10w40 hm to thick,can I thin?

I have a 1995 geo prism beater i use to go to the railroad and to run around in the winter.I have moil 1 10w40 hm in it now because of worn valve guides.The morng smoke has stopped but my problem is the oil is way to thick.The car has no power and feels like the engine wont wind up.I want to thin the oil. It is down almost a quart,can i add some 5/20 to thin it out.Cars calls for 10/30
 
I don't imagine that would hurt it any and it would thin it down a bit this time. Not sure I would add another quart of 5W20 after this one to this oil mixture. You may choose to just go with the correct weight of HM oil since it is the additives and not the viscosity that actually should have stopped your smoke. I know someone who had a Rav4 that used to smoke so bad it looked like her garage was on fire when she started it up. After 3 oil changes with Castrol High Mileage (not that the brand really matters that much) usually at 5,000 mile intervals it stopped smoking completely and she was using the correct weight which I believe was 10W30 as well. She even strayed away from the HM oil for a few changes and didn't have smoke again. Good luck with the car and do consider switching to a HM 10w30 for your next OCI.
 
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A quart of MMO will thin it much better than a quart of 5w20 will. If it truly is "too thick" as you describe that would be the route I'd take.
 
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Originally Posted By: KCJeep
A quart of MMO will thin it much better than a quart of 5w20 will. If it truly is "too thick" as you describe that would be the route I'd take.
Yeap, cheaper, thinner and some clean up smile
 
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If you thin it out , guess what? Oil consumption will increase. But it's your call... MMO is a good additive choice right now- don't go crazy with huge amounts . Smaller engines really do show power loss/gain from thin/thick oils.
 
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MMO will thin out the oil across the board without improving the oils VI. I'd add a quart of Toyota 0W-20. It's the lightest oil you can buy on start-up due in part to it's 214 VI. This will still leave you with a light 40wt oil with almost a 15 point higher VI. If the engine still consumes too much oil just top up with a cheap 5W-30 dino until winter is done them start with M1 0W-40.
 
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