this is my 88 yrs. old father in laws car and while he's in the hospital i'm trying to fix it up alittle...... the oil looks alittle light in color almost water base, now when i look in the oil fill port ...wow... it looks alittle sludgy in there , god knows what the inside of the oil pan looks like, i really don't think he had this car maintained in some time. i do want to change the oil , what can i do basicly remove all that crap ?

 

No much you can other than taking the motor apart. Using any kind of solvents could cause the sludge to break loose and clog a opening. I'd suggest just changing the oil as normal and use a quality oil and a Hyundai filter.

 

may be a blown headgasket causing that if the sludge look like a milky color. fairly easy to fix if you have so mechanical know how. look in coolant resevoir for oil also

 

I would do the same then drive it enough to heat it up real good and recheck the oil to see if it looks ok or is diluted with coolant or just dirty.
If just dirty I might be temped to change it again to drain out the crap.

I have seen folks put in a mix of Kerosene and drive a car around the block and then drain out all the stuff that will suspend in the Kerosene. But I would never do that to a car that did not belong to me. I am sure you can find other oil additive cleaners that might help also. But the risk is as NovaResource says possible loosening of sludge that can cause blockages in oil passages and cause major problems.

The age and miles on the engine makes a big difference in the approach you will take to clean it up some.

 

Stay away from oil additives.

The only way to really remove it would be to drop the pan and clean out what you can then start running clean oil through it to get out what you can. Sounds like the oil hasn't been changed in a long time.

I'd start with an oil and filter change and go from there. Use an OEM filter if you can.