Did it!! Changed Fuel Filter

[bobboyer5]

Guys & Gals:

Updating my longstanding (3-4 month) hesitation illness on my 77 450 SEL (Euro) with 64K on clock. Won't bother you with earlier details...

I didn't want to mess with the old fuel filter housing and hoses myself, so I brought it to a tech. After the first error (fuel filter on euro is different size than on US spec car), and after they broke the outward flowing hose attachment and had to get new one, I got car back. Guy warned me that it was still driving poorly - but said that it could have been from laying around in shop for a few days.
Anyway....took car home gingerly, and hesitated at first. Then it started clearing up. I think (my theory) that the weak fuel flow from filter had accentuated dirt clogs in forward areas and injectors, but once flow got better, it cleaned out progressively. I'm not flooring it hard yet (too scared), but over last 10 days, have gotten bolder. Results?

Hesitation gone on acceleration. Engine quieter and smoother. And gas mileage seems 3-4 mpg better....more like 16-17 combined city/highway. Feels like it once did - maybe even better.

Guy showed me old filter. Was completely blocked, heavy, and was oozing dirty fluid. Barely. He said it might NEVER have been changed!!

Like I said, I haven't gotten the courage yet to really floor it, but it's much, much, much better.

Could the fuel filter have really affected my car that much?????

[bill4247]

Absolutely! BTW, when I changed the fuel filter on my 4.5 I noticed that it was longer than the old one. Is this the difference between the USA spec and Europe spec? Is that a problem? The car seems to run fine but it's just something I wondered about.

[jim16671836]

A bad or clogged fuel filter can really shorten the life of most electric fuel pumps..

[bobboyer5]

Bill:

Yes.....US-spec filter is longer than euro-spec, for some reason. Found this out 2 weeks ago at the shop, when they ordered the US filter first. They said it was too long (right?), and didn't fit. So they got the right Bosch filter-euro.

As to performance differences between the two, my gut tells me there isn't any. But the one person who can probably tell you definitively is Steve Brotherton. Access him on the Tech Help forum, and - out of pure curiousity - let me know.

Like I said, seems my filter had NEVER been changed. I got car a year ago from the original owner. He did his maintenance, but didn't drive car much. And his mechanic never changed filter. Since it's not an easy task, I kind of believe that.

I'm not flooring or gunning car yet. But peformance is much improved.

Bob