[riddic1985]

how much oil does the 4.3 hold

 

[xtremejimmy]

4 1/2 quarts.

 

[riddic1985]

thankl you

 

[mcgruff1]

What weight oil does a '99 vortec take? 5w-30? Should I run the same weight oil for the break in period?

 

[peteyz24]

yeah run 5w30 all the time that is what the engines lub system is designed for, there have been tests run my the baldwin oil filter company that prove 5w30 actually lubricates better than 10w30 in todays auto engines

 

[xtremejimmy]

i believe so. I've been running 5w30 since day one that i've owned my truck. not a problem ever. I have 120,000 miles and still holds 40 psi oil pressure at idle. As long as u maintain these 4.3's, they will last forever and ever. LOL. so yeah, use 5w30. Some say 10w30 is just fine if the weather is not freezing where u live. but i dunno, i havent changed yet and dont plan to.

 

[mcgruff1]

Same for the break in period too--cheapo 5w-30?

 

[xtremejimmy]

well, that all depends quite honestly. first off, how many miles does your motor have? and second, if it has really low miles still, like less than 15k, switch to synthetic and dont ever look back to crude oil. I wish i would of been able to do that but i am the 2nd owner. lol. Eventually, i'll rebuild and run synthetics when my motor decides to die. but it seems that it will last forever right now!

 

[mcgruff1]

Theres 50k on this motor. After 500 miles Im running full synthetics, but your not supposed to during the breakin period. I already got some 5w-30, will that work ok?

 

[BlazerLT]

don't use synthetic during the break in period!

Worst thing for your engine. The synthetic oil is so good that it won't allow the rings to seat and break in and you will suffer from lower cylinder compression for the life of the motor.

 

[xtremejimmy]

then tell me this, why does the LS1's come with synthetics from factory?

 

[peteyz24]

who knows, but i have read the same thing on many other forums about no syn oil during break in

 

[97S10SS]

I run 10w-30, never had a problem with it. The temps don't drop below freezing much so thats why I run 10w-30. I also use full synthetic.

 

[BlazerLT]

then tell me this, why does the LS1's come with synthetics from factory?

Are we driving LS1's? Nope....

Use good quality dino oil until 5000-10,000 miles to make sure the engine is broke in properly and then do the switch.

 

[mcgruff1]

I said I knew that your not supposed to use synthetics during the breakin period. I just wanted to know what weight oil would work best?

 

[BlazerLT]

5w30 will be absolutely perfect.

 

[xtremejimmy]

lemme ask ya something BlazerLT, how much have u worked on your 4.3? Cause u answer me in a smart ass manner, because it seems that u think u are superior to me when it comes to knowledge of these motors. I only put my input in because of my previous experiences. And yes, i did have my codes checked out before i changed all that crap anyways, and still turned out to be the same problem. As a matter of fact, i have 2 other friends with CPI's that had to do the same exact thing i did. So not to sound like a dick, but i would appreciate u not talking to me in such a demeaning manner. That is all.

 

[CenTex]

Here's my 2 cents. During the breakin period, I monitor my gas mileage. When it quits fluctuating and settles down, I change to synthetic. So far this has varried from 12,000 to 22,000 miles.

Yes, some engines come with synthetic in them from the factory, but I believe they are prepared differently during the buildup.
I know that my neighbors Ford van did not need to have a breakin period. (per his owners manual). His van has over 170,000 without problems.

 

[BlazerLT]

then tell me this, why does the LS1's come with synthetics from factory?

I wouldn't throw stones in glass houses. Look at the above answer you gave me to my first statement.

I answered with exactly the same amount of attitude you gave me.

I don't think I'm superior in any way, shape or form, but I do know that synthetics are not to be used during breakin with our engines.

 

[NCHEVYHEVN]

I run 10w30 in the summer and in the winter I run 5w30. Gets kinda cold around here.

I wish I could run synthetic but I have a tiny tiny tiny oil leak for the oil cooler hose but I know once I pour in the synthetic it will turn into a puddle in the driveway.