I have a 180 stat with a 180 fan switch. Usually the temps stays around 180 when cruising around w/AC off. Outside temp is around 80. After the AC has been on for a couple of minutes it creeps past 200 and doesn't look like it plans on stopping. At that point I shut the AC off, and the temps starts to go down. I checked, and the air damn is present. I also pulled over and looked at the fan when the AC was on and it was working fine. The car has a new radiator, and a new water pump as well. The stat is new as well. Any idea's???

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89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.

 

Just a couple questions... Why the hell do you turn on the AC when it's only 80 degrees outside ? And... 200 is not THAT hot. These cars were designed to run in the 200-220 range anyway.

------------------
92 Z28 5.7
------------------
Trick Flow 23° heads, Comp Cams XR270HR-10 cam, Accel intake base + ported TPI,
TES headers, Flowmaster catback, MSD ignition, #24 SVO injectors, 1LE aluminum driveshaft.

Click here to see pics of my car !

 

If you have only one fan it will continue to over heat, especally this summer when it gets close to 100 degrees, I had the same problem,
till i got the dual fans and a 3 core radiator (autozone 120$)and the system wont go over 180 with the ac on and 100 degree weather..
hope that helps
jonny

 

Synergy, my RS is black on black - it gets hot in there pretty quick; esp. while at a light. I haven't let it go w/AC on to see how hot it would get. I'll leave it on and see how high the temp goes. How high can these safely run before damaging the engine?
I was just curious as to what would cause the temp to jump up 20+ degrees. At first I thought the AC comp might be seizing up causing the water pump belt to slip causing insufficient circulation, but the belt is fine, and I checked with it running and its definitely not seizing. Any ideas?

 

Will dual fans make that much of a differance, compared to a single fan? Which fans did you use?

 

Hey synergy, 80 degree heat is pretty bad when the humidity is around 95% like it is in south Georgia. You'd have that **** on full blast.
Simon, check to see that the water pump is operating properly. Close the upper radiator hose with your hand and then let it go. You should feel coolant rushing past. Or you can take the radiator cap off (when cold!!) start the engine and wait for the thermostat to open (check by above procedure). Blip the throttle open while looking at the coolant level. It should go down temporarily and then go back up. If it doesn't the water pump ain't working right.
bsa
bsa

------------------
"If they do not run, Then they will die." - Stonewall Jackson
#3
'87 IROC, 355 TPI, Converted to SD, 700R4, B&M Megashifter, 3.42, Trick Flow Twisted Wedge Heads, Edelbrock Intake, Accel Runners, Comp Cam, Crane Gold rockers, Lucas 24# injectors, Edelbrock headers, Flowmaster 3'' exhaust, Mallory Ignition, Transgo Performance Shift Kit, Corvette Servo, 2,000 Stall Torque Converter

 

The reason the car runs hot with the A/C on is really very simple. The A/C does not make anything "cold"... what it actually does, is take heat out of the air in the cabin, put it into the refrigerant in the evaporator, move the heated refrigerant to the condenser, and radiate the heat into the air stream that's on its way into the radiator. So the radiator's incoming air, instead of being 80 or 90 or 100 or whatever it is outside, is now 140 or 150 or 160.

It's normal for an emgine to run hotter with the air on. 200° is nothing. The electric fan switch in our cars doesn't even come on until about 230°. Of course with the A/C on the fan runs all the time anyway, but I'm just using that setting for comparison purposes. If the factory thinks the engine doesn't even start to need cooling until it reaches 230°, then 200° does not constitute a problem.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited June 07, 2001).]

 

By accident I broke my top radiator shroud and now I only have the A/C fan cooling the engine. Even after a complete flush and new coolant added, it still overheats with that one fan on. Mostly it stays at 220, but if I drive around for an hour or more in rush hour traffic it will go in the red and I have to pull over to spray water on the radiator. So with the AC on it will overheat right off the bat. So *I* think dual fans are far more efficient, and if you can stick another fan to PUSH the air in front of the radiator then that's even better.

