What is correct engine coolant temp?

[PhopsonNY]

Hi,

I have just been reading "how stuff works" and they say that the optimum temp for engine coolant is 93degC for best ignition timing.

Is this the case for the SR? I have an adjustable thermostat for my electric fans along with my Greddy coolant temp sensor. I have it set to 83degC now, but maybe I should have it higher.

In addition, can a turbo that is going bad cause higher than normal engine temps?. I am trying to find the reason for a loss in power with more turbo lag and my engine temperature geting higher quicker... ie my cooling fans have to come on more often than before.

thanks

car has:
1990 hatch with REDtop & stock turbo, Walbro 255 fuel, aeromotive FPR & filter, TurboXS MBC, Greddy Turbo extension & Megan downpipe, Exedy Stage 2, Greddy FMIC, Greddy RS BOV, 3" Catback, high flow cat, Toda Flywheel, B&M shortshifter, s15 Helical Diff, Koyo Radiator and Flexalite twin elect fans with thermostat

[2JZGTE]

I have mine set to run 88-90C. It's been working really good for a year now. I guess it wouldn't hurt to bump yours up a little.

Not sure about the turbo making your engine run hotter. Try flushing your coolant and then filling again and add 1 bottle water wetter.

Do you live in a place where it doesn't freeze? You can also had 75% water, 25% coolant, and bottle of water wetter. This made my engine run a lot cooler.

Billy

[Slidin240Wayz]

are you serious? 93 degrees, I have it set at 76, it barely breaks 80. So can a water temp guru set it straight for the sr?

[TheTimanator]

i searched around not too long ago and found someone suggesting 180degF (82 degC) was the optimal temp to run an SR. I have my first fan set to come on at 185 degF (85 degC) and then the second comes on at 190 degF (87 degC).

I have a Koyo aluminum radiator, Flex-a-lite e-fans, and a factory thermostat, about a 50/50 mix of antifreeze and water plus water wetter. At crusing speeds above 45 ish the car stays around 175-185. Idling, it seems to get pretty hot but I don't think my water temp guage is accurate when the fans come on for some reason (probably poor grounding).

Also, I don't the FMIC in yet which will change things I'm sure. It's funny you posted this thread, b/c I was thinking about this today.

[PhopsonNY]

Driving home today, I noticed the old responsiveness was there when I first got into the car.
It was still cold and maintained coolant temp at about 70degF. for a while.

Then after a couple of miles, the power was down again a mile later the temp started to climb like I described above.

I think there is a exhaust leak somewhere that only shows up after the car has warmed up. I suspect the exhaust manifold or the tubo gasket.

In order to find it will try driving the car around for a while till it is fully warmed up, use seafoam and plug up the exhaust and force it out the leak...

Anyone have any better ideas as to how to find it?

[2JZGTE]

In my car the temp. can jump around a little depending on outside temp, traffic, humidity etc. Cruising on freeway temps range from 70 to 80c depending on conditions. When its a little cooler ouside, sometimes my car doesn't even want to heat up to the 90c that I have it set to when sitting in heavy traffic. When it's warmer it always goes up to the 88-90c operating range. FYI my car has koyo radiator with twin FAL fans and Pivot fan controller.

Again, always check your coolant level. If it's been a long time change it and add bottle of water wetter, the stuff always makes my cars happy. Neglected coolant always gets the best of my friends' cars.

As far as the exhaust leak, after everything heats up...the exhaust leaks will actually seal off better. You will hear the exhaust leak the most when you first start the car and everything is cold. As your engine/exhaust heats, the metal expands and bad gaskets seal up a little. Doubt an exhaust leak would make your engine run hotter though.

Check your coolant...maybe change it. From what I've read I think your car's acting normal. Sometimes mine also runs down at 70degrees, and sometimes it goes up to normal 80-90c. Cars with Koyo radiator/twin fans etc. tend to sometimes run so cold they don't even get up to optimum temps. I don't like to run too hard if it's below 70degrees for fear that piston rings haven't completely expanded, but it's probably not that bad. I just always wait until it's nice and hot before stomping it.

Let us know if you do find a problem...but ya, probably just your Koyo running cold. They work really well.

[2JZGTE]

Also, if you want to look for exhaust leaks:

Check when you first start car and exhaust leak is easiest to hear when everything is cold.

Get a hose, put one end against your ear and run the other end around the entire system (mani gaskets, dp, exhaust etc). You'll be able to hear it really easily if you do have one. Again, check when you first start the car and engine/exhaust is still cold.

