What weight winter oil for forged motors ?

Those of you with forged motors, what weight oils are you using for the summer and winter? I have -13.7 Dimond Pistons. The issue I'm having is and inability to warm the car up without over heating in the morning. I had to let it idle for about 15-20 minutes this morning because I had to keep cutting it off due to over heating. Finally I got the temp where it needed to be after I reved the motor a bit. As soon as I did, the temp guage stabilized (where it normally is). FYI problem is only in the morning after the initial cold start. Its fine the rest of the day.

As per order of the engine builder, my summer weight was 15w50
and he suggested 10w40 for the winter. Ever since it started cooling off I've been having some prolonged warm up times with both oils I've used so far. This is Mobile 1 btw the 10w40 i just put in yesterday, and this morning was the first time it took this long. Perhaps I need a 15w40 ?


Thoughts!?

EDIt: Just got of the phone with my engine builder. He says that he thinks my thermostat is sticking, and need replaced. Does this sound right? Thanks in advance

Yea, engine oil weight won't effect how fast your car warms up that much. You have cooling system issues, not oil weight problem, unless you are going by an oil temp gauge. Either way no matter what, your car should not be overheating.

Sounds like air entrapped in your cooling system ... are you finding any puddles of coolant under the car? Entrapped air will cause the over-heating you are describing ... it usually dissipates itself (the way you describe) and the problem goes away. With yours being a recurrent problem I think you may have a leak somewhere.

I think a faulty thermostat would be a problem through out the day and not just a morning issue but it would be a good thing to replace.

If I were you I'd be using Mobil 1 0W40 ...

Quote: Originally Posted by Jared H... Sounds like air entrapped in your cooling system ... are you finding any puddles of coolant under the car? Entrapped air will cause the over-heating you are describing ... it usually dissipates itself (the way you describe) and the problem goes away. With yours being a recurrent problem I think you may have a leak somewhere. I think a faulty thermostat would be a problem through out the day and not just a morning issue but it would be a good thing to replace. If I were you I'd be using Mobil 1 0W40 ...

Checked the radiator for fluid and it was pretty low. So I
went to Auto Zone and picked up some DEXCOOL 50/50. I topped it off and will be keeping an eye out for leaks especially the next week err so. I have not found any puddles of coolant ever. If I do have a leak my engine builder said it might be small and its contacting a hot surface and burning up before it hits the ground. But if that was the case wouldnt I see smoke?

mine was leaking from the thermostat area- never saw smoke, just had the lingering smell under the hood. Also had it leaking from the water pump gaskets once. Same thing, except I never really saw that leak, just the smell.

thanks guys ... we shall see what happens the next few days

Topped off the coolant, and the car warmed up just fine. I guess there has to be a leak sum where. b/c somehow the coolant level got pretty low. IDK. I dont leave puddles anywhere or any traces of coolant in the bay around the coolant lines waterpump or radiator. sighs

... head gasket could be leaking into one of the cylinders ... hopefully not. You might try putting some dye into the coolant to help you locate the leak.