Using Heavier Weight Oil

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Are there any problems with using a heavier weight oil like 10W50, 20W50, 5W50, 10W40, etc., instead of 10W30 or 5W30 in a new car (Civic), besides lower MPG? Does it have any good or bad effects on the life of the engine?
 
There are no upsides. 20 and 30 weights have proven to be adequate. Newer cars are designed with bearing clearances and areas to run with lighter oils. Thicker is not better anymore.


Not sure anyone here can positively say that it can "hurt" though.
 
What is the reason you want to run the thicker oil? Obviously you can't go thicker than 10w30 in winter and it your temperature is frequently below 0 F, a 5w30 would be highly recommended, in fact synthetic would be better.

I just cold started my motorhome after a night it dropped to about 5 F and the motorhome had sat for 2 months. It fired up very nicely on the 10w30 Pennzoil SL Synthetic. Probably was around 8 or 10 F when I started it, not sure exactly. I think the Maxlife 10w30 I had been running would have been much worse for startup.
 
One way to determine that might be to see what the European oil recommendations are for the same engine.

The Euro's seem to rec higher weights generally, but we have CAFE here in the U.S.

I use a 5w-40 synth where the mfr recs a 5w-30. I just think its better protection and performance, although I surmise about a 1mpg hit.
 
If the engine is an overhead single/dual cam, I would not go more than (1) cSt@100 beyond what the new owner's manual recommends. I would be leery to purchase 10W oils also.
For instance... if it calls for 5W-30, the thicklest ones are 12 cSt. So I would not exceed 13 cSt personally - so start-up lubrication in your Chicago winters remains respectable.

Just my amatuer opinion here...
 
I'm not concerned about cold weather startup. I bought this Civic in 89 and consistently used those heavyweights of GTX for the first 90,000 miles. Then someone told me it was a bad idea, and I switched to xW30. I've got 120,000 on it now, and it seems to use some oil, maybe a quart every 6-800 miles, but doesn't seem to burn it. I don't see any smoke. And there are no leaks. I can't figure out where it goes. I'm just wondering if I jacked something up in the engine from all those years of using the heavier weight oil? What could be happening to the oil?
 
quote:

It seams to me that the clearances in your motor have increased in order to accommodate the heavier oil.

You may be on to something, but I cannot imagine how the clearances could increase in response to thick oil.
 
Goldenrod,splain to me how for a better term higher viscosity oil may not be able to "squeeze" into where it needs to go
 
Heavier oil doesn't "squeeze" into smaller spaces as fast. It doesn't flow as well as thinner oils.
The cam oil sensor light on my old GTi would take much longer to go out with 20-50 than 10-40.
The oil just couldn't get up there and do any good until more time, and wear, occured.
 
"You may be on to something, but I cannot imagine how the clearances could increase in response to thick oil. "
Nor can I but I can't say its unreasonable though.

Maybe the best would go give it a good AutoRx to free up the rings and then go thth the thinest oil (above a 20 wt where oil use is not excessive. Again..40's O.K.(albeit not necessary) but I wouldn't jgo to 50.
 
Either pick up two bottles of Auto-RX or a gallon of Lube Control. If you want to use a thicker oil try to use a 5W40,5W50 etc... It does not make sense to give up cold start performance just to get thicker. Now when it is warm out their is nothing wrong with 15W40.

The reason for useing either LC or ARX is to clean the ring pack area.
 
I'm a BIG fan of 5W40. Maybe bumping it to a 15W40 during summer depending on engine and driving habits.
 
thicker weight oils are generally for older cars with different clearances, like said above.

If you are currently using the thicker stuff and your engine is runing fine, you should be OK. The reason why you would lose a few MPG would be because thicker oil makes it more difficult for the crankshaft to slosh through it when reciprocating. This results in a slightl loss in power and slightly more fuel consumption. However, with thicker oils, they tend to burn off less easily and quiet noisy engines. You can't really lose either way because modern oils are pretty much all formulated very well.
 
It may be that engines just get 'used to' a particular weight of oil like when run for that many miles on them, I would think a 5w40 would be ideal for your situation.
a quart in that many miles you will not be able to see it, unless maybe you followed yourseldf and noticed a little bit of smoke every now and then, but it is going out your tailpipe. certainly the rings are a bit stuck and a good clean might eliminate your consumption.
 
it wouldnt hurt anything to run thicker oil. the question is, would it help anything?

i have ran everything from 5w30 to straight 30 and even 20w50 in the honda crv.

it didnt hurt a thing, although i dont believe it has anything positive to benefit.
 
In a new car, I'd go with recommended oil visc. and interval to maintain my warranty. If you want more protection, get some Redline or Synergyn SM 20wt unless your racing and then put something thicker in for the weekend. On a Civic I wouldn't go beyond a 40w for any circumstance.
 
Running 5w30 or 10w30 would likely be fine. However running Xw40 or Xw50 would both decrease your MPG and your HP, so i think any additional protection benefits would be more than outweighed by the bennefits of a thinner oil.

If you are racing or in a very hot climate and are concerned about using hondas recommended 5w20, try 5w30 or 10w30 and leave those heavy oils to the folks with old American and German cars
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