crazy fluctuating engine temps/ low coolant

[CJ0717]

If you've bled the air out of the system and it is full, ran the engine and it still wants to overflow into the resevoir then you have air being pumped into the coolant system. Sorry to say but I have seen this many times and fixed it just as many. It is a blown Head Gasket. You can keep denying that it's blown but I will only tell you what my opinion is. Head Gasket kit including new head bolts, which is a must, runs about $250. Once the heads are off have them milled at a machine shop to ensure they are flat (need to be flat within .001"). One back together it will run like a champ.
Figure a 3 day job. Day one remove heads and get them to the shop. Day 2 (hopefully) you can get the heads back by the end of Day 2. Day 3 reinstall and drive away. Easy job to do just time consuming.
If you continue to drive it the temp will continue to fluctuate as more air enters the coolant system. You can keep bleeding it but sooner or later you need to fix the problem. These engines are notorious for blowing head gaskets.
By the way, alot of people go after the sensing device fuguring that it is shot. 9 times out of 10 the sensor is telling you what you need to know. People tend to deny the fact that something larger is going on.
If you can replace sensors and bleed out your coolant system you can handle a head gasket change and don't woory too much about where all the wires are connected as you take them apart the car manufacturers are very good at making sure no two connectors are alike that are in close proximity to eachother.
I always end up with a small screw of somesort leftover. I just add it to my collection of miscelleaneous screws. Every car/truck I've done has run great afterwards.
If your a car enthusiast, this is the time to think of anything you may want to beef up since you will have the engine basically half way torn down. Good time to change the timing chain/belt, water pump, lifters, etc. or just do the head gaskets and go.

[TDWPgtp]

im not trying to deny it im just tryin to make sure that its that before i have work done. if air was being pumped into the cooling system, wouldnt i continue to get air coming out when i bleed the system?

[CJ0717]

I'm sort of at a disadvantage since I can't actually see what the cooling system is doing but from your previous post you were saying that the cooling system was bled and then topped off. After that the coolant overfloews into the overflow. Coolant systems on any vehicle run at a very low pressure maybe 5-6 psi. If the coolant is overflowing as the engine gets up to temp are you noticing after it overflows that you have to top it off again? If so then air in entering the system. A leak in an intake manifold will only allow coolant to leak out not air entering since there is very little air pressure. A combustion chamber has a tremendous amount of pressure on the combustion stroke and exhaust stroke, There is a kit you can either purchase or rent that can check for exhaust presence in your coolant. I saw it on a youtube video. Never used it my self but if you can find it it would at least confirm or deny a head gasket failure.
Now if the coolant overflows when warming up and afterward you open the radiator and it is still full then you have no problem. The small amount of coolant overflowing is from the liquid warming up and expanding a bit.
I did not mean to offend you in the last post it's only that I see way too many people continue to replace parts and sensors hoping the problem gets fixed when the sensors are only telling them what they need to know. The only one that makes out on that is the auto parts store.
Keep up the investigation, only through good diagnostics can you keep the cost of fixing a problem down.
If I run into that video I'll forward you the info.

[CJ0717]

Found the video I was talking about. I also gave you anther link to another vieo talking about air bubbles in the coolant when its turning over.
http://www.youtube.com/watch?v=WG-gDkWswjQ
and
http://www.youtube.com/watch?v=qIgOg9HSEow&NR=1
If no bubbles in the coolant system and no head gasket leak then I would suspect the temp fluctuation from being a loose belt on the water pump or a bad water pump. Usually when a water pump goes the seal goes from excessive bearing heat and there is a bleeder hole in the front of every water pump. It will piss a good stream of coolant when running
Hope this helps

[TDWPgtp]

only a small amount of coolant over flowed, not to the point where i have to add more again..ill watch those videos though. and i have another question. is there any spot on the engine i could use a laser thermometer to get a general idea of whether or not the gauge is accurate? and also i dont know if i mentioned this to you, but my low coolant light is always on until my engine reaches about 210 according to the gauge, even when its topped off

[CJ0717]

On the external temp question; Not really. The outside temp will be completely different in it's response to temp changes in the coolant. Possible you could monitor the temp of the coolant at the radiator temp with a thermometer to see if the fluctuations are the same swing back and forth but the temperature will most definately not match what the actual temp is near the temp sensor.

You know that a low defective level coolant switch or connection to this switch will also cause a coolant light to come on. Might want to check the connection. Look up where to locate this sensor.

Lastly, The thermostats usually regulate temp at about 185 - 190 deg F. If you run normally at 210 it might be the cause of restriction in the coolant passages i.e. clogging in the radiator or an crap near the impeller in the water pump.

Just food for thought.

CJ

[doctorhrdware]

One thing that you can check is the upper radiator hose. If the hose get hard before the warms up then you might have a head gasket failure. This is something that may be a possibility. Not saying that it is. just a thought.

[TDWPgtp]

theres a fairly new squeaking/grinding sound appearing to come from the water pump...im not 100%sure thats where its coming from but i was wondering if its likely that that is the problem. it started doing it recently, maybe the same time as the high temps..im thinking it might be related. im about to take it to a shop very soon if i cant figure it out though

[CJ0717]

Take the accessory belt off and wiggle the water pump pulley. There should be no play at all and you should not be able to feel any grumbling from the bearings when you turn it by hand. If you do then it needs to be replaced. Everything your doing is what the shop is going to do as well the only difference is that they charge about $90/hr for the troubleshooting and labor to replace parts.