Hello guys!

I am kind of a G35 newbie and am in desperate need of some more advice. I searched around the forums a little bit and found some answers, but nothing that really helps in my current predicament. I have an 03 G35 sedan 6MT, bought about 8 months ago with 90k in great shape, and I just hit the 100k mark. I was told by the dealer that the previous owner was very **** about bringing the car to the dealer, but from my experience with dealers, that kind of scares me more than anything. I have no idea what kind of service has ever been done to it, and I feel like I am just playing catch up now.

I am very reluctant to do anything that is not absolutely necessary to it, because I have had great luck so far, and do not want to destroy my baby, doing unnecessary maintenance.

First off, my very mechanically inclined buddy is insisting that I add a quart of ATF and even a quart of 5w30 conventional to my gas the next time I fill up. He says that it will clean the injectors and lube everything up really nicely. He has done it a couple of times now and says he has gained 2-4 mpg.

There are a couple of problems I have with this.
1. I know the Gs are not known for having great seals, and I am pretty sure my valve cover gaskets are already leaking.
2. I don't want to create new leaks, make them worse, or knock a piece of crud out that was keeping my engine together, and be screwed.

I would like to use some sort of fuel injector cleaner, but I don't know if I am better off just letting it ride. Is ATF a pretty safe bet, or is there a specific additive that would be better for my application? Also, is adding motor oil to your gas a good idea at all? I know it most likely would not hurt anything, but would it be worth it?

I have seen some people say to use Seafoam and other additives, but I dont know if that would be a good idea on a car with just over 100k that has never seen something like that. I have used seafoam before and I dont know if that kind of cleansing would be healthy at this point.

Also, I am running conventional 5w-30 and am assuming that is the only oil that has ever been in it. Would it be beneficial to switch to synthetic at this point or would I just be taking unnecessary risks? I know some people say after like 70k to not even think about using synthetic, but some people also say it helps. Im wondering if even a high mileage part synthetic would be the way to go.

I dont have any engine mods, other than a K&N box filter, which I highly recommend (like that matters lol), but I do want to start building NA in the next year or so. I have the south bend rally clutch (dxd pressure plate and exedy stage 1 disk) and SB billet flywheel, which is going in soon.

When we do the clutch, we are also planning on taking the valve covers off and checking valve clearances and seeing how bad my gaskets are. I know a lot of people say replacing the valve cover gaskets is not worth the money, but i was thinking about trying to get them to seal with some gasket maker. Would that be a horrible idea?

Im new to this car and probably just very paranoid, but its hard when you have 100k and have no idea what the car has been through.

I know I went in a million different directions, but I am lost and dont want to mess up a car that I love and has been so good to me so far.

Any input would be greatly appreciated and you are welcome to call me a dumbass.

Thanks in advance,
Dan H.
Northern VA (unfortunately)

 

Ok solved my valve cover gasket problem. I read on here somewhere that they were metal and $130 each but I'm finding rubber ones all over the place even advance auto for under $30 a pair. I don't know who said that or maybe I misunderstood but I'm definitely just gonna replace them when I have it apart. I thought that was hard to believe but I guess I'm gullible and/or stupid.

 

I get it now. If I have oil in my spark plug holes then its the valve cover itself. If that's the case I will probably be trying some gasket maker. It looks like I may be leaking some oil at the valve cover gaskets anyway so it's nice to know they are easy to get. Try to bare with me, I'm learning. I do still need advice for my other problems though.

 

First off, adding ATF or motor oil to your gas?? Really?? I wouldn't do that to my car, not in a million years. The reason they are called ATF and motor oil, not oil additives or treatment, is because they are not. Lube your engine and gear box not your fuel line. I'm sure your "mechanically inclined" buddy is messing with you, just bring a bottle of ATF to him and tell him to add it to his tank in front of you at next fill up and see how he reacts.

If you want to add injector cleaner some people use Chevron, I use Lucas about every 20k miles.

At 100K these engines should still be strong, well maintained VQ's last much longer. If the car runs fine now then you should be fine. You might want to check the plugs, though.

How do you know your engine is leaking oil? Anything visual? Any oil spot on the under shield? Any oil consumed between oil change? Some damp might show around the valve cover, but if not massive I'd just keep an eye on it. And for oil pooling in the spark plug tube, I figured it's accumulating little by little over time so I just wipe it off once in a while. And if you want to know if you have a healthy engine to build in the future, you should collect oil sample and send it in for analysis. There's an oil analysis thread on top with great info, also helps if you're going synthetic.

Is your clutch slipping now? If not then you might not need to do it right away, especially if the same "mechanically inclined" buddy is gonna do it for you.

You should check with the dealership if there's any recall needs to be done. And if you're not sure how the car was maintained before you bought it, you can always replace all fluids, and check for brakes and tires. At least from now on you'll know how it'll be maintained. Hope these help.

 

Actually, you don't even need to check with the dealership. There is a webform on the Infiniti website for that. You send them the VIN and they send you back their records on it. I did this on multiple cars when I was looking, and they were always quick to reply; much faster than the 2-3 business days promised on the form.

Just one more clue in the eternal "was it maintained?" question.

