EGR tube / coolant rerout conflict
 

Smog time. Trying to connect the EGR tube. I’m battling interference with the coolant reroute. I think I need to cut the tube and splice in an extension. I’m thinking a piece of high-temp silicone tubing and a couple hose clamps? Any ideas/thought/experience is much appreciated.

Also, in searching this subject, I saw one mention of just putting a valve cover breather on the intake side. I wonder if this will prevent CEL? Anybody know for sure?

I run MS so the EGR valve is dormant and the tube is removed, except during smog checks. Every time I’ve gotten smog checked, EGR functionality is tested; so I have to hook it up.

How do they "test" the EGR?

They actuate the valve with the car running on the dyno and confirm its affect on the emissions values.

Gay

Bringing an old thread back, I too live in a state that tests the EGR status during a smog check. Buried in one of the threads on here was a post about someone using Corrugated Stainless Steel Tubing(CSST) for the egr tube to be able to route it past the thermostat cover on the back of the head.

My attempt at the same idea... I cut the egr tube at both ends and used compression fittings to thread onto the 1/2" egr tube. I painted over the plastic coating with high temp engine paint to try and hide the bright yellowness of it a little bit. I am hoping the plastic covering won't melt under the paint but only one way to find out.

Brasscraft Procoat 1/2" diameter 18" length:
https://www.miataturbo.net/attachmen...ine=1364180045

https://www.miataturbo.net/attachmen...ine=1364180045
https://www.miataturbo.net/attachmen...ine=1364180045
https://www.miataturbo.net/attachmen...ine=1364180045

best way would be to cut and extend the tube with more tubing. have someone welded it. If you can cut it in a straight part of the tube, and get some more tubing that is barely bigger, slip it over the existing tubing, bend to your liking, mark it and have someone weld it, you'll be good to go

"Hope it wont melt" lol you realize its filled with EXHAUST right?

Good point, to avoid flammable melting plastic I had better strip the yellow plastic covering off of the CSST while it's easy to access with the engine off the car. I'll try a wire brush to strip the plastic off, the neighbors probably wouldn't appreciate me burning the plastic off with a torch.

I burned my unsecured coil and injector harness on the EGR tube. Thank you for realizing that plastic won't stand a chance.

The plastic is just a covering over the flexible steel tube under it. It MAY also be there to provide an extra bit of leak protection since the line is designed to be used as natural gas line for gas ranges and dryers in houses.

I'm aware of its construction and it will melt off and/or burn if he runs it like that. A puddle of burning plastic behind the engine is not something anyone really wants.

I am also unsure if removing the plastic coating renders the CSST porous as I don't know how it's constructed underneath. Once i strip the plastic coating off it I may fill the line with water to see if it leaks. If it does leak, I may wrap the line with something that can stand the heat to seal it better. Or as bmxfuel007 suggested I would use the flexible pipe to determine the best angles and bend a piece of 1/2" copper tubing to match the same profile of the flexible tube then weld or compression fit it onto the old egr tube ends.(Best option for an OEM looking install too)

The plastic coating isn't easy to remove, a wire wheel and sandblasting didn't work, but the torch did. It's easy to see by eye that the CSST line is still sealed under the plastic. The fit is very snug, I had to shave down part of the VIN number tab that sticks out on the block inboard of the dipstick to be able to attach the EGR fitting to the log manifold. If I were to do it again I would recommend the 24" long CSST line rather than the 18" line.

https://www.miataturbo.net/attachmen...ine=1364438827
https://www.miataturbo.net/attachmen...ine=1364438827

You might wanna try some exhaust wrap over that tube to protect whatever it may contact. It'll prevent beating itself up and getting a puncture, as well.

I was thinking that too, right now the contact points of the egr tube are the hoseclamp on the thermostat cover and the back of the thermostat cover. I believe when both heater hoses are reconnected to the chassis that the heater hose that contacts now should have daylight between it and the egr tube. I'll also heat wrap further down that heater hose thats got the white tie-wrap on it now.

One more thing...
I know it's your engine, but I would just do away with those crimp connectors if I were you. Just solder and shrink tube them, you'll never have to worry about it later.

Any final results Sclippy? Thinking of doing the same thing, but concerned about leaking from the flexible tubing.. Would soft copper tubing be the better way to go?

Is there any reason you routed above the BEGI thermostat housing instead of under it? It may just be the picture, but it looks like it's already oriented down and may fit better.

i would never solder in the engine bay. the solder will get heat cycle and eventually crack. i always use non insulated crimp connectors(easier to see what you are crimping) and then shrink tube them. takes up less space and looks much better.

Egr is a visual test. Just go to a shop that is less ----. I had a car that cracked its exhaust manifold and I had to swap with a non egr one. Car blew clean and passed smog.