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Anyone driving the new 2007-2008 Jeep Cherokee diesel yet?

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October 13, 2008, 03:14 PM
Anyone driving the new 2007-2008 Jeep Cherokee diesel yet?
Originally posted by TonyVideo:
The Jeep CRD 3.0L used in the Grand Cherokee is approved for B5 fuel only as per Mercedes who manufactures the engine. You will void factory warranty with anything over B5. This reply is from Jeep Engineering:
We understand the desire to run bio-fuels, and we would like to do so in the future. There are 2 main issues with using bio-diesels more than B5-B20.
1. Cold start - biodiesel fuel have significant issues with gelling
2. High pressure fuel system durability - biodiesel lubricity is not well controlled

When the fuel industry have a standard for the fuel so the lubricity and chemistry of the fuel are standardized, then we can really work on solving the remaining issues using bio-diesel fuel.
Thanks for the previous replies and this post. This time around I decided to do he oil change. The problem was finding an oil filter. After quite a search, I found a couple of products on I found the right filter for this 08 cherokee diesel and a oil tank heating pad. I had this pad put on on the base of my oil tank and it makes my block heater look like a popsicle. For those that are worried about the cold and the startup problems in winter, this pad has been great for my cherokee. she is not craky in the morning anymore.
October 22, 2008, 10:08 PM
Sam Crowe
Originally posted by TonyVideo:
This reply is from Jeep Engineering:
We understand the desire to run bio-fuels, and we would like to do so in the future. There are 2 main issues with using bio-diesels more than B5-B20.
1. Cold start - biodiesel fuel have significant issues with gelling
2. High pressure fuel system durability - biodiesel lubricity is not well controlled

Two tank vegoil system should cover these?

My understanding, regarding the conversion of the 6.4L Ford truck to vegoil, is that the problem with the DPF is that it uses diesel to burn the particulates, but since vegoil has a different ignition temp the particulate burner doesn't work correctly if the truck is running on vegoil when the sensor calls for the burn.

But, apparently there are third party computer flashes that will disable the DPF. To, of course, use off road.

I'd like to find a 4-wheel drive diesel to convert to run vegoil, larger and more comfortable than the Liberty, yet smaller than a truck. I'm looking into the Jeep Cherokee to see if it would work out.

Thanks for everyone's comments in this thread.


2002 F250 Vegistroke now with the new V3 module!
October 26, 2008, 02:55 PM
Originally posted by tombrown:
Originally posted by B.K. Hosken:
just wondered if anyone had gotten the new diesel Cherokee, and have you tried BD in it?

I have had my Jeep Grand Cherokee Diesel for almost 6 months now. so far 3 shell shocks. The unit is very loud on highway driving. I went to three lube shops and they all told me they could not even find the fuel filter in this vehicle. when I took it in to the dealership, oil change was $250 for this unit. Seeing as I am driving more highway, the higher price of diesel and the cost of maintenance, I have made a bad decision on buying this unit.

After my first shock with the oil change, I have done my own change this round and it cost me less than $75 now. I got 12L of Synthetic from C-Tire for less than $60 and got the fuel filter from and changed it myself. The stealership wanted $60 just for the filter and another $110 for 9L of oil. $75 for 10000KM is more like it.
October 26, 2008, 09:38 PM
I Roll
Oils filters (Mann hu821x) can be found online for about $12. NAPA sells an oil filter for $9.49. However, these are paper filters, not fleece. Best price on synthetic oil is Walmart but I haven't seen anything that meets the MB 228.51 standard.

Anyone know of a good source for fleece filters a the correct spec oil? I've been told that, with the fleece filter and correct oil, you can go 15k mi between oil changes. Is this correct? Is it worth it?
November 01, 2008, 09:42 PM
I bought a 2008 JGC Overland 4x4 in Aug'08, and now have almost 7,000 mi of mostly expressway on it. I have run mostly B20 biodiesel in it since new, but have moved up to B50 recently since there's now a quality commercial fuel outlet nearby for that. I notice that the engine seems to run a little bit quieter on the B50 as compared to the B20. No problems so far. I did a comparison between petro-diesel and B20 recently for mileage (I keep a log of every fill-up to calculate mileage) and have not seen an appreciable difference yet between either B20 or B50 and the two tanks of all petro-diesel I've run in it so far, but it's hard to compare given the variance in driving conditions. Averaging 18.8mpg normal driving, and got max 22.6mpg on a long trip via interstate at constant 73mph, so far.

