Duramax and Timing Belt

Cowpie · December 22, 2014

Shouldn't scare off anyone. Again, the 2.8L going in the Colorado is a carbon copy of the 2.8L VM diesel in my 2006 Jeep Liberty. Timing belt and all. The timing belt is a very strong belt. In my Jeep, it had a OEM recommended replacement of 100,000 miles. I did mine at that time, and it still had plenty of servicable life left. Another owner of one of these Jeeps, took his to 150,000 miles before replacing. I never heard of anyone busting one of these belts. But, one has to be meticulous about how they change the belt. All idler pulleys need to be replaced at the same time. And unless you have the specific tools to do the job, it is a dealer thing totally.

Subpar tuning? How is that? The stock 2.8L will reach the same torque as a small block V8 and do so at 2000 RPM, right where most folks actually drive their vehicles, compared to some jet engine screaming 4000+ RPM of the small blocks. They should use the 8 speed that they are putting in the larger pickups. No reason not to and it will make a difference. Jeep used the 545 transmisson from behind the 5.7L Hemi in my Jeep Liberty 2.8L. Good combo. But to be fair, a little tuning would be a good thing, mostly from a fuel mapping standpoint. EPA compliant tuning is not usually the best way to get the most out of an engine. But how much can be done will all depend on how the SCR and DPF systems operate. At a minimum, turning off the EGR is a great idea. Diesels do not react as well with eating their own feces as gassers do. The soot loading is terrible. And turning off the EGR can be done totally inside the ECM. No need to turn a wrench. It is ECM controlled. Very similar situation as turning off the AFM on our V8's.

And diesels are not designed for street rodding. Best way to ruin a good diesel is try to think it is a gasser. This is a working motor designed to do serious work more economically, and outlast a gas engine by several times. At road speeds, you can goose it and it will perform admirably. At start offs, any diesel is designed for more gradual acceleration, due to the slight delay in turbo boost development combined with fuel application to the injectors. It will take off from the light just fine, unless someone likes to use the traffic lights as their own NHRA starting lights and race to the next set of lights. But those folks have issues that I can't help them with.

Given my experience with the 2.8L in my Jeep, I am seriously considering trading in my 2013 5.3L Silverado for a diesel Colorado or Canyon. If it is anything like the 2.8L in my Jeep, I will not have any memory of the Silverado.

Edited December 22, 2014 by Cowpie

rvsixer · December 27, 2014

Cowpie looks like you killed every thread here LOL !

Edited December 27, 2014 by rvsixer

Cowpie · December 27, 2014

I hope GM kicks out with this engine soon and the threads will be alive and feisty! The holidays are probably more to blame for things than me. Happy New Year everyone!

rvsixer · December 28, 2014

I hope GM kicks out with this engine soon and the threads will be alive and feisty! The holidays are probably more to blame for things than me. Happy New Year everyone!

True true!. I just got a chuckle this morning when I logged on and noticed every thread here had you as the last poster days ago, but agree its simply holiday slowdown.

May kaos hit the showrooms and threads soon !

pm26 · January 26, 2015

Years ago I had a 1982 Datsun pickup with a 4 cylinder diesel. It had neither timing chain nor a timing belt. The cam was a direct drive by gear from the crank. The injection pum p drive gear laso was driven by the cam gear. So three gears meshed together and everything had to be timed right.

If I remember correctly VW diesels still use a timing belt and have for decades. The key to timing belt longevity are regular replacement intervals, but not just of the belt, but the blet tensioner pulleys and the tensioner itself. the tensioner pulley have sealed bearings which will eventually dry out due to intense heat and they will seize and destroy the belt. Some timing belts have hydraulic dampeners to dampen the belt oscillations on the slack side of the belt. My Mazda 626 V6 had one of those.

Everything I read about the Jeep Liberty diesel was negative. Bad fuel economy (23-26 MPG), numerous problems.

Edited January 26, 2015 by pm26

Colossus · January 26, 2015

My question is.. why would GM design this with a belt instead of a chain? If you keep the cost of maintenance down, that surely will attract more buyers.. but perhaps the dealers are hurting for revenue and need to see more service visits to make that revenue so they convinced the engineers to design it using a belt instead of a chain. Let's keep in mind here that a chain is expected to last the lifetime of the engine, where as a belt will need to be replaced between 70-100,000 miles depending on the conditions you live in. Yes belts are made better and stronger now a days but still I'd imagine the cost to change a belt is still going to be well over $1000. An unnecessary expense in my opinion and something that would seriously discourage me from buying if I am going to be keeping the truck for the long run.

kstruckcountry · January 26, 2015

Belt is lighter, and doesn't become less precise over its lifetime.

I'd still prefer a chain I think.

