running hotter than usual.....

mlbuxbaum

Registered User
I posted the original problems and symptoms in a post entitled "LONG cooling issues...again/still". Well I have changed the themostat, water pump, Preston Super Cleaned the radiator, flushed and filled it, properly( no air) ans I am still running up in between the R and M, with it occasionally falling down to the N. When the gauge hits between the R & M the low speed fan kicks on until the gauge read between the O & R. The hi speed fan never kicks on according to my LED's I installed on the motor legs. The only 2 things I have not changed out are the heater core and the radiator. The heater blows heat great. When I fill the radiator I have the defroster blowing on high speed at 90 degrees and it sure feels like 90 degrees to me.
I am at a loss.......a new radiator isn't cheap and I don't know what else to do, the car isn't "overheating" but I don't like to run hot, as it worries me (HG's) :confused: :confused: :confused: :confused:
 
Radiators are necessary....

Well, had the same issues on mine.....I even have a three row high efficiency radiator and still had problem. Took radiator to a radiator builder and had him clean it (looked clean to me!!???) and he blew out so much S&@T from it, I was amazed!!!!

The moral of the story is, if the radiator is over 10 years old, REPLACE IT!!! In Jersey, we can get them for $150 for a metal radiator and lifetime warranty!!!!



Give me a call if you need more info....

Don

(973) 277-4294
 
lube70 said:
The moral of the story is, if the radiator is over 10 years old, REPLACE IT!!! In Jersey, we can get them for $150 for a metal radiator and lifetime warranty
Nah... Its more fun to get a used one with a crack and a lot of buildup in the core and try to recussitate it using household things like water, vinegar, CLR, and solder.. :rolleyes: :rolleyes: I feel a bit silly as I could have had a new one for just a bit more. :(
 
1) Replace the radiator cap if you haven't already done so. If the cap doesn't hold the correct pressure, the cooling system will not function as well as a properly pressurized system.
2) The engine coolant temp (ECT) sensor, that signals the EEC to turn on the radiator fan at low or high speed, may be inaccurate. I don't have personal experience with this sensor, but I assume that it is similar to the coolant temp sender (the one on the thermostat housing that is used by the temp gauge). I have compared a number of used coolant temp senders and the resistance when cold varies between the units. In addition, the resistance is nowhere near what the manual states. If the resistance of your ECT sensor is higher than normal, then the low and high speeds will be triggered at higher than normal temperatures.
3) I've also compared a number of temp gauges and they vary as well.

I think that your best bet would be to borrow an infra red thermometer to check the sensors and temp gauge reading.
 
I think I'm going to replace BOTH sensors just to be safe. I want to replace this undersized radiator with one from Griffin but the wife would have my jewels in a vice if I spent that kind of money. I'm gunna call around today and see if I can find someone to flush and clean the radiator, if its cheap enough I'll do it. I did notice that the wire on the sensor at the thermostat housing is frayed, but I don't think thats the actual problem. I'll fix it any way.Thanks for all the input guys......
 
mlbuxbaum said:
I think I'm going to replace BOTH sensors just to be safe. I want to replace this undersized radiator with one from Griffin but the wife would have my jewels in a vice if I spent that kind of money. I'm gunna call around today and see if I can find someone to flush and clean the radiator, if its cheap enough I'll do it. I did notice that the wire on the sensor at the thermostat housing is frayed, but I don't think thats the actual problem. I'll fix it any way.Thanks for all the input guys......

The stock radiator is barely able to keep the motor cool when new. Once it gets clogged up a little or you start modding the motor for more power, it can't keep up.

Best mod I ever made to my SC was installing a Griffin aluminum radiator. I should have listened to some people around here and done it years earlier.

David
 
often over looked is your air scoop/dam under the front bumper. I drove for 2 years in the high side of normal till I put the old one back on,
so make sure yours is straight & tight where it should be, made a big differance.
 
