Community Forums

gstone · 07-05-2013, 02:04 PM

I'm having intermittent problems with my Exhaust brake on my 2008 ISB 6.7. Occasionally, the exhaust brake will not release, causing loss of power for about 15 seconds until it releases.

I can't seem to pin it down with when it will happen. Happens with the cruise on or off, happens occasionally when just starting off after sitting all night, and can happen after extended driving time, happens sometimes, than not others. The "check engine" light comes on, than after about 15 seconds, it releases on the light goes off.

Any ideas? Help please

Genset · 07-05-2013, 04:39 PM

Never had the exhaust brake, however have read where they need some lube to keepthem working smoothly, maye some obe can fill in the blanks.

Dave M

Papa_Jim · 07-05-2013, 06:05 PM

I suspect that you may need to lubricate your exhaust brake. Pac Brake sells their own proprietary brand of lubricant. Any silicone lubricant that DOES NOT have a petroleum base will work. Tri Flow is one brand that works, and is available at many hardware stores. Super Lube is another brand that works, and is available at many auto parts stores.

ardbark · 07-06-2013, 03:14 PM

Quote:

Originally Posted by jimkate

I suspect that you may need to lubricate your exhaust brake. Pac Brake sells their own proprietary brand of lubricant. Any silicone lubricant that DOES NOT have a petroleum base will work. Tri Flow is one brand that works, and is available at many hardware stores. Super Lube is another brand that works, and is available at many auto parts stores.

2x on the lube. The PacBrake butterfly valve (which is pretty standard OEM) is notorious for seizing up, at least on the older rigs. Typically they will seize in the open position, where they spend almost their whole life, but it sounds like your valve is trying to seize in the closed position, hence the loss of power and check engine light. When they freeze in the open position you just don't have an exhaust brake. When they freeze in the closed position you don't have a coach.

According to my mechanic (who I just spoke to yesterday on this very issue) PacBrake has come out with a new design which is suppose to fix the problem. But of course the new design A. won't fit older coaches without cutting the exhaust and welding some mods in place, B. you can't use your old actuator, even if it is working fine, which leads to C. you have to buy and entire kit to get the "new" fix which will set you back about $1,200 (parts only).

I'm screwed, mine froze up a long time ago, but I'd suggest lubing the holy heck out of your valve while it still "sort of" works. Maybe disconnect the actuator and manually rotate it to work the lube in the best you can.

jimcumminsw · 07-07-2013, 10:02 AM

Hi, you can not lube the exhaust brake on the 6.7L ISB engine. The exhaust braking comes from the VGT turbo charger and the sliding sleeve that regulates the braking effect. The turbo may be sooted up and this needs to be cleaned by a dealer. Is the engine installed in a motorhome or a Ram truck? This will determined were you will have the turbo serviced.

Cummins had provided a fix in mid 09 to this turbo issue. The turbo will need to be drilled and clean with a solution by the dealer service tech this may take a couple of hours to do cleaning.

After the turbo is cleaned I would use your exhaust brake when ever you turn on the engine and drive the vehicle. This will prevent the turbo from sooting up in the future. I run my exhaust brake when ever my truck is driven and I have not had any issues with my VGT turbo charger since it was cleaned in early 09.

Jim W.

gstone · 07-07-2013, 05:29 PM

First of all, thank all of you for your input. Here's an update on where I'm at with this issue. I did a bunch of research and stopped into a Cummins dealer to inquire about the issue. First of all, this is on a front engine diesel motor hope (Alegro Fred).

Interesting enough, of course the Cummins dealer has never heard of the symptoms I was describing, which I find disheartening. However, I was just talking to the service writer, so not sure how knowledgeable he was. However, in my research on other websites, I discovered that as all of you have said, it could be am issue of needing to clean the brake. It is the VGT, so it will have to be done by the Cummins dealer.

Interesting also was the fact that if it was a rear-engine diesel, it would be covered by the 5 year warranty, but because its a front engine diesel, its only covered for 3 years, which hopefully my extended warranty will cover.

What makes me believe that it is a dirty turbo, is the fact that it was intermittent. As I was returning from a 500 mile trip, I started in the morning with the brake not working. Then toward the end of the trip, and after I climbed a long grade in 100 degree temp, the problem went away, so I am of the belief that the high turbo temps burned it off (hopefully). My be wishful thinking. I am going to take it in to the Cummins dealer and have it serviced and have the codes on the engine read. We shall see. I'll update when I know more.

Thanks again.