Why hesitation when radiator is low

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*Additional: also, as for mine, I cannot figure intended use of the red lever on radiator cap, as to pressure, how it works, what it does, its intended purpose, or what.

Been trying to bleed and flush my system offa DexClone, is 100% water now... wanting it to run clear from lower hose before 50/50 Ethylene Glycol green/water.
 
The truck didn't come with that cap. The red lever allows you to vent pressure with less risk of being scalded if you do it wrong. Lift the lever to allow venting and if you hear boiling you can smack it back down.

Originally Posted By: TechnoLoGs
Why do cars and trucks hesitate on acceleration when low on coolant, or if there is air in the system?


Generally they don't. Some are programmed with overheat protection in the computer, but your Blazer doesn't have that. If you're getting the heads so hot that it runs badly you're probably causing damage. Stop doing that.
 
If it is running hot it is running lean, so it injects more fuel and doesn't advance timing as much. Also, running hot leads to pre ignition.

Also, if it starts to knock in most cars a knock sensor will retard timing and inject more fuel.

All this to try an prevent you from destroying your engine... But, some people will run a car without coolant and a new engine or new vehicle is inevitable.
 
Originally Posted By: yonyon
The truck didn't come with that cap. The red lever allows you to vent pressure with less risk of being scalded if you do it wrong. Lift the lever to allow venting and if you hear boiling you can smack it back down.

Originally Posted By: TechnoLoGs
Why do cars and trucks hesitate on acceleration when low on coolant, or if there is air in the system?


Generally they don't. Some are programmed with overheat protection in the computer, but your Blazer doesn't have that. If you're getting the heads so hot that it runs badly you're probably causing damage. Stop doing that.


Putting antifreeze in now.

Would you all advise I keep of replace the cap?
 
Originally Posted By: yonyon
The truck didn't come with that cap. The red lever allows you to vent pressure with less risk of being scalded if you do it wrong. Lift the lever to allow venting and if you hear boiling you can smack it back down.

Originally Posted By: TechnoLoGs
Why do cars and trucks hesitate on acceleration when low on coolant, or if there is air in the system?


Generally they don't. Some are programmed with overheat protection in the computer, but your Blazer doesn't have that. If you're getting the heads so hot that it runs badly you're probably causing damage. Stop doing that.


I thought air in the system caused the hesitation. I did not have level full until recently.

The hot heads may have gotten a risky steam-cleaning, but I put in 1 gallon Ethylene Glycol antifreeze and the engine is cooling now to top off with 1gal. distilled water.

I almost feel like that cap messes up the level AND releases the system of air when you raise it.
 
I'd leave the red lever alone. Fill the system, including reservoir. Take it for a drive. After it cools, check the reservoir and add if needed.

Your hesitation problem will need addressed after that.
 
Originally Posted By: AVB
Are you sure the hesitation isn't related to the spark plugs you just replaced?


I don't know enough mechanically to answer that question, or even how it could be. Went from Autolite to AC Delco CR43TS.. The hesitation is lessened.

I actually think my coil is loose. I will show why in a moment.

Think the new plugs "awakened" something?

And FWIW: I have had a few cars "low on coolant." They all ran rough to some degree. Then topping off a "Thirsty radiator" it ran smooth...

I kinda think running with water only made the water pump unlubricated and now that the antifreeze in 50% concentration 40% at the minimum, it will re-lubricate????? WAG.

But the Taurus had a binding water pump... that had been ran with just water, tons of rust came out. before coolant, then it ran fine when the proper mix was in..
 
Originally Posted By: 951Indy
I'd leave the red lever alone. Fill the system, including reservoir. Take it for a drive. After it cools, check the reservoir and add if needed.

Your hesitation problem will need addressed after that.


At this time, I have the water out of reservoir, am filling to top of cap, looking to make sure no bubbles (I never see any) and THEN add coolant mix to reservoir after shut-off, leaving red lever down.

Yes?
 
UPDATE! Turns out: Transmission fluid may be low due to a leaking transmission cooler.

This may have caused my "hesitation" as engine power (smooth) = transmitted to trans (low, maybe a quart hot.)

I wonder what all is involved to replace/change that. It's not gushing, but some drops can be seen if I let it idle for about 15 minutes or longer. Not sure if it drips when I shut it off. Depends on time and if full hot, I guess.
 
I've still had cars hesitate/run roughly when the radiator was low. They then ran perfect after their radiator had coolant added until the system was full. (Either via cap or tank, depending the car.)
 
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