1998 7.4 Vortec EGR tube replacement/repair

[MarkC73]

Does your RV use the same black box PCM that our trucks use? If so you could delete the EGR and have the PCM tuned accordingly. At least if you live in an area where that sort of thing is legal/acceptable

I thought about that, but around here it would honestly be cheaper to “fab” something than have the reprogramming done I believe

 

[MarkC73]

It's legal NOWHERE in the USA. Some jurisdictions don't inspect for it, though.





If this were me, and I was desperate, I'd bend and flare some aluminum or steel tubing to fit between exhaust manifold fitting and intake manifold fitting.

It'd be best if there was some extra material (length) to accommodate expansion/contraction.

Of course, the best system would involve the sort of flexy-tubing used by GM. Good luck finding that.

I agree fanning is seemingly going to be my only option, and finding a suitable material is going to be the next challenge

 

[MarkC73]

I agree fanning is seemingly going to be my only option, and finding a suitable material is going to be the next challenge

Fabbing that is... stupid autocorrect

 

[vr1967]

Give me a few days to dig, but I believe I still have a good one from the 7.4 I sold.

 

[MarkC73]

Give me a few days to dig, but I believe I still have a good one from the 7.4 I sold.

Thank you for looking, I would appreciate it. Just let me know

 

[df2x4]

If you haven't already, you might try looking for 7.4L trucks on https://www.car-part.com/. They index the inventory of salvage yards all across the country. There might be a truck in a yard nearby you could scavenge an EGR tube from.

 

[Crazydavez28]

Good luck finding a tube. Fittings are -14 JIC.

A feller might try cannibalizing a 5.7 hose or a stainless steel MagnaFlex Pipe and weld the ends to some female swivel fittings.

 

[MarkC73]

If you haven't already, you might try looking for 7.4L trucks on https://www.car-part.com/. They index the inventory of salvage yards all across the country. There might be a truck in a yard nearby you could scavenge an EGR tube from.

Did find two options on that site, but nothing within driving distance. But I did send emails to both yards inquiring if the tube was available.

 

[stutaeng]

What is the actual tube made of? Aluminum?

If you can't find a replacement, I'd be inclined to fab something up. Maybe some of that refrigerant "soft" copper and/or that corrugated copper line used for water heaters: https://www.homedepot.com/p/3-4-in-...er-Heater-Connector-7211-24-34FIP-S/202692481

I don't know if the plumbing solder will hold up to exhaust gases, so maybe look into getting it brazed or TIG welded. As as long as the fitting are somewhat close, the welding/brazing filler will fill the gap.

I still can't believe replacements are not available. I would think there's a lot of 7.4s on the road still. On the other hand, it's be discontinued for like 20 years.

Or delete it!

 

[andy396]

The corrugated tubing itself is made of very thin wall stainless steel. I blew a hole in mine when I was heating it with a torch to remove it. I just welded the hole back up before I reinstalled it. Can you take a picture of what degree of mangled-ness you’re working with on yours? Some more repair ideas might be discovered if we can see it.