Damp area around fuel pump - advice

Need technical Q/A then you're in the right place

Moderator: martauto

Post Reply
wilma84
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Tue Oct 19, 2021 1:21 pm

Tue May 10, 2022 4:03 pm

So I was taking a look at my fuel pump the other day as I noticed it was starting to whine a bit - when I removed the inspection cover I noticed what looked like a bit of a damp patch around it. See image below.

To me it looks like the fuel pump o ring may have perished, however would fuel actually be able to leak out the top like this?

And, considering it has started whining, would it make sense to replace the pump and o ring all at the same time? Any advice much appreciated as always!
20220508_163624.jpg
wilma84
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Tue Oct 19, 2021 1:21 pm

Thu May 12, 2022 3:19 pm

Just giving this post a liiittle bump as I'm planning a road trip to France in 6 weeks and want to work out if I should bother replacing my fuel pump... or just the o ring before I go?!

Anyone have any thoughts? The whine from the pump is quiet, only very noticeable when I remove the rear seat... and I've cleaned the whole area to see if the damp/wet patch comes back or not
Cloggy Saint
Old Skooler
Old Skooler
Posts: 8024
Joined: Sun Jan 09, 2005 11:00 pm
Location: zummerzet

Thu May 12, 2022 3:42 pm

Are you sure the whining isn't just normal operating noise? If I were you I'd buy a replacement pump and keep it handy for when/if the current pump dies. You may as well replace the rubber seal as a preventative measure, they probably don't cost much and it's an easy job.
Image

E30 zone - promoting adult illiteracy since 2004
User avatar
TriggerFish
E30 Zone Regular
E30 Zone Regular
Posts: 507
Joined: Sat Jun 30, 2012 11:00 pm
Location: Aylesbury, Bucks

Thu May 12, 2022 4:17 pm

The end of the large breather hose (the largest one, on the top left of the photo) looks a bit darker to me than the upper parts of that hose. Is that hose itself wet? I had an issue with that hose (since replaced, and the problem went) where it was fine with a low-fuel tank, but if I filled it up too high, it would slosh out of that pipe under cornering, wetting the top of the tank. As yours looks dark/wet, it hasn't started to perish, has it? (Mine was really brittle when I removed it...)

The stain is also more concentrated in that area too, rather than evenly around the fuel pump.
User avatar
paultv
E30 Zone Squatter
E30 Zone Squatter
Posts: 1541
Joined: Mon Apr 21, 2014 11:00 pm
Location: Auf dem Schnee: Germany

Thu May 12, 2022 7:52 pm

+1 for checking the breather...often perished underneath against the tank...just where you can't see it. If its split...cut a bit off and re attach...only if the rest of the tube feels ok, replacing this pipe can be a right pig to get it out of the feed through which is filled with putty...30 years old and hard as hell !!

Paul :-)
4th May 1990 325i Convertible.

BMW E30 Cabriolet Best Mod Ever:

https://bmwe30cabriolet-wdm.blogspot.com/
User avatar
Doobit
E30 Zone Newbie
E30 Zone Newbie
Posts: 146
Joined: Tue Apr 05, 2016 11:00 pm
Location: West Sussex

Mon May 16, 2022 10:02 am

I had similar darker pattern around the breather hose and a fuel smell outside the car. Decided to change the hoses and replace fuel filter first and that fixed the problem. I’ve left the hoses around the fuel pump alone.
E30 325i Cabriolet Alpinweiß chromie
F12 640d
G11 730d
wilma84
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Tue Oct 19, 2021 1:21 pm

Fri May 20, 2022 3:52 pm

Cloggy Saint wrote:
Thu May 12, 2022 3:42 pm
Are you sure the whining isn't just normal operating noise? If I were you I'd buy a replacement pump and keep it handy for when/if the current pump dies. You may as well replace the rubber seal as a preventative measure, they probably don't cost much and it's an easy job.
Yeah it could be normal operating noise as I can only really hear it when the rear seat is out... I thought I could hear it from outside of the car however I think that could just be something vibrating around the exhaust

Have ordered a new rubber seal and will replace that as soon as it arrives
wilma84
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Tue Oct 19, 2021 1:21 pm

Fri May 20, 2022 3:53 pm

paultv wrote:
Thu May 12, 2022 7:52 pm
+1 for checking the breather...often perished underneath against the tank...just where you can't see it. If its split...cut a bit off and re attach...only if the rest of the tube feels ok, replacing this pipe can be a right pig to get it out of the feed through which is filled with putty...30 years old and hard as hell !!

Paul :-)
Thanks for the advice... will check this when I also replace the rubber seal! Cheers
Post Reply