Ok guys I've checked a few links and still feel the need to ask.

Like some others, I have rebuilt my engine, timing is set at 6 - 7 degrees base timing, idles at 7-800 rpm after it heats up, otherwise idles at about 1000 rpm.

The temp on the car after heating up shows to be between 200-220 degrees.

No Check Engine Lights

I believe its a 170 or 180 degree thermostat I put in while reassembling the engine last winter.


While sitting at idle, without driving the car, just a couple minutes after starting the engine up, the top radiator hose gets hot as it should, the bottom rad hose is pretty cool. The overflow tank has fluid flowing into it and is boiling. As the overflow tank looks like its about to explode I turn the car off and it is steaming quite a bit.

Took a look at the temp again and it was between 200-220 both fans running.



What do yall think about this?

 

I don't know I'm tryin to figure that same thing out now. My upper hose is steamin hot and the lower is cold. Its up at the shop right now so I'll let u know when I hear somethin. We think my rad may be clogged somewhere down by the lower hose.

 

NORMAL with stock fan switch , now purge the air out of the system and try it. Sounds like its airbound and pressure from steam is keeping the coolant from circulating.
keep in mind that "heat soak" occurs after motor is shut off, and temp will creap up till it cools.
just my 2cents

 

Reverse flow water pump! Our single belt setups have a reverse flow water pump. It is very easy to buy a wrong one if you don't know about it. It sounds like it to me. If you have the right pump you will have to check and see few things.
1. Is the thermostat opening??? Even if its not the coolant should flow through the bottom hose. However, I've seen freak things happen when the thermostat fails. It also, usually, fails open not closed, but it has hapened.
2. Is there enough coolant in the system?? Good to check.
3. Is the cap holding preassure. This could be a problem that causes boiling!
4. Check the hoses for cloggs. Highly unlikely but can happen.

Boiling indicates either lack of pressure, or overheating due to an inefficient part of cooling system. Make sure everything works, and Flush that system right!

I am so compeled to write up a sticky of how to flush your system!
Damn its soo easy, and it takes 10mins.

Ok, now go and find out the problem.

 

At what point, temperature-wise, does the water begin to fill the overflow? If it's at about 210ish or colder, I'd look at the pressure cap.

 

id say either its and air lock sqeez the upper hose to draw water in or it could be your pump either belt not turning or its jsut all cloged

 

I'll go ahead buy a new cap and thermostat tomorrow to be safe, cheap insurance right? I'll flush the system and refill. Hopefully that'll do it. Afterwards I'll let yall know how it goes.

Thank you for the input. It does start to push fluid into the overflow at 210-220.

oh not to hijack my own threads topic; but this car has no heat, no ac, no smog, has the reverse pulley on the tentioner for my belt routing, why is it that when I shut the car off I hear a whoooosh, like something letting some pressure off? When I hit the throttle quick it almost sounds like a turbo spooling up too. wierd eh?

 

Mine ended up being my thermostat stuck closed. So I threw in a 180 thermostat and pressure tested and it was fine. Now it6 runs pig rich but I still have to get my prom tuned for the motor so I'll deal with it till then. My car loves runnin at 180-190 too, it feels a lot better.

 

When you replace the thermostat do so with one that fails in the open position- drill for 1/16" holes for air bleeds(the garden variety fails closed).This helps venting when you refill and helps blance flow till the thermo opens.And a new cap eleminates problems it can cause.Once you get the thermostat in let her run up to temp with the cap off(have your HVAC control set to heat and hot to get full flow thru the heater core).You'll notice when the thermostat opens(you can use a simple immersible thermostat - a cooking one will work well)to give you an idea what she runs.Under pressure it should be better in a good clean purged system.

 

Its pretty simple. If your coolant is boiling that means that there is a lack of pressure in the system. Preassure is what keeps the liquid from boiling and its the only way to withstand 220 degrees. If your top hose is getting warm fast, and your bottom hose stays cold it most likely means that your pump is pumping the wrong way. Usually, once the thermostat opens the water from the engine goes to the radiator thorugh the top hose, which in return comes out cooled through the bottom hose. Both of the hoses should be warm and the top one is always hotter. However, if the bottom hose keeps staying cool after the thermostat is open than means that the flow of cooled coolant is either blocked or reversed.
If your hose warms up quickly on start up there is a chance that A. your thermostat is stuck open, B. your pump is pumping the wrong way forcing the coolant into the engine through the top hose.

I would check to see if the thermostat is stuck open or closed. I would replace it. Than I would look into the water pump. If the thermostat does not solve your problem, and a new cap does not work check the pump.
If you are runing a single belt set up its very likely that you got the normal flow pump instead of the reverse flow. Which will pump the coolant the wrong way!

Go to howstuffworks.com and common sense will help you solve the problem.

Always check to see if you have the air dam on the bottom of the radiator support. Its a life saver!

Good luck and let me know what happens.

 

Here is an explanation for you.

The reverse flow water pump.

Basically due to the design and routing of the single belt setup the water pump pulley is spun in the opposite direction of what a normal water pump would spin. GM solved this with the reverse flow pump. basically it flows the same way, but it spins the opposite way of the normal one.

For simplicity sake, normal ones spin to the right. The reverse flow ones spin to the left, but have a reverse flow ending up spining to the right!

Hows that for an explanation.

 

My vote goes to pressure cap/thermostat. This doesn't sound like a case of misdirectional pumping.

And xlwhell, you need to work on your explanatory skills a wee bit....

 

ESL baby, I am from Yugoslavia. Cut me some slack

The reason I am thinking that it could be the pump is because he says that the bottom hose is cold. Now, if it warms up than NO its not the pump, but he did not say that. Thats why I gave him two options.

 

There can be many things wrong with the system. You could possibly have a leak or a crack. There might be a clogg somewhere. Always check the easiest things first.