High Coolant Temps

[rh77]

Here's what I'm working with at full engine "warm-up" (stumbled on this yesterday from the SG in the 'Teg):

Coolant Temps: 216-224F
IATs: 130-145F
Ambient: ~100F

A relatively new 'stat is installed and rated for 190F, no grille block, and a new radiator in the last 20K miles. Coolant is roughly a 50/50 mix, dark green with no foul odor, and a full reservoir (no loss of fluid beyond normal evap).

Of course the coolant temp is dependent on RPM -- if I'm in town, that translates to 1500-2500. It hasn't gone past 224F -- so that may be positive.

Concerns: how hot is too hot? A warmer engine is theoretically more efficient, but beyond 125F IAT, FE drops. It's been rough finding a good source of ambient air. In addition, I've been really listening to the engine and there's no evidence of ping/detonation. Should I hook up the data logger to track timing vs. coolant temp?

More concerns: heat destroys oil sooner and is harder on the auto-trans. Should those fluid change intervals be shortened...

The temp isn't speed dependent either -- at 60 mph, the temp isn't effected much at all. I popped the hood latch, tried a variety of speeds, and no change.

I'm just stumped on the IAT solution, and curious about the overall effect...

-RH77

[lovemysan]

I wonder if your HAI is causing the elevated temps. Are you using the air? I think you have 2 fans, are both fans working correctly?

If use the air in stop and go traffic I see temps between 210-220f. I recently took a trip. Outside temp was 94f cabin temp was kept around 80f using a/c. Cruising 75mph, temps hovered around 200-210 based on terrain. HAI temps stayed around 200f also. If I get into stop and go I generally see HAI around 150+ and water temp goes to 210+ if no eoc is used.

[rh77]

Originally Posted by lovemysan

I wonder if your HAI is causing the elevated temps. Are you using the air? I think you have 2 fans, are both fans working correctly?

Yeah, I broke down and used the A/C yesterday ...but yeah, both fans are working great. The HAI is a poor attempt at a CAI (or at least ambient), but the inlet is too close to the engine compartment. This is great in the Winter, but right now it sucks -- literally ...um, hot air. Anyways, the temps sound normal this time of year?

I'm thinking about ditching the K&N factory cone replacement for a standard paper cone. 60K miles of extreme temps is probaby long enough, and I don't run WOT redline much anymore to benefit the extra flow. I'm thinking it's not sealing the airbox completely and drawing hot air around the tube/box junction. The post-filtered air is safely sealed with the filter tightly on the rubber intake tube, but it just rests inside the airbox.

-RH77

[n0rt0npr0]

Rick,
Dang its been hot in your area!
But you could always reduce the mixture Rick. The guys I know in the U.P. of Michigan use 50/50 but with temps here only dropping to -5?F one day a year, we could use 36% antifreeze.

Looks like in the last two years your area only went down to 1?F, so I'd say you could safely use 34% antifreeze.

The result would be more efficient cooling as water is thermally more conductive than antifreeze: http://www.racerpartswholesale.com/redtech3.htm
Or you could just drain out the exact amount of that water wetter and throw that in there, check out the link.
This is the freeze protection chart I refer to come up with mixture ratios: http://www.peakantifreeze.com/images...tion_chart.jpg
~Will
P.S.~Shortening the fluid change intervals sounds good too, IMO.

[mrmad]

"Of course the coolant temp is dependent on RPM -- if I'm in town, that translates to 1500-2500. It hasn't gone past 224F -- so that may be positive."

Are you saying that depending on the engine rpm, the coolant temperature changes? The thermostat should be controlling the temp. I have a 2" aluminum racing radiator in my GSR and the stock temp gauge moves up to about 1/3 and is stuck there, even if I'm in 100 degree heat with the AC on, it doesn't move. The only time it moves is if I'm stuck in traffic it will climb up a little less then half the temp gauge until the fans kick in.

My CRX behaves the same way.

Where are you measuring the coolant temperature from?

[rh77]

I'm taking the numbers from the SG -- the stock gauge hasn't moved past the same "normal" mark since I've had it. Even if the fan kicks on -- no movement from the gauge. I really don't trust any of the stock gauges anymore: including the speedo.

So, I was thinking that the water pump wasn't turning as fast at the lower RPM -- since the stat was open, the system should bring the temp down. The assumption was that there wasn't enough circulation.

It's starting to look pretty common...

RH77

Originally Posted by mrmad

"Of course the coolant temp is dependent on RPM -- if I'm in town, that translates to 1500-2500. It hasn't gone past 224F -- so that may be positive."

Are you saying that depending on the engine rpm, the coolant temperature changes? The thermostat should be controlling the temp. I have a 2" aluminum racing radiator in my GSR and the stock temp gauge moves up to about 1/3 and is stuck there, even if I'm in 100 degree heat with the AC on, it doesn't move. The only time it moves is if I'm stuck in traffic it will climb up a little less then half the temp gauge until the fans kick in.

My CRX behaves the same way.

Where are you measuring the coolant temperature from?

[mrmad]

I think the difference you are seeing between the coolant temp for the ECO (read by the Scangauge) and the stock temp sensor might be the location of the two sensors. The sensor for the temp guage is on the downstream side of the thermostat and the ECU temp sensor is somewhere on the intake manifold, which I think is on the upstream side of the thermostat. This might explain why you would see changes in this sensor was the rpms vary. Does the IAT change with the coolant temps on the Scangauge change? I would think that they wouldn't since there probably wouldn't be time for all of the aluminum in the intake manifold to change temps and affect the IAT.

If you are questioning if yoyr car is running hot, I'd measure the resistance for the temp gauge's sending unit to see if it is in the correct range. If you don't have a Helmsmanual, PM me and I can send you the resistance readings.

[popimp]

My van also has 195F thermostat. It usually runs in the 200-210F range. Sometimes maxing at about 222F. The stock gauge never exceeds the midrange. I don't think you have any coolant issues.

[Bill in Houston]

Rick, it makes sense to me that you would see your highest temps when you accelarate and then come to a stop. Heat builds up in the metal parts during acceleration, and then when you stop, you have a lower flow coolant flow rate removing that heat.

I know in some of the cars we had in high school, the only time I saw the temp light was after I turned the car off and then restarted it a few minutes later. Anyway...

[Bill in Houston]

Hey, maybe this makes you feel better:
http://mgaguru.com/mgtech/cooling/cool_200d.htm
"50/50 mix of glycol/water boils at 223dF at sea level. Boiling temperature increases by3.25dF for each psi of applied pressure, so the 7psi pressure cap takes the boiling point up to about 245dF."
"15 psi brings the boiling point up to 272dF (with 50/50 glycol/water)"