How to engine flush a high mileage vehicle?

[jana519]

Hey AT Garage, what's your method to engine flush a high mileage (150K+) vehicle? I wonder if any of you have a particular brand preference for crankcase cleaning. At AutoZone and Walmart there are about 15 different options ranging from $5-$25 dollars. Any tips?

 

[pauldun170]

What is the issue driving this question? What engine?

 

[lxskllr]

I'm opposed to flushing high mileage vehicles. It gets rid of the crud that's holding it together, and it blows up. Yes, I'm serious. Mostly.

 

[Pacfanweb]

Why do you want to flush it? If you've changed the oil regularly, there's no need.

If you haven't, then I probably wouldn't because you may well break loose some gunk and kill the engine.

 

[RLGL]

Save your money

 

[HarryLui]

I have 200k on my engine, never did any flush on it.

 

[Torn Mind]

Flushing an engine seems counter-intuitive. More frequent oil changes, or some a light amount of some dissolver like MMO at most. You'll probably clog something up if large enough crud is broken free.

 

[bryanl]

Why do you want to flush your engine before replacing it? And you'll likely have to replace it much sooner if you do flush it, but the maker of the flushing chemical will deny responsibility for damage its product caused.

Just keep changing the oil and filter every 5000 miles using high quality oil like Mobil, Castrol, Pennzoil, Shell, or the house brands of Walmart and Autozone, but avoid dollar store oil.

 

[jana519]

Yeah I'm not going to flush it. Just going to change the oil out and replace with new oil. Seems like no one thinks flushing a car engine does any good.

 

[pauldun170]

Yeah I'm not going to flush it. Just going to change the oil out and replace with new oil. Seems like no one thinks flushing a car engine does any good.

Is this that 91 Volvo?

 

[HarryLui]

Save the money for coolant change.

 

[Pacfanweb]

Yeah I'm not going to flush it. Just going to change the oil out and replace with new oil. Seems like no one thinks flushing a car engine does any good.

And they are all correct. There's no need to flush an engine. Only reason I could ever see is maybe after a blown head or intake gasket put coolant in the oil, but even then, I'd probably just change the oil, start and let it warm up, then change it again, and repeat that process once or twice more and it'd be fine.

 

[jana519]

Is this that 91 Volvo?

Yes it is, a 91 Volvo 940 Turbo. Big, safe, and reliable car. Don't know if they still make them the same now.

Oh, guess you were asking about the radiator from the other thread? Yeah, I put a brand new Nissens aluminum radiator from Rock Auto in there. Cost me $160 but the peace of mind is worth it. The Chinese Auto Zone radiator was $90 or something ridiculous.

 

[who?]

Get it warmed up and drive it for at least an hour to evaporate any crud in the oil so that the pcv system will suck it out of the crankcase, then get an oil change.

 

[who?]

If your looking for a magic fluid you could add some Rislone to your oil before the long drive and oil change. https://rislone.com/product/engine-treatment-concentrate/

 

[Pacfanweb]

Get it warmed up and drive it for at least an hour to evaporate any crud in the oil so that the pcv system will suck it out of the crankcase, then get an oil change.

Say what?

 

[Torn Mind]

And they are all correct. There's no need to flush an engine. Only reason I could ever see is maybe after a blown head or intake gasket put coolant in the oil, but even then, I'd probably just change the oil, start and let it warm up, then change it again, and repeat that process once or twice more and it'd be fine.

https://www.reference.com/vehicles/engine-oil-flush-necessary-605887c0180ce317

Apparently, engine flush products are actually a fancy name for solvents that supposedly dissolve the carbon deposits rapidly and have them caught in the oil filter(what if the filter is already in bypass mode?). With regular oil changes, synthetic oils will leave the engine clean like new and "dino" oil would only leave varnish, which is no biggie.

 

[Rifter]

I only flush it if there are issues, like so bad of carbon buildup its loosing compression already anyways so not much to loose. And then ill just run seafoam through it and then change the oil right after, seafoam seems great at getting rid of carbon. I run seafoam straight into the intake through the brake booster vacuum line. Works good sometimes to free up the rings and blow some carbon off the valves.

Otherwise leave it alone IMO.

 

[Ferzerp]

a 91 Volvo 940 Turbo. Big, safe, and reliable car.

No. It isn't. It's 25 year old safety tech and 25 year old materials with 25 years of wear. I'd rather have an accident in a new compact car than that.

 

[NutBucket]

While you're right, it would be interesting to see its crash performance with modern standards. Obviously it only has one two airbags but structural integrity would definitely be interesting.

 

[HarryLui]

While you're right, it would be interesting to see its crash performance with modern standards. Obviously it only has one two airbags but structural integrity would definitely be interesting.

Here you go.
https://www.youtube.com/watch?v=emtLLvXrrFs

https://www.youtube.com/watch?v=2SDzLVMuxZo

 

[JEDIYoda]

Yeah I'm not going to flush it. Just going to change the oil out and replace with new oil. Seems like no one thinks flushing a car engine does any good.

It can ruin your engine by causing problems with debris that has come loose due to the flushing p[rocess clogging and causing your engine to not work properly!

 

[bryanl]

No. It isn't. It's 25 year old safety tech and 25 year old materials with 25 years of wear. I'd rather have an accident in a new compact car than that.

Some old cars did just as well in frontal crash tests as today's cars did, despite lacking airbags. But I would seriously doubt they would compare with today's cars in offset and side crashes.