# SAE 30 versus 10W-30



## ziggyzoomba (May 5, 2009)

I have a Craftsman walk behing mower that I haven't used for a while. 

I got it out for the first time in about a year today and it was very low on oil, so I put in SAE 10W-30 instead of the recommended SAE 30.

It started leaking oil very bad, but I didn't notice until after the engine lightly backfired, sputtered a bit, kicked out a little black smoke, and then went out.

I could not get it to start again, but I think that is more because of a faulty lamination/spark plug wire.

So my question is, and I am novice, but, could the 10W-30 have hurt the engine? If I am correct, the 10W-30 is just thinner than the SAE 30, right? Could the fact that it is thinner cause it to leak?

What woudl have happened if the engine overheated because of improper oil being used? Have I burnt up the engine?


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## Gocart (Mar 28, 2008)

You already had a slight oil leak (using 30W). You put 10-30W (which gets thinner as it warms up, your oil leaks out faster. I dont think the oil made much difference, other than it (10-30W) leaks out faster. Unfortunately it sounds like you may have burned your engine up. you can pull the plug and check for fire. Black smoke indicates fuel. Blue or white smoke is oil, or rings. Good luck.


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## ziggyzoomba (May 5, 2009)

Gocart said:


> You already had a slight oil leak (using 30W). You put 10-30W (which gets thinner as it warms up, your oil leaks out faster. I dont think the oil made much difference, other than it (10-30W) leaks out faster. Unfortunately it sounds like you may have burned your engine up. you can pull the plug and check for fire. Black smoke indicates fuel. Blue or white smoke is oil, or rings. Good luck.


I should probably clarify....even though the oil was leaking, there was still plenty of oil in there. It wasn't like it leaked dry. 

When you say "pull the plug" what plug are you referring to? 

Also, when I pull the start rope, it give me a real high wheezing sound, like it is not even trying to start. Again, note that I think my lamination unit for the spark plug wire is not connecting, so this may be related. Regardless, something caused the engine to shut off. 

Still think the engine is shot?


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## Gocart (Mar 28, 2008)

You can remove the spark plug from the cylinder head, reattach it to the spark plug wire, make sure the spark plug is touching the engine (grounded) and pull the rope and look to see if there is a spark. This is always a good start when diagnosing a no start condition.


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## 30yearTech (Sep 14, 2006)

As long as there was plenty of oil, 10W30 is fine to use in your engine. 10W30 is an acceptable substitute for 30wt, but will be used up faster by the engine, so keep an eye on your oil level. It would be a good idea to fix your oil leak, as this will cause a loss of vacuum in the crankcase and can lead to higher oil consumption when running.


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## Rentahusband (Aug 25, 2008)

Where is the oil leaking from.
Dean


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