Should I Switch to Synthetic and should I flush

[spook1]

Guys, I am new here and will admit I am no car expert. I have changed my oil and done other routine maintenance though forever.

I just bought a 2005 Chevy Trailblazer 4WD that has 72,000 miles on it. I am unsure of the previous owners maintenance schedules, etc. I have always changed my oil at 3,000 miles pretty regularly. I drive 21 miles to work on country roads and then back home. I do a little town driving as well.

My question is if I should switch to synthetic oil. I have read that leaks can happen when switching to synthetic, etc. I a was wondering if I should run a engine flush if I do switch. I just don't want to mess anything up or cause any problems, but would like to use synthetic if it is that much better.

I have also read to just switch to synthetic and then change the oil after 1,000 miles as the synthetics would clean as well. Or even to switch to a synthetic blend first, and then a full synthetic. Sorry for the lengthy question, but thanks in advance for any advice.

 

[tig1]

Look through the oil fill hole and see if there is any sludge. If not just change to a quality synthetic of your choice, and run 10K with one filter change at 5K. Do this a time or two then no additional filter changes are needed, and 10K OCIs will work well for you.

 

[Corvette Owner]

You are wasting modern oil changing at 3,000 miles. Any modern oil can go 5,000 miles. I do 7500 miles with synthetics.

 

[HTSS_TR]

Any name brand conventional with API SM/SN 5W30 will do well for 6-7k miles OCI with your driving conditions, if you like to use synthetic oil then extend OCI to 10-12k miles or a year whichever is first.

 

[mechtech2]

Use conventional oil and go 4K.
Pennzoil conventional is great.

 

[Donald]

Given that PP at Walymart is about $10 more than dino, why not go synthetic?.

 

[spook1]

I was thinking the same thing about the small price increase being worth it. But then others say just run the conventional oil and change at 4k. I have always used Pennzoil yellow conventional in the past.

 

[garlicbreadman]

do what youve been doing but extend drain to 6-7k. your engine wont benefit at all from synthetics.

 

[dparm]

Originally Posted By: garlicbreadman
do what youve been doing but extend drain to 6-7k. your engine wont benefit at all from synthetics.


I don't think I'd go as far as to say it won't benefit...

 

[chubbs1]

Originally Posted By: spook1
I was thinking the same thing about the small price increase being worth it. But then others say just run the conventional oil and change at 4k. I have always used Pennzoil yellow conventional in the past.




No changes need to be made to prepare for synthetic oil. You don't need it but it wont hurt. I personally spend the extra money for "syn" but I am not afraid of any of the major brand conventionals either. All I am saying here is if you choose a good "syn" there are no special steps to take. Just pour it in and enjoy.

 

[tig1]

Originally Posted By: dparm
Originally Posted By: garlicbreadman
do what youve been doing but extend drain to 6-7k. your engine wont benefit at all from synthetics.


I don't think I'd go as far as to say it won't benefit...


+1. When the benifits are really noyiced may be 150-300K. As we know there are several benifits to synthetic oil.

 

[ahoier]

I've always been a fan of "flushing" pre-owned cars....

I used 5-6 oz. of Seafoam in my 07 Rio7, and it quieted up a cold-start rattle....car only had 24k on it when I got it....BUT it was a rental car...

Then when I got my 08 Optima, It too had a bit of a rattle on cold-start, so had good luck with the Seafoam....added it to the crankcase and the fuel....never messed with the air intake/vac. lines.....


On my newest gem, the 88 Aries, I've had great luck with Marvel Mystery Oil in the crankcase....it's said to have only 50k on it, just hit it this past week, and the first couple OCIs with the MMO, the oil came out JET black lol....I call it success

As always, YMMV

But I swear by MMO as an engine cleaner (don't like the word Flush....since it's so commercialized...) - it's not to be used as a "flush" though.....you really want the MMO in there a good 3000 miles.....or 3 months, whatever comes first. Then drain it, and change it

 

[Artem]

I fully agree getting all the fluids changed until its 100% clear that it's fresh juice that has been changed recently. You can never be too sure what's in there and how long it's been in there.

As far as engine oil, if it's clean while looking through the oil fill hole, proceed to run the appropriate oil of your choice (synthetic oil conventional) with maybe the first oil change being a little shorter then needed, just to remove all leftovers. Then proceed to either follow the manufacturers recommendation or extend the oil change intervals as per a used oil analysis.

 

[gathermewool]

Originally Posted By: ahoier
I've always been a fan of "flushing" pre-owned cars....

I used 5-6 oz. of Seafoam in my 07 Rio7, and it quieted up a cold-start rattle....car only had 24k on it when I got it....BUT it was a rental car...

Then when I got my 08 Optima, It too had a bit of a rattle on cold-start, so had good luck with the Seafoam....added it to the crankcase and the fuel....never messed with the air intake/vac. lines.....


On my newest gem, the 88 Aries, I've had great luck with Marvel Mystery Oil in the crankcase....it's said to have only 50k on it, just hit it this past week, and the first couple OCIs with the MMO, the oil came out JET black lol....I call it success

As always, YMMV

But I swear by MMO as an engine cleaner (don't like the word Flush....since it's so commercialized...) - it's not to be used as a "flush" though.....you really want the MMO in there a good 3000 miles.....or 3 months, whatever comes first. Then drain it, and change it

In the Rio, was the first oil/filter change AFTER the Seafoam?

 

[spasm3]

I am not a fan of flushes. I would do a run of Pennzoil conventional and see it it uses much oil in a 5k run. If it does not use much then do synthetic at a 7500 mile interval. If it uses much oil, its cheaper to stay with a good conventioal like pyb( Pennzoil conventional).

 

[Oregoonian]

Originally Posted By: spasm3
I am not a fan of flushes. I would do a run of Pennzoil conventional and see it it uses much oil in a 5k run. If it does not use much then do synthetic at a 7500 mile interval. If it uses much oil, its cheaper to stay with a good conventioal like pyb( Pennzoil conventional).


+1....this is a good & safe suggestion....

5000 +/- for conventional....and 7500 +/- for synthetic....considering your driving habits.

Also...use a good mid-tier filter (Purolator PureOne, Napa Gold or a WIX).

 

[bluestream]

I would use the synthetic, but go longer OCI's.

Yes, you can flush; just put the seat down...

 

[cancov]

Pennzoil Conventional is discussed here regularly as a great conventional oil with very decent cleaning capabilities.

I, too, was taught the every 3,000 mile rule and agree with it in certain circumstances. Your circumstance is not one. Your vehicle gets up to operation temperature for at least 15 minutes, twice a day. This allows the oil to due what it is suppose to do, remove solvents and clean and protect.

If it were me, I'd inspect the motor as best I could, either down the pour cap, which may not indicate anything, such as the Toyota oil "flap" which oil can "singe" on but not necessarily give a good representation of the condition inside the crankcase. A better way would be to remove the valve covers or oil pan, however this can get quite intense depending on the vehicle. I'd change the current fill to your Pennzoil Conventional, run 3-4,000 miles and perform a used oil analysis (Used Oil Analysis) with a company such as Blackstone. This reports will give a good idea of how well your motor is wearing/operating.

Either way, Pennzoil Conventional out to 4-5,000 with a decent oil filter, such as WIX, Purolator PureOne, etc., and you'll be fine.