Change oil, then again after a week or so..

On a high mileage vehicle, anyone ever try back-to-back oil changes? Just wondering if it might flush a bit of extra crud out.
My Cobalt just broke 204K, zero leaks or issues, but not as responsive as she used to be. Go figure, right?
Anyone try this?

 

Probably wouldn't gain as a much as a can of Sea-Foam. How is timing belt/chain? Overall tune?

Gary

 

Overall, pretty good. Timing chain is supposed to last the life of the motor, swapped out the serpentine belt last weekend, still needs struts- but that's another issue.
So- Sea Foam in the crankcase? If I do that, I'll have about an hour tomorrow of drive time before I'd drain everything again.

 

I would run a can in the fuel to help clean the injectors. You could try a little in the crank per their insructions but if you have changed oil regularly I wouldn't expect it to help. Never heard of a lifetime chain, things can wear and or stretch. Maybe MasterMech will chime in also.
Gary

 

Thanks. Motor has a little noise, nothing anyone would worry too much about(slight exhaust tic.) . I pay attention, car has to last another 100K before I inherit the wifes CRV.
New plugs and coil boots in place, about 45K on those and no issues. I'll change oil again tomorrow, just to see if if I notice any extra debris. I've never tried this before, always changed it out on schedule but I figured what-the-heck, long weekend and I'm curious.

 

There are a number of products out there that will help, assuming that crud is your issue. Like people, cars slow down as they get older and short of engine rebuilds, adding stuff to the fuel will not bring back lost performance. You mention that you have 45K on the plugs....while there are all kinds of claims that plugs now last 100,000 miles, I don't buy that at all. Plugs can and do wear out long before that and new plugs are an inexpensive and quick way to restore lost performance. Take a look at the old plugs to learn about how the engine is combusting.....are there deposits, are the plugs scorched, ??? In terms of additives, one of the best additives is BG44k. It is not found in retail stores, but you can buy it online. Seafoam is excellent, and there is another way to use it that may be worth considering and that is feeding it through the brake booster line.

http://seafoamsales.com/vacuum-line-method-with-sea-foam/

A buddy of mine is a mechanic and he says that this is not recommended at all, however, some people swear by this method. If you do elect this method, I would suggest that you change the oil after the treatment as sludge deposits will have been dislodged.

If you want to stick with conventional fuel additives, Techron is another good one; look for the concentrate. While there is a lot of press out there that oil changes at 3000 miles are a waste, my philosophy is that an engine never ran poorly because of clean oil and filters. I used to use Gunk 5 Minute Engine Oil Flush with every oil change until learning that it is 90% diesel fuel. Now I just pour a quart of diesel into the crankcase and let it idle for five minutes before draining. If you are an oil change fan, be sure to select quality filters. Fram is absolute crap. Purolator One is a good choice as is Wix. Good luck.

 

Kerosene is a great cleaner and has less dye and stuff in it than diesel. I know in diesel oils castrol enduronS used to have the most detergents and would leave a top end very clean. I would only do it 30 minutes or less before the oil change.

 

Went ahead and did the second oil change. Only drove it about 20 miles but the oil was considerably darker.

 

I've heard of folks throwing in a quart of tranny oil right before an oil change. It's really high in detergents as well. I wouldn't drive anywhere with it in there but rather just let it idle for a while and then drop the oil.

I've heard of those lifetime timing chains as well and I'm suspect. A couple of my current vehicles have what is claimed to be lifetime transmission fluid...my lifetime, or the transmissions' lifetime? I guess if it makes it to the end of the transmissions' lifetime it'll be "true" huh? I still think that chains wear as well as the gears they run on and they will become noisier over time.

 

if it has been maintained regularly you should be good to go, Modern oils run very clean. A couple quick oil changes or additives are not going to undo 200000 miles of neglect. Also I think people are confusing timing chains with timing belts, chains are pretty much lifetime, belts need changed in the 60000 mile range.

 

2 issues here, 1: crud in engine is almost non existant due to modern oils and temp control (emissions) 2: even if there were crud in the engine, it wouldn't effect performance, and flushes wouldn't do anything. If anything, use a temp gun on the cat, check the enterance and then the exit. A clogged cat can inhibit performance, but will most likely cause a CEL. I wouldn't advise adding anything to the oil to "flush" it, just change it while it's hot. I also wouldn't add anything to the fuel other than Chevron Techron. Any fuel system cleaners may/will cause premature fuel gage sender problems. At 204k you should probably be on your 3rd set of plugs/wires and maybe a coil.

15 yr ASE Master technician.

 

Yes GM used nylon teeth on the cam sprocket, which failed, not the chain.
3-400k is probably considered lifetime for a gas engine.
agreed.

 

OK, but what about the '06 ECO-Tech in my Cobalt? I want to add a 80 HP shot of nitrous to it, just so I can get to work faster.
Any problems with that?

 

I wouldn't do anything to it other than change the oil regularly and use a quality filter. Engine today don't get as dirty as they used too. If you put a cleaner in it and there is some crud in the engine you may clog something up like the oil pump pick up tube. I know a guy that went to quick lube and they talked him into an engine flush. A few weeks later the engine in his truck was shot.

 

Go big or go home!