# Oil Question (5w30 versus 5w40)



## DrTacoElf2 (Feb 10, 2008)

So I changed my oil about 2000 miles ago and just realized that I didn't put in a 502 approved oil. I used castrol syntec 5w30 because it came in a 5 quart jug. The owners manual says to use a 5w40 or 5w30 if 5w40 isn't available. Walamart only had 5w30 for castrol syntec so I went with it. 
Do you think its necessary for me to change this oil to 5w40 immediately or am I ok to go another 3,000 miles and change it out at 5,000 miles. My car currently has 23,000 miles and is a 03 1.8T GTI. 
On a side note I've recently developed a clicking noise at idle only once the engine is warm. Could this be related to the lower viscosity of the 5w30 oil??. I think the culprit is the timing belt tensioner, but maybe it could be a lifter (?). Any chance this oil could have caused it? (I prefilled the filter before I put it on so the engine wouldn't be dry at first start). I used an OEM Mann Filter.



_Modified by DrTacoElf2 at 7:30 PM 5-7-2009_


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## pturner67 (Dec 27, 2002)

*Re: Oil Question (DrTacoElf2)*

dunno about the clicking noise
M1 5w30 is not 502 approved but you should be fine in the 1.8t engine...your owners manual says 5w40 or 5w30 if 5w40 isn't available


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## Buschwick (Feb 12, 2007)

*FV-QR*

5w-30 has the same viscosity as 5w40. The difference is the 5w40 can withstand a higher temp without losing its viscosity than 5w30...which is something I take seriously on a FI car. These motors are HOT.
It'll be ok, but you probably won't be able to go as long on 5w30 as 5w40.


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## Spa_driver (Jul 31, 2005)

*Re: Oil Question (pturner67)*

Casrtol Syntec 5W-30 doesn't eeven meet VW specs....get that crap outta there!


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## DrTacoElf2 (Feb 10, 2008)

Ran it for about 2000 miles. Changed to castrol syntec 5w-40 and a new OEM filter today.


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## gunnr0991 (Aug 1, 2006)

*Re: FV-QR (Buschwick)*


_Quote, originally posted by *Buschwick* »_5w-30 has the same viscosity as 5w40. The difference is the 5w40 can withstand a higher temp without losing its viscosity than 5w30


These two oils DO NOT have the same viscosity... their cold viscosity is the same, hence the 5, however their operating temp viscosity IS NOT the same, as the 5w-30 has the viscosity of a 30 weight when at operating temps, and a 5w-40 has an operating viscosity of a 40 weight when at op. temps...
The -0 or 40 is representative of the operating temp. viscosity, which is due to the addition of polymers to the oils, which are what change the viscosity due to the temp of the oil. 
Is it a big deal... not really, otherwise VW wouldn't have said it's acceptable when 5w-40 isn't avail. but for the best protection and longevity stick to a VW approved 5w-40 as often as possible.


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## Tom Long (Sep 21, 2007)

*Re: FV-QR (gunnr0991)*

40 has better protection


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