Mk1 Caddy fuel strainer issue

[veeman]

Just thought I'd post this one for anyone that might need it in the future...

With the cold weather recently, I kept having what I thought were gelling issues (using normal petro diesel and sometimes additive) in my caddy TD.  It hasn't been_that_cold lately, but I figured that it might be possible...

The engine would start to stumble above 2k rpm and acted like the fuel filter was plugged.  I assumed it was wax or something dropping out of the fuel.  I tried changing the fuel filter and the stumble didn't get better...  

I started looking around and found out that some (all?) of the mk1's had a strainer in the fuel tank right by the fuel pick up assembly.   I confirmed the suspicion in Etka and last night I dropped the tank in the caddy.  I went to drain the remaining fuel and when I pulled the main fuel supply hose off the tank, fuel only "dribbled" out.    A-ha!

Dropping the tank is relatively easy to do...hose connections, level sender plug and the two straps.  Unfortunately, the bolts on the straps were super rusty and I managed to break one of them off.   Grrrrr... (a friend helped me weld on another stud).


Anyway, I took out the fuel level sender and found this bad boy hiding in the bottom of the tank:



Pic of the tank with the sender out and all messy from trying to drain excess fuel:



I pulled it out with some really long needle-nose pliers and inspected it.  The material is actually a very fine metal mesh and it had become clogged.  I sprayed it out with brake clean and compressed air, cleaned the tank out one last time and reinstalled it.  The tank itself was_incredibly_clean.  The metal inside looked brand new.  I couldn't believe it since this vehicle had been sitting in a barn for 5 years... no sediment, rust flakes or debris.  

Put it all back together and everything's fine again!  Seems like it runs better at idle and has less bubbles in the clear fuel line (could be from the brand new filter as well though).

Anyone else had this problem?  Would it have been better to remove the screen altogether?  I see that you can still possibly buy those strainers new, but that didn't seem necessary after cleaning it thoroughly...

[hipifreq]

Thanks for posting the pics!

How was the screen attached inside the tank? I've been thinking of dropping my tank sometime soon to get at that screen, and would appreciate pointers on removal/installation. Could I use a coathanger to grab it by the hook on top? Does it screw in?

[veeman]

How was the screen attached inside the tank? I've been thinking of dropping my tank sometime soon to get at that screen,

There's an inner fuel pickup "well" made of plastic that sits in the bottom of the tank.  The upper part of it has four baffles and each one has a groove in it.   The strainer simply slides straight down into it.   I think you can see the four edges on the strainer in the pic.  

I tried to take a pic of that assembly, but it's hard to get the flash to work inside the tank and have everything in focus.  I'll see what those pics look like for you...

You could pull it out with a hook or a coat hanger, but to re-install it you'll need something like a long pliers to push it back down in place.

It's pretty easy (on a caddy at least) to pull the tank, however it took me a second to figure out how to pull the level sender.  It's "keyed" into the slots in the opening and you have to take a chisel / screwdriver and knock it open (counterclockwise).

[veeman]

Ok... How's this?



That vapor in there is from us blowing air in through the tank outlets to see if there was any blockage...and yes, that's ULSD.  Looks like antifreeze, smells not quite like diesel and as I found out last night, tastes nothing like Mello Yello (entirely accidental sampling).

[jtanguay]

hehehe... i had a sample of ULSD to inspect it... i put it into an open can and it smelt a bit like rotten eggs... so much for ultra low sulphur???  :lol:

this is great information... i will be sure to attempt cleaning that filter screen this summer

[hipifreq]

SWEET! Added this post to my "Bookmarks of extreme diesel usefullness"

[myke_w]

Back in the 80's (according to my old VW dealer mechanic buddy) there was actually a TSB that recommended getting rid of the strainers in mk1 cars all together because of their propensity to clog when dirt and guck adheres to the fine mesh and block flow..