Ive searched the board, but couldnt find the info on my issue. I used R& D factory's valve covers with gaskets to replaced my leaking ones. they had bad spark plug seals leaking oil. But after i got them replaced about 1 1/2 ago, im still noticing the car burning oil, about 1 quart per 1,000 miles. I checked the spark plugs and there is no oil especially in cylinders 3 & 4. ive seen mention of R&D's vavle covers failing but im assumiong that has to do with the rubber spark plug seals. For my next oil change ill use a heaver oil like castrol edge 15w-30 from my mobil 1 5w-30, see if that helps any.


So my question is has anyone still had oil consumption after replaceing the valve covers? i guess it could be other worn parts like piston rings and leaking valve steam seals.

thanks in advance.

 

oil consumption doesn't really come from bad spark plug seals. Bad spark plug seals only let oil into the spark plug tubes and that typically wont let it get high enough to start leaking out the tubes. It just fills the tubes up. Its more of an annoyance than a problem. It just sits there, it doesn't enter the combustion chamber and burn it.

Oil consumption comes from worn piston rings and/or cylinders or bad valve seals. (probably worn rings) 15w-30 is probably a little on the thick side. If you are going to change viscosity, I wouldn't venture past 10w-30.

 

Stop using Mobil 1 and it should get better.

 

You might try going to conventional oil as well. It's thicker than syn and won't burn off as fast.

 

I was under the strong impression that once you run synthetic, especially for a longer period you never go back to conventional oil?

Since the newer castrol edge syn is close to the german castrol synthetic (considered one of the best) in formula i figure that should be a good replacment for the mobil 1.

I find it strange because ive used mobil 1 on this car since it was new (over 100K) and on my previous cars and never had this kind of oil consumption.

I also noticed many people out one oil catch can for there plenum oil buildup, and i did notice a little when i cahnges the valve covers, so maybe thats a small source i can also eliminate.

 

Wrong. You can switch from synthetic to conventional as often as you would like. Just use caution if switching from conventional to synthetic on a high mileage car when you are unfamiliar with the maintenance history

Conventional motor oil is your best bet. Why would you want to soend the money blowing expensive oil oit the tail pipes?

Switch to conventional motor oil and monitor your oil level weekly. If it doesn't slow or stop alltogether, it will just be something you will have to live with until you replace the motor.

 

That being said, 95% of my miles are highway and currently since i use mobil 1 i change the oild every 7,000 miles, as recommened by manual instead of 3,000 miles so i can justify the added cost for sythetic if i need to change my oil half the time.

Unless 7,000 miles is just to long of a time interval regardless with these engines, which looks like might be the case, especially for me.

Id rebuild the engine if anything or just sell it, a new engine install wouldnt make much sense. hoping it can last me another year and a half.

 

It completely depends on your climate



I was using Syntec since 32k, I needed to change my oil before a tune and Penzzoil Platinum was on sale so I switch to it and used PU for an additional change, I started to have OC and switched to M1 0W-40 for Tail of the Dragon but my OC was pretty bad. 1 Quart in 500 miles. On the way home I had to put oil in again. No blue smoke no drips.

Anyhow I switched it out for 10W30 GTX and it slowed to 1 quart in 1.2-1.5k miles. I am about to change it again with GTX 10W30 and it should slow down. I believe my OC came from changing PCMO's which hopefully is true, and I should go back to 1/2 a quart in 5k miles I was getting before.

 

Your right it does, and im in chicago so i cant go too thick. why did you switch to conventional oil 10W-30 as opposed to going to synthetic 10w-30? just price? or was OC better with conventional?

I dont mind speding an extra $50 a year on oil, but i cant be worse OC if the oil weights are the same.

 

If you are burning oil no reason to burn something that costs more, and people have had luck with just going to GTX and it slowing down.

 

^^

I'm one of those people

https://g35driver.com/forums/g35-sed...oad-*****.html

 

I'll stick with synthetics(castrol edge) for now and just change to a higher weight, see what happens.

 

You're using one of the fastest burning oils coupled with one of the longest change intervals I've ever heard of to save money... but you can spend money to rebuild the engine?

I change every 3-3.5k with Castrol and burn maybe .5 of a quart.

 

right but unless its 130 degrees outside and the coolant is at 220F+, 15w-30 or 15w40 is probably too thick for a motor that calls for 5w-30 in normal conditions. air temp here in central FL is often between 95 and 115 on the roads in the summer but as long as the coolant is still running below 200F there is no reason to step up to a high viscosity unless you have OC problems. And I still stand by 15w being too thick. No reason to venture past 10w-30 if that cuts the OC down.