Questons about Diesel Cars and Oil

The run down: two weeks ago the mechanic put the wrong oil (oil for diesel trucks) in my 2007 CRD Jeep Cherokee 3.0 engine. The car was driven for two weeks. Then when they went to change the oil with the correct type of oil for the car, the oil was above the max. line on the dipstick when I left the garage. Three blocks later the car was spewing grey smoke, making a grinding sounds and difficult to brake the engine. Two questions: could the first oil have caused damage to the engine or turbo? What damage could be caused by too much oil in the engine? Thanks in advance for your responses!

Absolutely. Diesel oil is 15w40. If which is very heavy compared to what your engine is designed for. What probably happened is the oil pump could not pump the oil to where it needed to go. The oil pump was probably damaged and in the end the heavy viscosity of the oil causes parts to not be properly lubricated. They stick somewhat, this causes heavier mechanical wear and probably damaged the turbo to begin with, and possibly the valvetrain and rings. Other damage may have come to the crankshaft, main bearings, camshaft bearings, connecting rods… the list goes on and on. My recommendation is to first contact the shop and see if they will make right thier wrong and replace the engine if need be, or at the very least if it is repairable repair the engine. The grinding sounds and smoke tell me however that it is probably time for a new turbo and motor. Sorry to say it.

It’s hard to say… when you say it’s “difficult to brake the engine”, what do you mean? What kind of “grinding sounds”? Do the grinding sounds occur at all times when the engine is running, only on acceleration, only when braking, or?? Do you know what weight of oil was put in? How far above the max line was the oil level?

The garage that used oil for a diesel engine did NOT do any damage to your engine. Your engine can easily handle the 15w40 oil and there is a case for using this oil in any gas engine, especially a turbo charged engine.

Do you have a manual transmission? Or if you have an automatic transmission, does it have a drain plug in the pan? Here is an ugly scenario, I have seen it happen. The “tech” drains the transmission instead of the motor, then adds the specified amount of oil to the motor. Now its motor 8 qts, transmission 0 (or 6 if automatic). The symptoms that would result from this are exactly what you described.

Keith, you’re wrong. The newest engines can be heavily damaged by a oil with too high a viscosity. That’s the problem with All Aluminum engines and the turbo 3.0 that Jeep uses is subject to that. Especially with a Turbo. That’s why they tell people to not put the wrong oil in. You wouldn’t put 90weight gear oil into a diesel… you’d kill the pump and the engine. Especially if you overfill it. Sorry. This is an area where just finishing up more classes on auto repair helps. I’m a certified mechanic unlike some of the people that post advice on here. Knowing that some engines especially all aluminum engines don’t have the tolerance that engines that were built 15 years ago had. The newest engines are much more picky. It’s like telling him he can fill the fuel tank with diesel and it won’t do any damage.

benny, I’m not wrong. That motor can easily handle 15w40. BTW not all diesel rated oil is 15w40, there is a 5w40 version as well.

Rue, why did you go back to the shop? What tipped you off that they used the wrong oil in the first place? Do you know what was wrong with the oil they used? (For example, 15W40 or 5W40 as suggested above) And do you know the correct oil for your vehicle?

I don’t care if you are a certified deity, you need to put a lid on the knee-jerk defensiveness and insulting other contributors. It is possible for adults to have differences of opinion and still treat each other with respect and if you can’t participate in that fashion you will quickly find yourself most unwelcome.

Using the wrong weight oil for 2 weeks is in no way comparable to filling your tank with diesel instead of gas, and going over the top like that is just silly.

Wow! My head is spinning. Thanks so much for all of your expertise. I really need all the info. I can get at this point. I will try to answer your questions as best I can.

I believe the oil originally put in was a 15-40 wt (according to the receipt). When my oil light came on, the mechanic that looked at it said they either did not change the oil or used the wrong oil.
The “difficulty braking the engine” seemed to come happen if I tried to go above 25-30 mph–although I had only driven about 4 residential blocks. The car did not slow down and made a grinding noise–that is the best way I can describe it. It sounded like metal to me. The grinding sound only happened upon acceleration and after 25+ mph.–not coasting. The first time they changed the oil, with the 15-40wt., the oil was up to the oil line and according to receipt they put 10 qts. in.

