3100 COOLING SYSTEM / TEMPERATURE CONTROL

[GIANT MOTH]

Alright. I own a 95 GP with a 3100. I have the familiar temperature rising issues that many have after reading through these threads here on the w-body forum. I live in the desert so it is something I'm on before the desert starts reaching boiling points and my engine melts down. Here's a break down of where I'm at.

 

 

 

A)PRESSURE RELEASE VALVES

The rising temperature is due to hot air circulating in the cooling system. Opening pressure valves releases air. Ok got that down to a science. Just wish I had one of those air compressors everytime I have to let it out.

 

THERMOSTAT

Yep. It's sticking. Had it happen to me the other day. Need a replacement. Currently found low temp thermostats that are rated 160 degrees that are made with larger reinforced inlets. Most are for 3800's and other vehicles. What do you think? $15? I'm not going to replace this thermostat and everything is going to be ok. I have replaced the thermostat a few times already. In fact when all this began I opened it up and someone had clipped the thermostat housing out of the ring and left the thermostat ring in the car. I hope that made sense.

 

C) COOLING FANS

My air conditioning is dismantled and only the compressor is attached to run the belt. The electrical connector is disconnected from the compressor. Would this alter the cooling fans from turning on? Currently the fans do not turn on even at higher temperatures. Even overheated temps. I did a power check on the battery to both fans. They are functional. This is the one of the dead reasons of why my temperature has been rising near overheating. I would love to get a FlexALite 210 but not with this happening. I'm not entirely sure of how important it is to have the AC system hooked up and running. How intergrated is the AC system? I know one fan on the drivers side is for the temp sensor and the passengers side is for the AC system. Which to me is stupid because I would just love to power them up directly and have them constantly on.

 

D) RELAYS

Both relays are new and functional.

 

E) TEMPERATURE SENSORS

This is where I'm at trying to resolve the problem with the fans not turning on. That and I'm not sure how rational it is to have the AC system up and running. Both of my temperature sensors are new. However I would like to check them with an ohm meter if possible. Does anyone know how to do this? The one in the manifold block has one green wire. The other one by the thermostat has a few wires that run through the fuel injection harness. The one in the block with the green wire has a cracked connector clip that holds it together. I had taped it as tight as it gets. I'm doubting at this time that it is an issue. Yet I would like to know if these sensors are even functioning so I can have the blasted joy of working on connectors and wiring. Still don't have a code scanner.

 

F) WIRE HARNESS

This is the last thing I wish to avoid at the moment. That and connectors.

 

 

[Regal_GS_1989]

Well, how long does your engine take before it starts to warm up? If it seems to warm up really quick, or If you are already having over heating problems, i would venture a guess that there is air in the system. Im not too sure if its just way i understood it, but after reading part of your post, it seems to me that you are not bleeding the air out of the cooling system properly. As for the cooling fans, they can be wired up so they both switch on manually, or with the key. (I have my primary fan set up to come on with the key in the run position.) If there is air in the cooling system, that could prevent your fans from comming on when the temperature gets higher. There are 2 temperature sensors, one for the guage, and one for the ECM(This one controls the fans), but im not too certain where they are on a 3100. Just a warning though, if you are noticing any overheating issues, Dont drive the car, or you risk some serious damage, if it has not been done already.

 

 

[GIANT MOTH]

I have tried to step out what I'm doing down the line from A-F to make more sense of it. In step A I bleed the system as much as I can with both bleeder valves. Is it proper to do this several times? Where would all this trapped air accumulate the most? Does it get caught up in the heads?

 

- Alright check it out. Here is what happens. The car warms up in about 20 minutes. Around 190. Just under the half way mark like normal. It goes "zero" "210"(half), "260"(in the red - overheated). I can drive around for sometime in stop-and-go traffic then it climbs to the halfway mark. Now at this point I know under outside temperatures that this can be normal. When it gets hot outside from 90 to 115 degrees it can reach up to 220 on the temperature gauge. So normally when I drive it's between 180 to 220 degrees on the temperature gauge. So when I drive around, and my fans are not turning on to begin with, I can be sitting at a stop light or stuck in traffic and I can watch my temperature gauge slowly go past the halfway mark. It usually climbs up I'd say 240 - 245 and holds that temperature like it holds within the 180 to 220 range. This happens quicker if I beast around a bit. If I can maintain a speed of about 60 miles an hour (and I have maintained higher speeds for greater distances.) the temperature will drop back down and it will hold the 180 - 190 mark just below half-way.

