Just as it says. Anyone have any ideas? Does it mater which radiator hose goes where? Are you guys running the stock raditor?

i am not done with my swap but I am interested in your problem. I have heard that the northstar can be a bit warm when running. where I live you can have heating problems using a stock radiator and a stock 2.8. If you don't have at at least a new or just rodded out two core radiator or larger that could be a problem for sure. I would like to know which way the water flows on the northstar. in or out at the water pump fitting?

good luck.

You can flush the rad. or get a 4 core. Be sure you are using the oil cooler and its working right with good flow. Be sure the fan is kicking on at about 210 give or take. You could always add an engine conpartment fan. But then again I am in the middle of doing my swap so I am just giving out ideas of things I have been thinking about.

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Bobby from NW Indiana
86 Fiero GT, Looking to ad a 93 Northstar soon
thespeedshop@sbcglobal.net

Bottom of the page shows the rad. hose routing (backwards though)

http://www.fierodrivers.com/forum/index.php?topic=765.15

Thanks ryan.hess,

the way i see it from that picture, the passinger side coolant tube returns the cooled water back to the engine and in the northstar's case should be connected to the waterpump at the t-stat housing. the other tube, slightly higher and closer to the middle of the engine should be the hot water exiting the engine and going to the driver's side coolant tube. please let me know if i misunderstood this. thanks for the link.

quote Originally posted by cptsnoopy: Thanks ryan.hess, the way i see it from that picture, the passinger side coolant tube returns the cooled water back to the engine and in the northstar's case should be connected to the waterpump at the t-stat housing. the other tube, slightly higher and closer to the middle of the engine should be the hot water exiting the engine and going to the driver's side coolant tube. please let me know if i misunderstood this. thanks for the link.

No, that's backwards.
The thermostat housing is connected to the RIGHT coolant tube, and the other connection goes to the LEFT coolant tube.

I've been running a V6 manual transmission radiator in Florida summer with A/C on and no problems associated with radiator capacity.
I did have a waterpump belt fail, and a couple of other miscellaneous issues.

How is the rest of your cooling system set up? Do you have a pressurized catch tank or are you making due without? Inline filler neck anywhere? what have you done with throttle body coolant lines.

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'87 Fiero GT: Low, Sleek, Fast, and Loud
'90 Pontiac 6000 SE AWD: None of the Above

Luck, Fate and Destiny are words used by those who lack the courage to define their own future

quote Originally posted by cptsnoopy: Thanks ryan.hess, the way i see it from that picture, the passinger side coolant tube returns the cooled water back to the engine and in the northstar's case should be connected to the waterpump at the t-stat housing. the other tube, slightly higher and closer to the middle of the engine should be the hot water exiting the engine and going to the driver's side coolant tube. please let me know if i misunderstood this. thanks for the link.

That is right.

I think Will read a little too fast because he said you have it backwards and then told you to do it the way you just explained it above. So if you are confused I hope this clears it up.

As for your overheating problem, it may be because you haven’t been successful at getting all of the air out of the system. It took me a little thinking before I figured out the best way to get the air out of the system. There are two ways to do it that make a lot of sense.

1) Having a rear filler hose as can be seen in the link listed above and opening the end of the coolant line that heats the throttle body. What I do is fill the rad in the front, leave the cap off then fill from the rear filling tube until coolant overflows at the front. Then put the rad cap back on. Get a 4L bottle of coolant already mixed 50/50 and fill from the rear but this time I don’t use a funnel. Instead I use one of those hoses that screw onto your 4L bottle that have a valve to start and stop the flow. I then tape hoses together so that the coolant is filling from a higher point than the motor. This is where you want to start watching the hose you have left open on the throttle body. When coolant is coming out of that hose you are full. Close everything up.

2) If you don’t have a place to fill from the rear. What you can do instead is jack up the car in the front end so that the top of the rad is a few inches above the top of the motor. Open up this coolant tube that goes through the throttle body. It is the highest point in the cooling system (if you don’t include your jacked up front end). Fill from the front into the radiator until coolant comes out at the back. Reconnect or plug the coolant tube in the back (throttle body) then finnish filling the rad in the front (before you lower the car or after you lower the car doesn’t really matter). That should do it.

Trick: instead of just leaving the coolant tubes open and waiting for coolant to overflow I put a clear tube inside the other tube and make sure it’s water tight at the seal and tape the other end up as high as possible on my trunk lid. That way instead of coolant overflowing onto the motor, you just watch for the coolant to flow up the clear tube. Once it’s there you are full at the back. I can fill my whole system without spilling a drop this way.

