diesel maintenance

[Roofer]

I am looking for some maintenance tips on the Duramax. I have just over 1100 miles now, but I want to learn as much as possible now for oil change, fuel filter change, etc... I hate finding things out the hard way. I'm sure there are plenty of tricks to make things easier. I've also heard rediculous prices on filters. What brands are you all using?

Also, what about aftermarket air filters and exhaust. Amsoil or K&N? Exhaust, I've heard straight pipe duals sound good and loud. Anyone have experience?

 

Sorry for so many questions, but I am new to the Diesel world.

 

Thanks      

[99Silver6.0]

Ill just throw this in.  It is always a good idea to monitor the amount of Nitrite in the coolant.  Fleetguard makes Nitrite by the pint and test strips to check the nitrite PPM (parts per mllion).  If you dont watch the Nitrite its possible for the coolant to cavitate--produce tiny bubbles--that can with time cause pin holes throught the cylinder walls from the water jackets and even eat away at the liners. (if the DMax even has liners, I dont know that much about the DMax. I know this rings true on larger diesels.)  The cooling system should be drained (and flushed if you live in an area with especialy alkiline water) then refilled with a fresh 50/50 mix of coolant/water and one pint of the additive for every two gallons of coolant/water at 30,000 miles. Use only a low-silicate ethylene glycol-based coolant.  Where I work all we use are FleetGuard filters.  I dont know for sure what their filters cost to the consumer, but I think they are fairly reasonable.  We dont use the Fleetguard additive though, we use Penray additive and filters.  Whenever I do a PM on a truck and I check the nitrite, company policy is it has to be between 1600 and 3200 PPM.  Im gonna say the "D" word!  My friend has a 99 Dodge Ram 3500 with straight exhaust all the way to the rear, and it sounds awesome!!  That Cummins sounds sweet with straight exhaust, a bit smokey but hey.  There are only 3 reasons to buy a diesel; Sound, Smoke and Power!    I hope some of this helps you out.

 

Fleetguard Additive

 

FleetGuard Test Strips

[SWLA]

Roofer,

 

Welcome to the Dmax world.  I was in your shoes about a year ago (01 D/A CC 4X4).  This is my first diesel truck so I had a lot to learn.  I don't want to get in trouble, but seeing as how you are a moderator maybe you'll let me recommend another site, the Diesel Page.  Lots of good guys and grteat info for new diesel owner like myself.  

 

A few things I can recommend:

 

1.  Oil Change-  the factory filter must have been put on by a gorilla.  Most guys complain about difficulty getting it off.  I am able to change my oil without ramps or lifting the truck in any way.  Don't buy filters from the dealer.  I believe most say the best price on OEM AC delco filters is gmpartsdirect.com, a dozen for roughly 70-80 bucks IIRC.  Buy a fumoto valve.  Not only is it easier, but much cleaner.  The skid plate is positioned perfectly to catch the last 2-3 quarts as the stream slows down.  Makes one heck of a mess.  In fact, if I were you I would take it off first as its only 4 bolts and likely will have to take it off to clean it anyway.  Opinions on oil are as varied as you can imagine.

 

2.  Change the rear diff fluid earlier, most say at 500 miles of towing.  I changed mine at 2500 miles with very little towing.  There were lots of metal shavings on the magnetic drain plug so I was glad I did.  Talking about which fluid to put back in is stirring up a hornets nest.  Apparently to only thing that meets GM's specs is the grape GM synthetic fluid that cost about $20 a quart.  Takes right at 4 quarts, at least mine did.  Some are using aftermarket fluids (Amsoil, Mobil, Red Line, Royal Purple) without any problems, but others say ther could be warranty issues.  Pick your poison, just change it sooner rather than later.

 

3. Allison Transmission- It has an external filter that needs to changed, I think the recommendation is 5,000 miles.  Easy to do, just be sure to remove the ring magnet on top of the filter.  Clean it off and put it on the new filter filled with Dex III ATF.  Some did not know about it and threw it out with the old filter.  The factory fill is dino ATF.  Allison recommends a product called Transynd.  There has been a lot of good info on the DP about this.  I plan to change my ATF to synthetic soon, but will most likely use Mobil 1 as I can't find Transynd locally.  I figure any synthetic Dex III is better than the OEM.  No warranty issues as the extended warranty Allison offers to Transynd users does not apply to us.

 

4. Fuel Filter- I have not changed mine. Yet.  Plan to in the next month or so.  I did by a filter a few months ago to have just in case.  Bought it from DIS out of TX, cost $15-20.  Made by Racor.  My understanding is it is identical to OEM with different graphics printed on the outside.

 

5.  Air Filter- K&N vs. Amsoil vs. Paper.  A very touchy subject.  I may get flamed for even bringing it up. I won't recommend any one over the other.  I did buy an Amsoil 2 Stage filter and used it for 6 months without any problems.  Only took it out to clean it, but have been too lazy to do so.  I've had the OEM paper back in for the last 2 months.  Lots of guys are using K&N and swear by it, others claim they pass too much dirt.  To be continued.  

 

6.  Exhaust-  Most seem to feel upgrading to a 4 inch system is the best way to go.  But they say don't expect much in the way of performance gains that the manufacturers claim.  Main benefit seems to be lower EGT.  Many systems to choose from, but lately alot has been posted about Banks.  I still have the stock system.  Someday I'll upgrade, but no real need now.  Only system with dual exhaust I'm aware of is made by ATS, and both pipes exit on the same side.  Very expensive system.   I've been told that it isn't a good idea to have 2 pipes straight out the back as the diesel exhaust would coat whatever you were towing.

 

That may be a litle more than what you were looking for, but I hope it gives you a place to start.  I know you will enjoy the truck as much as I have.

[Roofer]

Thanks! Very good info. I just did the oil change and no problems. I don't have a skid plate, so no problems there either. Yes, the filter was on tight, but I got it off with a filter wrench. I think they need to tune down the robot that puts these things on. I went with Rotella 15W40 and a Napa Gold Filter.

Good point on the dual straight out the back. I may go to an exhaust shop and get them out the sides or just go with Banks all the way. I have always heard good things about Banks.

I plan on a K&N for air. I put K&N's on everything I have, excluding my 650 which has a good foam one.

The truck is going on a long trip in Sept. pulling a 20 ft.  horse trailer with miniature horses. I'm not sure if I'll get the rear diff and the tranny filter done by then.

 

My next move though is probably tires. I have seen tires from 265's to 315 MTR's on these stock rims and I can't decide yet. Especially with the GM threat of no warranty.

 

I have looked at the DP, but am reluctant as of now to pay for post priveleges. I think it's BS, and they don't offer good info. It's the posters that offer all the info. Even Ford-diesel is free, and they have pictures and tips on all the maintenance.

 

Thanks again

I am enjoying this truck very much so far.