 

Is this really due to more trapped air? Is it really still trapped air when maintaining high speeds? Wouldn't that remove the air from the system after driving it for miles on end? I was actually considering it to be because the AC is dismantled and the ECM is not picking up the compressor signal or the temp gauges are not picking up the compressor signal when the AC is turned on, so it just remains off. I'm even in the mindset that the other mandatory fan on the drivers side remains off because of the AC being intergrated into the system.

 

That is why I was hoping someone would help me test my temperature sensors. The one in the head and the other in the thermostat housing. If I can test those and make sure their still brand new that would be a check on the list. I'm just not convinced it's hot air. This vehicle seems to have had it's history with overheating. From warped waterpumps to wiring malfunctions from radiator fluid.

 

However it doesn't matter if it's just hot air anyway. I highly doubt it is. In the event that I am learning the cooling system I am taking note on replacing OEM parts with new shiny candy like ones. For instance an electric water pump. I haven't come across one yet. It's unfair that my engine has to suffer from being tied down by the water pump even if it's just a 3100. Also where are my pressure relief valves? I swear to God they make them that relief pressure on their own. Their like for fluid not these stupid ones that are for air compressors.

 

 

Regal_GS_1989 as you stated:

".......As for the cooling fans, they can be wired up so they both switch on manually, or with the key. (I have my primary fan set up to come on with the key in the run position.)"

 

WHAT? HOW? WHERE?

[94CutlassXtreme]

the air bleeder over by the water pump is real important. I'd reccomend doing a coolant flush with a new thermostat, then check your fans and see if they come on when the car heats up. Also, check and make sure the primary fan (driver's side) is coming on. If it isn't or the secondary is coming on first, switch the relays, or hook up a jumper wire to try and get the fans to turn on. Also, the next time your car starts to overheat in traffic, pop it into neutral and rev it and see if the temp goes down..it used to work for me.

[SigEpCutlass]

People have said the thermostat works great. I'd say its worth the money. Most people who have the 160 T-Stat have relatively modded cars, but at a minimum you need to replace it with an OEM equivalent. Like I said in the other post, please don't post in blue...thanks!

[Regal_GS_1989]

Well, if there is air in the system, this can cause the car to overheat unexpectidly. With these engines, it MAY be possible for all the air to bleed out after driving for a while, however, This would not be reccomended because it would take too long, and would cause engine damage. I am not 100% positive on how to bleed the air out of a 3X00 engine,so someone correct me if im wrong, but the steps to follow would be:

 

1. start the engine

 

2. Once the engine starts to warm up, open the bleeder above the water pump, and once only coolant comes out(No air) close it

 

3. Once the engine warms up to operating temp. open the bleeder above the thermostat housing, again, close once the air is out, and only coolant is comming out.

 

4. You could open up the bleeder above the water pump again, and make sure that there is no air that is comming out.

 

5. Once all the air is out, double check all the coolant levels, and top them off if necessary.

 

 

Regal_GS_1989 as you stated:

".......As for the cooling fans, they can be wired up so they both switch on manually, or with the key. (I have my primary fan set up to come on with the key in the run position.)"

 

WHAT? HOW? WHERE?

 

I knew that this was comming If you have some basic electrical knowledge, You could always come up with another way. The easiest way would be to run a positive wire from a switched source. (One the comes on only with the key in run) And run it to a switch that you could mount wherever you want inside the car. Than, run a wire off that switch, and splice it into the positive wire of your primary fan(Or both, its up to you). With it wired like this, you would be able to turn the fan on and off manually as you please, and it will turn off with the ignition, so you wont accidently leave it on and have it kill your battery.

 

The way i have mine hooked up is easier. I just ran a wire from the IGN terminal in the underhood fuse panel, and connected it to the positive connection of the primary fan. The positive wire for the fan is right at the relay, so just trace it back to make sure that it is the right one, if you are unsure. I have had it like this for almost 2 years and have not had a single problem.

