Over heating Problems
 

Wll just bought a 95 trans am about 3 weeks ago and it is starting to have overheating problems changed the fuse, thermostat, temperature sensor and fans and still the fans dont come on and the car is over heating anybody have familiar case?

Is it boiling over or just high on the gauge, stock t-stat is 195 and PCM turns on the fans at 225* (low) and 235*(hi). With mods and tune I assume you have cooler t-stat and fan settings. It needs the air dam to keep it cool when running, is that OK. Do you have a/c still installed, turn it on and the PCM should run the fans at low speed. If the PCM is commanding fans on and they don't run then you could have a relay bad, There are three relays in a '95 setup ref shoebox.. http://shbox.com/1/fan_schematic_1995.jpg . here are some trouble shooting hints. http://shbox.com/1/4th_gen_tech2.html#cooling

I am subscribing to your thread as we are having the exact same problem so maybe we can figure this out together. I am leaning towards maybe a ground issue but we will see, if you figure anything out let me know and I will do the same.

Dirty, did you replace the temperature sensor that's in the water pump?
Did you check the relays like I told you to?

changed it i did notice that to air dam below does need to be fixed though

Sensor or the relays?

The air dam will help cooling, but you need your fans to be working first.

Pressure test the system to make sure your not losing coolant due to parts failure.

Check out shoebox's website and look for the write up on making your own manual fan switch. its very easy and could get you by for the time being untill you fix the problem.

good luck, Josh.

ps, you didnt mention bleeding the system, make sure the step isnt skiped.

Could possibly have air in the system..the LT1's are a bitch to bleed.

Since you reported that your fans are not coming on, did you jumper pins 5 & 6 on the DLC as shoebox stated? It is the connector under the dash, just to the right of the steering column. You really need to verify that they are operational before moving forward.

^^I wonder if that works with the OBDII Cars that have the OBDII Connectors. His page is based off of the 1995 Model, so possibly.

I tried it on mine and my fans didn't come on so either my fans in fact are not working or it didn't go into field service mode.

The infamous Lt1 overheating problem.

I agree with Merv about the air in the system. It is a bitch to get that straightened out.

how do i bleed the system just changed the relay and still no fans

Take the Rad Cap off of it with it cold, start it and let it run untill the Coolant in the Radiator drops, that will be the T Stat opening. If it has Air around the T Stat, it will not open, so while it's running and cold you will have to open up the Bleeder Screws around it and get all the air out of it. All the air is out when the Coolant comes out in a pretty solid stream.

ok, I just went through the same stuff, turned out it was the wire leading to the coolant temp sending unit, it was reading wrong on the guage. I used the schematic on shbox's website and bypassed the realys to verify low speed on both, high speed on left and right individually then on both. After I verified the fans were functioning appropriately I turned the AC on with the relays out and verified the signal from the PCM. After that checked out I started it up let it get up to temp and started squeezing hoses to verify thermostat function and flow. After my guage was at 235, I shut the car off CAREFULLY removed radiator cap and stuck a thermometer for a turkey fryer into the rad and it read 175, confirmed on 2 thermometers. Hope this helps

ok i hope i bled it right still having problems

Ok found out that one of the relays are not getting any power too it now i think i am screwed anyone know how to jump the fans need help asap

are you not getting power from the ignition, the battery, or the pcm?

tell you the truth i really dont know i know it is the main coolant fan relay

http://shbox.com/1/fan_schematic_1995.jpg

use the schematic and figure out where your power is lacking and make sure you are checking it with ignition hot. Your car has the 2 relay sytem correct?? If so...verify you have 12 volts with the key hot on pins 5 and 1 on the primary relay and pins 4 and 2 on the secondary relay and we will go from there.