Leaking fuel filler line

[Stbentoak]

I probably don’t understand how it works, but I only see 2 hose connections… does fluids flow thru the blocks with the studs in them also?

 

[StephenPT]

Yep, the studded ports are for tranny fluid (higher pressure hence the bolted connection) and the beaded pipe connections are for engine coolant.

Here’s a picture of it in action. It’s right above the front diff. driveshaft.

This works in conjunction with a cooler mounted in front of the radiator. In between the two coolers is a thermal bypass valve (second picture) I believe it works such that unless additional cooling is needed, tranny fluid does not flow to the cooler mounted on the radiator.

 

[89Suburban]

Yep, the studded ports are for tranny fluid (higher pressure hence the bolted connection) and the beaded pipe connections are for engine coolant.

Here’s a picture of it in action. It’s right above the front diff. driveshaft.

This works in conjunction with a cooler mounted in front of the radiator. In between the two coolers is a thermal bypass valve (second picture) I believe it works such that unless additional cooling is needed, tranny fluid does not flow to the cooler mounted on the radiator.

View attachment 390076View attachment 390077

Looks like Space Shuttle plumbing Jesus.

 

[Stbentoak]

Excellent, thank you very much @StephenPT for the information !

 

[Stbentoak]

My guess would be that worm clamp has loosened a bit (classic problem with screw drive clamps). Also, I would shift it to the left by about 1/4". Clamps should be installed just after the bead on the tube. It's a bummer that access to the screw is on the wrong side (mine is the same orientation). I would put a box end wrench on it, loosen, turn 180, shift closer to the bead and retighten.

Well sadly, it’s leaking again. Should I…

Take it back?
Try to tighten clamp myself?
Try to put on a new or 2nd clamp?

If I remove this one to replace is there any fear of hose pushing off on its own? Any better clamp to use?

 

[DuraYuk]

Well sadly, it’s leaking again. Should I…

Take it back?
Try to tighten clamp myself?
Try to put on a new or 2nd clamp?

If I remove this one to replace is there any fear of hose pushing off on its own? Any better clamp to use?

Take it back. As long as you have warranty don't get your hands dirty.

 

[StephenPT]

Well sadly, it’s leaking again. Should I…

Take it back?
Try to tighten clamp myself?
Try to put on a new or 2nd clamp?

If I remove this one to replace is there any fear of hose pushing off on its own? Any better clamp to use?

I would just take it back - GM has an issue going on here and needs to see warranty claims coming in for this assembly so they can examine/root cause/fix.

 

[Stbentoak]

I would just take it back - GM has an issue going on here and needs to see warranty claims coming in for this assembly so they can examine/root cause/fix.

Have you seen this before or heard of this problem? They did replace the hose that goes from the filler to the tank but I don’t think they did a great job with clamps. They look like the cheapest hose clamps you could ever use. I’m about ready to buy some t bolt clamps and fix it myself but when I put my hand up on the steel part of the neck where the filler neck goes in, it’s wet with diesel. It could be wicking up there.
but there is a definite drip line from the very top of the assembly, running down the hose and dripping at the bottom, where it is clamped at the bottom. It could be just as simple as better, or new clamps, or it could be that the upper steel assembly where the fuel and DEF go in could be cracked or bad welds or something. I’m supposed to take it for a parts evaluation tomorrow and then if they need to order some thing I can keep driving it until the parts come in.
The dealership said that parts like this are pretty hard to get and could be weeks…

 

[richrice]

Update, had To order a whole new fuel filler neck assembly. Of course, part isn’t available…. they say hopefully less than a week.

What year? I'm having trouble locating a fuel filler neck assembly for my 2000 Tahoe Z-71.

 

[Fless]

What year? I'm having trouble locating a fuel filler neck assembly for my 2000 Tahoe Z-71.

This is the very late model diesel section so none of it applies to yours; post your question in the 2000-2006 forum and be sure to specify which engine is in your Tahoe.