Edited January 26, 2015 by kstruckcountry

Colossus · January 26, 2015

Yes, but isn't the chain good for at least 500,000 miles? A belt is only going to be good for 80,000-120,000 miles depending on conditions... In this day and age the Asian and Euro automakers are working to build more engines with chains instead of belts due to customer complaints of timing belt maintenance requirements and failures....

rvsixer · January 26, 2015

A belt is only going to be good for 80,000-120,000 miles depending on conditions...

That's actually well short of the scheduled replacement interval (read thread).

Cowpie · January 27, 2015

I am not so convinced that the design is GM anyway. Everything about the engine speaks of being based on the 2.8L VM diesel that has been around a while and has a strong track record. Why develop a new design when there is a very good design already out in the world market place. And VM, Penske, GM, etc have been playing with each other for a lot of years. We just haven't seen it here in the U.S. I have seen many pics of the 2.8L Duramax and it is a carbon copy of the VM 2.8L diesel. Only some very minor changes. The belt on the VM engines is very reliable. VM recommends they be changed out at 100,000 miles, but I have seen many instances of them going well beyond 150,000 miles without falling apart. I have only heard of one time the belt being a problem, but the owner never changed the belt and it finally blew up somewhere around 145,000 miles. And it is not that big of a deal to change the belt on one of these. A belt, a tensioner, and a couple of idler pulleys. The belt was not that expensive for my VM 2.8L. Belt is $85. A complete kit including belt, pulleys, gasket, water pump (advisable to replace while you have the cover off), etc is $400. Probably the gonna be in the same ballpark pricing on the 2.8L Duramax. I replaced the belt and other items on my 2.8L VM diesel at around 110,000 miles and it showed no appreciable signs of wear.

The VM 2.8L diesel was originally designed as a marine engine, but got moved over to autos, SUV's and small pickups. If the GM version is based on this engine, it will be a very good product. Cast iron block, wet sleeved, Dual OHC, common rail injection up to 20,000 psi at the tips, Honeywell variable geometry turbo. That is a very good combination. Only difference between this GM configuration and my VM one, is the common rail on mine is 18,000 PSI, the turbo is a Garrett variable geometry turbo. I would be willing to bet a lot of the internals are interchangeable.

Edited January 27, 2015 by Cowpie

pm26 · February 8, 2015

If this is such a good engine, why was Jeep Liberty diesel such a flop? Chrysler continued manufacturing Jeep Liberty for a number of years, but dropped the diesel version after two short years I think.

Edited February 8, 2015 by pm26

Cowpie · February 8, 2015

The Liberty 2.8L diesel was not a flop. Your government got involved. The 2.8L was offered for 2005 and 2006. But the EPA emissions thing that required DPF and more EGR kicked in for 2007. So, Jeep dropped the engine option because of not wanting to invest in engine changes. Do not equate dropping an engine with it being a "flop". In this situation, as in many others, the nanny state brought the option to an end. Remember, your government cares for you.

Pinnacle · April 10, 2015

Belt is lighter, and doesn't become less precise over its lifetime.

I'd still prefer a chain I think.

Its actually the belt that becomes "less precise" over time that's why it has a change interval. I have never hear of a chain becoming "less precise" over its lifetime and I had a 4.8L and 5.3L with 240000K and 280000K miles on them on a dyno and both trucks put out identical numbers to a 4.8L and 5.3L that had around 30000K on them.

I know of someone that puts 100K on his truck each year and keeps his trucks for 6 years or so, this will mean 6 trips to the dealer where you are spending $1000 each time and you are out without the truck for possibly 2 days or so. This belt is a terrible idea in my opinion. Thats $6000 more then Id ever want to spend. From what I've seen there is a chance that this engine will have to be pulled to do this job as well, I've been around long enough to know things go wrong when that happens that one never accounts for. There will never be a better more reliable less maintenance required engine then then GM's exceptional OHV motors, I will never own anything else.

Edited April 10, 2015 by Pinnacle

Pinnacle · April 10, 2015

With all the issues with the DOHC 3.6 engines in the Traverse/Acadia/Enclave/Outlook/CTS and their chain stretch, a belt is a welcome change. Plus, current day timing belts are night and day compared to 10-20 years ago. Wouldn't scare me one bit to own a mini Duramax.

Thats because GM cheaped out, they were poorly made chains with inadequate lubrication, GM fixed this problem with carbonitriding and better lubrication that required more frequent oil change intervals.

Likarok · May 16, 2015

Tons and tons of engines use belts. Personally I'd prefer chains but I wouldn't let a belt scare me away from the diesel if that was what I wanted. Plenty reliable, just don't ignore the change interval.

I agree! Volkswagen has had timing belt diesels for years . Yes they have to be changed at 100,000 km but I would never keep a truck that long anyway!