Alright. So I just did an oil change, and switched from Royal Purple 10w40 to Castrol GTX 20w50. When I was driving it home, it warmed up and went to the standard 1/4 of the way up the temp gauge. However, when I revved it up beyond 4k the temp gauge would go down to 1/8 on the gauge. I did it again, and again, and it always went down. And the sound has changed. It sounds REALLY high pitch at around 5k which sounds awesome. And it seems alot faster. It seems like I just did $1,000 of mods. (Not really, but it still rocks.)

Anyone else experience anything like this ?

 

naw, and i usually use 10w30 BUT HOLY HELL I NEED TO CHANGE MY OIL AND I KNOW WHAT IM GONNA DO LoL... I notice the diff btwn 10w30 and 10w40 a little bit too... It sounds a bit growlier (now THERES a word) with the 40 visc.
Hey also, where do you live and what temps are you in?

 

/me needs to put 20w50 in next weekend when i do the oil change... Last time I couldn't get the damn oil filter off though :/

 

I am in Minnesota. We are in about 80 degree highs currently, but I expect it to be around 90 degree highs by the end of the month with 100% humidity. Yuck.

 

damn lakes, where in MN, we should meet up if you're on the west, its a long jog to SF for me, but I'd enjoy it. I'm probably meeting up in Omaha for the meet there later this month

 

I used to live in Duluth, MN I want to go home

 

I remember drivng through on a road that cuts off I-90 to the twin cities and there was a the Green Giant guy... Was someplace like Blue Earth or Green Moon or some weird named town. That still there?

 

Well since no one else addressed this...
It seems strange to me that your temp gauge would go down when you're reving it. That's not something one would expect to have happen from an oil change and your car should have that behavior. Does it do it under all conditions?

Are you certain the performane and noise aren't psychosomatic effects? If anything I would expect you to lose a non-noticable amount of power by going to a heavier weight oil.

 

I agree with Snrub on this one.

Well, except I notice the power I loose :-p

You will too, you can try it, just run 5W-30 for a little while (a very, little while) and then try putting 20W-50 back into it. You'll see a difference. Or you're not observant. Or your car acts differently then mine

 

Problably psychomatic effects. But the heat DOES go down. MY theory is that the 5th/6th ports opening allow the engine to breath more. I have zero evidence of this, other than the fact that it seems to be the case. And I bet switching from old oil to new helped me gain back one or two hp wouldn't you think ? Non-noticeable. The sound is different though.

And I am in Burnsville MN.

 

Old oil tends to be thinner, specially in rotaries, where gas can easily get in the oil, specially on older engines.

Thinner oil is easyer to push :O

 

Last time I checked, thicker oil did a better job of cooling... even if it is harder to push :P

 

I've never heard of the temp gauge going down when you rev it up. I'm just saying I think you better get some advice on it instead of discussing oil weights. Maybe start a new thread like "Temp Gauge Drops when revs rise" and mention everything you did here. That way the right people will look at your thread.

Pure speculation on my part would be that it's an electrically related problem with your stock gauge, but who knows.