What to do what to do gm 305

[wapacz]

So I have a 95 GMC Sierra ext 4x4 with 305 and 118k miles. So any ways I was wondering what I should be doing here. I picked up some GC last night have 3 that I think are green and 3 that I don't think are. Well any ways I was kind of thinking of adding a quart to the first oil change with it then 2 quarts and so on until it is running on full out syn. I would like to be able to get a year out of an oil change. I drive about 10,000 miles a year. With most of my driving being 14 to 15 miles a piece with mixed driving. Oh yeah I leak a bit of oil, a few drip after it has been driven and then it stop. Think it is coming form the valve covers. This drip isn’t enough to cause any problems when the oil is changed ever 3 to 4 k miles. Right now I have 2200 miles on this oil and well I might be down an ounce or two.

I have had this truck since about 83k miles during the time I have had the changes done at the local gm dealership. So it has had what ever the gm oil is in it and what ever filter they use. The guy I bought it form seems to be the type that would do it him self because he changed his own brakes and such.

 

[texasproud]

In your case, I would do a complete Auto RX clean treatment then consider switching to syn. The syn may make your leak slightly worse as it seems to find weak spots in seals. I do not believe it would cause a leak but it sure could accentuate an existing one. I would be prone to run M1 T&SUV(5w-40) as an alternative, but GC may work fine for you. Either oil should go 10K or 1 year under normal driving conditions. There are several good threads on the Auto RX treatments in the "additive" forum. Good luck.

 

[wapacz]

Yeah I have read about the auto rx stuff. The problem is that since I am in school right now I don't exactly have a ton of cash to spare. The only reason I have the 6 quarts of GC is becuase it was on sale for 4 dollars a quart and then a 10 dollar gas card so it really only cost me about 15 dollars. The cash thing is what is also holding me up form getting the vavle cover gaskets replaced.

 

[wapacz]

Okay just one bump

 

[beanoil]

Agree with Bill. My Sis has a '95 with 130,000 on it. Has had 10-30 Rotella it's whole life. No oil usage over 4,000 OCI. You will be fine with Havoline and 5k changes. With that mileage, I'd run 10-30, a ST3980, and drive..

 

[wapacz]

The other reason the vavle gasket hasn't gotten replaced is becuase by the time I got motivated to fix it well it started to get cold. Like today it is -5 windchill and well my truck doesn't fit in the grage a bit to long. So you can see I have a bit of the problem.

Thanks for the advice guys it looks like I will have to do a bunch more reading to get really imformed here.

The most oil usage I have had was one quart in about 3000 miles or so. That was when most of my miles where coming form 200 to 500 mile trips. Other then that time I haven't really used any noticable amount.

Hopefully I will find and actuary internship this summer and have some cash to actaul put into my truck.

 

[Tremo]

OK, I have a GM 305, mine is in an 88 IROC Camaro, with nearly 160k on the clock. I run M1 T&SUV with a K&N filter. It doesn't leak a single drop, never has. It burns a quart or so between changes. Runs great. The innards have varnish, but no visible sludge. I've been running M1 in this engine for years. I change once a year, about.

 

[DriveHard]

Its really not that hard to replace the valve cover gaskets yourself. I also don't believe the gaskets would be vary expensive. If you aren't sure of yourself, find a friend with some experience and have at it. I'm sure you could easily have it done in an afternoon.

 

[Bill in Utah]

Take back the GC and get your self some good dino like Pennzoil, chevron, havoline.

Change it every 5k miles and don't worry.

Your not going to see any difference between the two oils (conv vs GC) and if your strapped for $$ (and even if your not) this is the way to go for your 10k per year driving.

My 3 cents! Take care, Bill

 

[Alex P.]

I used to have an 87 Caprice with a 305, and it leaked M1 pretty badly (well by my standards). But it didn't leak or burn a drop of US Syntec until the valve covers started weeping. By that point (15 years old), the valve covers themselves looked pretty bad, so I replaced those too. Although I could have blasted them bare and repainted them.

Anyway, gaskets are inexpensive, but get good quality rubber ones. I like Fel Pro Perma Dry gaskets.

 

[99]

What to do with that 305? Pull it and put a big block in it. j/k

Seriously though, with 118k on it I'd run a quality dino like Mobil 5000 10W30 and call it good. Chances are real good that the trans is going to die before the engine anyways.

 

[wapacz]

You know there are some times I wish I had the cash to replace this 305 with a 350 or something a litle bigger. That getting on the eway can be a pain and well that passing thing also. But then I remeber that a good engine would be worth more then my 11 year old truck is worth.

 

[Alex P.]

350s are everywhere. You can pick up a worn motor for dirt and rebuild it, or get a warrantied salvage engine for pretty cheap sometimes. Clean up it good, and off you go. If you wanted more power, it's very easy to do with a small block. But all of that costs money, and if its a working truck, just leave it be (except for the very cheap valve cover gaskets!). My 305 had pretty good power, but it had a 4bbl q-jet, and was very well maintained. Haven't been behind the wheel of a TBI 305, but I hear they're kinda dogs, for a SBC.

 

[wapacz]

Yeah the truck is going to stay how it is well unless it becomes a secondary vehicle then I might have some fun with it. Thought that is atleast another 2 to 4 years out. You know when I actauly get a job that will pay decent enough.

 

[Tremo]

1. - It costs *more* to rebuild a 305 than it does a 350.

2. - The newer center-bolt valve covers leak MUCH less than the old style perimeter-bolt covers.

3. - The carb'ed and TBI 305s may be dogs, but the TPI LB9 will burn off the rear tires no sweat.

Maybe I'm just real lucky, but my LB9 doesn't leak a single drop, and I've been running M1 for a long time. I can't believe that there is simply no oil seepage on the motor. You can work on it without getting filthy.

And yes, you can get a used and warranteed 350 for reasonable money, just swap it right in!

 

[Alex P.]

Who said anything about rebuilding the 305? I recommended he get a beat 350 and rebuild it. However, rebuilding a 305 should not cost significantly more. Either way I'd only rebuild a 305 if I was keeping a car in factory showroom condition.

It took my valve covers 15 years and over 150k to start weeping 5w30, at that point Syntec. So yeah, I'd say they're pretty good. Also, I actually was saying that the carbed 305 I had was pretty decent for power, even if mileage wasn't fantastic. But I've always heard that the TBI 305s were less aggressive. Apparentely you can get a top end kit from Edelbrock to convert a TBI SBC truck to multi port. For some reason they say truck only, but no longer having a small block I never questioned why.

 

[caprice_2nv]

While were getting off topic, lol, my 87 carbed 305 ran 15.5 seconds at 88mph in the 1/4 mile when it was in my 87 Cutlass Supreme (Canadian spec were 305's not 307's) with dual exhaust and 3.73 gears and almost 200k miles of wear being the only deviations from new. It would burn the back right tire off it no problem and it even chirped the tires when it hit 2nd gear. The rusted rear frame rails are still coated in particulate rubber as it sits in my friends yard right now wainting for me to pull the motor. The qjet 305's did run better than the tbi's. Also the center bolt valve covers also had a better rubber gasket instead of the cork style the older ones had. Not sure if thats why they didn't usually leak but mine was still perfect after 200k miles.