Biodiesel has a superior lubricity compared to petro-diesel, thus engines last longer. CO2 and most other emissions are dramatically reduced, altho NO2 is increased, compared to petro-diesel. Importantly, there is zero gain in CO2 to the atmosphere, as the carbon comes from a renewable source; the CO2 GHG addition to the atmospheric balance is coming from fossil fuels like petro-diesel.

I live in a quite temperate climate here in Western WA, and many folks here run B100 year round. Despite that, I do alot of skiing so will be up in the more frigid mountain temps and so will stick with max B50 during the winter. Biodiesel, as that is defined by state law here (!) is prone to cold temperature clouding and eventually gels as the temp goes down. One common measure of biodiesel quality is the "cloud point temp" and "gel temp", which seems to average about 30degF for B100; of course, that temp goes down as biodiesel is blended with petro-diesel.

Many people seem to be unaware that as of June 2008, the ASTM International org released a specfication standard for B110 biodiesel (ASTM D6751). ASTM International, originally known as the American Society for Testing and Materials (ASTM), is THE industry standards org for fuels (and many other things, particularly automotive), and most state and federal laws dealing with emissions require fuel compliance with ASTM standards that are called out in those laws. BTW, ASTM D975 is the fuel spec for petroleum diesel. ASTM International is a org made up of interested parties who collaborate on standards, thus automobile manufacturers, fuel producers, and distributors are primarily involved in the development of fuel standards. The ASTM D6751 biodiesel fuel standard is what diesel engine manufacturers have been waiting on in order to commence certification testing for their engines; thus, it is expected that within the next 24mos we'll see Mercedes, Chrysler, VW, and others bump up their certs from B5 to at least B20 (if not higher blends).

In a previous post, someone stated that car manufacturers will not cover a vehicle under warranty that is running biodiesel. This is NOT TRUE. Federal law in the USA prohibits car manufacturers from denying warranty service on their vehicles & engines regardless of what type of fuel is used by the owner. Manufacturers may, and almost always do, certify recommendations of fuels for their engines, typically after exhaustive testing. But since the vehicle manufacturer does not make the fuel that consumers use in their vehicles, they cannot warrant the fuel; this means that IF you have an engine failure that the manufacturer or dealer can demonstrate was caused by poor fuel quality, even when using petroleum diesel, then they can deny warranty coverage for that instance or repair. Thus, petrodiesel and biodiesel must be treated equally as far as manufacturer warranty coverage is concerned, again mandated by federal law. More info on this can be found at National Renewable Energy Laboratory and National Biodiesel Board websites. BTW, most states monitor & test the quality of all fuels that are sold to consumers. In my state, the Dept of Agriculture collects samples mainly from retail stations, but also refineries, that they test for compliance to ASTM standards in their lab, and a producer, distributor, or station must have a license to sell the fuel which must meet ASTM standards by state law. This includes gasoline, petrodiesel, biodiesel & biodiesel blends.

Most of the fuel-related failures that diesel car/truck owners have experienced is from poor quality fuel. Petrodiesel has a relatively high amount of particulate matter, as compared to gasoline and biodiesel, which has been known to clog up fuel filters or injectors. I've been told that manufacturers started putting larger fuel filters on their vehicles, but most of the diesel experts I know argue that they are not large enough yet on smaller vehicles (Mercedes, VW, Jeep). Dodge trucks (Cummins engines) also have undersized fuel filters. When the filter gets clogged, the injection pump becomes starved for fuel and can fail, which is a quite expensive repair. Upgrading the fuel filter is cheap insurance against this. I'm in the midst of investigating options for larger fuel filters for my new 2008 JGC; IF ANYONE HAS INFO/SUGGESTIONS ON THIS, PLEASE LET ME KNOW. The diesel mechanics around here seem to favor the Raycor filters, but the Raycor ones I've looked at so far (mostly for marine applications) are physically huge and I haven't found a spot to mount one in the vehicle yet.