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I took my IRC(M) apart and soldered a wire to pin 85 of the low speed relay. I then ran that wire inside to a switch with the other side of the switch to ground. I can now turn my fan on anytime I want to. I'll let you know how it works.
 
mlbuxbaum said:
I took my IRC(M) apart and soldered a wire to pin 85 of the low speed relay..
You the dude. I believe such an accomplishment is worthy of a pic or 2, dont you? ;)
 
David N is correct. The stock cooling system on the SC in particuliar is a joke.
When its 100% perfect its barely adaqeute for this engine and it certainly has no reserve capacity at all thus making it very sensative to buildup or anything at all that could dimish its ability to cool.
 
Here's my .02......................

I would get someone to clean the stock radiator. Usually about $30-35 for this. If it is the plastic one, look into getting a new rebuilt one (metal) for about $150. Mike also makes radiators, just not sure of the turn around time for it.


On the other side of the coin from David N. (and we ALMOST NEVER DISAGREE!!), I have a stock radiator in my 95SC and have never had cooling issues. This is though with a EEC tuner set for fans to come on at 188*.

David is right in the fact that the stock radiator, just slightly clogged will cause cooing issues. The Air dam piece 35thauto posted is supposed to help direct air at the radiator. It is a nice piece to have attached.

I would not run the car a long period of time running hot. These cars are not and will not tolerate high temps. The only other reason for running hot is if the head gaskets are going.

Hopefully, this is not the issue. I would look into the new radiator since it's easy, necessary, and pro-active in maintaining your car.




Good Luck!!!


Don
 
Even with the Magnum Powers FMIC, Tony Serno's 12 second 94 SC runs nice and cool with a stock radiator too. There are a handful of modded cars out there that seem to get by fine with a stock radiator, but most of them do not.

Might be the tune, might be manufacturing tolerances...who knows. Mine cooled fine when stock, but the more I modded it the warmer it ran. I tried 160 t-stat with low speed fan coming on sooner, then a 180 stat with low and high speed coming on sooner, then water wetter, then a bigger front air dam, then dual fans with the MP FMIC, then recoring the radiator to get a thicker core.

Each thing helped a little, but in summer the temps would slowly creep up to R and sometimes the M. When I was just about ready to start cutting holes in the hood for better ventilation, someone offered to sell me their spare Griffin radiator (thanks George).

The differince in cooling was shocking....I expected it to be a little better but it was much much better. Now I have to turn the fans off just to reach the "N". I can drive any distance or speed without worrying about the coolant temp, and I can even use the AC now. Even with the AC on in the summer it never goes past the "O".

Having learned my lesson, one of the first things I did on the 93 turbo SC I'm building was to install the biggest aluminum radiator I could fit under the hood.

David
 
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Another heating story.

My SC started to heat-up much as you have descrived for your ride. After a short run up Hwy. 101 it was heating up and I brought it home and jacked it to look under the car, as I had done all of the other diagnostics and was left scratching my head. I saw my down tubes red hot and the cats were doing the "Snap, crackle and pop" sound.
I had it towed over to the muffler shop and found that the cats were clogged! I replaced with new hi-flo cats and the issue was resoved. I had about 90k on the motor and had expected longer life from the stockers.
Are you running am underdrive water pump pulley?
 
J.D. said:
2) The engine coolant temp (ECT) sensor, that signals the EEC to turn on the radiator fan at low or high speed, may be inaccurate. I don't have personal experience with this sensor, but I assume that it is similar to the coolant temp sender (the one on the thermostat housing that is used by the temp gauge). I have compared a number of used coolant temp senders and the resistance when cold varies between the units. In addition, the resistance is nowhere near what the manual states. If the resistance of your ECT sensor is higher than normal, then the low and high speeds will be triggered at higher than normal temperatures.
That means we should be able to calibrate it. ;) Thanks for the tips. I'll take it as a summer challenge to see if I can calibrate mine. Should be doable using a resistor in-line or in parallel. :cool:
 
TbirdSCFan said:
That means we should be able to calibrate it. ;) Thanks for the tips. I'll take it as a summer challenge to see if I can calibrate mine. Should be doable using a resistor in-line or in parallel. :cool:
That's an elegant and simple way to change/tweak the trigger points of the low and high speed fans without the use of switches, relays, thermostatic controls, long runs of wiring, fuses, etc., etc., etc.

