50 Valvoline and 20W-50 Mobil Oil----Will they harm a 3.4?

[CHRISB]

I did another oil change today and I always see Mobil 20W-50 and Valvoline SAE 50 Racing oils. I know these are for high horsepower engines and race cars. They are very viscous and thick. They help against heat breakdown. Would these work in our cars, a 3.4L? If I try it will my engine performance be affected? Will it damage the engine in any way? Possibly the oil pump? Any one ever tried this?

[hockeyman]

That is VERY thick oil! It won't flow properly at startup (when oil flow is needed most) and could severely wear down your engine parts. 20w 50 isn't as bad as 50w. 50w is some thick stuff that has the flow potential of maple syrup. Our engines call for 5w 30, and in the summer I don't run anything thicker than 10w 30. If you are worried about heat breakdown, change the collant every 30-40k miles, run a 160-180 thermostat, wash out the radiator fins with a hose regularly to keep dirt and debris from building up in it, and make sure your electric fans are working properly.
Adding thicker oil will just make your problems worse. Oh, and thicker oil takes longer to cool down too.

-Marc

[CHRISB]

I actually had my radiator fan motor die last week and had to replace it. At the same time I flushed the radiator with a chemical radiator flush from the parts store and refilled with 60/40 water/fluid mix, water wetter and I did spray the core with the hose. And the 160 Hypertech thermostat I ordered a few weeks ago arrived last friday and I installed it :D . My car never goes past the 1/4 185 degree mark [img]graemlins/thumbsup.gif[/img] . I'm not worried about the engine overheating. I just did some reading about motor oil viscosity and read that the lower viscosity 5W and 10W oils actually flow worse at higher temperatures. A 20W-50 oil will flow in cold and hot temps. The "W" actually stands for winter not weight. Since I live in Florida, it never gets cold enough to need freeze protection. I read that the higher viscosity oils lube the lifters and valves and other parts better than lower 5 0r 10 weights. I am willing to try using 20W-50 if it won't harm my engine or have any major dangers [img]graemlins/fluffy.gif[/img] .

[Dr Todd]

W= winter?????????? Yep.

Try this: http://www.howstuffworks.com/question164.htm

And this:
http://www.vtr.org/maintain/oil-overview.html

[ March 21, 2003: Message edited by: Dr Todd ]</p>

[67-03 RIP]

With the quality of oils I think you'd be more than fine with what the motor calls for, especially with at least a synthetic blend. I don't have a dyno, but I'd wager a $1 that you lose HP with the heavier oil. That stuff is thick - imagine how much more it takes for your oil pump to push that around....

Ron

[CHRISB]

<blockquote>quote:</font><hr>Originally posted by Dr Todd:
W= winter?????????? Yep.

Try this: http://www.howstuffworks.com/question164.htm

And this:
http://www.vtr.org/maintain/oil-overview.html

[ March 21, 2003: Message edited by: Dr Todd ]<hr></blockquote>

Thats where I got my information from. I searched google and came up with those two sites. I always think before I speak ;) .

[black98V6]

my roomate runs 20w 50 in his 86 vette year round.. he has 205k miles on it and that thing still hauls booty..

he does it because of the fact that the motor is so high mileage so it helps keeps things sealed and flowing right.. but yeah you are gonna loose some HP with thicker oil.. though I also gotta say that when you start running anything that is not what the engine was designed to handle there is always the possibility (no matter how thin) that operating outside of designed parameters could cause problems

[HPbyChevy]

[img]graemlins/omg.gif[/img] I myself wouldn't go anything over 10w-40 or 15w-40 (synthetic) in a street motor. 20-50 is just a little to thick for me (unless I was running a racing motor).

I'm sure your not using you 3.4 for all-out-drag-racing. Or are you?

The oil is being used for lubricating purposes, not cooling (that's why we've got radiators). I would be looking for a oil that has good resistance to thermal breakdown in a range lower than 10-40. ;)

[venom]

wouldnt use any oil thicker than 10w-30 anything else it too thick (espicially in winter) and will cause premature engine wear upon startup (in cars newer than 88 or so, they are designed to use the thinner oils)

[F1GT]

If you have a HIGH mileage car, like the guy above stated about an 86 Vette. If you have lots of miles and the car is leaking, then go for the 20/50. Otherwise, stick with 5w30 or 10w30.

GoodLuck
[img]graemlins/burnout.gif[/img]

[strobhen]

I wouldn't put it in

Your engine is designed for 10w-30, and so is your oil pump.

It is quite likely that by putting in something that heavy your car will not be able to flow the volume necessary to properly lubricate the engine. Probably can't even build up proper oil pressure.

You are not risking just premature engine wear, you are risking all-out engine failure.

The "High Performance" labels on products like Mobil-1's 50 weight is very misleading. Its more for deisel trucks & huge engines. NOT for your 3.4L v6. Stick w/ 10w-30.

[ March 24, 2003: Message edited by: strobhen ]</p>

[lando_pr]

What should be the oil pressure at idle, high RPMs etc.?
I use 20W-50 and most of my friends do too. Temperatures here are pretty hot most of the time and winter is around low 80s day/50s to 60s Night. My oil pressure in hot days is about 35 @idle and I think somewhere around 60 at high RPMs. Is that bad?

[PalmHarbor]

Re: 50 Valvoline and 20W-50 Mobil Oil----Will they harm a 3.4?

I have a rebuilt engine 3.8 liter and its burning oil and oil pressure at idle in hot Florida is at 10 oclock...I am considering 10-50...any specific comments?

[ssms5411]

Re: 50 Valvoline and 20W-50 Mobil Oil----Will they harm a 3.4?

I use 10w40 and works well for the AZ heat.

[vanbibber]

Re: 50 Valvoline and 20W-50 Mobil Oil----Will they harm a 3.4?

dude this thing is 9 years old. why wouldnt you just make a thread?