 

With the fan running all the time, my temp never climbs over 175-180. Driving, idling, stopped in traffic, it makes no difference, it never goes any higher. Even through the winter, with the fan running, i never had an over cooling problem either. The car got up to temperature fairly quicly, and would maintain it, even on the coldest of days.

[GIANT MOTH]

Alright. I figured out how to change the color of my text but I'm going to have to switch back to black since many of you hate color.

 

 

Ok. So after I put in my 160 rated thermostat made for a 3800 I'm gonna go ahead and fill her back up again. This time I'm going to let all the air out of both valves like last time. I think I'm getting the hang of it now. Just as long as I don't spill any fluid on the fan wires including the main wire harness it should be ok. It sometimes burps up all over my belt line too. I swear it's just as bad as salt water. If not worse.

 

 

However I have this feeling that it's not going to really resolve any temperature control issues until my AC is back online. I really like the idea to hookup the fans to a switch, which means I'm going to have to dig up my wire harness. It was my intention all along to go through and rework the wire harness. It's been a dream of mine for a long time. Then again I bet it goes haywire from not having the fans on while the AC is on . I'm just saying that because I have no idea how computers work or how intergrated they are to the AC and cooling systems. I would assume the computer would tell the temp sensors and/or the AC that the fans have been disconnected . . . . or something like that.

[Regal_GS_1989]

Well, Just FYI, having the AC disconnected will not have a negitive effect on the cooling system of your car. Im not too sure of the exact temperatures that they switch on, but the primary fan is supposed to come on when the temperature gets around 200 or so, and the secondary comes on when it reaches around 227 or so. If you continue to experience cooling issues again after replacing the t-stat, and setting up the fans, than there could be some other problem, like a clogged radiator, or possibly even a cracked head/Bad head gasket. Hopefully it is just something simple though.

[19Cutlass94]

Could have air in the system as well. Theres many things that it could be. Dont even bother with the swtich for the fans. Its the job of the senors and computer to turn them on. So if it aint broke, dont fix it.

 

Unless you have an exposed wire somewhere, spilling a little anti-freeze on them isnt going to hurt anything.

[GIANT MOTH]

My 3100 has been rebuilt with them sporty Fel-pro head gaskets. The radiator is also new. I suspect the only way air is getting in is the openings of my upper and lower radiator hoses. I still have those spring clamps on there. I notice once in awhile a little bit of fluid coming out from heat expansion. Do you think it's time I get them "performance" clamps on there? There might be a cap that's leaking on the head facing the firewall. I'll check it over when I rip the alternator and stuff off for something else. I doubt it though there also rebuilt and the funniest thing happened awhile back. I opened my radiator cap when it was still hot. You should of seen that gusher. It streamlined right into my hood and windshield.

 

Also I am having trouble finding a 160 rated thermostat for a 3100. Like I said before most or all are for 3800s or 3400s. Do these 3x00s all use the same size thermostat? I checked locally and its all commercial crap ranging in the 190s. Checked the 3800s and 3400s at these stores and its all the same temp rating. I checked a few performance shops too but of course they have to order it. Does anyone know of any online stores?

 

 

I read some threads on here about 16lb radiator caps. Are radiator caps rated 16lbs standard? or are they something I need to find like a thermostat?

[19Cutlass94]

If you have fluid coming out at the ends of the hoses, it means either you dont have the hose on far enough or the clamp isnt tight enough. and my dad worked with someone that opened a radiatoe cap when it was hot, yeah thats a stupid thing to do. He has permanent scaring on his arm from it.

 

All the radiator caps are standard.

[95oldsVan]

Theres no reason to use a colder T stat,especially a 160...why? because IF the radiator and fan set up isnt cooling right,its still gonna overheat.The colder stat just opens at a lower temp and stays open until it cools down enough again to close.If the car is overheating,this will not fix your problem.I always stay with a 190 or 195 stat and never have any issues.

 

One of the tricks I do when bleeding air out of the system,after I fill it and let it sit for a few minutes,I open the bleeder valve(car is off,cold and not running) and I squeeze all the hoses I can find and air bubbles push out of the bleeder hole.I keep doing this until Im satisifed it wont bubble anymore.It takes a while but I dont chance that problem with my cars.I notice after a few times the coolant level in the rad drops down alot...so I keep topping it off until I can do no more.

