This is my first car, and i have a few questions about the cooling system.
1. Im used to dirtbikes and quads, and they dont have coolant resevoirs. isn't the radiator supposed to be full when cold or will it syphon when the motor warms up.
2. my heat isn't working 100% i think its the core, should i try to flush dexcool out of the system first?
3. if i want to change the thermostat, im thinking of a 180, does it make a difference by any chance or only run cooler?
Thanks for your time

 

#1, you should always have the radiator full. When the system warms up, the pressure builds and it will push a certain amount of coolant to the res. When the engine cools, there is a vacuum created in the cooling system (provided there are no leaks) and coolant is drawn back into the radiator from the res.

#2, If your radiator isn't full, then you may have problems getting heat inside. Fill it and recheck. If you have any buildup on the underside of the radiator cap, then I would recommend a full system flush, replacing the radiator cap and thermostat while you have the system apart. Remove the lower radiator hose Part of the flush should include removing the heater core hoses from the engine and flushing through, switching hoses a few times. Buy yourself 2 gallons of Prestone All Makes, All Models Extended Life coolant (not 50/50 mix) and about 6-8 gallons of distilled water. On the final flush, use the distilled water to flush through the radiator, engine block, and heater core, making sure that you have atleast 2 gallons of distilled water left when you put all of the hoses back on, new stat in, and close the drain in the radiator. Then dump in 6 quarts (1.5 gallons) of coolant into the radiator and top off with distilled water. Now, with the front of the truck up as high as possible and the radiator cap off, run the engine until it reaches operating temperature while monitoring the radiator level. Once warm, top off and install the radiator cap. You may also want to clean your res if it has scale built up in it. It is fairly straight forward to remove. Clean it with some general purpose cleaner, a rag or two, and a hand full of nuts/bolts thrown in. Shake this concoction around and then dump and rinse, repeat as necessary. Then fill the coolant jug with approximately a 1/2 gallon remaining with distilled water, shake to mix and use this to fill the resevoir to the cold mark. Over the next few days monitor the coolant level in the overflow to make sure that it gets atleast to the hot mark after 15-20 minutes of driving.

#3, A 180*F stat can cause a check engine light when used in OBD2 vehicles. This is due to the steady state temperature that the PCM is attempting to achieve is close to the normal temp of the 180*F stat which will result in the PCM bouncing between closed loop and open loop fueling, wasting fuel, not to mention causing the emissions readiness monitors to be 'not ready' which may or may not affect your vehicle inspection.

Hope this helps!

 

Kyle, so what is the standard stat used in the 4.3 Vortec? This may be important for me to know, because my mechanic recently replaced my stat. I just want to ask him what he replaced it with. Thanks.

 

Stock is a 195*F stat which will result in temps around 200-205*F under normal operating conditions.

 

Hi, when I first got my first 2001 Blazer LS 2WD, I was very much pleased aside from being underpowered so I started to work on squeezing some extra ponies, I did the exhause/cold air intake and a new smooth throttle plate sold already customized(no bump!) I then stuck a 165 degree stat to lower my intake charge but I kept getting a codebecause of it, I put the OEM 195 degree back in and everything is peachy but my engine seems to be running a tad too high 200-210, the clutch fan works, I had the coolant system flused and sealed, still the same high reading which doesnt change on the freeway if it were a fan issue, I now have a 180 degree stat but I am leary of sticking it in and triggering a code again, since I am running a tad hot would the 180 stat bring it down in the 190-195 factory OEM temp? Is it possible to not get a code light using a 180 degree stat or is it pretty much a safe bet to say that it will...thanx for any advice..peace...boulonman

 

200-210 is nothing to be worried about. Sounds like normal operation for the relative inaccuracy of the stock gauge. If it is steady no matter what you are doing (freeway, stop-n-go, A/C on max, etc) then it is operating the way it is supposed to. Chances are if you put in the 180* stat, you'll get the code back again.

 

Thanx for the prompt reply bro, that's what my gut told me too, those factory OEM sensors aernt the best made and soaking in hot rusty coolant for a couple of years must do something to their accuracy..Too bad about the 180 though..I figured it would give me a cooler/denser/charge.
peace, boulonman

 

As Kyle said, stick with the 195 thermo. New cars are too computer controlled to use the old-way modswithout knowing exactly what you're getting into. Another example of those dumb old $100,000+ a year Detroit engineers knowing what they're doing.