# 8.1l Vortec



## azthroop (Jun 16, 2007)

I was wondering if anyone has to add some oil to the 8.1L between oil changes. I sometimes have had to do that and I finally asked my mechanic to look at it. He checked everything he could and he said that this engine is made to be "run" not just for driving the kids a mile to school or the store. He said that once we start really "using" it, it should be better. He also said that these big blocks have "piston slap" and until they get going they can have some seepage.

I guess that is why I am asking. Both the mechanic and I have checked the exhaust, looked for drips, and checked the coolant. The engine runs great, not a single problem except that every couple of oil changes it needs some added.

I will say that after our 4,000 mile trip to get the trailer and the drive back I only added 1 quart. Not bad??

I am just used not adding anything to our smaller cars.

Let me hear what you have to say.

Jim and Sandy


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## jfish21 (Feb 14, 2006)

I'v got the same '01 8.1 and If I drive alot it does not seem to need much added.
If it sits alot more so in the winter months I may need to add a qt. or so. 
I was told this was comon in the big block.

Jerry


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## azthroop (Jun 16, 2007)

Thanks. At least there are a few that have similar situations. I will just make sure to check it more often since it is primarily used by the DW to drive the kids around. I guess I will have to give her my Rav4 now then so that I can give it a workout!!

Jim and Sandy


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## battalionchief3 (Jun 27, 2006)

I have the 8.1 and on a trip from Ga to MD and back then to southern VA I had to add a qt. Normal for a BB. My mother had a 5.0 in a crown vic and it did the same thing. I checked the chevy truck forums and they all said the same thing, 1 qt every 3-4000 miles is OK.


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## NJMikeC (Mar 29, 2006)

Piston slap?

I wouldn't worry about it using oil. If you driving it around town especially in cold weather here is what happens. You dilute some of the gas due to the rich running engine. Once you warm it completely up or run it kind of hard that diluted oil will be vaporized, burnt , whatever.

All engines would inhibit the same issue. As a case in point my BMW says 15K oil change intervals are ok. They also say to never warm the vehicle. Just get in and drive, thereby allowing that rich mixture to actually propel the vehicle as opposed to just warm it up. I of course change at half the inteval but still don't warm up that car.

So by warming your vehicle you are polluting your oil. It is fact.


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## Collinsfam_WY (Nov 9, 2006)

Err...in the hot rodding world piston slap typically means "rebuild your engine". Good thing you are towing and not rodding







I heard your 'Burb and it did not sound like it had piston slap to me. Typically when people talk about piston slap - they are talking about what sounds like an audible engine knock. Some people think GM's have this more than other mfg's - you can read up on it at pistonslap.com but I dunno - guy who made the site could just be a hater for all I know.

Since there are no visible leaks or spots on the garage floor, I suppose it could be real mild and that might explain some of the oil loss due to the bore being larger than it should be so the rings are not seating.

The motor you see in my "dyno pulls" post eats a small amount of oil - I would guess that if it turned the miles yours did - it would probably be similar. 'Course a chunk of the loss on mine comes from the craptastic taiwanese valve covers that MP sells.

I still would love to see you chip that motor and drop an intake and exhaust on it







'Course that would mean we would need to trek out to AZ to check it out too. Those 8.1's are awesome machines.

-CC


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## 496silverado (Sep 28, 2006)

Hi









We just returned from a 1400 mile round trip to Tennessee and I had to add a quart before I started home.

You asked the question I was going to ask the group also, thanks!









I really don't think it's a major issue,IMHO.

It still tows like a champ!









Never a lack of power.









Good luck!

Russ


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## mswalt (Sep 14, 2004)

Mine uses a little oil, too, but since I change it every 3000-3500 miles, it's hard to say just how much. I remember one of the technicians telling me it was about a quart low at one of those changes.

Mark


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## battalionchief3 (Jun 27, 2006)

I was told by a Dodge rep once. The engine bore is so percise now and the pistons are not as perfect so..... a little oil will sneak by and a qt is ok as long as your not leaking it. Unless you have a pre-98 3.0L engine, then they drop the valve guides and the seals pop off so oil gets sucked down the guides and they smoke like a freight train. Easy fix though, I must have done a hundred or so.


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## jgerni (Nov 10, 2003)

Mine uses a little between changes. I switched to 10w 30 oil and it helped. From what I have read a quart every 4000 miles is nothing to worry about with this motor.


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## ron4jon (Sep 26, 2005)

Yes - my 8.1 also uses about one quart every 1000 miles during heavy towing and almost none during in-town and mild country tooling around (i.e if my lead foot is not kicking it). It has ~ 18K miles on it now. Same low oil consumption towing my bass boat. I have heard that the heavy towing oil consumption is pretty common for large bore gas engines. I use Mobil One Extended Miles 5-30 but maybe the next time that I change oil I wiil use 10-30 Mobil 1. All-in-all, I love this truck and how it tows. I used to have two Corvettes a long time ago (a '63 split window coupe with 327 and a '68 with 427) so this truck is now my "sports car substitute". I have had GM trucks off and on for a long time and this one is the very best ever. The ride is actually great even for a 3/4 ton & 4x4. I didn't have to mod the suspension this time to tow my 5er - it rides level as is. I just guess I lucked out this time. Now it's gas consumption is not pleasant to talk about.....! But I am having a ball with it and it's my only "toy".


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## azthroop (Jun 16, 2007)

Thanks to all of you! I used to have (in my olden days) a '74 Ranchero with a 351 Cleveland, 4bb heads, Holley 650 double-pump carb, Sig Cam, etc. it did use some oil, but I was also able to beat most vehicles out there and of course I would try.

Since I am now a law abiding driver (ha!) I try not to blow by too many people with the 'burb. I was just worried because my little Japanese cars never take oil. I guess I just had to go back in my youth to remember!

For Curtis, 
I do have a Flowmaster exhaust on it. That's what makes it sound soooo nice, unless you are my DW and she hates the "noise"! I do want to put on a K&N cool air intake (or do you have any recommendations?) I have been reading here and other places that it helps quite a bit. Give me your opinions. That goes for everyone, but I already know you would!!

Thanks again.

Jim and Sandy


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## Collinsfam_WY (Nov 9, 2006)

Jim - I am not familiar with what works and what doesn't regarding intakes for Chevy's. I'd find a late model Chevy tuning/rodding forum and see what they are saying works well for 8.1 Burb's that tow. For instance - after reading about one intake I was interested in, I found it made great power - about the best of any of them. However, every person who towed with it said it drove them nuts from the noise it made under constant load. Most had already taken it off and either replaced it with the stock one or a different aftermarket. If you get one, let me know what you think.

Love the sound of that 'Burb - the Flowmasters are working well









-Curtis


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