------------------
92 Z28 5.7
------------------
Trick Flow 23° heads, Comp Cams XR270HR-10 cam, Accel intake base + ported TPI,
TES headers, Flowmaster catback, MSD ignition, #24 SVO injectors, 1LE aluminum driveshaft.

Click here to see pics of my car !

 

Oh... 80 degree weather here in Las Vegas is PERFECT. 110 which is what we see almost every day.. I'd say requires AC. LOL

 

I first put the dual fans before the 3 core, and that fixed it, but it would still go to about 220, but wouldnt pass that temp.. I have a friend that use to work at gm dealership for I think he said 10 years, any way he told me that our cooling system suck!!! thats why most z's have the daul fans. Go to a junk yard!! Ive seen 4 or 5 of those set laying around. Depending where you live..I got mine for 30$...good luck..
jonny

 

The dual fans are kinda nice, but I think I would've been ok with just a single electric fan. When sitting and idling, with one fan running, my A/C high side pressure gets up to around 300 psi. I don't like it that high, but I don't want both fans running all the time, just when the second one is really needed. I'm trying to find a pressure switch I can hook up to the system to kick the relay when the pressure gets over like 250 psi. Anyone have any suggestions?????

RB had the reasoning exactly right. The A/C just transfers the heat to the condenser, right in front of the radiator.

------------------
Working on:
'84 Z28 LG4 305 with 200,000 original miles!
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350 (ZZ430)
using primarily GMPP parts.
Short block sitting on a stand. (Man, those Fast-Burn heads look good, (just sitting there doing nothing!LOL))

Starting to look like the Kicker poster child!

ASE Certified Master Tech

 

bsa, I've heard about that method for checking pump circulation in the past. If I understand correctly, this procedure must be done with the engine cool first - as you stated. This brings another question to mind: After my engine warms up the upper and lower hose have so much pressure its impossible to pinch them shut; is this normal? Could a blown head gasket cause this? I've thought about that in the past, but at no time has my car ever blown any white smoke out the back - even on startup. How would I be able to determine if its a blown head gasket which could be causing all my probs?

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89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.

 

Synergy- I also live in Vegas, and got a 92 RS with the 305 around 2 days ago, and mine is overheating in this hot weather. I replaced the T-stat with a 160 unit, and that did nothing. If i cruise on the freeway, it stays around 180-200, but if i sit in traffic, it goes into the red almost immediatly. What else can i do to make this car run cooler?
Tyler

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<A HREF="http://www.pro-touring.com/featured_cars/Tyler_Beauregard/tyler_beauregard.htm" TARGET=_blank>
68-LT1-T56
</A>
<A HREF="http://www.pro-touring.com/featured_cars/Tyler_Beauregard/tyler_beauregards_project_5050.htm" TARGET=_blank>
50-50
</A>

 

Hey Simon,

Where in Glen Burnie do you live? I used to live out there for about 22 years but just moved to Egdemere 2 months ago. Do you still have your hood blanket installed? I removed mine about 3 weeks ago and before I had the same problem. My fans are set up to run constatly regardless of engine temp., and I have a 160* stat, 50/50 raditor coolant mixture, and a new air damn yet with the A/C on in traffic it would typically get close to the red line if I left it on and sitting for a while. I find that now I can drive through Baltimore city light to light with the A/C on and it sits at just under 220* without the blanket. Just a thought, but if you remove it nicely you can reinstall it if you want later. Mine is sitting in my buddies garage. On the down side though, my car is unpainted where the hood blaket used to be for some reason. I am not sure if they are all like that or not. But I am sending the car off to the paint shop next week anyways so that will not look that way for long.

