Flushing Your Engine

[sierraclasic]

Hello guys. I just bought a truck that needs a new head gasket which is not a problem, but I thought that I would see if you all had some advice on the best way to flush the contaminated oil from my engine. Any thoughts? Thanks.

[Nytemare]

I use a shop vac, and lots of hot water to get everything nice and clean...Or pop out the block drain plug and keep pouring hot water down the passages. Than after everything is back together I get a good coolant flush chemical and run it through without a thermostat in there. That gets rid of any left over residue, and scale that has built up over time. I run it for 15-20 min, drain fill with HOT water run that for 10-15 min drain, than pop in a thermostat, and fill with coolant. If you are reusing your water pump, toss some royal purple "Purple Ice" in the coolant...or a similar coolant booster to lub the seal of the pump...but for the cost, just buy a new one.

 

I always buy new hoses, and flush the rad with hot water and a little dish soap....just make certain you get all the dish soap out. Same with the overflow bottle.

 

I also always buy a new rad cap... if the vehicle has one.

[Stevens03]

Run some Seafoam in the oil, vaccum line and gas tank. Congrats on the new truck.

[Black02Silverado]

Sounds like the coolant flush post above has that covered well.

 

Another option for the engine oil is to run short drain intervals with Shell Rotella or Delo diesel oil. The heavier detergents in those will help to clean things up and then switch to a synthetic which also cleans well.

 

You could also run a bottle of AMSOIL's engine flush through it right after you put it all back together to get a good bit of the mess out. Just run fresh oil and new filter, top off with a bottle of AMSOIL engine flush, let it fast idle around 1,100rpm for about 20 minutes and then change out the oil and filter and you should be good to go. Do not drive with the engine flush in the oil. It is only to be used for a 20 minute fast idle cleaning.

[sierraclasic]

Thank you guys for the input. It will come in very handy when I work on it tomorrow.

[Nytemare]

For cleaning the oil passages I also use diesel...about a cup with really cheep oil...run it for 15-20 min while running it with the coolant flush...under no load, that means DON'T drive it or rev the engine at all.

 

I haven't used the Amsoil stuff before but that sounds good too.

[alwcurlz]

Hello guys. I just bought a truck that needs a new head gasket which is not a problem, but I thought that I would see if you all had some advice on the best way to flush the contaminated oil from my engine. Any thoughts? Thanks.

 

If you're wanting to get the coolant out, I would just change the oil, put a new filter and refill with oil and then drive it for a couple hundred miles and change it again. Coolant isn't going to hurt the engine. If it's water you're concerned about, draining the oil will work as water sits in the oil pan and will come out first. The rest of the water will evaporate/boil away when the engine is hot and get sucked out through the top end of the motor through the PCV and vent tube from the valve covers.

[alwcurlz]

I use a shop vac, and lots of hot water to get everything nice and clean...Or pop out the block drain plug and keep pouring hot water down the passages. Than after everything is back together I get a good coolant flush chemical and run it through without a thermostat in there. That gets rid of any left over residue, and scale that has built up over time. I run it for 15-20 min, drain fill with HOT water run that for 10-15 min drain, than pop in a thermostat, and fill with coolant. If you are reusing your water pump, toss some royal purple "Purple Ice" in the coolant...or a similar coolant booster to lub the seal of the pump...but for the cost, just buy a new one.

 

I always buy new hoses, and flush the rad with hot water and a little dish soap....just make certain you get all the dish soap out. Same with the overflow bottle.

 

I also always buy a new rad cap... if the vehicle has one.

 

I don't know about the thermostat idea since it's built into the water neck on the GMT800 on up.

[Nytemare]

You reuse the old water neck...and if you cannot get the thermostat out, you just pull the center out, or drill it our....basically whatever you have to do to allow the water to pass through unrestricted.

 

Oh yeah...and coolant is really bad for the main, rod and cam bearings...It does not react well with Babbette.

[minibike132]

There are shops out there with oil flush machines. The one I used worked great with the chemical provided but I don't remember the manufacturer.

 

I do remember they gave me an N body with a 3.4 at 140K and had me pull the right valve cover and install a new one. Then flushed the engine and removed the left side for a before and after. The 3.4 got pretty hot up top and would varnish pretty good. One flush cleaned it to almost brand new. That is what the customer saw on the valve cover before and after, I got to see the difference in the upper components on the head and I was pretty impressed.

 

I wish we had one where I am now, once I had it I wouldn't do an intake or head gasket without doing the flush. It just worked that good and wasn't that much of an add on to not do it. I did mine 2X a year just because it was there.

[Nytemare]

your talkin about something like the hot oil flush machine that GM has??

 

If so...yes those are freekin awesome man...I too have seen what they can do. I have seen guys that would have oil that looked like black coffee after 3k miles on it...they had a hot oil flush and the next oil change it came out almost the same color as the new oil that was going in.

[Spurshot]

I agree with Abner, just change the oil and you'll be fine. If you are really wanting to get some of the contaminated oil out, dump some solvent thru the valley and into the pan with the drainplug out. Mineral spirits from the hardware store is pure solvent that will work great. If you're worried about the residual solvent in the pan, dump a quart of oil thru the valley and pan with the drainplug open as well.

[spbutler]

I add some Marvel Mystery Oil when I do an oil change. I warm up the motor and that add about a pint , depending on how much oil is in there. Then run it for 5 minutes and drain.

[alwcurlz]

You reuse the old water neck...and if you cannot get the thermostat out, you just pull the center out, or drill it our....basically whatever you have to do to allow the water to pass through unrestricted.

 

Oh yeah...and coolant is really bad for the main, rod and cam bearings...It does not react well with Babbette.

 

I thought before that the water pump had a thermostat built into it and later found it was built into the water neck but, it is able to be replaced separately now?

[alwcurlz]

your talkin about something like the hot oil flush machine that GM has??

 

If so...yes those are freekin awesome man...I too have seen what they can do. I have seen guys that would have oil that looked like black coffee after 3k miles on it...they had a hot oil flush and the next oil change it came out almost the same color as the new oil that was going in.

 

So, it's actually residual used oil left in the motor that never gets out that a motor flush would get rid of? I thought oil got dark over time from combustion chamber leakage around the piston rings and/or a low flash point. My thought about changing oil was to change it every 3k miles or when it started getting dark as it was losing it's ability to provide proper viscosity/lubrication and valve function.