot and finally being able to pump easily causes other heart issues in many cases. Blowing into a straw with a finger over the opposite end, you are trying hard to push, then you let the finger off and can breath easily. Not sure if I can explain it right but after the pump has fought a long time against blockage, the amps it took to pump through the clog were raised, after the new filter the amp draw goes back to normal , but the pump can't take it being used to running against the back pressure.

 

Andrew,
Another thought. If the OEM filter was as dirty as you say it was it may be a good idea to run a couple of tankfuls thru the purolator filter and then replace with the OEM ACDelco filter.

 

Service Tech. at my dealership said the filter is in the tank with the pump / pick-up assembly and no need to change it unless I have experienced trouble.
My 2001 has travelled 60,000 miles with no issues so I do not plan to touch the filter.

Is that true ? Is the filter in the tank?? Appreciate opinions. Thanks

 

On a 2001? I think you should find a new dealership.....

 

Gosh I hope not, but 8 out of 10 is not good odds...

A good suggestion, thanks. Am thinking the easiest option is to first replace the filter again, with an OEM. An earlier comment that 'if it was fine before' kind of points to the filter. No reply yet from Purolator.