The second time the oil was changed (after I had brought it back to tell them they had put the wrong oil in the vehicle) it was above the max. line of the dipstick. I know this because the mechanic made the point of telling me. He said he put in the right oil and 10 qts. but the dipstick showed it is over the max.–I don’t know how far over. He said not to worry as the oil would work itself into the engine…

The car is at the dealer now. I just want to be able to get as much info. as possible to be able to advocate for myself in this situation and make sure that I get back the car that I drove into the garage (well maintained, great running with no engine problems for past 65K). I bought the car because it is a great tow vehicle for our RV and is a great everyday car in between vacations.

“Keith, you’re wrong. The newest engines can be heavily damaged by a oil with too high a viscosity.”

That is true, but the oil specified should not have caused any real problems other than a little lower mileage. You would not want to repeat the use of the wrong oil and what is there should be replaced, but it is not going to

Um, the CRD engine is a diesel. What weight oil is specified?

The correct oil for my car is" SAE 5W-30 engine oil, meeting the requirement of Daimler Chrysler Material Standard MS-11106 or Mercedes Benz MB 229.51 and ACEA C3 Qualified engine oils". The mechanic who discovered I had the wrong oil printed the above out for me so I could show it to the garage.

The oil light came on? When were you going to tell us about this. We need ALL the facts in order to give you an accurate opinion.

Please list all the events in chronological order. You got the oil changed. You go back two weeks later and get it changed again. What made you do this? Is this when you got the “oil light”? Was the oil light what sent you into the garage the second time?

When was the first time anyone noticed that the oil was over filled? The first oil change? Before the second oil change? After the second oil change?

They put 10 quarts of oil in? Do you have an oil cooler?

@Keith, the CRD engine (common rail diesel) has a capacity of 10 qts.

Joe, “heavily damaged”?

There’s a warning for this engine when the oil is changed “Wait 15 minutes after the new oil is added before starting the engine!”

If you took off right after the oil was changed, the turbo probably burned up. Thus no power, smoke out the exhaust, and the grinding noise. Turbo bearings being destroyed.


I realize it is confusing: Chronological events:
8/27/11 Go to “Garage 1” for inspection and oil change.
9/6/11 afternoon commute, oil light sensor comes on–only at a stop. Flashes each stop and beeps. I drive a short distance to pick up kids and come home. Read manual which says to turn off engine and restart. I just leave it overnight.
9/7/11 Morning commute: oil sensor still coming on at stops only–not while I am driving. Afternoon commute, it does not come on, but I take it by Garage 1. He checks the oil, it is at a normal level, but he says it “looks dirty” and asks me if I get the oil changed regularly. I say, “Yes, every 5K” (factory recommendation). He states it looks dirty because it is a diesel.
9/8/11 My regular mechanic looks at it and states Garage 1 either did not change the oil or used the wrong oil. He tells me to take it back to Garage 1, prints out the correct oil to be used and tells me to request the oil be changed again.
9/8/11 I go to Garage 1 and repeat what my regular mechanic told me. He admits they used the wrong oil. I agree to bring the car in on 9/10 for an oil/filter change.
9/10 Garage 1 changes oil/filter to specified recommended oil. Tells me if I check the oil, the level will be high, above the max. line on the dipstick and still look dirty because of the previous oil put in the car, but the oil will work its way down into the engine. He put 10 qts. because this is the amount of oil the engine calls for. I drive away. Grey smoke starts coming out of the exhaust and the car starts to make a grinding sound when I accelerate above 25 mph. I drive a total of about 8 blocks and return directly to Garage 1. The mechanic states he is going to change the oil again. I return later to the garage. He states the oil is at the correct level. Shows me, looks nice and clean. He cleaned the engine area and let the car run 30 minutes and said he drove it around the block. I drive off, within 2-3 blocks the car is expelling so much gray smoke, I cannot see out the back window. I return to the garage. The mechanic states “it just needs to be worked out”, gets into the driver seat and guns the engine. The car sounds like a jet engine, black smoke spews out the back, the car is making lots of noise. The engine does not shut off when he turns the engine to off. The engine does stop eventually–apparently there is a kill switch which shut it off.
The above is the chronology. Sorry for any prior confusion.

