well i decided to check my oil today. found out it is reaaaaaaaaaaaaaaally low. and black. And its burning oil but theres no leaks or smoking what so ever. awesome. anyways my last oil change i used mobil 1 0w-40 w/ a mobil 1 filter, and i seafoamed it. i heard from other 240sx forums that mobil 1 0w-40 was great for a high mileage ka and it got rid of valve ticking. Which it didn't do. well, i was satisfied with it i guess, but i want to see if there is anything better. i just tried searching again some of the 240sx sites AND GOOGLE (zilvia, nico, 240sx forums, etc. to name a few.) and alot of people say different things and it seemed like they couldnt make up their minds. so with that said, id though id ask nissan tech what their opinions were. im looking for the BEST kind of oil and filter to use. i like to buy the best quality stuff for my KA. lol.
BTW it has ~235,000 miles on it.

 

synthetic is probably the problem.

replace valve guide seals, check compression, leakdown, fix whatevers worn, and just use regular oil.

id run 10w30 high milage conventional, or 20w50 in a ka.

 

id go VR1 or rotella. I was using rotella as of lately in my 280k mile truck. I just used it for the extra zinc it had in it

 

I started to use 20w50 conventional what ever after I got over 200k. I also use the STP oil additive. I used to use 10w30 because thats what was always used before I got the car.

 

^what brand of oil?

 

Castorol GTX mostly, but I think I've used penzoil once or twice.

 

Ew, Penzoil. Paraffin wax is bad.

 

You don't have a lot of options in 20w50 these days. All the car manufacturers are going to 5w20, 0w20 and WD40 to get that last 1% gas mileage. Out of all the oil choices on the Walmart aisle, for 20w50 it was either Castrol, Pennzoil, or Supertech/some generic brand. My past experience with Castrol in my old car was that it broke down fast and felt like water at 1500 miles. I chose Pennzoil and it held my mildly rod-knocking KA together for several thousand miles of abuse before I switched to Mobil 5w30 and killed it for good. (I thought the rod knock was some sort of valvetrain noise because it was very mild. It wasn't so mild after running the car hard on the lighter oil for a week.)

I'm probably going to compromise and run a 10w40 or 15w40 in my new-used KA. The manual recommends 5w30 but with an older engine and the kind of abuse we put on them, after my recent experience I think I'll be going a bit thicker.

 

im using castrol gtx 20w50 high mileage right now. im not liking it so far.. makes the car feel sluggish. i think its too thick. i might go back to mobil 1 0w-40. i liked it. made my car run great, and it got rid of my valve tick and timing chain rattle for a few hundered miles. only problem is that it broke down way too fast, and it burnt up to quick. and it got really nasty quick too. i might try valvoline vr1 or royal purple; i heard that they were pretty good.

 

STP oil additive makes a big difference. I've never really had a problem with Castrol.