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Hello to my favorite forum and forum people. Again here I am asking all yall to advise me . I've changed the thermastat,new plugs and wires (if that would effect it)distributor cap and constantly check my antifreeze and keep it full.Yet my 96 takes no time to get hot(the needle to the middle and sometimes further past). I'm not going far or driving long at all and it starts getting hot.Any ideas?
 

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With just what you typed I'm going with you did not reinstall WP drive coupling after doing the
I've changed the .......... distributor cap .........

others:
blown h. gasket
infamous clay pellets finally sealed the flow

Or, simply did not burp sufficiently/properly.

Ques: Are you losing AF? If so, then mayhaps break in system and not maintaining pressure


Or, as simple as a sacked out cap.


Probability of each above depends on the actual duration of "takes no time to get hot"
 

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OP

did you bleed the cooling system after you changed the thermostat?

the gen 2 LT1 is a reverse cooling motor, opposite all other SBC, and you need to bleed the air from cooling system if you open it up like by changing T stat, WP or hoses.
 

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Hi

What makes you think that its overheating,is steam coming out? The temp gauge in the middle is not to hot. These cars normal running temp is 230 degrees. The fan should come on around 227 and the second fan about 232. Oldhead
 

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Yah Oldhead - sure 1/2 is not officially overheated. But mine "almost always" stays under 1/4 except the rare occasion of real hot out and long crawling traffic. So anything out of the usual is noteworthy. Let's see how many boxes the OP can check off with all the replies so far.
 

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What makes you think that its overheating,is steam coming out? The temp gauge in the middle is not to hot. These cars normal running temp is 230 degrees. The fan should come on around 227 and the second fan about 232. Oldhead
This is where it's at. First I like to get the OP's definition of overheating, and if it's that the guage get's to almost 1/2 way, then this is a moot point.

I've got a mechanical gauge in the cylinder head, and my PCM & cluster temp coming from the F-Body sender in the water pump.

1/2 on the cluster gauge is somewhere around 190-200'F. My car runs that temperature all the time in city driving.
 

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Temperature sitting still will quickly rise to 180 degrees (OEM). At which point the thermostat will open and hot coolant will circulate through the radiator. You can feel this occur. Sitting still, the temperature will continue to rise to about 225 degrees where the fan will cycle on and cool things down. Rinse / repeat. If the car is moving and not under duress (towing, torquing, hill climbing, traffic, desert heat, etc) it will generally tool along at highway speeds at 180-195 degrees all day long ... by design. In traffic or under load, etc, the fan will cycle on and off and on and off as the temperature climbs to 225 and back down again.



Get yourself one of those $30 temperature laser guns at HF and monitor the temperature of the aluminum plate on the front of the water pump. See what's actually going on in real numbers. The gauge on these cars is not all that telling.


If you did not properly "burp" the air out of the system, the temperature will rise quickly and will not fall when the fan engages. The fan cannot cool the air that is stuck in the system and things get hot fast ... but that will generally lead to a red temp light, not just a higher than normal running temperature. Worse, this air rises and hangs out about the cylinder heads and things go bad quickly.



If your coolant cap is leaking, or if the system will not hold pressure, it will not automatically generate a hotter running condition, per se, till the temp gets above 212 degrees at which point the coolant will boil and then it's a race to the red temp light.



If your water pump is not turning or broken, or if the radiator is clogged or blocked, the engine will go red light on you.


If your heater core (under the dash) is blocked, you won't get any heat in the winter, but it won't overheat your engine. It'll run hotter, but it can handle it.
 

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If you disconnect the H2Opump temp sensor, the fans should turn on in about 30secs or less; 1st one, then the other.
If both fans come on, then I'd burp the system [again], sometimes these cooling systems require several burps over the course of a week or so.

If both fans run, and the cooling system has been thoroughly burped, and the reservoir cap does not appear to be leaking, get your pcm reprogrammed so as to lower the fan-on temps to something under 216°F, instead of ≈ 230°F.
If you live where the ambient temp never ever goes under 41°F, you may even consider a 160°F thermostat.
(imeo, every LT1 should have its pcm reprogrammed, and not merely to have its fan-on temps lowered, but that's beyond the scope here.)
And to follow-up on the thoughts regarding the PCM being reprogrammed, also have your programmer reduce the speed at which the fans turn off. The OEM programming has both set to not turn off till 77 & 75MPH. That's just rediculous, because once the vehicle is moving along, it's just a waste to have the fan motors run.

I turned mine off at 25MPH.
 

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I thought it was 45 or 55. Turning off only AFTER you're already 'speeding'? Crazy
 

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In excess of ≈ 49MpH, enough air makes it through the AC condenser & radiator quickly enough to spin the fans at roughly the same rate as the fan motor can achieve.

In fact, the fan motors can effectively be worn out by being on while they are facing headwinds over 50MpH [for extended periods of time].
 

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I thought it was 45 or 55. Turning off only AFTER you're already 'speeding'? Crazy
No I looked at the stock '95 file in TunerPro prior to writing this. I actually just reprogrammed my PCM the other day because I realized this.

Here's the programming from my '96 OBD2 PCM:

Fan 1 Disable MPH, High A/C Pressure 77 MPH
Fan 2 Disable MPH, High A/C Pressure 75 MPH
 
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