There have been a few instances of poor quality biodiesel fuel problems occur here in my state that were caused by biodiesel being put into older petrodiesel tanks at fueling stations. The particulate matter in the petrodiesel, particularly the older diesel (ie, before ULSD), accumulates along the walls of the underground storage tank. Later, when the station chooses to begin selling a biodiesel blend, the biodiesel's solvent action begins to "clean" the petrodiesel junk off the tank walls, resulting in a surge of dirty fuel for several months. This is not a problem with a new tank, particularly with one that has held biodiesel (or the new ULSD) from the git-go. The problem can be solved by the fueling station installing a fuel filter on their tank or pumps, but some are not willing to spend the money on that until such time that they have to pay for a customer's engine repair bill (typically enforced by state law) for dispensing fuel that doesn't meet state/ASTM standards. With that said, it seems to be a rare problem at least here in my state.

What if the hokey-pokey is what it's all about ?
November 01, 2008, 09:59 PM
I'm looking for a performance/mileage fuel computer for my new 2008 Jeep Grand Cherokee Diesel (Mercedes 3.0L engine). You know, one of those things that you either plug into your OBDC port or otherwire wire into the vehicle harness, and can select various engine control profile programs (eg, "power", "efficienty", etc). The only one I've come across on the web so far is made in Germany and costs $1700 here in the states (not inc intallation).

Anyone know of a computer (or "chip") that'll increase mileage for this vehicle?

What if the hokey-pokey is what it's all about ?
November 01, 2008, 11:27 PM
Originally posted by Magellan:
BTW, here's an interesting thread on what turned out to be a fuel injector problem on an 07. Not conclusive it was due to BD use, but the owner ran B99 in it.

I am having trouble getting this engine to fire. I have fuel to the injectors, but not into the combustion chamber (no smoke out the tailpipe when cranking). It was originally brought to the dealer after it stalled (no MIL and no fault codes stored) and wouldn't start back up. They determined that the entire fuel system needed to be replaced (not under warranty) to the tune of $14k, on account of biodiesel being used in it.

Without a diagnosis of what is wrong with the vehicle, the dealership wants to start replacing $14,000 worth of parts?
And it turns out to be a set of injectors (which should have been obvious from the problem description).

And, aren't these jeeps rated to run either B5 of B20? So why replace the entire fuel system if a higher percentage is ever used in the fuel?

Isn't there a requirement that a mechanic actually has a head attached to their shoulders?

Or is the only requirement to being a mechanic that one owns a big fishing boat that needs a few more payments!!!!!!
November 01, 2008, 11:46 PM
Ok, so I still have my Ford Ranger... gas...

This spring gas prices hit $4.05/gal.
There is a gas station in Eugene Oregon that sells E85... (and no self service in Oregon so there is an attendant to pump the fuel).

Anyway, so when I was cruising through Eugene, I pulled in and had it Filled with E85.

The attendant looked at my '91 Ranger and asked if I really wanted E85 as it isn't factory certified... At $1.20 per gallon difference, what do you think my answer was?

A couple of tank fulls and I had pretty well flushed out my system to pretty close to true E85.

And, wouldn't you know it that dang thing started running very very rough.

Thank god I didn't take it to the dealership the Jeep person had used here in Portland :P

Anyway, I decided to replace the set of plugs and wires. The dang pickup has 8 spark plugs for 4 cylinders, and I had never gotten around to digging out the driver's side spark plugs anyway... passenger side ones are much easier to replace.

Still running rough with all new plugs and wires Frown

I saw the great big car graveyard in sight...

