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Discussion Starter · #1 · (Edited)
I recently took a long road trip. The last stretch was from Reno to San Francisco over the Sierra mountains - about 200 miles. There are a lot of 5-6% downgrades. I downshifted a lot to keep from overheating the brakes.

When I got home the oil level was down a little. It makes me wonder if the engine braking could have caused this. I don't see any leaks anywhere.

Can engine braking cause oil burning?
 

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This should be an interesting discussion. Wish I had something to offer in the way of info, friend..

Sent from my SAMSUNG-SM-N910A using Tapatalk
 

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Discussion Starter · #3 · (Edited)
The car has about 30K miles on it. I have been using Pennzoil platinum full synthetic. The OLM was at 45% when I got home.
 

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It makes sense, but you typically see that correlation with older motors. Engine braking = high vacuum = more oil pulled past valve stem seals/ringlands and less recycled by typical PCV system setup baffle setup on turbo cars.

I would investigate your intake manifold to see if the orange check valve is still present. Take off that corrugated PCV hose and look inside with a flashlight for the little orange telltale dot.
 

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Discussion Starter · #5 · (Edited)
I checked the intake, and the little orange nipple is there. Then I pulled the spark plugs. They all look great. Then I stuck my snake camera into the cylinders. There is a little carbon on all of them, but not bad.
 

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Discussion Starter · #6 ·
I ordered some Amsoil PI. Going to see how that cleans up the carbon.
 

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First question is why are you down shifting in car and not using your brakes. The braking system in these cars is completely able to handle down hill in mountains with out down shifting and not over heat. Trucks carrrying large loads or semi yes engine breaking makes sense but in a car there is no need for that unless you are fullly loaded with cargo and people.

Are you sure when you downshift you didn't over rev the engine? This could easily cause the issue you had.
 

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First question is why are you down shifting in car and not using your brakes. The braking system in these cars is completely able to handle down hill in mountains with out down shifting and not over heat. Trucks carrrying large loads or semi yes engine breaking makes sense but in a car there is no need for that unless you are fullly loaded with cargo and people.

Are you sure when you downshift you didn't over rev the engine? This could easily cause the issue you had.
Mine would shake like crazy once they started to overheat. Didn't take much.

I always drop a gear or two (or sometimes the automatic does it itself) to hold speed back on steep downhills. Even if you didn't, long coasts still put the engine in heavy vacuum for long periods.
 

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Typically when brakes over heat you get loss of pedal, the pedal goes to floor not usually a shaking feel from them. Brakes are stil a lot less expensive than a transmission or engine.
 

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Typically, but I've experienced the same thing as jblackburn. Have you ever driven a Cruze down a steep hill, miles long, at 60-70 MPH? The engine doesn't offer much resistance, but it does a little good. Once I even turned on the A/C (wasn't cold outside but I didn't necessarily need it) to add a little more resistance. :D
 

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Discussion Starter · #11 · (Edited)
First question is why are you down shifting in car and not using your brakes. The braking system in these cars is completely able to handle down hill in mountains with out down shifting and not over heat. Trucks carrrying large loads or semi yes engine breaking makes sense but in a car there is no need for that unless you are fullly loaded with cargo and people.

Are you sure when you downshift you didn't over rev the engine? This could easily cause the issue you had.
Sounds like you have never driven over the Sierras. It's about 2 hours of mostly downhill driving, sometimes with heavy traffic that causes you to brake more than normal. I have seen people on the side of the road with smoke coming out of their wheels. I have seen hubcaps melt off the wheels, and once I even saw a car with the wheels on fire. Even with engine braking, I still experienced some brake fade in my Cruze, which is not a good situation to be in if the traffic suddenly comes to a stop from 65 MPH on a 6% downgrade.

You may not know this, but all automatic Cruzes do engine braking automatically when going downhill. I only added additional engine braking. Obviously the car was designed to supplement the brakes with the engine. I never went above about 4500 RPM.

(BTW: braking is what you do when you press the brakes, breaking is what you do when you hit something with a hammer.)
 

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Discussion Starter · #12 ·
Typically, but I've experienced the same thing as jblackburn. Have you ever driven a Cruze down a steep hill, miles long, at 60-70 MPH? The engine doesn't offer much resistance, but it does a little good. Once I even turned on the A/C (wasn't cold outside but I didn't necessarily need it) to add a little more resistance. :D
Sometimes I use the AC as additional resistance as well.
 

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Discussion Starter · #13 ·
Mine would shake like crazy once they started to overheat. Didn't take much.

I always drop a gear or two (or sometimes the automatic does it itself) to hold speed back on steep downhills. Even if you didn't, long coasts still put the engine in heavy vacuum for long periods.
My Cruze also gets a lot of vibration when the brakes get hot. The OEM brakes are not the best, and I think the brakes are a little small for this size and weight of car. I have considered the larger brake upgrade that someone posted on this forum. I do a lot of downhill driving in and around San Francisco.
 

