-
Detroit Diesel Valve Adjustment
I had my 2011 Liberty in the shop yesterday for a valve adjustment @ 66,500 miles. Every injector adjuster was very loose, and all the exhaust valves were also quite loose, and not in sync with each other. All of the intake valves were too tight. The injector hold down bolts were checked and are fine.
This is the second coach that has had incorrect valve settings that I have had. The first engine was an August 05 production and this is a November 09 production with aftertreatment. The first coach was also done at about 65,000 miles. That also had some injector issues due to loose hold down bolts.
It appears that despite the 4+ year difference in production, there remains an issue with the adjustments not being correct at about the same mileage. If you have not had yours checked yet and have at least this many miles, it may make sense to get yours looked at. It should be able to be done for approximately $800 dollars depending on the shop rate and how much acces you have. XLII’s will have to have the floor in the bedroom pulled to get access for the valve cover to be removed. That can be quite a lot of work depending on the converter.
I was told that in addition to mileage and performance issues, if they get too far out of adjustment, you could incur mechanical problems that could be expensive to repair.
After they did mine yesterday, they also updated the firmware in the engine electronics. It was a couple of revisions behind. It idles smoother and sounds better than it did. It remains to be seen how fuel mileage and performance changed. I should know that in about three weeks when we take our next trip.
-
34 Replies
-
I’ve kind of taken the approach on my buses that if nothing is out of order to leave it alone. But, all of mine have been close to or beyond 100K in mileage. So information like Mark has provided makes me wonder if I’m doing the right thing.
Mark – Any idea if the later vintage engines say 05 and beyond are more prone to needing adjusting? The older stuff like I have had doesn’t seem to have a history of needing valve adjustments. I’m sure DD has a magic mileage number that should be followed, but I don’t recall many having the valves adjusted on the older stuff.
-
Had all three coaches that I have had done ,one had 300,000 miles S60 motors in all of them nothing on first one the other had 230,000 and nothing on that one , and the one I have now done all in order 116,000 nothing done on it either , maybe it’s just luck , but I always have mine checked out after 50,000 miles, cheap to have checked out just to be sure , I agree with Mark it’s good to have it checked out
-
If you’re having a valve adjustment done on a DDEC VI have the tech
disconnect the injector harnesses at the valve cover and check for engine oil
in the connectors. DDEC VI has an emissions component on the crankcase vent
that causes crankcase pressure to be higher than previous engines. The higher
pressure actually forces oil inside the injection harness wires. I discovered
thisproblem when working on a friend’s 2010 H model. I called the
Detroit dealer and asked if there was an updated part to stop this problem and they
said no, Detroit had declared oil in the harness was not a problem because oil did
not conduct electricity. I was not going to send my friend on his way with oil in
the harness all the down to ECM. I checked with the parts department and they
had 12 injector harnesses and 7 engine harnesses in stock. Why stock all those
harnesses if oil in the harness is no problem? When I picked up the harnesses I
talked with a tech I knew and found out the rest of the story. It’s simple, oil
alone doesn’t conduct electricity. Unfortunately all engine oil in a running,
working engine contains some metal particles which do conduct electricity. The
component causing the problem can be removed. Of course the dealer can’t do it.
The tech also said he had occasionally seen the problem on DDEC V. I’ve never seen
the problem any DDEC V I’ve worked on and DDEC V doesn’t have the component.
Found a couple of pictures but can’t load them for some reason. Maybe later today.Ken
-
Ken, that is very interesting. I was wondering what the tech was talking about when he checked the harnesses at the ecm. He said something about it was dry, no oil on this one. I thought he was talking about spilled oil. Now I know that that was all about. I will quiz him more next time I am at the shop.
-
Mark – Any idea if the later vintage engines say 05 and beyond are more prone to needing adjusting? The older stuff like I have had doesn’t seem to have a history of needing valve adjustments. I’m sure DD has a magic mileage number that should be followed, but I don’t recall many having the valves adjusted on the older stuff.
I don’t know the answer to that question. The guys in the shop are mainly saying that the factory is sloppy when building the engines (or were, since they no longer are producing new ones). All I know for sure is that both on mine have needed adjustments, and that they both were fairly far out of spec at the same mileage and length of service.
