what is the best way to flush your oil and cooling system?

 

Reverse flush the cooling system with water via the heater circuit nipple on the inlet manifold.

You flush your crankcase by changing the oil on a schedule that's suitable for your driving habits.

Duke

 

This is what I have heard as well. About 20-25 years ago, I worked at a NAPA and the Valvoline Oil Rep, said if you have a engine that has been poorly maintained, IE: sluge build up, then change the oil often and let the detergants in the oil disolve it. The problem with the flushes is, if they break it loose all at once, it can stop up your oil pick up screen. By the way, he also stated that oil does not wear out, Oil is designed to suspend carbon and other containaments, and then when you drain the oil, you drain the carbon as well. If you dont change your oil, then at some point, the oil will not hold any more carbon, and it will start depositing it on the sides of your engine parts.

 

Engine sludging is rare today because of good crankcase ventilation and oil additives. The oil does not technically "wear out", but over time it will oxidize and degrade from other contaminents such as acids that can form from blowby gas. Detergent/dispersant additives capture these contaminents and hold them in suspension so they are flushed out when the oil is drained.

I recall about ten years ago I was at my Mercedes Dealer when a guy brought in a late model 190E with a ticking in the valvetrain. It turned out the car had 25K miles and the oil had never been changed. Sludging was probably starting to starve the valvetrain. People's stupidity never ceases to amaze me. I suspect that his four-year/50K mile warranty was voided due to lack of performing the required maintenance. What an idiot!

Modern engines with precise fuel control, quick warm up, and tight combustion chamber sealing are pretty easy on the oil, but the primarly reason why modern cars such as C5s can go up to 15K miles between changes is the use of synthetic oils, which have greater oxidation resistance, and when combined with oil quality monitors that monitor the oils dielectric strength, such extended change intervals are okay.

Duke




[Modified by SWCDuke, 6:56 AM 10/28/2002]

 

Intresting, The reason why I am asking is cause I found some metal shavings in my filter when I changed my oil, I was horrified so I tore down everything, still haven't determined exactly where it came from, I suspectied my cam and lifters, but they look smooth, though the edges are pretty sharp. So I am replacing my cam with a roller hyd, and am getting new heads in the process. I just want to make sure everything is good before I start pumping the oil through again.

 

Are the shavings magnetic or non-magnetic?

Duke

 

I believe they are magnetic, though they are very very fine shavings, almost liquid with the oil, but after leaving a magnet in the oil for a few hours it came out all clumped together.

 

I've had internal sheet metal parts fail on my Cosworth Vega due to the second order unbalanced vertical shaking force, which caused steel shavings to get in the oil, but the bearings looked fine, so after I replaced the broken pickup and windage tray and cleaned the pan and crankcase, I put everything together with new oil and filter, and it's been fine ever since.

You don't say what kind of engine you have, but V-8s don't generate any shaking forces or rocking couples below fourth order, so they have a benign vibration environment relative to an inline four. Check carefully for any part to part abrasion that might be generating particles, especially any sheet metal parts and make sure everything is secured with the proper fasteners and torqued to spec. Installing a magnetic oil drain plug might help you determine if the shavings are still being generated as it will trap some of them before they get to the filter.

Duke

 

I will be doing that, I am going to check my oil flow rate to my turbos before I throw everything together again, "gonna use a oil primer of course" perhaps inlarge the the lines running to them. Other than that I have basically replaced everything in the top end while inspecting everything in the bottom end.