I don’t have a problem with overheating and I’m using the stock V6 rad. My thermostat in my gauge panel reads just under 1/4. But my computer tells me that the Northstar temp sensor is actually reading 205°. It’s not too bad but if I can’t get this down to 190° then I’m going to put in a 4 core rad.

Aaron

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[This message has been edited by aaron88 (edited 05-26-2004).]

I don't like to post without knowing an item I want to talk about but isn't there an anti-freeze out right now for race motors that run cooler than normal anti-freeze. I can not remember the name of it and havn't heard how its been working.

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Bobby from NW Indiana
86 Fiero GT, Looking to ad a 93 Northstar soon
thespeedshop@sbcglobal.net

quote Originally posted by GSXRBOBBY: I don't like to post without knowing an item I want to talk about but isn't there an anti-freeze out right now for race motors that run cooler than normal anti-freeze. I can not remember the name of it and havn't heard how its been working.

The limiting factor to coolant is the water... There's additives like "water wetter" and purple somethingorother that allow you to use up to 50% less antifreeze while still retaining corrosion/foam resistance and proper boiling temp/pressure point... I've heard those reduce your temps by 10-20* (give or take, depending on the condition of your rad). However, all that being said, coming from an engineer that worked on the northstar:

"the engines are happier and are cleaner (for emissions and internally), get better fuel economy and last longer running at the higher temps. The cooling fans are only activated at 225 or above so anything below that is considered ice cold by the engineers that designed the system."

I wouldn't worry about it until you hit 230-240*.
err... the last comment is pointed more towards Aaron.

[This message has been edited by ryan.hess (edited 05-26-2004).]

quote Originally posted by ryan.hess: I wouldn't worry about it until you hit 230-240*. err... the last comment is pointed more towards Aaron.

If your souse is accurate, I’ll live with it. I know you can get a little more power with a cooler running motor but honestly I don’t know much about the northstar (aluminum block) specifically. 225° isn’t that hot really but most motors are well into the red by 210°. However we are also talking about an Aluminum block here. To have the coolant running hotter doesn’t mean that the motor is running hotter because the aluminum transfers the heat much better than iron. Meaning an aluminum block with coolant at 225° may actually be running cooler than a cast iron block with coolant running at 195°.

But anyway, I’ll figure it all out eventually.

Aaron

.

A 6cyl radiator does fine but if your radiator is a non replaced older 4cyl radiator you might want to think of getting a new one and BTW all radiators are all 6cyl ones so if you have a 4cyl you will still get a 6cyl one if you ever have to replace it.

I used to have the old 4cyl one and my 4.9 would overheat within a hour of driving in the sun it would slowly climb and usaully I ended up shutting it down when it reached anywere near 250 But part of that problem was because my 4cyl radiator was old and worn and clogged and my fan motor was not turning full speed. Soon the radiator burst

After I put the new 6cyl one in my motor never goes above 180 and this weekend was hot!!! and I drove for hours, Im sure it would got higher in tempeture if I put in a thermastate

[This message has been edited by 86fieroEarl (edited 05-27-2004).]

quote Originally posted by aaron88: 225° isn’t that hot really but most motors are well into the red by 210°.

Maybe older cars... My grand prix does the same thing (3.4 DOHC)... likes to run quite warm... After some spirited driving it spikes the temp up to around 220-230, and the fans kick on, and the temp drops like a rock... If I ever saw it go above that (with the fans on), I'd be really, REALLY worried. This beast has aluminum heads too... Can't remember off the top of my head if the block is Al or not though. Anywho, food for thought.

thanks for all your input guys! According to that pic. my hoses are correct so I suspect either air in the system or a clogged radiator. I also noticed a huge trans cooler mounted in front of the radiator that I'm gonna relocate.

quote Originally posted by ragerc92: thanks for all your input guys! According to that pic. my hoses are correct so I suspect either air in the system or a clogged radiator. I also noticed a huge trans cooler mounted in front of the radiator that I'm gonna relocate.

Becarful with the huge tranny cooler because that can very well be your ac condenser, The fiero has there tranny coolers built into the radiator.

I just heard an interesting piece of information. I’m told that the northstar produces the most horse power on a dino around 210 to 215°F. So for those that are running your motor a little warmer it might not be a bad idea to let your engine run a little cooler.

