Hello,
im new to this forum, and forums in general.

I currently am the family mechanic, and my cousin just a 2000 Monte Carlo.
The badging on the car Claims SS, but the motor is a 3400, and the Vin states that its suppose to be a 3.4. Did SS come with 3.4?

The big issue right now is a over heating problem.
After checking that there is coolant and no obvious leaks, i went to check the Fan.
I had noticed that the Fan will not turn on, ever when i turn the AC on, which does no cool.
And when i drove the car, the fan never came on.
I tested the Fan by wiring it directly to the battery and it worked.
So i went ahead an started messing with the relays.
There are 3 relays, and one starter relay so i swapped them around and they all seem to work.
So i change the coolant temp switch, and the thermostat (which was a pain) and in the process, i noticed that, there was no thermostat installed.

So after the work that i did, the car still overheats.

Any ideas???

thanks.

 

First, a 2000 Monte SS had a 3800 v6, so based on the VIN and engine, someone falsely badged it as an SS.

Regardless, I am wondering if the car is not really over heating. Since you said the T-stat was missing, that means the coolant is constantly circulating (I've seen the 3100, which the 3400 is based off of, with a t-stat stuck open, car NEVER gets to operating temp).
Since you tested the fans and they work the next thing I think you may want to do is find out if you can trust the reading from the temp gauge. The PCM tells the fans to engage when certain conditions exist (such as high temp). What you need to do is get a hold of a scan tool that can read sensor data via the ODB-II diagnostic port. Read the temp reading the PCM has and check it against the instrument cluster. My guess is that you are going to find the temp reading from the PCM is fine and the cluster is reading incorrectly.
I would do that before doing anything further. Otherwise you could vest a lot of time chasing a problem that may not really exist.
Again, I base this off your statement that the car was overheating with no T-stat in it.

 

Thank you for a response.

Yes, the Vin states that the car is not a SS, so someone thought it would be cool to add the badging at one point.

I was surprised to see that it was missing the thermostat.
But i thought that it being missing, might have slowed down the coolant getting to operating temp, but not completely prevent it from ever getting there.
The car "claims" to be overheating usually at stop lights or stop and go traffic. So it being the fans jumped out at me.

Worst case scenario, would i be able to just wire the fan to a switch?

Right now the engine is smoking a bit, but i think its from spilled coolant when i removed the thermostat housing. I'm hoping once it dries off it will stop.

 

Another thing!
Would the PCM prevent the fans from turning on when the AC is turned on?

 

If you know someone that has an infrared heat gun you could check actual coolant temp; If you have no thermostat in, (and the fan isn't running) the temp should be pretty close through out the system (if your water pump is working that is...)

 

There are a lot of different things going on. The fans may not turn on due to damaged wire, PCM may have an issue (or may have been re-programmed).

When the gauge claims to be overheating, turn your heater settings full blast, do you get HOT air? If it's not hot (only ambient or somewhat warm), I doubt you are overheating.

In theory, I suppose you could hardwire a control for the fans, but that is REALLY going overboard (as most of the time, their is a reason for this issue).

I go back to validate what the gauge is telling you is accurate to what the PCM is reading from the temp sensor. If it is NOT accurate and the temp sensor reads that it's running fine, then you have a problem with the data stream going from the BCM to the cluster OR something in the cluster.
If the PCM reading matches the gauge, then my next thought is do you have air in the system. If you do, bleed it out (hot air reads differently then hot coolant).
I had a 3100 (same basic engine as the 3400) that kept getting air pockets, temp gauge indicated an overheating situation, yet I had no heat from the blower when the gauge was spiking. I began carrying the ratchet and socket to open the bleeder valve. I literally would pull over, pop the hood, open the bleeder and kept getting air out of the system. Long story short, it was a blown head gasket. Fixed it and all issues went away.
Had I hard wired the fans, I was only going to cause problems trying to get my issue diagnosed (and by trying to "band aid" the issue, I could have destroyed the engine by not having enough coolant or paying attention to other symptoms). I discourage the idea of tampering with the fans until you knwo why this is happening.

 

Maniac...you are awesome.
Ill get to more testing and report back here.
My cousin (the owner) just told me that the car is turning off at stops now.
That's a new issue. I'ma see it in the morning and see whats going on.
Thanks.

 

With this new symptom, I wonder if it threw an engine code with the stalling out at stops. That may lend a clue to some of these issues.

 

how do you create a new post on this thing?

 

i have a issue simmilar to yours my fan for ac wasnt working and i replaced the fan assembly and it all came together nicely but that was a wild lucky expensive guess. mine is overheating after a few drives back and forth and cooliant is bubbling out of the resviour and i have no idea why? can someone narrow down the problems for me?