Overheating my 2000 4cylinder vitara jeep is overheating ,fan is working, radiator is good.

Yes you can use Car Quest Anti-Freeze in your Suzuki. I would first flush the radiator and heater core and replace the Thermostat as well. It is also a good time to replace the Radiator cap as they wear out as well. I would also recommend getting your cooling system Pressure Tested before doing anything so you know you do not have a blown head gasket.

Obstructed radiator or plugged radiator, I didn't think that the Liberty had a fan clutch, I thought that it used an electric fan.

Picture of cooling fan

In the case of an electric fan there are relays and sensors involved plus the ECM (computer) is also in the mix to make that fan work.

I would suggest having the cooling fan diagnosed before doing anything else.

A mechanic would use a scanner to check the engine temp sensor.
The temp sensor tells the computer what the engine temp is and the computer activates the fan relay when the temp reaches about 230 degrees.
Since you said relay I am assuming your Jeep has an electric radiator fan.

I have fixed my own 2002 Jeep Cherokee twice for the overheating issue. Overheating can be caused by a number of different problems, but one of the most notorious problems for the Jeep is the 'radiator fan relay switch'. When the temperature thermostat goes over 210, it tells the relay switch to turn on the radiator fan to cool down the engine. If that relay switch isn't working, the fan never turns on and thus your engine overheats. Here's a simple test to check if this is your overheating problem:
1. Start up your Jeep, open the hood, and let it run to the point where the temperature gauge on your dashboard creeps past 210.
2. Once it goes past 210, go over to the engine and see if the radiator fan kicked on. (the radiator fan is right behind the grill, circular with big plastic blades) If yes, then the relay switch is working. If no, then you probably need to replace the relay switch or the radiator fan motor is bad. But more than likely, it's the notorious relay switch.
3. Turn off the Jeep asap to avoid damaging the engine.

You can purchase a 'radiator fan relay switch' from most Jeep dealerships if they have a service dept. It should be around $75.
(I saved over $700 by not taking my Jeep to an auto shop to fix this) To change out the relay switch, you need to take off the passenger side front headlight. There's a black plastic guard behind the headlight and the relay switch is located under/behind that guard. If your Jeep ever experienced this problem before, you may see a cut-out where someone replaced this part before. If there's no cut-out, you can check out this link to see a picture of where to cut.
http://rigs.corequipment.com/cebby_WJsite/cooling.htm#relay

Once you switch out the part, you should be golden.

If the fans don't come on to cool the radiator then maybe it's the thermal fan switch, which sends the turn on signal to the fan relay, that might be bad.

Typically its either the thermostat or radiator fluid issue. On mine, I flushed the radiator twice, changed out the thermo and then inspected it for a while. Still overheated. I noticed the auxilary fan wasn't coming on, fuses were good, thermo is good. I just hotwired the dang thing to a switch inside. Works great. Engine stays cool now.

One of two possible problems.

1. Faulty fan (replace fan)
2. Faulty fan relay (replace fan relay, about $45 DIY)
let me know if you want instructions on fan relay

check the thermostat or your radiator might be stopped up

This might help you as it looks as though you have an electric fan to cool , there should be a sensor on your radiator hoses upper and lower.they are actually switches triggered by the coolant temperature in side the hose. While your Jeep is sitting idle, shut off the AC as it adds to the heat off the engine not to merntion useing more gas. you should make sure both high and low speeds on the coolant fan work. good luck if this does'nt help check out the post, with more, on the 1995 Jeep heating up..

Are you quite sure it is not overheating? Your mention of heavy traffic, ie. stop and go, would tell me that your radiator fans are not working. I had a car with bum electric radiator fans. It worked fine if it was moving a lot. But in slow traffic, it would get warm enough to have a vapor lock or something without setting the engine-hot light.