However, the ECT sensor can be calibrated only to a certain degree of accuracy because:
1) The temperature to resistance relationship is not linear. Here are a few points on the temperature to resistance graph:
120 deg C = 1180 ohms (248 deg F)
110 deg C = 1550 ohms (230 deg F)
100 deg C = 2070 ohms (212 deg F)
90 deg C = 2800 ohms (194 deg F)
80 deg C = 3840 ohms (176 deg F)
70 deg C = 5370 ohms (158 deg F)

2) There are more than one trigger point:
high speed on = 109 deg C (228 deg F)
low speed on = 106 deg C (222 deg F)
high speed off = 104 deg C (220 deg F)
low speed off = 101 deg C (214 deg F)

3) You will be using a passive component, i.e. a resistor in series. The resistor will be in series since you obviously want to trigger the fans to come on at a lower temperature (a higher resistance).

So, assuming you want to lower the trigger points by 20 deg F (approximately 11 deg C), you will have to add a series resistor of xxx ohms (TbirdSCFan, I'll leave that for you to calculate).
 
Not possible...

J.D. said:
That's an elegant and simple way to change/tweak the trigger points of the low and high speed fans without the use of switches, relays, thermostatic controls, long runs of wiring, fuses, etc., etc., etc.

However, the ECT sensor can be calibrated only to a certain degree of accuracy because:
1) The temperature to resistance relationship is not linear. Here are a few points on the temperature to resistance graph:
120 deg C = 1180 ohms (248 deg F)
110 deg C = 1550 ohms (230 deg F)
100 deg C = 2070 ohms (212 deg F)
90 deg C = 2800 ohms (194 deg F)
80 deg C = 3840 ohms (176 deg F)
70 deg C = 5370 ohms (158 deg F)

2) There are more than one trigger point:
high speed on = 109 deg C (228 deg F)
low speed on = 106 deg C (222 deg F)
high speed off = 104 deg C (220 deg F)
low speed off = 101 deg C (214 deg F)

3) You will be using a passive component, i.e. a resistor in series. The resistor will be in series since you obviously want to trigger the fans to come on at a lower temperature (a higher resistance).

So, assuming you want to lower the trigger points by 20 deg F (approximately 11 deg C), you will have to add a series resistor of xxx ohms (TbirdSCFan, I'll leave that for you to calculate).


As an electrician, I can tell you that it would work if the sensor was used just for THAT purpose.

Unfortunately, the ECT is used to calculate fuel and spark timing. SEVERE damage could occur if you lowered the perceived temps too much. The PCM would not see the correct ECT and it would not retard the timing with ECT's rising and not lean the fuel out as much. This could cause engine damage.

The best and tried way is to alter the PCM's readings through the tuner. The tuner can "switch" the fan on at a lower speed because it knows to do that through the program.


I understand your thinking behind it, just won't work properly.



Don
 
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lube70 said:
As an electrician, I can tell you that it would work if the sensor was used just for THAT purpose.

Unfortunately, the ECT is used to calculate fuel and spark timing. SEVERE damage could occur if you lowered the perceived temps too much. The PCM would not see the correct ECT and it would not retard the timing with ECT's rising and not lean the fuel out as much. This could cause engine damage.

The best and tried way is to alter the PCM's readings through the tuner. The tuner can "switch" the fan on at a lower speed because it knows to do that through the program.


I understand your thinking behind it, just won't work properly.



Don

You're absolutely correct Don.
 
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