 

Other than fixing any leaks you may have and making sure you do the scheduled mtc (most of which you can do yourself), I wouldn't F around putting things in my gas and such. And do get the recall records as well as the mtc records if you can.

 

Great advice above. Either your "buddy"s messing with you or he's an idiot. You want to keep oil/ATF out of the motor not put it in. The only thing I would add is to check with the Infiniti dealership that he took the car to. They (and any other Infiniti dealer) can pull up the service records with the car's VIN number. It will show any work done at dealers around the country. Try to stress a little less and enjoy the car a lot more. We have a thread on high mileage cars and there are a lot in there with 150K miles and more, even a couple at over 300K that have gotten there without any major mechanical issues.

Take care of her and she'll take care of you.

 

Thanks for the great responses, guys. I am going to go to an infiniti dealer and try to get the service history. I am also going to look into any recalls. This car is just a mystery to me because I bought it at a GMC dealer with a clean carfax. They definitely won't give me any info seeing as i am currently fighting with them to try and get my spare set of keys (God i hate dealers).

As for the ATF and motor oil, he definitely was not kidding. I might not be a genius when it comes to cars but i know some things, but he works as a diesel mechanic so he deals with motors and trannies and drivetrains everyday, only on a huge scale. Thats why i called him mechanically inclined. He said he added a quart twice when he filled up his 08 malibu and his mpg have just been getting better. I argued with him for a while about it, but he's the kind of person that even when he's wrong, he's right. So i just gave up, but now i know my gut was correct, and that is a stupid idea.

I may try some of that Chevron Techtron because i have heard good things about that.

The reason i think my valve cover gasket is bad and i have oil in the plug holes is because i have to add a quart of oil every 1500 to 2000 miles. I feel like i am constantly putting oil in this thing and that i could probably get away with not changing it at all (J/k kinda). The oil has to be going somewhere, but i dont have the rev-up engine so i am hoping my rings are fine and its not blowing through there. Also, the valve cover gasket looks a little damp, so it could slowly be seeping through, even though my car never drips oil.

I will be doing the plugs soon and replacing the valve cover gaskets, so ultimately, i will find out what is going on. Sending in an oil sample is a great idea and i would like to do that, just to see whats been going on in my engine. My clutch isnt slipping yet, but it lets out very quickly at the very end of the pedal. Its basically on/off and im pretty sure its about toasted.

We will be doing all of this at the same time, because my afformentioned friend has done quite a few clutches, and has a garage, while i have never done one and would be doing it by myself in the street. He may have some dumb ideas, but hopefully hes as good with clutches as he claims. I could do the plugs and valve cover gaskets by myself no problem, but i figure it would be easier in a garage with the right tools and some help.

I thought the whole ATF thing sounded retarded from the begining, but he kept trying to convince me, and it worked so well for him apparently. I will spend a little extra money and stick with something that is made to be mixed with gas.

Thanks again! I will let you know how i make out, and I will try not to worry so much!

 

You want to hear something scary?

I have my A&P (Airframe and Powerplant) license for aircraft.

I just constantly second guess myself.

But now you know how easy it is to be an aircraft mechanic!

(They didnt teach me **** about cars)

 

There are only two things you put in your gas filler....(1) Gas (2) Fuel injector cleaner. (RedLine is the best) Let the dealerships (stealerships) work for you, if the previous owner took good care of your G they'll have service records. Having the service records will tell you what maintenance needs to be done. Normally 100K mile service includes all fluids, belts and filters. At 100K spark plugs s/b changed if the previous owner hasn't done it. When you find out what has been done and needs to be, find an independent shop for the service. Did the previous owner use synthetic oil? Use nothing else and it doesn't require an additive....ever! Stay away from "Friends" that make recommendations like what you posted, they're scary dumb!
Gary

 

Gary,

Thank you or being so straight forward. Having the records would help a lot and I didn't realize I could go to Infiniti and get them. I should have done that to begin with. I will order some redline if its the best, which I am assuming it is, because I have seen your posts on here and you seem to really know what you're doing. My friend is not that dumb. He also has his A&P and he's right about a lot of things, but he's definitely wrong this time. He's kinda cocky tho and makes me think I'm wrong when I have actually done the research. I'm just glad I didn't go dumping ATF into my gas because he insisted it worked for him. He thinks that manufacturers specs are just guidelines but I know that is not true for a lot of things, especially an Infiniti. I will be more careful. Thanks again to u and everyone else who has set me straight!

 

As far as I know synthetic has never been in that car and I am keeping it that way, unless I am proven wrong by service records

 

Your buddy might have knowledge in diesel engines/drivetrans and got those "tricks" from dealing with diesel engines, it doesn't mean he can apply it all to another type of engine and drivetran. That's what makes it scary. At the end of the day anything he breaks is on your tab, and you'd feel dumb not paying someone who really knows your car to work on it. Do some search I'm sure you'll find better options.

Check or replace your PCV valve and see if it slows down the oil consumption. Heavier oil might help, like 5w-40. The amount of oil seeping through the valve cover gasket and spark plug tube shouldn't be that much to cause the observed consumption, so you shouldn't need to worry too much about gaskets. Anyway you might want to get to know more about the history and the status of your car before doing any major mechanical work on it. Just my .02.