------------------
1987 Camaro IROC-Z28
"Slower than a wal-mart cashier"
Ram-Air Intake/Modified air boxes & aftermarket MAF w/ K&N's
Hypertech Air foil
Hypertech 160* stat/TB coolant bypass
MSD 6A ignition & MSD SS coil
Crane AFPR
Accel 8.8MM 300+ Race wires
R134A A/C retrofit
Prof. built 355 TPI
Mobil 1 synth. fluids
New GM 700R4
Posi disc 9 bolt rear 3.23:1 (G80 & G92)
TCC lockup switch
T-tops/roof console/all power opts.
Engine oil cooler
Custom Flowmaster 3" exhaust with dual chrome tips
All new interior
Macewen White face gauges & hyper blue/white dash bulbs
ADS super chip - stage I
Dunlop SP sport 5000 P245/50 ZR/WR 16's

 

es87, I used to live in MD, I just moved to FL this past week - need to change my sig. So let me get this straight - I take off the underhood insulation and it should help with cooling - I'll give it a try. Its getting past 220* with the AC on. You said your car used to go into the red? My red limit says 260* - was your car running at 260? If so were there any probs; i.e. knocking or anything. Also, my car is bone stock except for the mods in my sig. So that means straight from the factory these things would overheat under the same conditions - you've got to be kidding me. Its not like I'm dropped in a big block. ... Just venting

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89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.

 

I double checked and it seems I don't have an airdamn!!! It must have ripped off. Does anyone have the GM P/N? Think this will solve my prob? I guess these make a huge difference in sufficiently providing air flow through the radiator. Thanks All

------------------
89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.

 

220° (or even 230°) does not constitute overheating!! The behavior you described in your original post is completely normal for a stock cooling system.

You may be confused, since no doubt you are convinced that water boils at 212°. Well, it boils at 212° if and only if 2 things are true: it's pure water, and it's at atmospheric pressure. Neither of these things is true in a car's cooling system. Antifreeze raises the boiling point of the water, just like it lowers the freezing point; and raising the pressure on the water also raises its boiling point. In reality, a 70/30 mix of water and AF (about optimum for most parts of the country, where the temp doesn't go below -20 or so) under a pressure of 16 psi (your stock radiator cap's setting) has a boiling point of well over 260°.

I have a 400 in my 83. It has the stock radiator out of a later model car; the stock 83 single electric fan; a 70-30 mix, or thereabouts; the hood blanket still intact; and a good radiator cap. Until a few months ago I lived in Memphis, where the temp is regularly over 100° and the humidity nearly as high. I ran the A/C continuously about 7 months out of the year. I had no trouble with overheating at all. I have even less out here where it's considerably cooler.

Leave your hood blanket alone, it's not hurting anything and removing it won't make a bit of difference. Put a new, high-quality radiator cap on it. Put in one gallon of anti-freeze and fill it the rest of the way with water. Then as long as it doesn't boil into the overflow bottle and spew everywhere, it's not overheating until the gauge is fairly far into the red.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

[QUOTE]Originally posted by RB83L69:
[b]220° (or even 230°) does not constitute overheating!! The behavior you described in your original post is completely normal for a stock cooling system.

RB83L69 - I'll probably end up replacing the air dam, checking my coolant to H20 ratio and then see where that gets me. Thanks for the info.

------------------
89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.

 

Simon,

Gothca, FL is probably much hotter. Anyways I have to disagree with RB83L69, I took the blanket off and saw about 10 - 20 degree drop in average operating temp. This is the way it is on my car. Think about it, it's a -blanket-, right? And what are blankets for exactly? Okay. Yes, these cars were engineered to run at 220*, but they tend to run like crap at that temp. At least the TPI cars do, and I am pretty sure that heat not being good for your engine is a widly accepted fact. So I am wondering what high quality radiator cap will do for you? No flame intended, just wondering if there is something I am not aware of. Onto the air damn. It needs to be there for highway driving. However, it will not do a thing for you while you are sitting in traffic. It's an air damn after all, a piece of plastic. Passive. It needs the car to be moving for the air under the car to hit it and be channeled up onto the radiator. The air damn should not cost you over $40 from the dealer. Out here it cost me a little under $30 for a new one from JBA chevrolet. How about this, take your blanket off carfully and save the plastic mounting buttons. Try it and see what happens, if nothing then you can always put it right back where you found it, no loss. Either way, post back with the results. Maybe I am nuts!

