Cleaning EGR to hopefully fix LHM - anything else to inspect?


Hey Folks-

I'm the second owner of a well used 2007 Freightliner Sprinter, 3.0 V6 OM642 ~184k miles. Since getting the van I've replaced the rear end with a remanufactured unit, replaced the turbo (horrible shaft play), replaced the intake manifolds (swirl valve problems), glow plugs, alternator, and several other o rings/seals/hoses. Prior to this work, I didn't drive the van much as I bed been focused on the RV buildout.

In November I took her on a ~1200 mile road trip and noticed what I think is LHM. About 500 miles in, with no other symptoms or CELs, the van was not responding to the throttle and it was difficult to climb hills. Downshifting didn't seem to make things any better, but turning the van off for a while and then back on seemed to fix the issue... sometimes for another few hours of highway driving and sometimes for much less. It probably went into this mode maybe 3 or 4 times on this trip.

I also noticed during idle I could smell diesel fuel from within the cab when the recirc was not on. There was one morning I idled for ~20 min to charge the batteries and warm up the van where the diesel smell was most noticeable. This was before I did a lot of reading about how bad it is to idle these vehicles...

Probably not related to LHM but definitely worth of more research was the dreaded rumble strip noise during acceleration under certain loads, which seemed to get worse / more sensitive with the longer drives.

I only recently bought an Autel AP200, so I don't have any live readings to reference. When I installed the AP200 I noticed a few codes but I have no idea when those posted since the KM readings were bogus.

The codes I saw on the Autel were:
2359 - 1 Charge pressure control - too low boost pressure (59026 mi)
2052 - 4 B28 (Intake manifold pressure sensor) - the signal voltage is too low (59080 mi)
2679 - 4 B76 (Fuel filter water level sensor) - the component is faulty (59738 mi)
(The WIF error was because connector wasn't pushed on fully)

The mechanic noted the codes were cleared after doing work, did Autel somehow retrieve codes he didn't clear? I noticed the WIF error when I picked up the van from storage (where the mechanic stored it after the work).... but storage is only 20 miles from the shop, so I don't see how the low boost code posted 700 miles prior. Each code has a milage number associated with the code, but the number are either extremely old, or just plain wrong. I only include this to say I think there were no newer codes posted to the ECM on my trip during the LHM. Anyway...

Now that I am home I have some time to dig in, so I decided to remove the EGR and clean it up. I also plan on removing the elbow near the EGR and cleaning/inspecting that Some questions:

1 - The EGR was stuck on there pretty good, and required a bit of persuasion from a hammer. Theres no damage on the housing, but should I do anything to ensure a good seal for the coolant? I see there is a seam between the top and bottom, held together with security torx, should I be worried the water seal might be compromised? The EGR didn't seem excessively sooty or clogged, below is a video of the spring return after some cleaning.

2 - Should I do anything to test or clean the EGT sensor? Or is that simple enough to swap later if needed?

3 - I've been reading about cleaning the EGR cooler, is this a worthwhile venture?

4 - I noticed a bit of dripped residue on my alternator, maybe from charge piping? I don't think I have the older defective charge pipes, but maybe it's worth removing these and inspecting for damage?

5 - Should I look elsewhere for the cause of this LHM?

Thanks in advance! Happy Holidays and New Year!




Well-known member
I'm sure you did so already but....

You did replace the metal EGR gasket with a new one, didn't you?

Only time I've been able to smell diesel in the cab was when I had injector issues (black death) - again, you sound like you know your stuff so I'm sure you've already inspected those.


Well-known member
Diesel fuel smell or diesel exhaust smell ?

Diesel exhaust smell related to EGR at higher mileage cause by EGR pipe cracked at the flex connection by the cooler.


Thanks for the replies -

@showkey - diesel fuel smell, but thanks for the heads up about the crack near the cooler I'll keep an eye on things. I know aging motor mounts can sometimes be blamed for cracks near that area... hopefully we don't get to that stage There is significant oil/crud on the vacuum pump cover (photo below) but from what I've read that is a trivial fix.

@sparkplug - I didn't reinstall things yet, but I will definitely use a new gasket. I don't see any early signs of black death yet... fingers crossed.



New member
I bought my same year/model sprinter from a guy who bought it from the dealer new. He told me he had symptoms almost identical to what you're experiencing; lack/loss of power on grades, no CEL, pulled over-turned off-waited-turned on-issue resolved, but it would reappear regularly. Dealership said there was a "glich" in the ECU, and 20 minutes on their computer fixed the issue. I dont know what specifically they changed, but since Ive owned it, Ive never had this issue, and its been 150k+


Diving back into things now and reassembling. Any tips for getting both of those gaskets on the EGR elbow (that feeds back into the intake)? Seems silly but it's driving me mad - I can line up the holes on the bottom gasket but when I try to install the second gasket, the elbow pinches the gasket and makes lining things up difficult.

Thanks !

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