What oil weight & brand is everyone using in their 4.3? I have been using Mobil1 5W30 synthetic since day one and have issues with seal leaks and now the oil lines. BTOG are advising me to go to a Mobil1 10w40 High Mileage oil or other brand but stick to a 40 weight. I wanted to see what everyone here is using and their experiences. thanx

 

I Use Castrol 5W-30 Regular Dino Oilin My Truck its a 97 Blazer, Did it come from factory with Synthetic or Reg Dino Oil. Synthetic is really thin and causes leaks on engines not designed for it so if you switched its too late bc you cant go back.

 

Who on BITOG recommended a 40W? Unless you have a reason (consumption, etc.) I would not recommend it and I am a poster on BITOG. If you have a lot of miles (over 100k) you might consider a 'high mileage' oil, butI say stick with 5W30 or 10W30.
To BlazinMike89:
It came with conventional oil, not synthetic, in the engine. Synthetic oils are not 'thin' by nature. A 5W30 is a 30 weight oil that has the properties of a 5W oil when cold whether it's synth or dino. The myth of not switching between synth and dino is just that - an old wives tale. Feel free to do so without fear.

BTW, I use Havoline 10W30 in mine.

 

Yea i understand That, I was going to Switch to Syntetic but Heard stories of oil leakage and seeping out thru seals and gaskets. So I'll just stay with the 5-30 Dino Oil That I Use, I Havent found any reason to switch. I Thought that Synthetic had more lubricity than Dino Oil and if used then switch back it would sort of under lubricate the engine

 

I have nothing against synth especially when used in the correct applications. I use dino because our engines are not high temp, high stress machines and are not at all picky about anyname brandoil. If you want to switch to synth, it won't hurt a thing, and you can go back to dino if you choose to later. What you may discover is that the synth might soften any engine seals that might have hardened, causing a temporary leak until the gunk is flushed away in an oil change. If I were to use synth, I think it would be Pennzoil Platinum.

 

False. Plain and simple. The thickness of the oil is the viscosity rating and the range it can fall in. Some oils are at the low end of the viscosity range for a 5W30 and some are at the high end. Same thing for conventionals and synthetics. It all depends on the manufacturer of the oil. Mobil tends to fall into the thin spec for a 5w30. Pennzoil is more in the middle.

I would not recommend going to a 40 weight oil.

Where are your leaks (other than the lines)?

 

Swartlkk

Theonly current leaks areat the oillines (knock on wood) but you know of my past crank & pan seal leaks;and I'd like to try and not replace the lines right now, as money is really tight right now since my wife was in an accident and totalled her Malibu. I was considering using Mobil 1 High Mileage 10W-30 HM. It gives you a ZDDP level of 1000, HTHS is on the order of 3.6, 100C cSt close to 11.8, it does have the added seal conditioners, and great cold pumping. I'm trying to save every $1 to get a coolant flush this spring as I am nearing my 5yr Dexcool date in August. What do you think? 29K original miles!

 

5yrs. If everything looks good, just drain and refill with either premix or mix it yourself with distilled water (saves money). I would use the Zerex extended service coolants.

 

Thanks on the Zerex, I was leaning towards that or Peak Global Lifetime. What's your opinion on switching to Mobil 1 HM?

 

When HM oils first came out, they were a reason to charge more money for something that was not a whole lot different than the regular stuff. Now, with some of the additive packages, they can be good for a loose engine.

As far as curing your leaks, if the lines are the only thing leaking, a 10w30 would be better than a 5w30. In that respect, I do not know if a HM oil will be any different than a general use oil.