Keep in mind that I have other cooling mods, the stock thermo will keep you running above 198* I believe. I am using a 160* unit and dual fans setup for constant running with the car on. On the highway with the A/C on it sits at 160* and in traffic if I have been sitting for a while about 220*. This is in DC beltway traffic.


------------------
1987 Camaro IROC-Z28
"Slower than a wal-mart cashier"
Ram-Air Intake/Modified air boxes & aftermarket MAF w/ K&N's
Hypertech Air foil
Hypertech 160* stat/TB coolant bypass
MSD 6A ignition & MSD SS coil
Crane AFPR
Accel 8.8MM 300+ Race wires
R134A A/C retrofit
Prof. built 355 TPI
Mobil 1 synth. fluids
New GM 700R4
Posi disc 9 bolt rear 3.23:1 (G80 & G92)
TCC lockup switch
T-tops/roof console/all power opts.
Engine oil cooler
Custom Flowmaster 3" exhaust with dual chrome tips
All new interior
Macewen White face gauges & hyper blue/white dash bulbs
ADS super chip - stage I
Dunlop SP sport 5000 P245/50 ZR/WR 16's

 

my car doesnt get over 160 on the interstate and it gets to about 200-205 in traffic with the a\c on and the hood blanket removed. why does my car run so cool on the interstate? in the winter it doesnt get above 130 on the interstate. whats up with that?

 

bubbz89, one word, airflow. At highway speeds, you have plenty of airflow to disipate the heat. (Assuming your airdam is intact!)

simon, if after you have followed some of the good advice you've received, your still running too hot, you may want to consider going to a dual fan setup with a shroud. I first switched from the stock dual fan setup to a Spal dual fan w/shroud setup, then added a 16" pusher fan in front of the A/C condenser with a manual switch as insurance for those times when I-95 becomes a parking lot!

Good Luck!

Ken

 

is it good for my engine to not get above 130* in the winter on the highway?

 

Bubbz,

That's pretty cool (in the literal sense).

Since you said that it doesn't get above 160°F at highway speeds in the summer and 130°F in the winter, I'd guess that you've got a 160°F thermostat. I think that, with few exceptions, people will tell you that 130°F is too cool. Do a search here - this subject has been covered quite well with just about all the posts recommending 180° or 170° as the lower limit. I'm sure glad I'm not riding with you in the wintertime if the heater is only going to put out 130° max!

I would like to add just one teeny tiny point that RB83L69 probably just forgot (everything else was right on the money) - that water will boil at 212°F (100°C) at atmospheric pressure but AT SEA LEVEL, just as compression specifications are generally given at sea level - the higher you are above sea level, the lower pressure you'll see. That is why if you take a compression reading and notice that they are lower than what the factory specification states, be sure you've compensated for your altitute (I forgot that rate, I think it was you lose 3% per 1000 feet above sea level or something like that).

I cannot remember if the boiling point will be increased or decreased when the altitude is increased. Am I getting old or what...

[This message has been edited by Stuart Moss (edited June 10, 2001).]

 

Thanks All, I planning on trying the solutions one at a time from cheapest to most expensive. I live in FL and its going to get a lot hotter before it starts getting cooler.

Simon

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89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.

 

let me clear this up. i run a 195* stat all year round and my heat works fine when the car is at 130*. i know my guage is right because if i let it get up to 225*,viola, the fan kicks on. that cool of a temp cant be good for gas mileage or oil can it?

 

I got the air dam from the dealer today.
THAT AIR DAM IS HUGE!!!! But I guess it has to be to get into the air-stream and direct the air to the rad. It does help, esp. while on the hwy. Its effects when the car is not in motion are marginal at best...as would be expected. I will probably install a pusher in the region of the condenser.
I should have bought those air dams in bulk, as it will probably rip off again - with my luck.
Thanks for the info All.

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89 RS 305 TBI,Ultimate TBI Mods,2.73 G80 rear,Open element,Flowmaster exhaust.