1998 7.4 Vortec EGR tube replacement/repair

[MarkC73]

Hello all,
First time member looking for a lead or some advice here.
I have a motorhome that has a 98 vortec 454 and I need advice on repairing a EGR tube from the the drivers manifold to the EGR. The tube has been twisted and now has a good sized hole blown through it. I cut the section out and tried a high temp silicone replacement tube, but it lasted about 20 mins before it blew out as well. My assumption is my EGR valve is bad, so I will replace it; but I need ideas on the best way to repair the tube properly (to handle the heat and pressure) or if someone knows where a good replacement maybe be that I could purchase, that would be awesome.
Thank you in advance for the help.

 

[stutaeng]

Welcome aboard!

Does your EGR tube bolt to the manifold? If so, you should be able to bolt a new one. It has very hot gases because that's the way it works. If you don't have any SES codes, it's likely working fine. You can remove the valve to inspect it and clean it, but that's probably all you need to do. BTW, those little EGR valves are spendy at the local parts store, well over $100.

Here's an article on checking them with a digital DVMO meter:

https://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/egr-valve-tests-1

They are the same as your 7.4.

Good luck!

 

[MarkC73]

Welcome aboard!

Does your EGR tube bolt to the manifold? If so, you should be able to bolt a new one. It has very hot gases because that's the way it works. If you don't have any SES codes, it's likely working fine. You can remove the valve to inspect it and clean it, but that's probably all you need to do. BTW, those little EGR valves are spendy at the local parts store, well over $100.

Here's an article on checking them with a digital DVMO meter:

https://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/egr-valve-tests-1

They are the same as your 7.4.

Good luck!

I appreciate the information. The tube itself has what appears to be flare or JIC fittings on the manifold and EGR.
Removing the old one isn’t the problem, it’s finding a way to repair the hole/ missing section or find a complete replacement tube.

 

[stutaeng]

I appreciate the information. The tube itself has what appears to be flare or JIC fittings on the manifold and EGR.
Removing the old one isn’t the problem, it’s finding a way to repair the hole/ missing section or find a complete replacement tube.

Um, Rockauto does not list the tube. Is it like this one:
https://www.autozone.com/engine-management/egr-line-tube/dorman-egr-line-tube-598-200/964216_0_0

 

[454cid]

The tubes are NLA from GM, and Dorman doesn't offer one last I knew. People ask insane amounts for them on ebay or ruin them when they part out a truck. It would be nice to figure out if some standard industrial fittings/tube would work.

 

[MarkC73]

Um, Rockauto does not list the tube. Is it like this one:
https://www.autozone.com/engine-management/egr-line-tube/dorman-egr-line-tube-598-200/964216_0_0

No, the one you found is for the small block Vortec engines.

 

[MarkC73]

The tubes are NLA from GM, and Dorman doesn't offer one last I knew. People ask insane amounts for them on ebay or ruin them when they part out a truck. It would be nice to figure out if some standard industrial fittings/tube would work.

Yes, I did get that response from GM, and I agree, thus far find a used one has been virtually impossible for a “reasonable” price or that is useable.
I think I am going to have to hunt for some materials and see if repair/ rebuilding may be possible.

 

[df2x4]

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

 

[Schurkey]

At least if you live in an area where that sort of thing is legal/acceptable

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.

 

[Carlaisle]

If compression fittings could be sourced with the appropriate thread/fitting on each end it would be fairly easy to fabricate a replacement from copper or stainless tube.