My mechanic and the dealership suggested that I get an engine flush. My car has over 200,000 miles (original LG4) and they said thiswould clean out the inside of my engine like new, therefore letting my oil flow to all areas of the engine. Will this be good for a engine of this age? Cost $140.00.

 

i'd pull a valve cover and see how crapped up it looks, also if there is a lot of build up in the engine there's a very good chance you'll have oil leaks you never knew about. the important parts that the oil goes too very seldom get blocked because the parts move and the oil is forced to them. running synthetic will also clean your engine out ,at less cost.

 

I've used engine flushes many times on older cars, but not as high mileage as yours. Most say to idle the engine a few minutes to circulate it, others say driving a few minutes is ok. The point is you want the engine to get hot. This loosens up the crud deposits. Whether you use an engine flush or use synth oil, change your oil filter before and after the flush to be sure you have one with enough capacity to catch the crud that comes loose, otherwise the oil filter may plug up and the bypass valve will open and no filtering will be done.

 

Wow, an engine flush is usually a good idea (assuming you have no minor leaks, as they can become serious leaks after being thoroughly cleaned out), but I wouldn't pay anywhere near $140.
If you don't mind possibly changing a gasket or two (from the possible resultant leaks), I'd recommend just a good parts-store flush. Repeat a few times, if the oil is especially sludgy. This way, you will save about $110.

 

Save the $140 on your next rebuild.

If it ain't broke, don't fix it.

You cannot magically flush out any varnish/debris/gunk. If any stuff is there, it needs to be dissolved to exit the engine. So you run an aggressive solvent "engine flush" with the engine running and all the gunk ends up in the pan to be sucked up by the oil pump. Hopefully the filter will catch that stuff.

You could add a quart of tranny fluid a few hundred miles to the crankcase before an oilchange. Tranny fluid is a high detergent oil.

You will see ZERO gains from flushing your engine. Please don't do it.

Find a new mechanic.....

 

I agree with a73camaro, don't do it. As far as I am concerned those flushed do nothing but harm your engine. They are thin and very hard on your internal engine parts. Engine gets very hot, yes it may start to dislodge buildup but that is not a good thing especially if you have managed to get that many miles out of your engine. Obviously you have taken care of your motor. If it aint broke don't fix it, very good advise.

 

I think I will just do the over the counter stuff and leave it at that. My engine runs fine now but we did see some gunk when we replaced the valve covers but still I like the "If it ani"t broke don't fix it" method.

 

The "over the counter stuff" is simply a solvent. You could add a pint of kerosene and have the same effect. A quart of synthetic per oil change will do more good.

AMSOIL makes a good flush that has solvent, detergent, & dispersives. It's an idle-only type. Before they came out with it, they recommended one quart of synthetic, balance petrolem for one change interval; two quarts the next, and so on, until you did an entire change with synthetic. This was just to clean up all the crude left by the petroleum-based oils. For a high-mileage engine like yours, that method is a pretty good idea.

What I typically do (and what I did with my 123k-miles Camaro change-over) is use the flush, run full synthetic, then re-do the flush at half the oil change interval. I found that my valve stem seals were hardened and cracked, so I had to replace them (no additive in the world will restore them). But, no other leaks after that.

One issue you need to be aware of with SBC's is the intake splash shield. Petroleum-based oils and their additives will coke up under that pan and on the exhaust cross-over passage. That becomes a constant source of contamination as new oil (even petroleum-based) disolves a little of that crude. The only solution is to remove the intake manifold, pop off that shield, and scrap off all of that carbon.

 

to be honest when u flush a high mileage engine all the crap that gets flushed is generally holding it togeather. itll leak everywhere and the engine will go to crap happend to a friend of mine. on a slightly different note, I changed the tranny fluid in my 70 mustang that I had no idea when it was last done. didnt know the history of the car. it fell apart and started sliping. it died in a month and I put a new one in. do as they say save your pennies and your motor dont do it man. l8tr good luck

 

What I do is drain the oil first put new oil in like some cheap stuff run it till warm. Drain oil take off oil filter replace with a K&N filter an add full synthetic oil partial not full considering you have 200,000 miles an it can get expensive. and just change oil regularly or even sooner, depending on your conditions. My engine at 200,000 did not like how thin full synthetic oil is, diffrent strokes for diffrent folks I guess

 

I use the ATF method; I've used it on countless cars (probably 10 of my own and my wife's at least) as well as on other people's cars; it has worked every time.

Add a quart of ATF when the motor needs oil. Change the oil after 500 miles or so, you won't believe how black and nasty it comes out. ATF will generally dissolve all the gunk and hold it in suspension, so you don't have to worry about crusties plugging up oil pump screens or the like. Use one quart of ATF instead of one of oil when you fill it back up. Keep some ATF in the oil until the oil quits getting black with dissolved formerly encrusted schmutz.

