My car has been letting out a puff of smoke at startup ever since I took it out of storage. It has done it in the past but not every time after starting the car when warm like now. I've been using 5w30 mobil1 for the last 32,000 km's of the total 180,000km. The manual recommends 5w30 (also on the fill cap) but I don't drive this car in the winter at all. Can I go with the 10w30 mobil 1 (is it thicker?) and would this help with my blow-by problem at startup when the engine is warm?

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89 GTA G92
305 TPI WC 5spd w/3.45
Accel Cap & 8mm Taylor's
Custom 4" Cold Air Induction
Jet Airfoil
K&N Airfilter
160 deg stat/fan switch TB Bypass - Steel Rad
Cat back 3" Exhaust w/Terminator Muff.
HiGh FlOw Dynomax Cat
Spohn LCA's - KYB GR-2's
Moroso Crank Bolt and roller pilot bearing.
New Fuel Pump!
Autometer Vac+Oil Temp
2000 Yamaha R1 150hp 385ibs

 

Anyone?

 

Yes you can use 10W-30. No it is not appreciably thicker.

I doubt the oil viscosity has anything to do with that. More likely the POS valve guide seals the factory uses have just finally turned to dust and fallen off, like every other SBC with lots of miles or years on it. The only sure cure is replacing them. That's very easy and cheap, it should take no more than a couple of hours and less than $25 for the seals and valve cover gaskets. On the other hand, it doesn't hurt anything, and once the seals have all fallen to pieces it never really gets any worse, so unless it really bothers you, you can leave it alone.

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"So many Mustangs, so little time..."
ICON Motorsports

 

The seals probably got hard from storage. I've seen this before. Seal conditioner(like the stp stuff) sometimes works. Also, just driving the car on a few long trips can soften up the seals. You could be stuck with a start-up smoker until you replace the seals.


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkim bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro