I know this subject has been beaten like a rented mule!
I have tried everthing i can possibly think of?
i have a good three core brass radiator,the correct vaned water pump,the divider plate clearance is correct,no thermostat,
(no diffrence with thermostat) fan shroud,upper and lower baffles,18 flex fan located 1/2 into shroud. does'nt matter what the outside temp is the car runs between 180-190 around town, as soon as i get on the freeway and hit a steady r.p.m of 2800 it just starts to climb slowly and never stops climbing? I've also tried diffrent pulley sizes with no change. I'm a converted chevy guy and just am not use to these temps so how hot do these engines run or how hot are they designed to run?

If automatic, do you have a transmission cooler external to that on the radiator? An auto trans dumps a lot of heat into the cooling system.

Flex fans move LESS air at higher engine speeds. But that's not generally an issue, as the movement of air through the grill scavenges the radiator's heat.

Never stops climbing is bad. 180-190 is great, peaks to 210 are common.

I would suspect some sort of water restriction in your cooling system, whether it's a lower hose that collapses partially when running at speed, or a radiator core that is partially clogged.

get some water wetter, or some "be cool". worked for me

Maybe a new waterpump is needed.

-Also, As Vikki noted, the lower radiatorhose, should have a spiral, or spring inside it, to prevent it from collapsing (waterpump sucks it flat)..

Sounds like a circulation or restriction problem.
I use 19" flex fans with 170-180* stats.
Factory used 195*, and temps were 210-220*.

any issues with running a 160 stat?

Thanks,
Dave

You dont say where you are living...whats the outside temps...are you in South Texas or in North Dakota? theoutside temops will have some bearing on it too...In summer I run 200-210 on freeway here in Texas...at 80+_...in winter , 185-190....but when I run 200+ and come to a stop, it will climb for a bit until I get going again , = normal...220 would be ok...but i`d be worried if 230 and abv...

when I bought my car many items you describe were missing and it ran 220 -230 my first trip from Dallas to Houston , climbing in every up hill...but I improved several as[pects plus took off an extra 'helper' fan that was in front or radiator and only slowed air going thru..

You dont say where you are living...whats the outside temps...are you in South Texas or in North Dakota? theoutside temops will have some bearing on it too...In summer I run 200-210 on freeway here in Texas...at 80+_...in winter , 185-190....but when I run 200+ and come to a stop, it will climb for a bit until I get going again , = normal...220 would be ok...but i`d be worried if 230 and abv...

when I bought my car many items you describe were missing and it ran 220 -230 my first trip from Dallas to Houston , climbing in every up hill...but I improved several as[pects plus took off an extra 'helper' fan that was in front or radiator and only slowed air going thru....

this has been discussed many times before too, but i`d keep a T-stat in there, a 190....

Once at a big BIG cruise in Sweden (Vesteraas) there was so many us-cars (10.000+) too many to cruise -only traffic jams) -I ran so hot that my accellerator pump melted!!! -Now THAT is TOO hot!

(everybody was 'cruising' with an open hood -w. a beercan up front to keep the hood open.. ;-) )

-the old 350 buick was running an idle at 650 rpm's but it was too low ,-when 'cruising' was actually sitting in a biiiig traffic jam, -having fun though...

-that was with a mechanical fan, and they only run as fast as engine is spinning, -so maybe that is another factor?? -Also, try putting the old fan on, -my bet is that the flexfan isn't cooling enough.

Just a thought..


Ohh, and if you don't like running with a stat. -put one in anyway, and drill just a 0.200 hole in it.. -or a little bigger.. -160 degrees is recommended.

Is this a new engine or old? How's the flow look out of the top hose? If it's climbing at speed it's a coolant flow problem.
Have you reverse flushed the engine? Block to head passages tend to plug over time.

Hey Claus

Don't mean to highjack, but did you get the new engine running right?

And you never may be able to find a solution along with many others.

As for long term engine operation in such an enviroment, my engine has operated @ 233' to 240' for 20 years, has had the dogchit ran out of it, has 168k on the clock. It might need some upper engine work, but the bottom end--and assumed rings--is still rock solid.

Well thanks for all that replied, It was the radiator! I installed a four core griffin copper/brass rad, It was in the 70's here yesterday and driving in traffic or on the freeway engine never got over 165 degrees! Thanks

Please post an update when your outside summer temps hit into the 90s. I thought I had solved mine with an alluminum rad and then the first 95 degree day I was right back to square one. Mine turned out to be a timing issue more than anything I beleive...

Just as a reference, my cammer runs at 200° while under way on 90° days both in town and on the freeway. Stopped at a light it will clime to 210° before getting under way. Idling in say a slow fast food line it will climb to 225° without overheating or pre-detonation. I have seen as high as 230° with no problems.

This is with a 190° stat, 4 blade fan, no upper or lower baffles and the stock 3 core rad from my conv when I upgraded to a 4 core. The rad is the only upgrade from a 2 core. All the other items are stock.

Just remember all; the boiling point of 50/50 coolant/water is much higher than water under pressure. If your car is puking up coolant at idle in temps above 70° I'd say you have some problems to solve.

when you reach the upper rhelms of 230' and above your risking head gasket failure. i understand pontiacs run hotter but you shouldn't exceed 210' in normal climate and operating conditions. if you live in hotter weather add 5-10 degrees for the sun baking the engine and stagnant air. there are some mods you can do to the water pump to get it to flow more but like others said you should check the lower hose to see if its collapsing. at this point im saying its a flow problem because the hotter you get the less coolant gets to your engine and the faster the temps rise.

Is the temp gauge accurate? I had a bad gauge once and couldnt figure out why the engine ran hot. Used a "laser" temp gun to determine it was not as hot as it was indicating.