I mostly use straight 30 weight oil in my old motors, with a quart of ATF. I don't have any real high mileage cars I run like that though, I only have one 305 El Camino with 342,000 miles on it that we've had since the early 80s, a 74 454 Caprice convertible with 250,000 miles on it that we've had since the mid 80s, and my wife's 4.9 Cadillac with 210,000 miles on it that we've only had for 4 years or so, and all my other cars'motors are newer than that, so I don't know if it works over the long haul.

 

I will not even use the over the counter stuff. I will try the ATFluid and rechange my oil at 500 miles. Now I have been running 20w50 in the summer and 10w30 in the winter. I don't drive it to much in the winter. I heard that on high mileage cars synthetic oil is not to good. True or not? Should I switch to synthetic or stay with the heavier oil?

 

Here is my experience with engine flush's. When I first bought my iroc it was slugged up bad and I say very very bad. I bought some parts store engine flush. Ran it through, changed the oil and filter. Ran engine again for a little while then changed oil and filter again. Then something happen to the thermostat while i was changing it next day and I stripped the bolt. It sat that way for about a week. I fixed it then started up the engine and guess what it was doing? Fricken knocking!!!! man I was so pissed. Well I had the extra cash so i decided its time for a rebuild anyway since the 130k millage. Well when we pulled the engine out and took the pan off. By this time there was no oil, but the whole sump of the oil pan was filled with nasty sluge. Heads were still full of sludge and there was a ton of nasty slude doen the dist hole. I was like wow how did this thing even run. Let me tell ya though I will never do a store engine flush like that again. My dad told me it was build up like that from running hot. It ran hot when I bought, hence the reason i changed the thermostat. I wouldnt do a flush unless you have the spare cash to do a rebuild.

 

89Iroc,
Sounds like a typical result from using cleaner in an older engine. It does its job of reducing crud buildup but then exposes worn parts and leaks you never knew you had because the sludge plugged them up.

86NiteRider,
I'd stay with the heavier oil. The synth may be too thin and find leaks due to your high mileage.

 

I know this is an old topic, but have a question! You keep one quart of ATF in your engines continuously? My 305 runs like crap, lack of power etc. At the moment, I'm running 10w30 Mobile 1 and was thinking about flushing the engine real good. The engine does have a small oil leak somewhere. The only reason I use Mobile 1 is, there is no dipstick (long story) & it uses oil.

Brandon

 

84,

If you've been using Mobil 1 for some time, the engine is already getting cleaned. You may want to change the filter between regularly scheduled oil changes if you're getting a lot of contaminants in the drained oil.

What's the deal with the dipstick, anyway? I'd be trying to fix that.

 

The previous owner added a chrome dipstick/tube POS. He had to grind some metal off the dipstick for it to work. Pulled the thing out one day, to check oil, and wouldn't go back in. I have a nice new GM dipstick/tube ready to go in. But don't have the $$$ to put in. I'm using the oil pressure gauge as a "dipstick" for the time being. Yesterday it was running near the red mark at idle. Time for a half a quart. Thinking about going to a conventional 30wt. due to the oil usage (have a feeling a oil leak exists).

Brandon

 

It should cost about $0 to install a dipstick tube, give or take about $0. You will probably have to remove the starter, and may It may be a little bit of work, but it shouldn't prevent you from sliding in a new tube. That may be the biggest part of your oil leak, too.

Oil pressure usually doesn't start to slide until you're a few quarts low, not just one. I'd forget about the engine flush completely until you get the stick back in place.

 

I changed the oil filter and added 2 quarts, pressure is back to normal. Did notice the oil in the filter was black (just changed the oil last month). Anyway...good to hear the labor costs. Will I need to remove the exhaust manifold?

Brandon

 

yeah i dont see where the $140 comes in. The only "engine flush" i know that gms performs is just a can of "Top end Cleaner". you just pour it in, let it rev for a little while and then change the oil. It'd run you about $20 at a gm dealership.

Seeing how your engine has 200k miles on it....i'd say its a pretty good bet you dont need your engine flushed, if it did need flushed it wouldnt of made it to 200k.

But if you're really worried about it go right ahead and pull a valve cover and check out how much crude is in there. Or you could just put a flexi-light down the oil fill tube to check it out.

If it is dirty, just grab a can of Top end Cleaner from a gm dealership and follow the directions on the can.

 

both GM (well one is Saturn) dealers i worked at have engine flush machines

first one was a buick dealer we used a Bilstein machine there


now at saturn, we use an EnviroLution engine flush machine

 

I read about something similar in a newspaper when I was on vacation a few years ago... it was a local rag, and I went to the automotive section. They had an "Ask the mechanic" section.. guy wrote in, had a high mileage import, and he flushed his motor. He said he was driving on the highway when his motor stopped, and when it was towed to the mechanic, the guy told him that the engine seized up. He wanted to know what happened. The newspaper guy told him that the cleaner must've clogged the oil pump's pickup with sludge, starving the motor for oil.