I’m also going to increase my running temp to between 210 and 220°F.

Aaron

.

quote Originally posted by aaron88: 1) Having a rear filler hose as can be seen in the link listed above and opening the end of the coolant line that heats the throttle body. What I do is fill the rad in the front, leave the cap off then fill from the rear filling tube until coolant overflows at the front. Then put the rad cap back on. Get a 4L bottle of coolant already mixed 50/50 and fill from the rear but this time I don’t use a funnel. Instead I use one of those hoses that screw onto your 4L bottle that have a valve to start and stop the flow. I then tape hoses together so that the coolant is filling from a higher point than the motor. This is where you want to start watching the hose you have left open on the throttle body. When coolant is coming out of that hose you are full. Close everything up. 2) If you don’t have a place to fill from the rear. What you can do instead is jack up the car in the front end so that the top of the rad is a few inches above the top of the motor. Open up this coolant tube that goes through the throttle body. It is the highest point in the cooling system (if you don’t include your jacked up front end). Fill from the front into the radiator until coolant comes out at the back. Reconnect or plug the coolant tube in the back (throttle body) then finnish filling the rad in the front (before you lower the car or after you lower the car doesn’t really matter). That should do it.

I gather from your instructions that you DON'T have a filler neck at the rear? Do you purge the air through TB line fitting?

Coming from Allen Cline, another GM engineer, the TB coolant line is also an air bleed that serves to purge the system via the pressurized catch tank. They use the pressurized catch tank because the Northstar water pump is sensitive to cavitation and requires pressure at the intake in order to function properly. The Fiero cooling system is especially sensitive because there are TWO high spots and TWO places from which air must be purged.

What I have done is to cap off the fitting for the TB lines. I only use it as a tell tale when I fill the system. I also have a rear pressure cap. If you have a rear pressure cap, you MUST have a higher pressure cap on the radiator than on the rear fill. As the system heats up, it will purge air out of the rear first, but when it cools down, it will draw coolant in from the stock Fiero catch tank and purge both ends of the system at once.
To fill, just take off front and rear caps and remove the cap from the TB line, then fill at the rear until the front is full, replace the front cap and continue to fill at the rear until coolant comes out the TB lin fitting. Replace all caps and you should be good to go. There will inevitably be some air left in the system, but it will purge on its own... just keep an eye on the level of coolant in the Fiero catch tank and fill as necessary.

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'87 Fiero GT: Low, Sleek, Fast, and Loud
'90 Pontiac 6000 SE AWD: None of the Above

Luck, Fate and Destiny are words used by those who lack the courage to define their own future

I do have a filler hose in the rear, however it’s not a proper filler neck with pressure cap.

Yes, I do purge the air from the throttle body fitting.

Aaron

.

THIS THING STILL OVERHEATS. NOW ONLY WHEN I DO A CCOUPLE OF FULL THROTTLE TAKE OFFS. I'VE SWITCHED THE WATER PUMPS HOSE TO CORRECT POSITIONS, OPPOSITE OF THAT PIC. NEW WATERPUMP, NEW 20 LB RADIATOR CAP IN FRONT, ADDED A SURGE TANK IN REAR WITH A 15LB CAP. ITS PLUMBED IN LIKE A 99 STS, TO T-STAT BYPASS, RELOCATED TRANS COOLER AWAY FROM THE RADIATOR. I'M PRETTY SURE I GOT ALL THE AIR OUT, ESPECIALLY SINCE I'M USING A SURGE TANK.

SEEMS THAT ALL THE COOLANT GETS SUCKED OUT OF THE SURGE TANK AND SHOVED INTO THE THE FRONT RESEVOIR. ANY GEUSSES ON THAT 'WILL'? ALSO, MY SURGE TANK IS ABOUT 1/2 THE SIZE FOR FITAMENT REASONS. IS THAT MY PROBLEM? HEY "WIILL", IF YOU TALK TO THAT ENGINNEER RUN THAT BY HIM AND SEE WHAT HE THINKS. I ALSO HAVE THOSE GENERIC FLEX UNIVERSAL RADIATOR HOSES, IS THAT CAUSING A FLOW PROBLEM? I APPRECIATE ANY HELP YOU GUYS GIVE.

I had a similar problem too. Solved when I removed old top return hoses that go into the heater core. A bubble formed there I guess cause every time I used the heater the temp would raise. I installed a T-fitting there. Started the car to warm up and gradually let some of the air out until fluid would start to flow out. Caution: fluid is hot so were gloves and goggles.

