This question does not relate to the CRD, but I know that there are people in here who are "experts" on engine oil and I suspect I can get an answer.

My employer has given me a leased Chevy Trailblazer to use instead of paying me to drive the CRD. I dont know how that is benificial for them, but as the vehicle was originally leased for another person who left they may have to keep paying until the lease is up.

In any event, because it is a leased car they asked me to only do the minimum maintence as required by the owners manual. When I got the car, I had the oil changed at 30,000 miles and reset the oil change light. The book does not list a mileage for change, but instead talks about the sensor knowing when to change the oil. I now have almost 9k on the oil (dino oil). The change light is not on and looking at the oil on the stick shows it dark, but certainly not black. So my question is: how long can the oil last in the car? I put on about 1.5k per month so its also been about 6 months.


Also, FWIW the Trailblazer has been a suprisingly good vehicle. It rides well on the hiway and is capable in heavy snow and dirt roads. I have only been in one situation on a dirt logging road where I would have taken the Jeep, but did not take the Trailblazer due to its lower clearance. In addition, I looked at the service records and other than one service for rough idling when new, it has had only oil changes (unlike the CRD).

I have the Envoy XL which is the same car, and I wondered the same thing. I think I could have put 12k on my oil but I never waited that long. I own the car and I want it for a long time so now I use full synthetic and let it go at least 9k. I have the 4.2L and it seems to be a very clean running engine.

I think you're fine.

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2005 Black KJ Sport CRD,
GDE Full Torque ECO TUNE, GDE Transmission ECO Tune,
Samco British Racing Green Hoses
Build Date 1/05
200k miles.
Original Owner

I run mine for 10k and it tested fine at a lab.

Some oil life monitoring systems just use the amount of fuel consumed as a measure of when the oil needs to be changed. Theory being that when you're using more fuel (idling, towing, racing) it's harder on the oil too, so they go hand in hand. The computer will just monitor fuel usage and tell you to change the oil after it measures, say, 500 gallons of fuel used.

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05CRD: GDE Hot ECU & TCM tunes, Provent, Cat filter, Facet lift pump, TransGo kit, Florida TC, Samcos, stainless brake lines, HDS thermostat, Renegade light bar,
Bilstein adjustables, Al's Gen 4.5 Arms, 235/85-16 Duratracs, DTT rear, Elocker front, EVIC+TPMS, Turbo timer, McNally pillar gauges, Weeks Stage II kit.

Time to change. Back in the day they used to say 3 months or 3000 miles which ever comes first. No way would I run conventional dino oil past 5000 miles. No way.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

My wifes VW interval is one year or 10000 miles.

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2005 CRD "Ol' Blue"
Red Ryder carbine-action, two hundred shot range model air rifle with a compass in the stock and this thing which tells time.
My build page- RL Komodo Rear and TJM Front Bumper, armored, lifted, JBA Steel D30, 4.10s and ARB air lockers.

It's leased. Who cares?? Go with the light.

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2005 sport crd-SOLD No regrets

It's NOT using conventional oil.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

Oil change lights are great. I changed quite a few camshafts on BMWs and Toyota Cressidas because the owner trusted the oil change light.

Follow onthehunt's recs on oil changes and run E85 as much as you can to keep it purring like a Junk Yard Cat.

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2006 Pearl Green CRD
Magnaflow 2 1/2" Cat Back
KJ Extra Leg Room Brackets, Carter Lift Pump, V6 Airbox, ORM
Fuel cooler, Oil Separator, Progard 7
Gauges EGT Boost Trans Temp Oil Pres, Michelin LXT AT2 245 70 R16
7,000# Draw Tight hitch, PML EX Deep Trans Pan
Centrifuge, SunCoast, Transgo, RAM TCM, InMotion Stage 2
Wife's 99 TDI VW Beetle

its leased, and as long as you follow their recommendations of when the light comes on or ever 12 months they can not deny warranty service.

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'06 Midnight Blue CRD Sport
Born 5-06
Mopar Skids and Tow Hooks
Deer Killer Mod

As a side note: we all know that diesels are considerably more "dirty" regarding oil than gas engines. With that in mind, Detroit Diesel now has a 50,000 mile recommended oil change for the DD15 engine, on conventional oil. Now I realize it has a larger sump, but it is also a 15L engine and works considerably harder than anything we put autos and SUV's thru. Does that give any idea on how long conventional oils are holding up nowadays.

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Environmentalist Green + Socialist Red = Facist Brown

2006 Liberty CRD, Frankenlift II, Al's A Arms, Moog LBJ's, GDE tune, Etechno GX3123 Glow plugs, Fumoto drain valve, Elephant hose CCV mod.

They have much better filtration. Kinda apples to oranges comparison. I'd love to see the fuel dilution% numbers. 20-25k max is what I see here. That's with C-13's and ISX's. Aftertreatment systems are increasing fuel dilution on everything we run. Uoa's are done at every service and this what I notice the most.

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2005 sport crd-SOLD No regrets

Not really. That is their long haul recipe. Everyone knows you can run longer on oil changes if you do more highway driving and less stop and go.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

But, Cat and Cummins do NOT recommend the oil change interval that DD is recommending now. You are trying a apples to oranges brand comparison. I own an ISX. Best I ever got was near the manufacturer recommendation of 25,000 before starting to see the UOA's starting to show that oil needed changed. DD recommending 50,000 miles is actually being done by a some that I know.

Also, just highway miles not a solid indicator that oil will last longer. It is also common for large OTR highways diesels to also idle more than what most would do with their family auto or suv.

Also, fuel dilution not really an issue that I have seen. The UOA's on my ISX have always shown fuel dilution less than 1% in 25,000 miles.

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Environmentalist Green + Socialist Red = Facist Brown

2006 Liberty CRD, Frankenlift II, Al's A Arms, Moog LBJ's, GDE tune, Etechno GX3123 Glow plugs, Fumoto drain valve, Elephant hose CCV mod.

What's the build date on your ISX?

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2005 sport crd-SOLD No regrets