I still have my unopened can of Motor Flush that I bought back in '94 for my car. Brought it home and decided against using it- back then, my 2.8 had 64,000 miles. This weekend, that motor just turned 249,000 miles! Don't even bother with the flush. Regular oil changes are where it's at.

Oh, and yeah, it'll clean the inside of the engine out like new- because you might be putting a new engine in! $140.. wow...

 

well i wouldnt call any motor flush additive junk because it killed a few engines. I mean, it sounds to me like the cleaner did its job just fine. The problem was the engine was just too dirty, all the filth it knocked loose just clogged things up.

Thats one thing to consider though, if you're engine is TOO dirty you may not want to add a cleaner. I've seen that a few times, some customer would come in because they noticed theres a whole lot of sludge in their engine (although they never seemed to realize they drove it 30k miles without and oil change) and they'd want to get it flushed out.

I just have to tell them no if its a real dirty engine, the chances of clogging things up are just too great. I wonder if those fancy flushing machines do any better job at it...

 

I like the sounds of the ATF method. I'm concerned about my daily driver (98 **dge Intrepid, 2.7) because they are know for sludge buildup. I'm always right on or early on all maintanence on it, but I only know about the last 15,000 miles, out of 89,000 on the clock. The ATF sounds like the safest to me! It's not a solvent type cleaner trying to clean it out all at once, therefore shouldn't be any issues with clogging up the bottom end, along with the fact that it should keep the crub in suspension anyway! In general, I've always been AGAINST ANY engine flush, or oil additive as anything more than a short-term solution.

 

How do those engine flush machines work?

 

86 what kinda car didja get your ss badges off of or are they decals? they look good nice from what i can see in pics

 

I have almost 200,000 miles too on my 350. I don't like the idea of the over-the-counter stuff or the engine flush machine. I might like to try the ATF method though. Just one quart next oil change instead of a court of oil? Now this isn't going to interfere with the oil's lubrication job is it? Because I've heared by putting in oil additives, you that can do more harm than good, by getting in the way of the oil doing its job. I change my oil every 3 months (far less than 3,000 miles) and my engine runs great, nice and smooth, like I said before, it has almost 200,000 now, proud to say dino oil all its life. Would you guys suggest me keeping with my short interval oil changes or should I run a quart of ATF along with my normal changes? Or should I stick to the: don't fix it till it breaks? Suggestions? Thanks.

 

Wow sorry guys, just relized this post is OLD.

 

Replying to an old post isn't a bad thing! It keeps old topics from just being repeated, instead, they get added to!

Now, back to the topic....

Do you have suspicion that you have sludge, or oil buildup in your engine? I would venture to say that changing the oil as frequently as you say you do, you should be fine. If you have good reason to believe you have some oil buildup, I would reccomend the ATF trick for the next couple oil changes, maybe not even a full quart, maybe just a half.

As for the ATF hurting the lubrication, the ATF IS a lubricant, just a bit (Not a lot) thinner and it has more detergents in it then Motor oil. I can't say it won't cause harm, but I really don't see how it could! Besides, the detergents in ATF probably aren't aggresive enough to knock all the oil buildup loose at once, or in big clumps like the "cleaner's" or "flushes" dowhich is why they can cause so much harm!

Just a side note, my 305 that I pulled out of my 84 a few months ago had very little oil buildup in it, in fact, the pushrods weren't even black on the entire length, and that engine had 215,000 miles on it, with the last 60,000 or so being pretty hard run miles!

 

No, I have no suspicion that it is dirty at all....idle is smooth, torque is great, little blue smoke at start-up, though it burns a quart of oil every other month. I don't want to take off the VCs because right now I've got too much going on, and I don't feel like getting new gaskets. Just like everyone else, though, the thought of a nice clean engine is nice....that's why I originally asked about this. I think I would be more comfortable with the half quart ATF method. Should I idle it for 10 minutes with a half quart in, then drain, then fill with fresh oil, then maybe just add a quarter of a quart of ATF just to slowly keep it clean inside? If the engine has lasted this long, it shouldn't be too bad huh? That's basically what my dad said. Suggestions? Thanks.

 

Well, I don't think 10 minutes is gonna do a whole bunch of good, maybe more like a few weeks. I don't think the detergents in the ATF are aggressive enough to do any good in 10 mins. Maybe halfway between oil changes, add a half quart of ATF to replace what the leaky valve seals smoked away each time you start it up (typical small block!!!!) Don't take what I'm saying as being exact, although I wouldn't reccomend anything that I wouldn't do myself! There are guys around here with many more years of experience than I have, maybe some of them will chime in!

 

Ok, that makes sense. I think what I will do is change the oil, then add a half quart ATF, then half-way between, I'll add another quart, so slowly, and safely it will get clean (if it is even dirty.) Thanks.

 

Any guys around here with many more years of experience than I have, wanna chime in? lol