Coolant Temp-Hot or Not? (Thread split from "Water pump/front cover" thread)

[scdmarx]

I'm not really convinced you have a hot problem. But here's another idea. If you have a temp probe for your DVOM. Good for remote temp sensing while driving. I have used it mostly for air conditioner apps. But I have in the past used it for cooling systems. The probe will shove between the radiator fins at any location you want. I have shoved it inside the radiator hose or heater hose and tighten the hose clamp around it. Leave it there as long as you want and plug the meter in whenever you need to. The lead is only about 3' long, if that, so you'll have to tape or strap the meter down where you can see it if you want to check something while driving.

 

[dan filipi]

I did peg mine until it started boiling out the cap.
My little temp gun's limit is 250 and it was over that.

 

[AApple]

I kinda had the same idea, Ron, believe it or not. I just don't happen to have a temp probe right now. Maybe Friday, the Matco man will be good to me, and have one on da twuck.

Dan...I'm pretty sure by the time mine gets to 250, I'll know it....it'll be puking it's guts out! :smilie_happy:
So...could we realistically say that the actual start of the redline on the gauge would be somewhere around 235*-240*? If 1/2 on the gauge is around 180*-190*? I'm comfortable with a 200* temp...I'm just curious as to what temp would actually be too hot.
One other thing. Once I stop, and kill the engine, with the fan running, it only takes a couple of minutes for this thing to cool back down to below 1/2 gauge. Once the fan goes off, within 5 minutes, the gauge will be back down to just above the blue line. It has always been this way, no matter how hot the gauge shows it to be....it will cool down quickly....and that's gud, right? k:

 

[joedrum]

not in my book ...that shows extreme exspansion ...we all know what i think :smilie_happy: :mrgreen:

 

[mcgovern61]

So...could we realistically say that the actual start of the redline on the gauge would be somewhere around 235*-240*? If 1/2 on the gauge is around 180*-190*? I'm comfortable with a 200* temp...I'm just curious as to what temp would actually be too hot.

Just above half on my gauge is when my fan comes on and I know that my fan comes on at 205*.

 

[AApple]

Ya...my fan kicks on right past 1/2, too. So...if the fan comes on at 205*, then 210 or so should not be considered HOT, or overheated. The fan coming on at 205*(or whatever temp it comes on), it will not keep the temp there...the temp will continue to climb some. At least that's how automotive stuff works. I wonder if there would be any advantage to kicking the fan on sooner....would it really keep it from getting any hotter? Maybe in town/traffic, I'm sure it would help some, but how much?
On my '85 Corvette, the fan(s) don't kick in until the coolant temp gets to around 215*. On that car, 235 is NOT out of the ordinary when in traffic, with the A/C on. 223-225* is fairly normal. The "Stop Engine" light isn't designed to come on until 245*. I've never seen the light come on.
On either of the Cads, 215-220* in the heat of summer with A/C is normal. One of those cars has the all aluminuminum Northstar engine, too. In cooler weather, the temps stay in the 200* range while cruizin down da road. Might see 210* in traffic.
Not that any of that matters....just throwing it out there for discussion. :mrgreen:

Might need a new thread to go in that direction....

 

[joedrum]

well my policy of no thermostat and fan hooked up on the 83 gets a fan that never comes on hardly at all ....ican feel the heat the motor looses on hot days for sure ...but its good knowing its gone ...i think i want my oldwing to run in the 180 to 190 range on the hottest days....

 

[scdmarx]

Ya...my fan kicks on right past 1/2, too. So...if the fan comes on at 205*, then 210 or so should not be considered HOT, or overheated. The fan coming on at 205*(or whatever temp it comes on), it will not keep the temp there...the temp will continue to climb some. At least that's how automotive stuff works. I wonder if there would be any advantage to kicking the fan on sooner....would it really keep it from getting any hotter? Maybe in town/traffic, I'm sure it would help some, but how much?
On my '85 Corvette, the fan(s) don't kick in until the coolant temp gets to around 215*. On that car, 235 is NOT out of the ordinary when in traffic, with the A/C on. 223-225* is fairly normal. The "Stop Engine" light isn't designed to come on until 245*. I've never seen the light come on.
On either of the Cads, 215-220* in the heat of summer with A/C is normal. One of those cars has the all aluminuminum Northstar engine, too. In cooler weather, the temps stay in the 200* range while cruizin down da road. Might see 210* in traffic.
Not that any of that matters....just throwing it out there for discussion. :mrgreen:

Might need a new thread to go in that direction....

I don't think 220* in hot weather is unreasonable. Turning the fan on sooner?....hard to say. It might lower the working temp range, or it could just make the temp rise time slower. I think what would really make the differences here are things like CFM/volume and surface area of the radiator. The surface area can be increased with a larger radiator. Wider/longer/more rows. The CFM can be increased by vehicle speed, a larger fan, faster fan RPM, steeper pitch on the fan blades, air dam configuration, including a fan shroud that gathers more surface area not just half of it. Too bad there's not enough room to stack 2 radiators to gain more surface area.
I imagine the biggest difference between your Vette and Cad would be the surface area-air dam configuration. But you'd also have to consider the entirely different operating conditions of the two animals, along with performance and emissions strategies programmed into them.