The car now runs around 200-214 degrees. Sometime in Bat area traffic it may start to crep-up a bet. I just rev on the gas and it shoots back down. I hope this helps.

Also, the reason for the over-heating was do to changing out the old heater core thus creating a bubble some where in the system.

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[This message has been edited by madcurl (edited 06-21-2004).]

I have a universal flex hose in my system, so that's not the issue.

Can you draw a diagram and scan it? Or use windows' paint program to sketch a diagram of your system? Remember to keep the width under 640 and size under 100,000B for PIP.

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'87 Fiero GT: Low, Sleek, Fast, and Loud
'90 Pontiac 6000 SE AWD: None of the Above

Luck, Fate and Destiny are words used by those who lack the courage to define their own future

will..

check your email for the diagram, couldn't figure out the pip.

So you have the heater lines connected to the stock Caddy heater connections, with continuous circulation?

your pressurized surge tank is plumbed into the fitting on the water manifold and into the heater return (? or supply?)

Are you using the Caddy catch tank or a custom one?

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'87 Fiero GT: Low, Sleek, Fast, and Loud
'90 Pontiac 6000 SE AWD: None of the Above

Luck, Fate and Destiny are words used by those who lack the courage to define their own future

USING THE STOCK CADDY HEATER CONNECTIONS. THE HEATER HOSE FROM THE WATERPUMP COVER IS TEED TO THE SURGE TANK. THE SURGE TANK IS FROM A SATURN ACTUALLY, SO ITS ABOUT HALF THE SIZE.

I DROVE IT AGAIN YESTERDAY. AS I DROVE IT THE COOLANT WORKED ITS WAY FROM THE REAR SURGE TANK TO THE FRONT RESEVOIR. I DIDNT BABY IT AND I DIDNT DO ANY FULL THROTTLE LAUNCHES EITHER. ITS TEMP SYAED BETWEEN 190 AND 200. I THINK IT OVERHEATS AFTER THE REAR TANK GOES EMPTY BUT I'M NOT CERTAIN.

THANKS FOR POSTING THAT DIAGRAM!!!!!!

Is your surge tank hooked up correctly?
The heater line should be connected to the bottom and the bleed fitting should be connected to the top. ( I think...)

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'87 Fiero GT: Low, Sleek, Fast, and Loud
'90 Pontiac 6000 SE AWD: None of the Above

Luck, Fate and Destiny are words used by those who lack the courage to define their own future

[This message has been edited by Will (edited 06-23-2004).]

thats how its hooked up. i'm having trans issues too, whatta project!!!

I have a 92 Corvette surge tank. It looks Factory...........at least to me it does. But I run a 20 pound cap in front and dont want it to vent or "suck in water". I just let the surge tank with a 16 pound cap do ALL the work. The TB heater lines run into the surge tank and constantly circulates coolant throu it. This is at the highest point in the car so any air in the system is purged out of the system into the tank.

To fill I take off the front cap/plug and the rear cap. Lift the front/right end to get any air to go to the fill cap at the rad. Then fill from the rear tell the front overfills. Put on the front cap/plug and let it down. then top off the rear. Thats it, just fill and go. If I think air is in the system I just take off the rear cap (when it is cool!) and run it with the rear cap off for a wile and if the coolant goes down I just fill it up.

I think you have a problem with your front cap. If all the coolant is going to the front and into the surge tank the front cap is not working right. You are running a high PSI front cap so it should not even vent at all. Get a better non venting cap for the front and check the rad for a good fill neck seat. If the rad/cap cant seat (messed up fill neck) the cap cant work. If the system cant pressureize it will overheat.

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Rickady88GT QuadCam 3.5 V6

I plumbed my N* with the water manifold to a modified Fiero therostat housing from a 4 cylinder Fiero. I cut off the bottom housing and added a hose connection. Removed thermostat and then ran to left side coolant pipe. I kept the top of it at the hight of the water manifold and used the Fiero rear cap on it. Right side comes back the thermostat housing on the water pump. I bleed the system the same way you would a Fiero. Engine temp is runs at 195 same as thermostat. I had a bigger problem with oil temp so I added an oil cooler and a fan to move air under the hood. I let the ecm control the radiator fan. I think it turns the fan on when the coolant temp gets to 180 degrees.

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Signature courtesy of MinnGreen.

[This message has been edited by Fiero STS (edited 06-25-2004).]