90 Fuel Heater leaking?

[BarlowCummins]

My friend and I changed his fuel filter on his 90 Cummins and I think fuel ia weeping from the top of the filter but I think that it may be coming from above the top of the filter. From what I have read is that it may be from the fuel heater gasket maybe? I was wonder if anyone has pictures of the fuel heater and/or instructions how to find out how to check that gasket. I am just really unsure how to change that gasket. I can't find any pictures or a schematics of the heater. Any help would be appreciated.



Corey

 

[Greenleaf]

The pipe nipple which the filter threads onto has a shoulder. That shoulder holds the heater in place. Unthread the pipe nipple and change out the O ring (quad ring) A small drag link end is used to turn the pipe as it has a large screwdriver slot in the end.



You can also delete the heater by way of a different pipe niple. I have part numbers for the items if interested.

 

[BarlowCummins]

Thanks for the reply. I will try to change out that o-ring. Is that a cummins part? I called my local cummins shop and they had no idea what a quad ring was. Do you know where I can get one?

 

[JLEONARD]

 they had no idea what a quad ring was

AKA "square" O ring. They might know it as that name.

It is a square or rectangular cross section as opposed to an o ring which has a round cross section.



If you were looking one up in McMaster Carr for example, they are called square o rings.

 

[Greenleaf]

Part number is 3834185-s

Fleetguard part

 

[SZwemer]

Do not mean to hijack this thread, but thanks for this info.



I have spent hours and 3 new fuel filters trying to figure out where my fuel leak is coming from... . (thought I had a bad fuel filter)... . ,



But now I think it is my fuel heater O ring too... ...



I have a 91 with 300,000 + miles on it... . guess O rings do not last forever.



Wish the Cummins parts man would have known about this O ring... ... It could have saved me a lot of time and $$ so far.



I wonder if NAPA would have O ring like I need ?? Cummins is not open on SAT.



Hate to wait until Monday to get the part.

 

[JLEONARD]

If you have the old one take it there and match it up.

If they have a square o ring assortment you'll find one that fits.

 

[SZwemer]

If you have the old one take it there and match it up.

If they have a square o ring assortment you'll find one that fits.

Thanks for the idea... ... I just called my local NAPA guys and they said they do not have any square O rings..... SDF on that... ... but thanks. !!!



I am soaking the O ring in lacquer thinner to see if it will soften and swell the O ring so it will work for a few days until I can get the right O ring from Cummins.



I think I will try to deleate the heater if I can find the right threaded fitting.

It is 2 different sizes, ( it is necked down on the end that fits up in the housing or boss... . what ever they call the flanged thingy for the filter) so I can't go to LOWES or Home Depot and get a piece of pipe thread to run up in there and just run the Fleetguard filter alone...

 

[SZwemer]

Well here is the latest update on the O ring situation.



I was able to take an old O ring from a fuel filter and get it to seat down into the heater housing enough to use it as an O ring in the fuel heater groove. It was wider and taller, but it did fit and did not crush over when I tightened it up with the pipe fitting !!!!!!!!!!!!!!!!



The lacquer thinner did not work as intended on the original O ring... ... . it did not swell as anticipated, it made the diameter increase way too much to the point that it would not fit in the groove anymore #@$%!!!!! the fuel filter O ring fit well, just a bit taller than the heater filter O ring. Call it luck , or call it an alternative to the original fuel heater O ring.

Nice to get lucky once in a while... ... . I have driven it for over an hour now w/o and leaks, drips, or runs !!!!!!! Hope it continues to work until I can get the OEM O ring.

NAPA, ADVANCE, Auto Zone, and everyone else in the phone book did not even carry a square O rings anyway !!!!! thanks

 

[JLEONARD]

You can get square o rings from McMaster-Carr online. Their standard shipping is overnight. You'll just have to know the dimensions and find the right one.

And you may have to buy more than one but it still might be cheaper than a Cummins part.

 

[SZwemer]

You can get square o rings from McMaster-Carr online. Their standard shipping is overnight. You'll just have to know the dimensions and find the right one.

And you may have to buy more than one but it still might be cheaper than a Cummins part.

Thanks, I'll check it out.



The fuel heater O ring is still holding tight. ... . for now!!

 

[JLEONARD]

If you buy from McMaster you want Buna for a material.

Or Viton.

They are both A rated for diesel fuel.



Not EPDM

 

[SZwemer]

If you buy from McMaster you want Buna for a material.

Or Viton.

They are both A rated for diesel fuel.



Not EPDM

Good info..... thanks.