So I got oil leak after oil change to 0W-40 fully synetic

[Dongoesby]

So I done my research and decided to change the oil myself for my 98' 240sx 5spd, but after that I found there is always one to three drops of oil weverytime when I park my car for awhile. Today is the thrid days. The car was always using fully synthetic oil (not sure which grade the previous owner uses) and the car has 80 miles. Am I not suppose to use Mobile -1's 0W-40 Fully Synthetic? Or is this totally normal for minor oil leak?

[bone_stock_240]

Maybe it is a little too thin. I don't really know anything about synthetics, but maybe you should switch to a thicker oil? I would only run that if I lived in antartica.

What area of the engine is it leaking from?

[Dongoesby]

I can the oil filter along too, and it is also Mobile-1. I tried to feel if there is any oil leak under the oil filter, but there is none. I will try to test other areas later. If u check the oil recommendation in here, then u will see 0W-40 is the best. I'm in CA.

[david gussie]

Way too thin. I believe your car should be speced for 10-30 or 5-30. 0-20/30/40 is for o5, 06 or 07's depending on the mgf and if it is the winter.

the problem in the past was that the syn mgf's didn't put in any additives to help with seal problems. some still don't do as much. Drop your oil and save it. go up to 10-30 , 4 qts and one qt o-30 each oil change if you want to save money or throw it out.

The syn oil is so good it cleans off all the goo that is keeping the seals from leaking with an older car. you may have created a monster.if that doesn't help. go to the partstore and get a bottle of "STOP LEAK". That might help.

Also all the reading I have been doing, here is what I found. Don't let the oil go over 10,000. at around 13m t0 14m the oil loses all its additive protection and you actually get less mpg. also the filters may not last that long and they will start to bypass. actually prior to the 1940's their was no oil filters. go figure. The best filter for the price is AC Delco Duraguard. This is from a study and a 50+ year in the business mechanic. the mobil 1 and others are ok but pricey and about the same

Hope this helps. let me know what happens

[Dongoesby]

Hey thanks David for the well input. However, I'm still confused at what you said, can you define what 10,000 at around 13m or 14m, and mgf. If you mean 10K miles, I change oil every 3K approx 3 months. Is there a difference between fully synthetic and synthetic?

I'm not sure for where I get 0W-40 is best for 240 now. I remember I read it somewhere, and I went to get it. So 5W-30 is what I'm suppose to get now?

[david gussie]

1. Your wasting your money! Full Synthetic can easily go 10,000 miles per oil change with a good filter.2. It must say All, full , etc. Synthetic. Some are Blends of 25% synthetic and regular oil. Cheaper too. I read from a news paper mechanic that a 1 to 5 ratio of synthetic and regular oil will give you all the benefit of full Synthetic oil. That might be better for you if you change so often.

3. You original Manuel will spec out what you were to use. The lower the first number is, the lighter the oil is at start up. For winter a 5-30w for your car is fine and a good all around one too. But it probably was speced for 10-30w for all around use. The lower the weight the easier to start and an initial small savings on gas milage. As a car gets higher milage on it and the parts wear, you can go up a 5 or 10 weight usually over 100,000 miles on the odometer,( that’s why u see 15-50 w oil. But if you change oil that often I would not bother.

4. A car wears out internally, most at start up without the car being properly oiled, not while its running. Fast cold starts in winter with out waiting (one minute only) to get oil pressure up is a killer. Also let the transmission go into reverse twice and once in 1, 2 ,D. This will circulate the fluids better. That is suppose to help. I have been told that. Do I do it, NO. My cars go 175 to 250,000. So I don’t worry about it too much.

5. The research data I read said that (most applications-useage) Full Synthetic oil went bad for most car owners around 14,000 miles and when they changed it they got a 10% increase in fuel milage. Therefore, for most applications an 10,000 mile oil change is fine. The oil is good but the cleaning additives are worn out or used up. Oil is oil and could be heated up to a high heat, burning off the impurities and used again. They did that in wwII to save resources and they pick up oil now to make it into grease Hope this helps

[david gussie]

Alsoas I understand the numbers, the first #of 5-30w the 5 (VISCOSITY)flow rate is what the weight is at 0 degrees in cold weather and the 30 # is how it acts under heat and it's overall ability to reduce friction under heat. I would have to look that up again on the net. Just remember use a good oil regular oil( rated (SF OR HIGHER) and change it 3,000 miles if you do lots of stop and go or 5,000 for regular driving and 10,000 for full Synthetic.

when I was a kid they were at S C on the oil cans now there up to SF or G or H. This is the Sicintific engereers who rate oil. the higher the letter the better the oil, like the good House keeping seal of approvel for oils. it cost them money to get it and you pay for the quality control.

[Dongoesby]

Hey thanks again. Just let you know the update, I wanted to change the oil again to 5w-30, but before it, the oil leak just stopped! It stopped yesterday, but I wasn't sure, so I checked again this morning, and there isn't any oil drops over the nite. Normal?

[nismofly]

i run mobil 1 5w-30 in winter and 10w-30 in summer and havent had a problem yet, engine has just over 93k miles

[jdm_master_X]

your car is supposed to take 10W-30. maybe the number faded on the manual.

[paulw]

I switched to synthetic about a year ago and now I have an oil leak from behind my timing cover on my 1999 Maxima. Should I switch back to a regular or thicker oil?

[david gussie]

10-30w is as high as I would go. Try a bottle of "STOP LEAK" at Napa and if you have easy acess to the bolts near the leak just give it a "little " tightning.Let us know what happens