Car cooling issues? maybe?

Whizbang · 06-18-2013, 09:16 AM

Might be paranoid or it could be the exhaust fumes getting into the car but anyway...

I noticed that when im at low speeds or stopped with the fans on the car sits at about a hair under 180*F to about 185*F. When im driving at speeds over 25mph, it actually starts to get a little warmer.

The commute to work was okay, freeways getting about 195 degrees at maybe 55 ambient temps.

I noticed yesterday during my commute home from work, doing freeways speeds (65-70) the car got rather hot like 230-235*F. Or is that even reallly THAT hot? this was flat ground, no hills. Hills caused a little creep, but not much. Outside temp was 95 degrees. Fans on or off didnt make too much difference. This was the same situation the weekend of the Idaho Rally driving in to the mountains. Not even really "getting on it" the car just got hot going up hills but cooled down once i was flat or going down hill in neutral.

I had no ducting around the radiator AT ALL. Nothing. So im thinking there is less resistance for the air to go around the radiator than through it at higher speeds. So last night I made some ducting from aluminum. Need to support the lower part since it bent down on the freeway (doh!) and the one side was rather complicated so i want to use rubber there instead of Al.

Going to work this morning, its cooler outside (55ish) and the temps where better at about 195. So it could be the bent ducting on the bottom, but not really looking too different. I'll see on the way home.

thermostat is 180*.
miata 1.6 engine
saab 900 turbo radiator and fans
nothning fancy about the coolant
4,78 gears

thoughts?

t_g_farrell · 06-18-2013, 11:36 AM

The radiator offers resistance to the air flow and at higher speeds the air it will try to spill around
and not through the radiator and you will see higher temps.

Pete_89T2 · 06-18-2013, 02:03 PM

Perhaps the radiator is internally clogged in spots, or has enough bent fins to impede airflow through it? Possibly a defective thermostat? Either would cause less than optimum cooling. You can visually check for bent fins. As for clogs, run your hand over the entire surface area of the rad and see if you feel any spots that are relatively cooler than the rest - that's where the clogs will be.

Ducting the radiator so air flows thru rather than around it should help. If either the radiator, its fan or ducting is deficient, you can expect temps to go up as you drive faster, as the engine is working harder and producing more heat.

mattallac · 06-18-2013, 04:59 PM

Things I would do are 1 put a new thermostat in the car (180 degree), they are cheap. 2 there is a product for cummins diesel that is made to clean the motor and radiator while you drive , When I find my bottle I will get the name for you 3 drain your coolant and use 85% REd line water wetter and 15% red coolant ( toyota or gm ) the reason for the red is because it controls ph levels for motors that have aluminum parts . Also water pump blades could be rotted off .And if the radiator is clogged get an aluminum champion radiator from e bay , there is no epoxy in the radiator and they are 100% welder . I have one for an rx7 in a glc 12a car and the radiator works great ( I never pass 190) good luck

06-18-2013, 09:16 AM	#1
Whizbang Respecognize! Join Date: Jul 2008 Location: Δx = ħ/2Δp iTrader: (5) Posts: 3,190 Rep Power: 20	Car cooling issues? maybe? Might be paranoid or it could be the exhaust fumes getting into the car but anyway... I noticed that when im at low speeds or stopped with the fans on the car sits at about a hair under 180F to about 185F. When im driving at speeds over 25mph, it actually starts to get a little warmer. The commute to work was okay, freeways getting about 195 degrees at maybe 55 ambient temps. I noticed yesterday during my commute home from work, doing freeways speeds (65-70) the car got rather hot like 230-235F. Or is that even reallly THAT hot? this was flat ground, no hills. Hills caused a little creep, but not much. Outside temp was 95 degrees. Fans on or off didnt make too much difference. This was the same situation the weekend of the Idaho Rally driving in to the mountains. Not even really "getting on it" the car just got hot going up hills but cooled down once i was flat or going down hill in neutral. I had no ducting around the radiator AT ALL. Nothing. So im thinking there is less resistance for the air to go around the radiator than through it at higher speeds. So last night I made some ducting from aluminum. Need to support the lower part since it bent down on the freeway (doh!) and the one side was rather complicated so i want to use rubber there instead of Al. Going to work this morning, its cooler outside (55ish) and the temps where better at about 195. So it could be the bent ducting on the bottom, but not really looking too different. I'll see on the way home. thermostat is 180. miata 1.6 engine saab 900 turbo radiator and fans nothning fancy about the coolant 4,78 gears thoughts? __________________ For current updates and event coverage check out Follow on Twitter! @WhizbangRally Whizbang Rally's Webpage \| Facebook

06-18-2013, 11:36 AM	#2
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC iTrader: (0) Posts: 757 Rep Power: 0	The radiator offers resistance to the air flow and at higher speeds the air it will try to spill around and not through the radiator and you will see higher temps. __________________ 1980 GS stockport, Fat Nikki, RB Dual Facetfuel pumps, Holley regulator, RB Street port exhaust, 2GDFIS, MR2 MK I electric fans, 2G strut bar, relayed fans, lights and fuel pump, LEDs Project Fat Nikki Budget 12A rebuild Video setup < $30.00

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

06-18-2013, 02:03 PM	#3
Pete_89T2 Lifetime Rotorhead Join Date: Apr 2010 Location: Elkton, MD iTrader: (1) Posts: 874 Rep Power: 15	Perhaps the radiator is internally clogged in spots, or has enough bent fins to impede airflow through it? Possibly a defective thermostat? Either would cause less than optimum cooling. You can visually check for bent fins. As for clogs, run your hand over the entire surface area of the rad and see if you feel any spots that are relatively cooler than the rest - that's where the clogs will be. Ducting the radiator so air flows thru rather than around it should help. If either the radiator, its fan or ducting is deficient, you can expect temps to go up as you drive faster, as the engine is working harder and producing more heat.

06-18-2013, 04:59 PM	#4
mattallac Rotary Fanatic Join Date: Aug 2011 Location: crockett ca. iTrader: (1) Posts: 176 Rep Power: 0	Things I would do are 1 put a new thermostat in the car (180 degree), they are cheap. 2 there is a product for cummins diesel that is made to clean the motor and radiator while you drive , When I find my bottle I will get the name for you 3 drain your coolant and use 85% REd line water wetter and 15% red coolant ( toyota or gm ) the reason for the red is because it controls ph levels for motors that have aluminum parts . Also water pump blades could be rotted off .And if the radiator is clogged get an aluminum champion radiator from e bay , there is no epoxy in the radiator and they are 100% welder . I have one for an rx7 in a glc 12a car and the radiator works great ( I never pass 190) good luck