Thread: Terrible Gas Mileage!

Originally Posted by machinegunsquid

Someone's panties need to be changed.

Partially blocking the radiator will help regulate the temperature in the cooling system, keeping it at operating temperature when it's cold as balls out. Sure, warm the car up to operating temps, then go drive it at 70mph in 0* weather and watch it go back down.

No, you should not block the whole radiator, and no it won't help it warm up any if the thermostat is functioning properly, it will only help maintain that temperature.

I dont think you understand that there is ZERO NONE NO NO NO coolant flow when the thermostat is closed. When the coolant in the engine reaches opening temp it will allow a small amount of flow untill the temp goes back down.

I will take a video for you if you would like. In fact here is one I posted a few days ago of me having some fun on the interstate. Notice the temp (On the scangauge not the stupid stock gauge) before I did the pulls? That was after about 10 miles of 75 mph in the freezing south dakota weather. Feel free to look up the temperatures from the last week in rapid city SD. Its ****ing cold.

ditch that 180 t stat, put a 195 back in, or block the rad with cardboard. once your car hit proper temps, it will run better.

those are your options at this point. by pass wont help this case. it would run even colder if the coolant was moving into the rad.

hell i took a 1 hour drive the yesterday, when i got back i was checking over my rad due to a cracked rad tank, i patched it with JB weld a while back and i wanted to make sure it was still holding, i touched my rad cap and it was ice cold. yet my temps were right where they always are and my heat was good and hot.

so that tells me that even my stock 195 t stat is not opening up all the time. it pops then shuts, pops then shuts, just like its supposed to. its there to keep the engine temp @ that 210 mark.

Originally Posted by Buggsy

I don't want to play on technicalities, but the thermostat is designed with a weeping hole, or some other bypass method.

Any ideas how much get past this? I know on my truck there is an entire by-pass system to alleviate strain on the coolant pump. It puts out about a pencil-sized stream of coolant straight into the expansion tank. I would like to know how much this system is designed to allow through it.

On the 3800 there is no bypass unless you drill a bleeder / bypass hole in your thermostat. Generally the water pump is plenty happy moving coolant around in the block / heater core and skipping the radiator. Some cars do some crazy stuff like you are talking about though.

It's not just a hole, there should be a hourglass shaped thing in the middle, or sometimes a small steel ball that will be in one position when the engine is not running since the water pump isn't spinning, which allows air to bleed. When the engine is started air may keep going past but once coolant hits it, the force moves it forward blocking the hole so no coolant can bypass.

thats a different type of t stat, he talking about 1/8 drilled hole in the t stat ring that moves. called a drilled t stat iirc. some come like that, some drill them themselves, its kinda like a fail safe if it locks shut.

just read all these posts lol. By the way the cardboard didnt do much i tried this out blocked half the rad. My car simply won't warm up something is wrong for sure. But then again i am seeing warmer weather so now its starting to warm up not bad but still needle never goes near the half way mark

Change your thermostat. It is a 5 minute job no joke.