What is correct engine coolant temp?

[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...

[DrtyRat]

just curious about this optimum(sp?) temp thingy...I have an s14 sr and recently the hg blew...I had it replaced, head resurfaced the whole 9 yds....I also upgraded the radiator to an all aluminum 1 row radiator w/water wetter in it and have 2 10" universal electric fans. I installed my water temp gauge and have noticed that the gauge stays pretty much at 180 when I'm driving on open roads/highways but when I get into stop n go traffic the temp goes up to 195 +/- a few degrees and I start to notice some white smoke from the exhaust...is this normal and do you think upgrading the fans would make a signifigant diff.....sorry if I'm thread jacking but this seemed like a better place to post then starting a new thread....oh head I also have a hipro fmic if that makes any diff(blocks the radiator)

[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.