5W20 vs 5W30 Oil
01-10-2009, 09:17 AM
#1
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5W20 vs 5W30 Oil
I just did an oil change but ended up using 5W20 instead of 5W30. Any thoughts on whether this will be harmful? I live in the NY area with typical winter temps.
01-10-2009, 11:52 AM
#2
There are no HTO-06 approved 5W-20 weight oils. 
That being said, and after spending a little time over at BITOG, not all oils at the same grade are equal. There are 5W-20s that are thicker than some 5W-30s.
What brand oil did you use? You can search the manufacturer's site for the product data sheet on the oil and compare the viscosity range of the 5W-20 oil you used to an HTO-06 approved 5W-30 oil (PP, M1, or 0W-30 Amsoil). The spec you're looking for is viscosity centistrokes (cSt) @ 40 and 100 degrees C. This will give you an idea of the oil's thickness at temperature. The 100 degree number will be more relevant with our K23s.
IMHO, you will be just fine. Most 5W-30's end up near or below 5W-20 viscosities due to shearing and fuel dilution anyway. If it makes you nervous change it out in the spring or at 50% oil life.
That being said, and after spending a little time over at BITOG, not all oils at the same grade are equal. There are 5W-20s that are thicker than some 5W-30s.
What brand oil did you use? You can search the manufacturer's site for the product data sheet on the oil and compare the viscosity range of the 5W-20 oil you used to an HTO-06 approved 5W-30 oil (PP, M1, or 0W-30 Amsoil). The spec you're looking for is viscosity centistrokes (cSt) @ 40 and 100 degrees C. This will give you an idea of the oil's thickness at temperature. The 100 degree number will be more relevant with our K23s.
IMHO, you will be just fine. Most 5W-30's end up near or below 5W-20 viscosities due to shearing and fuel dilution anyway. If it makes you nervous change it out in the spring or at 50% oil life.
01-10-2009, 05:40 PM
#3
Burning Brakes
You probably won't do any damge to the engine and the turbo short term, but the turbo might go belly up in the long term due to the high temps it operates under. I would change the oil to Honda approved 5W-30 ASAP just to be sure. 
05-17-2018, 04:29 PM
#4
05-19-2018, 08:24 AM
#5
mrgold35
The RDX requires syn oil because the same oil lubricates the turbo bearings. Conventional oil would turn to a thick sludge compared to full syn oil. You didn't say if the 5w20 you used was full syn or a blend of syn/reg oil? I wouldn't take any chances with conventional or blend oils with the turbo engine.
Last edited by mrgold35; 05-19-2018 at 08:27 AM.
05-19-2018, 07:14 PM
#6
Suzuka Master
It buffles me when people ask if its ok to use oil that is not the oil specified by manufacture. What is the point of this question, try it out see if your engine works, if you have problems dont complain.
05-20-2018, 06:15 PM
#7
The RDX requires syn oil because the same oil lubricates the turbo bearings. Conventional oil would turn to a thick sludge compared to full syn oil. You didn't say if the 5w20 you used was full syn or a blend of syn/reg oil? I wouldn't take any chances with conventional or blend oils with the turbo engine.
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