EGR cooler: sealant or no?

[CruiserTrash]

Did some searching and can’t find an answer. Because I’m both pedantic and overly thorough, I removed my entire EGR system, disassembled it, cleaned it piece by piece. Yes, I live in a smog test locale.

So now that I’m on reassembly, I have a [relatively] clean EGR cooler in two halves and I’m wondering if I ought to use some extremely high temp sealant when bolting the two back together.

I’ve taken apart three EGR coolers and have never seen evidence of sealant from Mr T. However, this thing will obviously have exhaust gas at some pressure in it so I would assume it leaks without sealant. Maybe Mr T didn’t care about that. The 2F exhaust and EGR systems seam to have enough leaks at 35+ years old, so I’m trying not to shoot myself in the foot and introduce yet another small leak.

What do y’all say? Sealant or no?

 

[Spike Strip]

I'm not sure I'd use sealant there (I didn't). I'd be afraid the stuff would eventually burn out and then have leaks... I just made sure the surfaces were perfectly flat by rubbing back and forth on some fine sandpaper taped to a level table top, and then bolted it up.

 

[OSS]

If the EGR system is functional and working correctly, the only time that the EGR intake plumbing (J-pipe, cooler and valve) is under significant pressure is when driving away in the morning when the engine is still cold and it hasn’t warmed up enough to open the EGR BVSV.

At idle, the EGR valve is always closed of course, but exhaust pressure is low at idle too, so the EGR cooler won’t be under much pressure. And when the engine is warm and EGR is open while driving around, there’s virtually no exhaust pressure in the EGR system since it’s getting sucked into the engine.

Bottom Line:
I’d follow @Spike Strip ’s advice

 

[CruiserTrash]

Well, the experts have spoken. My inclination was to bolt it up dry since the mating surfaces look really good, perfect really. That’s how Mr T did it and I assume it worked fine when new.

@Spike Strip I hear you on putting sealant in, the sealant burning up, and there being a gap left behind (even if really small).

FYI @OSS this is a different cooler than the one I posted a few weeks ago. MUCH cleaner. Half of the ribs inside the one I previously posted were rotted away - about 3/16” of metal just gone in a lot of spots. Certainly it’s a relatively non-critical part, but that didn’t bode well for future long term use.

 

[Spike Strip]

It's just a radiator for EGR hot gas so paint it flat black with some BBQ paint or other high-temp stuff for best heat dissipation.

Amazon product ASIN B003CT4AKC

 

[CruiserTrash]

It's just a radiator for EGR hot gas so paint it flat black with some BBQ paint or other high-temp stuff for best heat dissipation.

Amazon product ASIN B003CT4AKC

I got some of that VHT “flame proof” spray paint at the shop that supposedly handles 2000*F. I was gonna blast it with that before install.

 

[Spike Strip]

That should do it. Any left over, touch up the BBQ

 

[OSS]

this is a different cooler than the one I posted a few weeks ago

My suspicion is that those who disable the EGR valve ultimately ruin the cooler because it then never heats up to burn off moisture and is basically a sump in the morning as water dribbles down the J-Pipe into it as the engine is warming up.

I’ll betcha that the egr coolers on 30 year old cruisers that have a functional EGR system look pretty good inside while the coolers that are part of a disabled system are totally rotten rust bombs inside.

 

[CruiserTrash]

My suspicion is that those who disable the EGR valve ultimately ruin the cooler because it then never heats up to burn off moisture and is basically a sump in the morning as water dribbles down the J-Pipe into it as the engine is warming up.

I’ll betcha that the egr coolers on 30 year old cruisers that have a functional EGR system look pretty good inside while the coolers that are part of a disabled system are totally rotten rust bombs inside.

This completely makes sense.