But, had one last look at it. Well, somehow when I was installing the new plugs and wires I had bumped loose an injector wire. Plugged it in and the pickup has purred ever since. And, yes, I still put in E85 whenever I can find it.
October 20, 2011, 01:50 PM
It's been a few years. How has everyone faired running biodiesel in their Jeep Cherokees??
April 14, 2012, 06:02 PM
I bought a new '07 Jeep Grand Cherokee diesel when it came off the line. It has the same engine as the Mercedes Sprinter CRD. I've driven it with ASTM certified bioDiesel since day one. I've used blends depending on ambient temperatures and availability. It's great to have the option of using straight diesel or all bioDiesel. ( I just posted mine for sale in the classified section )
November 19, 2015, 04:27 PM
Stumbled across this forum again, and just posting an update on my use of biodiesel in my 2008 Jeep Grand Cherokee diesel 3.0L CRD engine...

I'm now at 156,000mi on the vehicle. It's been filled at least 50% of the time with biodiesel (BD) blends, mostly B20 but frequently B50 and B99. I only use commercially produced BD for assurance that it meets the ASTM quality standards and to meet EPA emissions standards, particularly for emissions from excessive residual soaps in poor quality homebrew or coop production that are nasty carcinogens.

I have had NO problems so far from use of BD, or even petrodiesel (the BD keeps the system clean of the petrodiesel particulates, which helps). I changed the fuel filter at 50K mi, but will be doing that again out of just routine preventative maintenance soon (someone asked in another post where it's located: it's right in the middle of the topside of the engine; you have to remove the engine cover, the filter can has a block plastic knurled nob in the middle of it, and it's not hard to change).

I change my oil every 8000mi with a synthetic oil imported from Germany called "Liquid Moly" that does meet the MB spec for this engine. It costs me $56 per gallon at my local NAPA auto parts store, and takes just short of 2 gals for the engine.

Now the problems:
(1) I have experienced much shorter glow plug life than expected. Replaced 4 of them so far: 1st one went at 70K mi, 2nd one at 90K mi, 3rd at 120K mi, and 4th at 155K mi. Fortunately, they're easy for a DIYer to replace, typically <30 min each time, are inexpensive abt $35 each at my local NAPA store ($20 on eBay). See additional info inc photos I posted on that at, search there for "glow plug life".
(2) Crankcase Ventilation Valve (aka "breather valve" aka "PCV valve): this part gradually fails/weakens allowing too much oil vapor to enter the engine air intake system (right at the turbocharger inlet), which can accumulate in the intercooler, connecting hoses, inside the intake manifold and into the combustion cylinders where once it burns into soot can clog up the diesel particulate filter. Mercedes has updated the design of this part (newest is p/n 6420101891, price at most online sources is $160, price at MB dealers is $200). In light of all the Jeep, Sprinter, and Mercedes users who've have problems, there are several after-market oil-air separators that can be purchased and installed to trap the oil vapor out before it enters the engine air intake, most of those run $150-300 but can be cheap insurance. I made my own separator out of a Ball canning jar and lawn sprinkler hose/pipe fittings for <$15.
(3) Stir motor failure. To help meet emission spec requirements at engine idle speeds, MB designed a mechanism inside the intake manifold with flaps near each intake valve that are powered by an electric motor that turns out at idle speeds, and that "stir" the air as it enters the cylinders. The stir motor is infamous for wearing out prematurely on several models of MB diesel engines, particularly where the motor shaft sleeve is at on the intake manifold, allowing motor oil to leak into the intake manifold. I've not replaced mine yet, but am fretting that I may have to before long as it seems so many others have had to do this. The stir motor is $400, is supposedly difficult to access and replace, and if you have a dealer shop do it can easily add another $1000 to the repair...and Jeep is not covering it.

FWIW...good luck on your experiences with your Jeep diesel.

What if the hokey-pokey is what it's all about ?
July 06, 2016, 01:59 PM
Thanks for your informative posts about using BD in your Jeep 3.0 CRD. I have the same vehicle (07MY) but have been warned away from BD due to the concern of dilution of engine oil associated with the post injection for DPF refresh. I'm curious if you ever got a used oil analysis, or how did you address this concern if at all? I'd love to run B100 during the summer months but have been hesitant to take the plunge. A DPF delete isn't an option here in Colorado as it results in an automatic emissions fail.