EGR junk

[VXRaNgEr]

I just found and tightened my EGR tube....fixed a problem I didn't even know I had. I thought this beast was SUPPOSED to sound like a diesel! Does running the truck with the loose EGR do any damage to the engine?

[SGT.BATGUANO]

How long was it loose? There have been posts suggesting that a defective or broken EGR may contribute to engine damage. There have also been several posts on the loose EGR tube being somewhat common. At any rate you're not the first to experience this. Just for cheap insurance you might want to do an oil/ filter and PCV change soon.

[Eckstream]

I had that problem and mine stalled often and the idel ran higher so Id think it affects performance. As for damage I wouldnt know... my service dept. says no its not but I had them check everything else out just in case....

[VXRaNgEr]

It's been like that since I got it so who knows how long its been loose....is it better to go with an aftermarket PCV?

[Zu4two]

A loose EGR tube does no damage. It will throw a check engine light code and mess up the idle though. I have no idea why you would need to change your oil or the PCV valve after re-tightening it?!

[SGT.BATGUANO]

Anita posted some time back about how her friendly Isuzu tech had mentioned that some defective EGR valves on our engines may be contributing to internal engine damage.

If the EGR tube has been loose for a long time and since EGR gases actually COOL the combustion gasses, I figured that is going to make the engine run hotter and dirtier, aging and contaminating the oil sooner. The pcv is thrown in for good measure since most people overlook its replacement at the recommended intervals, and it's cheap. A brand name aftermarket replacement should be fine.

[Hotsauce]

Please explain how adding hot exhaust to the cool incoming air can cool the combustion.

John C.

[SGT.BATGUANO]

I know this from experience, but quick and dirty,here's the first link I found with a google search.

http://library.thinkquest.org/19199/...xhaust/egr.htm

[SGT.BATGUANO]

Don't hold me to this . I think it has to do with oxygen dilution lowering the combustion temps.

[Hotsauce]

so, its adding hot air that is oxygen diminished to thin out the charge volume, I think that with the egr bypassed, and correct mixture/timing you could make more power.

John C.

[VXRaNgEr]

Sarge is right. It's just like watering down beer....the recirculated exhuast gasses are inert (at least in terms of combustion) so they dilute the mixture: less O2 buring = less heat, just like less beer = less buzz John - that makes perfect sense and the engine does just that....it closes the EGR at above-idle RPMs to get a richer burn. It is only the low RPM combustion that results in a much higher temperature and more greenhouse pollutants...that's why it used to be the worst thing in the world for an engine to idle for long periods - it was pre-EGR and the combustion temperature would be much higher, resulting in all sorts of carbon deposits and other crap. Hope this helps.

[Zu4two]

The whole EGR process was created to help engines run cleaner at idle. It's disconnection (either intentional or not) will not cause harm to the engine.

Please change your oil and filter at regular intervals. And change your PCV as needed. But don't use the functioning of the EGR circuit as the impetus to do so.

[SGT.BATGUANO]

My understanding is that generally the EGR is only functioning at part throttle range. At idle, it can and in some cases does, cause stalling. At W.O.T. it kills performance. At those 2 extremes it should be closed. In between is when it's opening is metered.

How long ranger's has been loose is unknown, since it was loose when he bought it. So the combustion temps have not been fully reduced for who knows how long. Again, he probably been running hotter to some degree, and there's also the matter of hotter blowby gasses in the crankcase. Combine that with what Anita's tech friend said about defective EGR related engine failures. That's why I surmised that just for good measure, he should do a cheap oil change, if he hasn't done one recently.

I'm not saying that he has definite engine damage, just that since the duration of the loose and leaking EGR tube is unknown, an oil change is just sensible preventative maintenance.

[VXRaNgEr]

Never hurts to be safe....I'll probably run a couple bottles of EFI cleaner through it too.