So my 2000 1500 is acting funny... The water temp gauge will heat up like normal then when it gets to the normal temp, it shoots up to the max. It stays like that for about 20-30 seconds and goes back to normal.

Just tonight (when it was 9 degrees) i found out that the heat no longer works...

So here's my question, would it be a faulty thermostat, or something else???

 

It sounds like a faulty thermostat, and they're cheap enough to take a gamble with spending for a new one. Do that and see what happens.

 

alrighty ill give it a shot... on the 5.9 do you have to take the Alternator off to get to it?

 

first off, you don't want to take any chances with overheating because if true, it can cause catastrophic damage to the engine.

the temp gauge shooting rapidly to and from the max sounds like a faulty sending unit - as i don't think the coolant can climb that rapidly. even if the t-stat locked up closed, i'd think the temp would climb over 1-2-3 minutes, not instantly. based on this, i would guess sending unit first.

on my 01 i'm able to unbolt the t-stat housing, leave the hose attached to use as a handle, and pull it out w/o removing anything else. however - its tight and there's no room to clean the gasket surface. if you get it off, grind off the "front" tab to give yourself a little more room.

don't let your truck overheat...

 

also check your fan clutch.........i think your problem is the sending unit, but you said you had no heat....id take a look at the fan clutch.

 

Wow? Really? T-stats? Sending units? Fan clutches???

This is classic low coolant symptoms. Whether or not there's a leak (probably is), lack of cabin heat and erratic temp gauge readings are textbook low coolant level symptoms.

 

Well all you guys who said T-stat were right... I went out and got one, put it in (<----- ROYAL PAIN IN THE @$$, that thing is freakin BURIED!!!) and now my temp gauge is good and i have my heater back!!! Thanks guys

 

I promise the coolant was low. It only has to be a couple quarts to cause that condition. Never hurts to replace a questionable T-stat, but that wasn't the cause of your issues. Just seems that way because you filled the cooling system after replacement. It was your lack of heat in the cab that gives it away. Heater core is the highest point in the system, thus the first thing starved of coolant when the level drops. The ECTS is not much lower, and that fluctuation was caused by it being immersed in coolant one second, and hot air the next.

If your T-stat had been sticking closed, causing the temperature spike, the heater would have been blowing even hotter. Of course, if it did stick and the truck got hot enough the first time, it would have pushed a fair amount of coolant out and caused the low condition. Was you reservoir full to the brim?

 

Not to rain on your parade , but I have the no heat in the cabin and has nothing to do with low colant . I have flushed and filled my system 2 times and it is full and still no heat . Next is t-stat .. But just because there is no heat doesn't mean that it is just low on colant , a stuck t-sat in the open position can cause that by not letting the colant warm up enough to blow hot air from the core .

 

or you're not bleeding the system right.......


this is the right way to bleed our coolant systems.

1. jack the front of the truck up/ drive it up on ramps.

2. fill radiator

3. turn heat on full blast/defrost

4. start truck (MAKE SURE HEAT IS ON FULL BLAST)

5. add coolant accordingly.


ive never had a problem with my heat. granted ive replaced my radiator, fan clutch, t-stat, water pump, and hoses, but i did all of it because my water pump had a slight leak (which actually turned out to be the timing cover LOL)

ive been very low on coolant and still have had hot air.