cooling questions

[a2j]

little background:
test drove my car last night after installing new 2'' radiator, 1.1bar radiator cap and relocating big oil cooler in front of that radiator. I also did a/c delete (some time ago). it was about 25F deg outside. cooling system filled with 50/50 mix.
so two question now:
1. logger shows 177-182F coolant temps while cruzing. Upper rad hose is really hard. Aluminum radiator is really hot. AM gauge shows only 160. Slim fans hotwired and working at full blast. I have a feeling that I'm overheating. Is this normal and I'm just paranoid?

2. My "normal" oil temps during summer are at 175-180F. Now its only 140-150. Is this too low for oil to lubricate things correctly? At what point oil is not warm enough? Oil is 10W40

thank you for your useful input.

[BigTyla]

Those water temps are good but are both fans on the whole time? And are they supposed to be? In other words, most cars only run the second fan when a certain temperature is reached and then shut off when the water temperature has decreased a certain amount. If the secondary fan is wired like this and it's staying on the whole time, you might have some reason to be concerned (especially if it's doing this during the winter).

As for your oil temps, if that is measured after the cooler, you should be fine. Ideally though you need to measure oil temps before the cooler.

[a2j]

rad fans are hotwired and controlled by ON/OFF switch (me). oil temp sensor mounted in sandwich plate above the filter.

[BigTyla]

If both of your fans are wired, I guess you'll just have to wait until summer to see if you'll overheat.

That oil temp in that location is rather cool but it should be fine.

[MR2]

well, the Slim fans have a very bad reputation, whether they will perform in your instance is anyone's guess, but if you can fit the stock fans your best using those, I run a big oil cooler in front of my Radiator and since I have left the thermostat in the oil filter housing the only time the oil cooler heats up is when the oil starts to get decently hot! I assume your in the same situation.

why don't you just let the ECU control the fans?

[a2j]

so, 180-185F coolant temps nothing to worry about? what about that hard as rock upper rad hose? just to compare those slim fans, during summer, I was using stock junk radiator with only 1 stock fan running low speed, and temps were ok. This "upgrade" is what makes me paranoid. Trust, but verify.

[MR2]

the system is designed to pressurize a bit during normal operation, the pressure stops the coolant from boiling even at over 100 degree temps(not much further though). 180 to 185F is around the 85 degrees mark which is fine I cannot remember the exact time when each fan turns on but see here

Normal operating temperature?? - 3000GT/Stealth International Message Center

[Trevor]

Whooo...lots of things to address.

- Anything under 208F in a 3/S is perfectly safe and within OE specs. 208-221F is iffy and 221+F is bad. Many many cars run at 199-213F nowadays in the interest of improved gas mileage and emissions.

- Without A/C a properly ducted/engineered cooling system should never need a fan while moving (let alone two) regardless of ambient temp. The only time your fans should ever be on is when you're idling for an extended time and then they should cycle on & off. You're wasting power & fuel by running them 24/7...power that could be making you go down the road. Hell, I went on a 50 minute drive the other day skirting the edge of town and on the highway in 72F weather and the fans didn't turn on once until I pulled in my garage after idling thru my neighborhood.

- You get more knock resistance with a cooler motor so you can advance the timing or run more boost and make more power.
-- On the other end your gas mileage & volumetric efficiency will go down; and parasitic drag (thicker oil), engine wear, and emissions will likely go up.

- Oil temp needs to be 170F+ (maybe even 180F) for it to do it's job well and it's actually a good thing if at least occasionally is gets up to 220+F to boil off water contamination that builds up over time. If you're running at 140F your stock oil cooler thermostat must have issues or be modded (If I remember right it should be closed under 168F so the oil warms up).

- 11-23 psi is A-OK for the stock cooling system and your ridgid radiator hose is generally a good thing. That pressure keeps the coolant from boiling (even localized boiling occurs at 180F coolant temps in a really stessed car at full throttle if the pressure isn't high enough). On a modded car the higher the better IMO (all the way up to 23 psi).

- 50/50 coolant/water may be the standard "one-size-fits-all" for Mom's mini-van but its not really a good thing unless you store your car where it gets to -20F or colder. Antifreeze's specific heat is lower than water's which means when you add X amount of heat to a 50/50 system you'll end up with higher temps than say 20/80 + an anti-corrosion additive like Redline Water Wetter. If you want the absolute best performace straight distilled water and one of those anti-corrostion additives in the directed amount is the way to go but most places freeze so that's not an option. Personally I run 12.5% coolant + WaterWetter which is well within what I need for the coldest temps I see in Tucson (low 20's F in a cold snap). (BTW - That higher pressure radiator cap from the previous bullet also unlocks the door to lower coolant concentrations since it raises your boiling point significantly higher)

- Where is your Autometer gauge's temp sensor? If it's in the return from the radiator there's your issue. If it's right next to the stock sensor I'd trust the logger over the AM gauge. It's still really nothing to sweat. Hell, 207F isn't anything to sweat.

[mb3000]

Glad to see you over here Trevor

[MR2]

Glad to see you over here Trevor

Sames