Looks like they well and truly damaged the engine. And Keith , contrary to your beliefs, an engine which calls for 5w30 can easily be damaged by even a day of driving with 15w40. The oil is much heavier and can easily cause the oil pump to be overworked. The sound and heavy smoke are probably caused by a trashed turbo. The grey smoke is oil burning. These 2 are not a good thing. If the engine is sounding like a Jet engine and there is a grinding noise, obviously there was damage to the engine. Whether it be in the turbo or not, from what he had stated, garage 1 did plenty of damage by putting in the wrong oil. Also, As a certified mechanic, not deity, I have already proven that I know what I actually know what I am talking about.

Here is what has most likely happened. 1 The turbo has blown itself out due to the wrong oil. Which can easily be damaged by high viscosity. Turbo bearings can be very picky. Then with the sort of smoke you are describing it says a mixture of oil and coolant. The same is true with diesels as with gas engines regarding color of smoke. The thing I suspect may be the case, the turbo has been damaged by the wrong oil. This can cause a higher amount of black smoke due to the IP pumping more diesel fuel in relation to air than normal because of the lack of turbo pressure. I also suspect that there may be oil getting into the intake manifold via the plumbing from the turbo. I would suspect that the dealership knows this and will be looking into it right out the gate.

Hmm…are you sure the owner’s manual said to turn the car off to reset the light then keep driving? I downloaded a Cherokee owner’s manual for the 2007 model and the only oil light I can find says,

10. Oil Pressure Warning Light
This light shows low engine oil pressure. The light
should turn on momentarily when the engine is
started. If the light turns on while driving, stop the
vehicle, and shut off the engine as soon as possible. A
continuous chime will sound when this light turns on.
Do not operate the vehicle until the cause is corrected.
This light does not show how much oil is in the engine.
The engine oil level must be checked under the hood.

So, I’m afraid you may have contributed to wrecking your engine, although I don’t say this with certainty.

(If you have a second oil warning light that I did not find in the manual, then ignore this answer.)

I don’t know why the oil light came on. @Beninsd may be correct that the thicker oil was too much for the oil pump and so was not getting pushed around the engine as it should have been. Meaning your engine was not properly lubricated. Since the oil pump is driven by the motor, pressure is lowest when idling and higher when you are moving, so it is certainly possible that you had insufficient oil pressure at idle, which is why the light came on only when you were stopped. This is hard to believe because there is so much overlap between 5/30 and 15/40. It’s not that much thicker. But it’s hard to argue with results.

If you drove the car with low oil pressure you wrecked it. The oil light is one of those warning lights that means “pull over and stop right now or else.”

Then the next question is why did the low oil pressure light come on after 2 weeks. Possibility #1, coincidence. #2, the pump failed because of the thicker oil. Again, this seems unlikely, but it should definitely be checked out.

Final thoughts.
A. Garage #1 are incompetent at best and crooks at worst.

B. Don’t tell anyone you drove with the oil light on.

C. Dealer may blame it on the wrong oil, using @beninsd’s theory. Garage 1 will try to shift the blame to you for driving it with low pressure, saying that if you had stopped right away, they would only have been at fault for the pump.

D. Good luck.

Thanks so much for your input. As a professional to a non-professional (me), what should I request or expect to have this fixed? My goal is to get a car back in as good condition as I had brought into Garage 1. I want to make sure that I don’t have long term problems with the vehicle as a result of the incidents. Should I request a new engine? Or feel ok with the current engine being rebuilt. The car is currently at the dealer who will give me an assessment and make recommendations and Garage 1 has stated they will get the car fixed. I just want to be able to make well-informed decisions so I don’t have any future problems with the car.