1996 LT4 6spd
Thread Starter
Instructor
Joined: Aug 2017
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1996 LT4 6spd
Ok got her back from the trans shop 3k later. Shifts good and stays in reverse when selected.
So now i am dealing with overheat issues. So far i have changed the 5A fan fuse, and changed the thermostat. The fans do not come on.
What should i be looking for next?
So now i am dealing with overheat issues. So far i have changed the 5A fan fuse, and changed the thermostat. The fans do not come on.
What should i be looking for next?
Team Owner
Joined: Sep 2003
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Do you have the FSM (Factory Service Manual) for your car. With the 3 relay multi stage fans I'd think it wise to have the FSM and do diagnostics from that.
Thread Starter
Instructor
Joined: Aug 2017
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Every time i ask a question, you immediately solicit me to buy your download. So to be perfectly clear here. I NEVER invest in ANYTHING i cant hold in my hands.
A hard copy of the FSM i would buy. Until then, its other enthusiasts or the Haynes manual.
A hard copy of the FSM i would buy. Until then, its other enthusiasts or the Haynes manual.
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Team Owner
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Maybe the first check should be the DIC function display for the PCM COOLANT TEMP on the cluster. Maybe there ain't nothing telling the FANS to run. Who knows.
Here's the Cooling Fan Cell from a '96 FSM - if you've got basic diagnostic instinct and correct tools you could confirm I'd think MUCH!
Here's the Cooling Fan Cell from a '96 FSM - if you've got basic diagnostic instinct and correct tools you could confirm I'd think MUCH!
Racer
Joined: Sep 2012
Posts: 491
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From: Mardi Gras City
St. Jude Donor '19
40 A fuse
and is located in small black box under the brake booster. it took 3 "mechanics" to find this blown fuse was the cause of my lt4 overheating issue.....AFTER I spent $800 replacing cooling system. a 96 can also be reprogramed through the ECM to turn fan on at lower temp, mine is set @ 95 C on / 90C off .
Last edited by johno504; Mar 31, 2018 at 12:43 PM.
Le Mans Master
Joined: Jan 2006
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From: Orlando FL
The fans should come on when you turn on your A/C.
Or, the fans should come on low speed at 226* on the digital display
If these conditions are met, these are some possibilities but not all:
The fuse you checked is probably only for the solenoid coils of the relays for the fans but not the fan power. There are probably 2 (30 or 40 amp) fuses for the actual fan power which are maxi fuses located in the engine compartment in one or 2 fuse boxes (I don’t have that layout for the 96 but it might be #2 & 5 in block 2))
In low speed mode both fans run together. They are in series so relay 1 is energized and both fans themselves have to be good (brushes and all) as well as the connectors to them to operate.
Grounds have to be checked (some around the relays).
Thread Starter
Instructor
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So you are saying the fans come on at 226 on the digital screen. What would you folks say the "normal" operating temp is?
Also, is the digital temp regarded as more accurate than the analog gage? Both me and my son's 96s have been close to the bottom on the analog gage.
Also, is the digital temp regarded as more accurate than the analog gage? Both me and my son's 96s have been close to the bottom on the analog gage.
Le Mans Master
Joined: Jan 2006
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From: Orlando FL
The digital readout for temperature is the one to go by. It also inputs to the PCM where it makes decisions for engine performance like A/F mixture and going into closed loop plus others.
The analog gauge is really for reference only. Some are accurate and some are not. The reading in my 94 tracts pretty close and guess I'm the lucky one. You can try replacing the sensor in the head to see if it makes a difference but not much else can be changed other then the gauge in the dash.
The analog gauge is really for reference only. Some are accurate and some are not. The reading in my 94 tracts pretty close and guess I'm the lucky one. You can try replacing the sensor in the head to see if it makes a difference but not much else can be changed other then the gauge in the dash.
Team Owner
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There's always +/- to consider for evaluations so something close to. I believe a '96 FSM actually specs the PCM fan to be F-220°/C-106°. There's much taken into consideration of later PCM fan control. way more than just TEMP.
Thread Starter
Instructor
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Maybe my ideas of cooling performance were way off (realizing that now). I just thought, water boils at 212 so anything approaching that mark was bad. Not considering coolant likely has a much higher boiling point than water, i can see how i was way off!
I am getting the cars ready for the NCM event next month and need them to make the trip with no problems.
I really appreciate everybodys input in this community. I have found that shops are starting to respond to C4 cars like someone brought them a Fiero! In the end, the guys on these forums will be the ones keeping the design alive. Kinda like ZF Doc and the 6 speed. The Fiero design is surviving exactly like that.
I am getting the cars ready for the NCM event next month and need them to make the trip with no problems.
I really appreciate everybodys input in this community. I have found that shops are starting to respond to C4 cars like someone brought them a Fiero! In the end, the guys on these forums will be the ones keeping the design alive. Kinda like ZF Doc and the 6 speed. The Fiero design is surviving exactly like that.
Team Owner
Joined: Sep 2003
Posts: 25,389
Likes: 2,741
Maybe my ideas of cooling performance were way off (realizing that now). I just thought, water boils at 212 so anything approaching that mark was bad. Not considering coolant likely has a much higher boiling point than water, i can see how i was way off!
I am getting the cars ready for the NCM event next month and need them to make the trip with no problems.
I really appreciate everybodys input in this community. I have found that shops are starting to respond to C4 cars like someone brought them a Fiero! In the end, the guys on these forums will be the ones keeping the design alive. Kinda like ZF Doc and the 6 speed. The Fiero design is surviving exactly like that.
I am getting the cars ready for the NCM event next month and need them to make the trip with no problems.
I really appreciate everybodys input in this community. I have found that shops are starting to respond to C4 cars like someone brought them a Fiero! In the end, the guys on these forums will be the ones keeping the design alive. Kinda like ZF Doc and the 6 speed. The Fiero design is surviving exactly like that.
Le Mans Master
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From: St. Charles MO
I don't know about "much higher," but probably a bit higher. OTOH, water boils at 212F at sea-level atmospheric pressure (14.7psia), but much higher at higher pressures. The cooling system runs at something like 15psig (15psi above atmospheric), which allows water to remain liquid until 250F. So pressure is the main reason why it can run hotter than 212F without boiling.
Last edited by MatthewMiller; Apr 1, 2018 at 08:55 PM.
Le Mans Master
Joined: Jan 2006
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From: Orlando FL
I think the 95-96 has a superior fan setup system where air is being drawn in using both fans utilizing both sides of the radiator.