Breaking in question

[marpel]

Hello,

 

Am in the process of breaking in a new truck. I anticipate towing the travel trailer in the next two or so months. The manual indicates for the initial break in period to essentially drive normally, except keep the speed below 55 mph (88 kmh here in Canada), for the first 500 miles and not to tow during that period. It also indicates when towing for the first time, to keep the speed below 50 mph for the first 500 miles of towing. My question -

 

Is the real purpose of the speed limit, during the respective breaking in periods, to keep the RPMs below a certain level or is this requirement strictly limited to speed only? Although I am a conservative driver and have not had the tach over about 2500 RPMs (am driving in the greater Vancouver BC area), I think, especially upon starting from a stop, it would be easy to hit quite high RPMs while not hitting the 55 mph limit. As well, when I tow for the first time, the areas surrounding Vancouver are, except for going south into the USA along I5, quite mountainous and if I was to go east into the mountains, I could easily hit high RPMs while still maintaining the manual's 50 mph limit. Your response may assist me in choosing the route of the first tow.

 

I initially thought the speed restriction in the manual was to allow the vehicle to break in without excessively high RPMs but, logic also suggests if that was GMs intention, they would state so in the manual. Anyone have an idea what the real purpose of the speed restriction is??

 

By the way, I have also been wondering why the U.S. went to metric description of engine size rather than the old customary measurement. I happened to be in Denver and rode in my son's father-in-law's truck and noticed it was a 6.0 litter, rather than traditional cubic inch. He didn't know why this had changed. Seems strange to keep all the other stuff the old way but change engine sizes.

 

Thanks

[gmtech4]

follow the manual and the engine thing is what it is i guess ,

 

just dont red line it lol

[ken1mod]

Gentlemen,

 

There is very little break in in the engine dept. Large truck diesels have no break in requirements and airplane engines require that the engine be run very hard for the first 50 hours.

 

The break in is mainly for the gear units on the truck and a gentle 500 miles will develop the nice polished gear tooth surface that leads to long happy life.

 

Ken

[RyanbabZ71]

The break in for the new Camaro ZL1 is to keep it below 80 mph

[gnet158]

I thought the big think was to vary your speed, and not stay at one speed for an extended amonut of time. I found it hard to drive 55, espically on the freeway. Everyone flying by me like I was standing still. I was so glad when I hit the 500 mile mark. No hard breaking either.

[yukon_denali_05]

And that's definitely a challenge

The break in for the new Camaro ZL1 is to keep it below 80 mph

 

[BlackZ71Silverado]

This may sound strange to some BUT the "take it easy" approach is not properly breaking in the engine. I know it's a different engine but on our 358 small block race engines, we hammer the crap out of them during break in at the shop. Need to get a good seat for the compression rings to the cylinder wall and putting around will not do that properly.

IMO, improper break in has a lot to do with oil consumption on these trucks. An engine not broken in properly will allow excessive blow by and push oil out of the breather. I am not saying drive your truck like a race car, just drive like you always do. Putting around and being easy on it because it's new will not help.

[waumo1]

I enjoyed the break in instructions in my Challenger owner's manual -

 

"While cruising, brief full-throttle acceleration within the

limits of local traffic laws contributes to a good break-in."

[BlackZ71Silverado]

I enjoyed the break in instructions in my Challenger owner's manual -

 

"While cruising, brief full-throttle acceleration within the

limits of local traffic laws contributes to a good break-in."

 

 

Yup, that'll work.

[marpel]

Thanks to everyone for the responses.

 

Funny how opinions vary and each seems to be offered with some surety (from "a gentle 500 miles" to "we hammer the crap out of them - Putting around and being easy on it because iit's new will not help"). Coincidently, I was at a GM dealer for an oil change today and asked one of the service techs the same question. He couldn't confirm whether the speed restriction (on both initial break in as well as the trailer tow) was intended to limit high revs or not. He also stated that he had seen a lot of new trucks being used to tow right after purchase without even the initial 500 mile "do not tow" restriction.

 

When it's all said and done, I have been driving fairly normal, within the 500 mile 55 mph limit, and when I do tow, will probably be a bit gentle for the first 500 miles but not get too crazy.

 

Thanks again.

[BlackZ71Silverado]

You will have no issues towing with a brand new truck....Most people buy a new truck for towing and tow heavy with it the day they drive it rom the dealer lot. Just keep driving your truck the way you would always drive and you won't have any issues at all....Funny how the tech. doesn't know the proper answer to give you.

 

Here is some good educational reading for you about engine break in.

 

http://www.mototuneu..._in_secrets.htm

[tanked_darren]

I beat the piss out of my truck and did not follow the break-in instructions. I found the speed limit of the truck the second day I had it.

[savillian]

I enjoyed the break in instructions in my Challenger owner's manual -

 

"While cruising, brief full-throttle acceleration within the

limits of local traffic laws contributes to a good break-in."

 

 

I am going to pretend that you said this was in the SIERRA owner's manual when I get mine!

[MikeNH]

Everyone has covered the break in question already as for engine size- it seems that you started seeing that here in the 80s when the US started flirting with the metric system.

[jandersinc]

I hooked up my 7,000 pound (I now have a 9,000 lb boat) the day I got this and drove it to the lake and have towed with it ever since. I haven't had a single problem with it.