 

[dan filipi]

I can almost guarantee installing air deflectors in front of those fairing lowers will drop the temp about 1/4 gauge.

 

[mcgovern61]

"SURVEY SAYS".......I rechecked my '83 engine with my infrared gun and the fan comes on at 206* every time and goes off at 189*. The temp gauge dead center (needle straight up and down) is 198*. A couple clicks past center is 206* and the fan and thermostat are operating at the same time. When the t-stat opens, the temp at the outlet (and the location of the temp sender) is 205* and drops to 202* in about 3 seconds. As the t-stat opens the temp goes to 206* and the fan comes on every time!

At the inlet to the water pump, when the gauge is at more than half just before the t-stat opens, the water is 189*. As the t-stat opens, it takes about 6 seconds for the water to reach 195* at the inlet. With the fan on, the water temp drops to 184* as the water at the t-stat reaches 189* and the fan stops.

Love a good working coolant system! :Egyptian:

It would be my guess that the maximum performance of the engine is engineered at that 202* mark.

So Joel, a little past center on the gauge is when the fan comes on and it is 206*!

 

[joedrum]

i wish i could shoot mine on the temp with one of those guns

 

[Anonymous]

i wish i could shoot mine on the temp with one of those guns

or maybe a Glock!! :yahoo: :yahoo:

 

[AApple]

All good tech! :thanks:
I checked again when I got home this evening. Strange thing...the head outlets were 214*. This is with the gauge well past 1/2. At the same time, radiator temps at the top were 190*, at the bottom, 173*. Now...when I checked the aluminuminum water pump inlet, it showed 204*. What? Wonder if the aluminuminum stuff is holding way more heat than actual temp?
This is just getting too stoopid. I'm gunna just let it go, and say the gauge reading hotter than before HAS to be the different sending unit. The readings on the rad itself show to be well below HOT.
I don't think I can get to the sending unit to change it without disassembling half of the crap on the front....which I am really reluctant to do, considering the road it took me down last time.... :Awe:

I think what I want to do is look at the old t-stat housing, and see what kind of mechanical gauge I can safely use. I'm gunna also get a temp probe set-up for my multimeter, as Ron suggested....I wanted one of them anyway. Now I actually have a reason to get it. :clapping:
Stay tuned, and thanks for all of the good info! It do help. :yes:

 

[petefan1]

Ok, book says fan on is 208-216 deg and off at 199-207 deg
And your temp gun, I use one all the time. plain aluminum is hard to get accurate reading. yellow painted is closest, while black is sometimes colder....beat that one!

 

[petefan1]

Neat, book also says that if you hook a pressure tester up, warm up engine. relieve pressure and it builds rapidly...blown head gasket (DUH). if pressure rise is slow, pump up pressure to 12.8-14.9 psi and watch the needle.
needle vibration or fluctuation is blown head gasket and will slow or stop when the affected cylinder is shorted out

 

[AApple]

Otay ya'll...I put "The Turd"(and my patience) thru a sooper-dooper pressure test today. I got stuck in a major traffic jam this evening on the way home. 15 solid miles of stop/go traffic, in 100* temp. Temp gauge never got more than 3/4 at the very hottest....I, on the other hand, was waaaaaaay hotter than that! :rant: :heat: Once I cleared the trafffic, and got rolling again, it did cool back down to what has become "normal"....just a tad past 1/2 on the gauge. I think the cooling system is working fine, and the sender unit is just causing the gauge to read higher than before.....thass my story, and I'm stickin wid it. :cheeky:
:mrgreen:

Now...I fooled around with some stuff yesterday after I got home. I found an old front air dam/spoiler off the front of some kind of pick-up that I have had laying around here for years. I cut it in half, did a little here/there trimming, and the pieces fit perfectly along-side the radiator, to use as a scoop of sorts to direct more air into/thru the radiator. The pieces fit perfectly behind the chrome grill at the top, and curve around toward the front at the bottom. They taper from around 4" wide at the bottom down to about 3" wide at the top, and they're shaped to form a kind of funnel shape. All I need is a piece to connect the two pieces along the bottom that will also act as a scoop to direct the air upward. I have all kinds of stuff around here to use, including a large sheet of 5/16" clear plexiglass, and some sheets of aluminuminum. I have been looking at some of the pics in other threads to get ideas....I think I can make this thing look pretty neat, AND do what I want it to do. I'll be able to put some more time in on this fabrication this weekend, and gets some pics. :good:

 

[Anonymous]

Not sure I would use one of those scoopers (the ones that look like snow plows?) air on the oil filter helps keep it cooler

 

[AApple]

:roll: Man...I can never do NUTTIN around here.... :crying:

:hihihi:

 

[Anonymous]

:roll: Man...I can never do NUTTIN around here.... :crying:

:hihihi:

:smilie_happy: Ahh dont mind me - Im not a fan of the aftermarket (call it the disaster market ) :smilie_happy:

 

[petefan1]

well, you could try relocating the filter. Maybe even find a way to allow air to still get to the filter...