This car was serviced 12 months ago, as you can see the oil is sludge, in this case it's not just change the oil and filter. A seperate flush was needed.
1. Drain all sludge from sump, in this case it took 1/2 hour.
2. Buy some cheap oil, gulf western is good for this type of change and the only case that i would use gulf western oil.
3. do not use the good oil for the flush
4. Add a good engine flush, nulon flush is excellent for this.
5. change the oil filter
6. fill the sump with cheap oil
7. start the car and let idle for a good 1/2 hour
8. when you have idled for 28 mins, rev the engine to 3000RPM for the remainder two minutes.
9. shut off engine
10 drain sump for a good hour with oil filter removed, take the cap off and remove the dipstick, if you can leave it overnight to drain would be better, but drain it while hot.
Note: Be careful as the Oil will be very hot, use a protective glove to protect your hands.
After all the oil and flush is drained, secure new drain washer to the plug and new oil filter, fill the sump to spec's
Note also, if you have a ford ranger, you cannot use engine flush as oil must be present at all times in the oil pump, if you flush these engines the oil pump will have air and won't prime. Some other engines are the same, refer to manufactors specs before attempting this procedure.
Finally, if the sludge is still present after this flush, do not flush it again as the flush chemical can harder oil seals etc in your engine, wait 5000 km and then repeat this procedure, then all of the sludge should be gone, between the first flush and 5000km make sure you check your oil level regularly note the condition of the oil and check for any leaks. In severe cases a flush may not work at all and you could be up for a new engine.
Conclusion: Change your oil every 6 months or 10 000km , vehicles that have high km change every 5000 or 3 months, prevention is better than cure!