martinjp

I just purchased a 2006 Silverado Crew Cab with 5.3L 4x4. I was unaware of the engine break in process. It recommends under 55mph and varying engine speeds until 500 miles. I have 550 miles and am wondering if I should do the break in now, or is it too late? What negative problems may I have as a result of not breaking in motor properly? I drove the car about 200 miles from the dealership at 65mph and not varying speed at all. The dealer never manetioned any engine break in procedure!! The rest of the first 500 miles have been in town, so that part is pretty much per the break in procedure. Also, when can I expect to start getting 15-19 mpg. I know a fresh engine is a lot tighter and may take a while to get better gas mileage. I currently am getting 13mph average.

SLJ2137694

I would say, "Don't loose any sleep over it"!!! The main thing you want to avoid is working the engine and drivetrain real hard and getting things overly hot. When you vary the engine speed with speeding up and slowing down you load the rings and that assists them in seating sooner. Todays vehicles require very little break-in because of the precision machining and close tolerances that are possible. If it was my truck, I would drain the oil and install Mobil 1 in it of the viscosity recommended in the owners manual, probably 5W-30. I did that on mine at 100 miles. Synthetic will not prevent proper break-in, if it did manufacturers would not install it as a factory fill.

martinjp

Steve,

Thanks for the info. I will change the oil as you recommended. Since the synthetic oil supposedly slows down the engine break in process, will that be an advantage since I did not break it in properly? Also, should I continue with the ring seating process up till 1000 miles, or does it matter. How about gas mileage. I am only getting 13 mpg, however, I know new motors are tighter and am wondering if and when I should expect to see a change in mpg.

Thanks again for your feedback.

Joe

SLJ2137694

The critical break-in period for the engine and rings is over. In a precision fit engine, rings will pretty well seat themselves within the first 100 miles. The "GREEN ENGINE SYNDROM" as GM calls it, will continue for 3000 to 5000 miles. In this time period fuel economy should continue to improve and parts will continue to burnish themselves into a proper fit. When I build an engine I make 10 moderate accelerations with long coast downs after each acceleration and after I do this 10 times I consider the major portion of ring seating to be accomplished. Rings will continue to wear in but the critical seating is done. If the rings are not loaded during the break-in, sometimes the rings never do break in properly, however with todays rings this is a very rare event. As I said, don't loose any sleep over your so called lack of proper break-in. Many people do not concern themselves with this detail and vehicles are generally going to break-in properly if driven reasonably. The important thing is to avoid heavy loads and high heat for 500 or so miles. Enjoy your truck, I have a 2005 Crew Cab Z71 4X4 that I really enjoy. You might want to get a chassis grease job also ASAP. There did not appear to be a comfortable amount of extra grease in the joints of my truck when I got it. I didn't want to chance it so I grease mine at 100 miles. This may really be a "make me feel better" thing but I would rather have a little extra grease than take a chance on not enough.

matador

On mine I didnt realize the proper breakin was there until I had a couple hundred miles on it. I was getting appx 17 mpg with it but that has since went down to 15 with 10,000 miles on it now. It also uses appx 1 qt of oil in 5900 miles. I changed the oil at 500 miles and then at 2500 miles on the oil and then at 5900 miles on the oil. I also checkd the oil filter by taking it apart and looking at the pleats. I was amazed at how many bright specks of metel was in there on the first oil change. the last one there was very little specks of metel in the pleats in the filter. Is this all normal?

SLJ2137694

You are questioning if the use of 1 quart of oil in 5900 miles is normal?!? I hope you don't expect your engine not to use any oil. The auto industry standard for oil consumption is 1 quart in 2000 miles and you are way better than that. Specs of metal in the oil filter during break in. Of couirse there will be a little metal, thats what break in is all about, wearing in all the machined parts.

matador

Thank you very much for your reply SLJ! It does put my mind to ease a little bit.

martinjp

Wow--1 quart per every 2000 miles. Thank you for that spec. I have owned many cars and have never had a single car that burned that kind of oil. All the new cars I have purchased have never burned any measurable amount of oil. Could this spec be in place due to what appears to be a common lack of proper engine break in? I have spoken to many people, and many are unaware of a break in process. The dealers seem to forget to mention this procedure(as did mine). Why would one new Silverado 5.3L engine burn a lot of oil, while another does not? I am not an expert by any means, but the only reason I can think of is oil getting past the rings, due to poor seating(new engine). Steve, what other variations in the engine would cause such a variation between one new motor and another? Does your Silverado burn that kind of oil?? Thanks!!

Joe-2006 4x4 Crew Cab Z71 5.3L

matador

I have about 12k on the truck now and I am thinking about putting mobil1 syn in it the next oil change for the winter. Is that enough miles on it for breakin?

SLJ2137694

Manufacturers install Mobil 1 as a factory fill on some new vehicles. Does that answer your question?