-
Mark
Do you ever have any trouble with regen on the engine exhaust system ? I heard that the 08′ & 09′ model Detroit 14L could have some problems with that and could possibly strand the coach? If so Detroit probably has it covered by now.
Thank you,
Chris
-
Mark, what DD shop do you use ? Geo.
-
I have not yet had any problems, but have only put about 15,000 miles on it since May when we got it. It has not required any parked regens so far, but has done some passive (while driving) ones. You can tell just a bit of power loss when it seems to be doing them, and if you happen to stop while one is running, you will get a high exhaust temp light on the dash for a short time.
According to the DDEC reports run for me after the tune-up, the engine has done only 2 parked regens, and has done 186 while driving. It has burned 248.85 gallons of fuel to do them all!
The mechanic said that most of the ones he has seen have been pretty trouble free as far as regens go, and overall have been as reliable as any other series 60.
-
Mark, what DD shop do you use ?
I have been using Boyer Truck in Superior, WI (just across the bridge from Duluth) for service since I bought the last bus in 2009. I have been pretty happy with them overall. They are a Freightliner and Western Star dealer and also do Allison and Cummins and Cat. Some of Boyer’s other locations also sell International, but not this location.
They work on a lot of plastic coaches, but I don’t think they have ever had a Prevost in except mine.
-
Mark
Thank you for sharing that info. We are looking at coaches in that year range and your information is very helpful.
Thank you,
Chris
-
Mark,
I just wanted to clarify that you can get a vavle adjustment on your H3 for around $800? Can your shop do it without removing the engine or the bedroom floor? My 03 Marathon H3 is past due and am trying to find some
place that will do it without tearing the coach apart or pulling the engine. I keep getting different stories.
Prevost says take the bedroom apart to do it. Danny at American Fleet says the engine has to come part way out. 22hrs of work and $2500-$3000. For $800 to $1000 I’d drive up to your shop in a heartbeat!
Thanks for the info.
Kit
-
I was just looking into the valve adjustment for my H3 coach as well. 153,000 miles and I do not know if it was ever done (4th owner). I got a quote from Prevost in Richmond, BC, for 12 hours. Pacific Truck, near Marathon in Coburg, Oregon, says 5-6 hours.
Update-Had the valves adjusted by TEC next to Marathon in Coburg, Oregon. $750 flat rate. Unfortunately there was a check engine light after I left – problem with my Jake. I got that fixed at Pacific Truck in Medford, Oregon. TEC has picked up the repair bill for that. I would go back to TEC for engine service.
-
You gotta wonder why such a HUGE difference in time estimates. Experience? Someone knows a trick? or someone doesn’t realize what they are gettting into?
-
Yes, my adjustment on my 2011 Liberty (2010 chassis year) was about $800. Nothing had to come out to do it except the intake tube and some other DD related stuff. Also Liberty puts in a storage box to hold oil etc. That also had to come out, but only has 4 1/4″ bolts holding it in. Easy to take out.
Mine does not have a Jacobs engine brake, it has a transmission retarder. That makes the job easier and quicker. I don’t know how much more having a Jake brake would add.
I just found the invoice from August of 2015. Total was $795.33 I am not sure what they charge today, and I know they are backlogged with work. The technician who did mine is no longer working there either. I still use them for oil changes etc.
It does NOT take 22 hours to do. 5 to 8 hours is much closer to what it should take. Even my 2006 chassis year XLII was not too much more to do than this one. I had already taken up the bedroom floor area so they could get the valve cover off. That one had a Jake brake too. I don’t have the invoices for that any longer, but is was not that much more than my 2011 Liberty was.
-
Just for your info, Brian at American Fleet was out of town for this week so I talked to a tech who asked somebody else. So the info I received may have not been correct. I’ll wait and talk to Brian.
I do know there is a guy in Coburg that does the adjustment on H’s by crawling up in there for a reasonable price.
Just very much out of my way right now.
I’ll let you know what I find out from Brian.
KT
Log in to reply.