B

[TheTimanator]

Originally Posted by 2JZGTE

In my car the temp. can jump around a little depending on outside temp, traffic, humidity etc. Cruising on freeway temps range from 70 to 80c depending on conditions. When its a little cooler ouside, sometimes my car doesn't even want to heat up to the 90c that I have it set to when sitting in heavy traffic. When it's warmer it always goes up to the 88-90c operating range. FYI my car has koyo radiator with twin FAL fans and Pivot fan controller.

I just recently installed a Pivot fan controller. The guage jumps up tp 10 deg F or more when the fan kicks in. Once the fans come on the engine seems to pulse slowly when it's idling. Does yours do that at all? I've been trying to figure out what is causing it...

[PhopsonNY]

Originally Posted by 2JZGTE

In my car the temp. can jump around a little depending on outside temp, traffic, humidity etc. Cruising on freeway temps range from 70 to 80c depending on conditions. When its a little cooler ouside, sometimes my car doesn't even want to heat up to the 90c that I have it set to when sitting in heavy traffic. When it's warmer it always goes up to the 88-90c operating range. FYI my car has koyo radiator with twin FAL fans and Pivot fan controller.

Again, always check your coolant level. If it's been a long time change it and add bottle of water wetter, the stuff always makes my cars happy. Neglected coolant always gets the best of my friends' cars.

As far as the exhaust leak, after everything heats up...the exhaust leaks will actually seal off better. You will hear the exhaust leak the most when you first start the car and everything is cold. As your engine/exhaust heats, the metal expands and bad gaskets seal up a little. Doubt an exhaust leak would make your engine run hotter though.

Check your coolant...maybe change it. From what I've read I think your car's acting normal. Sometimes mine also runs down at 70degrees, and sometimes it goes up to normal 80-90c. Cars with Koyo radiator/twin fans etc. tend to sometimes run so cold they don't even get up to optimum temps. I don't like to run too hard if it's below 70degrees for fear that piston rings haven't completely expanded, but it's probably not that bad. I just always wait until it's nice and hot before stomping it.

Let us know if you do find a problem...but ya, probably just your Koyo running cold. They work really well.

Thanks for the heads up..

My coolant level is fine and I have always been aware of my engine temp. When I first got the swap with the stock rad, the coolant would temp quickly pass boiling till there was no more cooling effect and the stock temp would actually go into the high area. This was cured by my Koyo radiator. As I said, I did not have the new overheating problem till after the power loss situation.

I will check for a preturbo exhaust leak both when the car is hot and when it is cold. As I said, I already checked for a leak, but it was on a real cold day an could find nothing. I will try again after warming up the car
... who knows what is causing it.

[Dousan_PG]

i have a thermo because at the track the temps go up up up
run on streets/freeway around 72-76C
at the track usually around 80some to low 90s max
depends on day and all that stuff.

so a aftermarket thermo is good for the seutp

if u just street drive a aftermarket thermo isnt really necessary for the most aprt, just upgrade the radiator
but a new thermo is so cheap for aftermarket might as well

its really up to you.
car will run fine either way

[richardxfeng]

Kind of off topic, but I was wondering if the Pivot fan controller is discontinued. I saw it on pivot's website, but can't find any stores sell it. They only sell the Super Temperature Controller. Is that what 2JZGTE and TheTimanator using?

Thanks!

[TheTimanator]

Originally Posted by richardxfeng

Kind of off topic, but I was wondering if the Pivot fan controller is discontinued. I saw it on pivot's website, but can't find any stores sell it. They only sell the Super Temperature Controller. Is that what 2JZGTE and TheTimanator using?

Thanks!

I using the Pivot FCG-x which is discontinued (plus two bosch relays). To be honest I'm not sure I like it. When the fans kick in the temp jumps around 8-12 degrees at a time, plus when it's idling and the fans come on the car starts to pulse (although the rpm's don't change). I think it might be a grounding issue though just haven't had time to work on it.

Look into the greddy multi-switching system. Does the same thing plus more.

[2JZGTE]

I'll have to check about my pivot controller to see exactly which model it is.

Timanator ~ I had the same problem you mentioned earlier and solved it with some bosch relays hooked up to the Pivot controller. The car doesn't pulse anymore and there's no loss of power when the fans turn on. The temp also doesn't jump more than 1degree celcius after the fans turn on...as soon as the fans turn on the temp immediately drops back down.

I have mine set to turn on at 88celcius, and when it gets up there the fans kick on and temp doesn't go past 89celcius. It's a really nice setup with the koyo radiator... really like it.

I'll take some pictures of my setup to show you. Just got back from Taiwan and jetlag has been a b@#ch.

B

[TheTimanator]

hmmm, I have have two bosch relays. One for each fan. How do you have them wired? I need to figure this out ASAP as I have a couple days in town next week then I'm gone for a month

[Ritz S14]

Ok.

So 180deg F is optimal. At what temp should you shut down the motor and start praying you don't have a BHG?