McSlides

iTrader: (1)

I've been trying to figure this out but thought someone else might have the same issue.

I live in Florida, it get pretty hot in case you're unaware. It also doesn't help that my car is black. During the day when it's hot as *****, my oil pressure reads 0psi at idle, but has plenty of pressure while driving (which is most important, right?). At night when it's much cooler, my oil pressure is at a solid 8-10psi at idle, and again, normal while driving. I'm wondering if it's so hot that out that it's causing the viscosity of the oil to thin out too much?

I went from running AmSoil 5w30, to Redline 10w30 to thicken the oil during the summer because it does thin out so much, but it didn't really help at all. Any thoughts or suggestions? Thanks

Also, I took the hood vent out and ran it open (just the "chicken wire" mesh). It helped with heat soak tremendously (can ran much better, but the oil pressure was still the same), but with so much rain here I put it back in. Is it safe to run without it?

meckert

iTrader: (11)

Get yourself another oil pressure switch--they are cheap and its likely the culprit. Could also try a 10-40 weight oil and change it fresh for the summer months.. I am in tx and have noticed the same thing---seems to work for me.

McSlides

iTrader: (1)

I'll look into doing that on the next oil change. Does the 10w40 cause too much pressure at night when it's cool?

joseph143

iTrader: (8)

shouldn't your car shut off if its at 0psi of oil pressure? I've never logged it so idk... also 10-40 is fine for a built or older motor... and if the pressure is higher then usual its no big deal...

whats not good is 0psi of oil pressure... even at idle... I would look to make sure your oil squirters or something didn't come off...

running without the mesh isn't gonna kill anything... hundred of people do it...

McSlides

iTrader: (1)

When I first start the car, the oil pressure is normal. Even when it's fully warmed up it's normal (8-10psi). It only drops down to 0-2psi during the heat of the day when I've driving for 10-15 minutes. I'm thinking it's just the oil thinning out so much the gauge isn't reading it properly.

I'll go back to running without the vent in the hood and see if it helps any more. Can't hurt.

chu

iTrader: (72)

10w30 is the OEM recommendation. In hot Florida weather, its not a bad idea to bump up to 10W40 as suggested. I've seen many people report low pressure at idle like what you're seeing, but not go down to 2psi. What are your pressures during WOT, and also during cruise (70pmh?)

McSlides

iTrader: (1)

WOT 2nd and 3rd was at ~95psi. I can't exactly drive anywhere nearby at 70mph without getting a huge ticket, but at 45mph in 5th gear it's at about ~40psi. The car runs and drive perfectly fine and seems healthy. Again though, it only drops down that low at idle during the day. At night, it's fine.

barneyb

20W-40 is the OEM recommendation for hot weather. 20W-40 is impossible to find so 10W40.

chu

iTrader: (72)

If the pressure comes up, you should be good. The rule of thumb is 10psi per 1k RPM, so I think you're fine.

Is that in the manual? Never seen it. Never even heard of 20w40. I would go to 20w50 then if the weather is hot enough to require it. I use to run 10w40 in my car for track purposes, and it did great for the heat and humidity of the Northeast.

jspecteggy

iTrader: (13)

The number before the "W" only applies during engine start up as the oil is cold, or during cold temperatures, it allows it to flow quicker instead of starving your engine until the oil is up to operating temps. The higher number 30,40,50 whatever you're running determines the viscosity of the oil when its at operating temps. The lower the number the lower the viscosity and more engine wear essentially. You should get a little better pressure switching to a 40 weight.

AMSOIL has a great article on this:

http://www.upmpg.com/tech_articles/motoroil_viscosity/

barneyb

Yes it is in the manual - 2003 Evo VIII shop manual. My car has 10W-40 in it now.

McSlides

iTrader: (1)

Thanks. If anything seems to start acting wrong then I'll know something isn't right. Or if i start dropping oil pressure while driving. Thanks for the reassurance.

barneyb

Since you have readings you must have a gauge. It could be that the gauge quits reading before the pressure drops to zero. Is your oil light coming on?

McSlides

iTrader: (1)

No, no oil light. Only check engine and that's from not running a cat and needing a tune. The gauge doesn't seem to shut off because you can see it slightly move around the 2psi mark. I think it's just super thinned out from the heat because other than idle during the heat of the day, it's fine.

barneyb

The manual states that minimum hot engine idle oil pressure is 4.2 psi. The manual doesn't say at what pressure the oil pressure switch is suppose to close and illuminate the warning light but I assume it would be near or hopefully above this pressure. So, if the oil pressure switch is working you should be okay. Gauges are never quite accurate.

I'd at least go with a higher viscosity oil during summer for insurance. I'd want that gauge reading some pressure all of the time.