 

Alot of local shops or even newbies asking online,may not know there is a special procedure to burp the air out of the system and it has alot to do with the bleeder valve as well.If you cant get the air out,it will run hot and the coolant level will be too low to transfer heat even if the fans are working as they should.

 

One last tip I do when working on coolant systems,If the T stat is where I can fill the head and block with coolant,Ill top it off there first.Then add the T stat and housing back on then keep filling and burping the air out by hand until it cant take anymore coolant.This usually helps my cars to never get hot the first time out and overheat for a few before it starts flowing everywhere.

 

 

 

 

 

 

 

 

[GIANT MOTH]

OK everyone. I really appreciate the feedback. I understand that hot air in the cooling system can circulate around and cause quirks in the temperature gauge on the dash. However MY FANS DO NOT TURN ON at all when the temperature reaches the point in which they need to turn on. Its not the thermostat either. The air in the system and thermostat are not causing this problem.

 

The temperature rises above normal and holds around 245, which is a step away from overheating. MY FANS DO NOT TURN ON.

 

As far as anything blocking this system I thought possibly the inlet and outlet on the firewall. Everything else is pretty much new and clean. On the firewall is this a problem area that can clog up? I put on a new hose back there so I was just wondering but overall the fluid flows through the system.

 

MY FANS DO NOT TURN ON. I am about at the point where I'm gonna say the problem lies in the temperature sensors, ECM, wiring harness. No SES light comes on in the dash. If the temperature sensors don't work they would set off the SES light right? If not I don't have a code scanner. I really wish I had a code scanner or better yet the computer software. An EPROM programmer and eraser too. But I'm just not in that bracket. It would be great to see what my ECM is doing.

[ron350]

 

I have a 96 W-Body service manuals is your 95 use OBD1 or CBD2 computer?

 

Other 95 owners please chime in.

 

 

 

 

[GIANT MOTH]

Hey I need about $300 for my scanner. It's a 12 point OBD1.

 

 

MY FANS DO NOT TURN ON. I have some wire diagrams out of the 'ole trusty Haynes book for my 95 GP 3100. I got to doing what I always wanted to do and that is working on my wire harness. This has been very troubling since I am not fully up to date when it comes to the wire harness.

 

I couldn't find the temp sensor's anywhere on the main diagrams at first. There are two, one in the thermostat housing and one in the engine head. Couldnt find anything on the fans either. Found one line going to the ECM for the fans. Thats all. Well flipping some pages I found the Air Conditioning circuit and it was all there. Everything is in the AC Circuit except the MAIN TEMP SENSOR!!! The one in the head. I cannot find the thing anywhere in these schematics. But looking over the AC circuit has me guessing that BOTH my fans are integrated into this Automatic Temperature Control System and that the COULD BE REASON my fans do not turn on is that my AC SYSTEM is dismantled and my compressor's electrical connector is off the hook as well. The 2ND RELAY, the one that is for the AC that works with the Temperature Sensor in the thermostat housing, has one line out to the ECM from the PCM called the AC REQUEST.

 

The 1ST RELAY is what I don't get. RED wire is for the main 60A line. Orange wire is for the 20A ECM BAT fuse. BLUE wire goes directly to the fan. GREEN wire goes to the ECM???(shown going to the PCM) called RELAY CONTROL? Wheres the signal come from thats sent by the TEMP SENSOR in the head. There are no lines on the diagram for this green wire going to the ECM. It's separated from the 2ND RELAY but the diagram does not indicate any lines out except the AC REQUEST which is part of the 2ND RELAY circuit.

 

:arrow: Currently my theory is that I can rewire the RELAY or the wires from the RELAY in order for the fan(s) to stay on all the time when the car is started. I am totally confused on how the ORANGE and GREEN wires are activating the RELAY. I had my start on it already. I cut the RED wire (60A) and connected it to the BLUE wire. Directly to the fan. That was a mistake since its active power straight from the battery. That leaves me with the ORANGE and GREEN wires plus not knowing where to tap power thats only activated by the ignition.

 

 

DOES ANYONE KNOW HOW TO PROPERLY HOOK UP THE FANS TO RUN ALL THE TIME?

 

 

Even though I made the mistake of hooking up the wrong power source I went ahead and hooked up the battery and let the car run. It held the 195 mark for about 30 minutes.

 

Also I would like to thank everyone for telling me there is hot air trapped in my system.