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Discussion Starter · #14 ·
As a side note, the speed limit east of Reno on I-80 is now 80 MPH. A couple times on my long drive I exited the freeway and went from 80 to 0 quickly on the off ramp. The first time, the steering was shaking hard and the whole car was surging near the end. It went away after the brakes cooled. After doing this a couple times over the course of my drive, the brakes actually seemed to be working better and had less vibration. Maybe it's not a bad idea to brake from 80 to 0 occasionally.
 

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First question is why are you down shifting in car and not using your brakes.
Brakes are stil a lot less expensive than a transmission or engine.
Two different issues here. Downshifting for a long downhill is a good idea. That doesn't harm the drivetrain. Certainly a lot less harm than crashing into something. Where it becomes a problem is when you have people who downshift for every stop or every corner - because that's what racers do. But racers rebuild their cars every year, if not every race. And even racing brakes won't last more than a few laps if they didn't.


You may not know this, but all automatic Cruzes do engine braking automatically when going downhill.
Yup. I think it's about 7 seconds of continuous significant braking that triggers it. Just another example of the car managing itself.
 

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My thoughts:

I used to drive max-loaded pickups with trailers behind them for years. Typically I was behind the wheel of a Duramax, so the drivetrain was substantially more stout than a Cruze, but it was also under exponentially more stress. Would engine braking cause harm to the drivetrain over the long run? It's plausible, but not likely IMO, unless you're being a moron and going from 5th to 2nd or 1st gear and bouncing the tach off the redline.

However, it is verified that overuse of the brakes will cause failure, and I've seen plenty of that. That's a short-term issue that quickly can turn into a disaster, so anything that can be done to eliminate the threat of the brakes failing is a win-win in my book.

With regards to oil consumption, I never saw either of our diesel trucks lose oil from extremely heavy use, and both were at around 200k miles, and both were tuned.
 

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As a side note, the speed limit east of Reno on I-80 is now 80 MPH. A couple times on my long drive I exited the freeway and went from 80 to 0 quickly on the off ramp. The first time, the steering was shaking hard and the whole car was surging near the end. It went away after the brakes cooled. After doing this a couple times over the course of my drive, the brakes actually seemed to be working better and had less vibration. Maybe it's not a bad idea to brake from 80 to 0 occasionally.
Yeah, burned some pad buildup off the rotors that create high spots that shake when braking hard. But the Cruzes stock brakes deal pretty poorly with heat between a mix of pad compound and rotors made from cheap steel - hence, shaking.
 

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Discussion Starter · #18 ·
Yeah, burned some pad buildup off the rotors that create high spots that shake when braking hard. But the Cruzes stock brakes deal pretty poorly with heat between a mix of pad compound and rotors made from cheap steel - hence, shaking.
I did a couple more 70-0 quick stops yesterday just to see if it would improve more. I did it similar to what you do when you are breaking in new brakes. It definitely made a difference. With the quick stops and long braking I did on my drive, and a couple more stops yesterday, the brakes almost feel like they did when they were new. Might be something for people to try if they think their brakes are are starting to warp.
 

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Never could contribute excessive oil consumption to engine braking and have done a lot of this. Like to go 100K miles before having to do a brake job. But always have to stay on top of the brakes with this stupid road salt, brake drag is the key reason why they wear out and quickly.

Ha, with the Cruze, loaded have about a 4,000 vehicle trying to slow it down with an 86 cube engine and this happens whenever you take your foot off the gas. Only thing that slows it down is engine compression, and really don't get much of this because the TB is closed, not very much air going into the cylinders to even get some compression.

But when oil consumption increases, first step is to do a compression test, super easy in the Cruze, only four cylinders to get at and super easy. Pop off the fuse relay cover, pull the starter relay, have a couple of tabs on my remote starter switch since I am doing this alone. Should read 150 psi across the board when cold. If low, can try Seafoam to clean the carbon off the rings. Most of the time this works, but when it doesn't, time to pull the pistons, can have a broken ring or something.

If this is good, can be worn valve guides or even the valve seals. PCV is another issue, removing the air intake into the turbo, will see excess oil. On older engines, PCV was mounted high on the valve covers, and even had a filter underneath it. Not finding this on the Cruze, so always find a little oil to the inlet to the turbo, but not worth writing home about.

Another cause of low compression is excessive carbon build up under the intake valves., if you toss a can of Seafoam in a full tank of gas about every 4K miles, won't have this problem. Not anything new, been this was for the last 100 years or so, with 5.5 pounds of carbon in very US gallon of gas.

Recall pulling pistons where the rings were closed tight with carbon, and even a 1/4" of carbon build up under the intake valves, was really a job to clean this up.
 

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Heck, my Cruze engine brakes itself with the cruise control on. Say I have the cruise set to 70, if I'm going down a grade here and I hit 78, my Cruze revs itself to 4k and tries to help it slow down.

FWIW, the cruise control is amazing on these cars. Seems to literally have eyes on the road and predict what grades are up ahead.

Just curious, how high were the revs when you downshifted? If it's below 5k I wouldn't think it'd matter.

Edit: Never mind, didn't see there was a &^#@ second page, lol
 
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