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I need help figuring out why my 400 is overheating

It is a 1987 gen3 Fire-bird Formula (reFormulated) with a 1971 Pontiac 400 block casting #481988 bored .030 over with Keith Black dish pistons, crank has been turned .020/.020. Rotating assembly has been balanced, Number 16 heads with new valves and springs, 72cc cambers. Howard's CAM in.482 ex.470, true dual exhaust, new water pump with cast impeller, divider plate clearance set as close as possible to impeller. New 4 core aluminum radiator with 2 10 inch electric fans pulling air and 2 12 inch electric fans pushing air. A/C condenser removed to allow maximum air flow. Removed thermostat, still overheating. Installed a flow restrictor hoping the water was flowing to fast through the radiator for efficient heat transfer. No still HOT. New 180 degree thermostat. With each change it continued to overheat, although the time it takes to overheat varied. I really hope someone here has an idea what I am facing.

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Welcome to FP Dr Jones. I run a 455 with a Mr. Gasket wide mouth 180 degree thermostat. Thank you for posting your pictures of your engine bay. What is the story on the electric fans? Do they both come on at a pre-selected temperature? Are they working properly? Are you loosing any coolant?

What is your oil pressure / temperature like when your water temperature is rising? Is your oil pressure low? Oil temp high? Is your oil level low at all? I ask because I know when my engine loses oil, the water temperature rises because the oil is getting too hot due to the oil loss.

 

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Frosty, valid questions..
 
No coolant leaks and my oil capacity is 7 quarts due to remote oil filter and it is not low
 
As it stands now I am running the fans manually. Under normal conditions the 10 inch pulling fans come on at 190, thermostat opens at 180 and the 12 inch fans are manual controlled for now, ultimately the 12 inchers will come on at 195 if and when needed.
 
Idling at 220 degrees oil pressure 20psi

Other test I performed,

I forgot to mention my radiator is hot from top to bottom so I know there is no blockage and water is flowing through it. Besides it new.

Also this, removed the upper radiator hose pointed it to the ground and started feeding the top of the radiator water from a garden hose. Making sure the rad was full at all times, started the engine let run after about 5-6 minutes water started trickling out of the hose pointing to the ground within another minute or so I had full flow dumping to the ground. Another minute or so the flow diminished to a trickle again. This cycle continued every minute or so, telling me that the thermostat was doing it's job as intended. I let this continue for a good 30 minutes just to see what was going to happen and the temp averaged 180 the whole time. Of course it dipped to 160ish and rose to 185ish give or take a few degrees.

I am baffled as to what the problem is, everything seam in order.  Ideas? Anyone? Anyone?

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As a first guess, you might have a trapped air bubble in the coolant system which means you have to burn it out.

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Make sure your electric fans are rotating the right direction you can tell by putting piece of paper on front of radiator should suck up to it. If not rotating right direction just reverse the two wires hope this helps.

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Thanks guys

The possible trapped air bubble how would you recommend "burning it out"?   I've seen the temp go up to 240 at its highest. And it was spewing water from the overflow bottle.      I have not let that happen again.

Fans are not in contention with each other. The 12 inch fans on the outside are pushing air into the front of the radiator and the fans on the engine side of the rad are pushing towards the engine.

Read that timing could have an affect on Pontiacs. In my 35 years of knuckle busting I haven't seen timing make that much of a rise in temps before. But then again this is my first shot at a performance Pontiac.

Man this will bum a man out,

Oh yea, running out of hair....!

Hey two lane

Im in NC also, Moyck

You?

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I am in Winston Salem Still think I would look at my fans again just to be sure the air is flowing correctly .Timing would not have that much of an effect on temperature also check carburation make sure not running way lean.Also make sure no vacuum leaks. saw that has new water pump I have seen new water pumps that didn't work like supposed to because of too much clearance between the pump housing itself and the impeller not necessarily divider plate.Excessive clearance will cause the coolant not flow as fast as it should if at all . More common problem than you might think might be worth looking at.

Edited by TWO LANE BLACK TOP

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Is this a fresh engine? Are you 100% sure with out doubt that there not crack in cylinder head ? Have built couple of engines thru the years that have had cracked heads that did NOT show up during pressure testing or magna fluxing But opened up slightly when the head is torqued . and engine gets to operating temp.Especially if they have been cut down and the intake and exhaust ports ported and reshaped  for max air flow at high RPM the spring pockets opened up to accept larger diameter springs. and running really radical cam profile....Thin walled castings can crawl around quite a lot. Causes all kinds of issues such as cracks in the bottom of the spring pockets around the edges just enough to let just miniscule couldn't even measure amount of water what little there was  pulled out by evac system and wasn't getting into the oil only symptom was what we thought was condensation in top in valve cover due to hot engine exposed to cold outside temperature while cooling off after racing 100 laps got to wondering about it put valve cover that was cut open on top watched engine run awhile saw water bubbling up around one of valve springs.If had been street engine without super radical cam profile and matching valve springs and not turning 7500 rpms probably would been OK just an example of things you run into when racing thin wall casting iron head Pontiac engine Was ruthlessly fast though sorry about rambling on   sometimes cant help myself pretty sure none this would apply to your problem. SORRY again for rambling about stupid stuff realize this isn't place for it.....

Edited by TWO LANE BLACK TOP

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One other thing missing duct work in front of radiator can make third gens run hot by not channeling the air correctly into radiator maybe some of these suggestions will help?

Edited by TWO LANE BLACK TOP

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Here are some simple DIY ways to burb the system. I also agree with Two Lane on checking the directional flow of your fans. It is one less thing to eliminate. Also it is important that the flow plugs between the water pump and block divider plate are installed. For the moment, I am going to assume they are installed correctly.

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http://automotivemileposts.com/garage/v2n15.html

http://www.doityourself.com/stry/how-to-burp-a-vehicles-coolant-system

http://www.jalopyjournal.com/forum/threads/burping-air-from-radiator.790032/

 

 

Edited by Frosty

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Guys thanks for taking the time to put thought into my problem

Fresh engine yes, maybe 10 hours

the air dams are in place

100% fans are moving air the correct direction

I did check for vac leaks, none. Also I have it running way rich on purpose

I don't see a lot of value in that burping funnel thingy. If air was trapped in a cavity I see no way that device would remove it any better than just taking your time purging. Not that I don't appreciate the idea because I do, thank you. Just being honest

New water pumps are not always the right water pumps, I think I'm leaning this way. Because I had the 8 bolt timing cover and pump on first and as we know did not cool as well as the 11 bolt.... BUT  the 8 bolt was cooling better than the 11 is now and without the 2 12inch fans pushing air. What gets me is with the cap off the rad and water level about 2-3 inches below the top you can watch the water jetting out of the core tubes not dribbling but imagine taking a hard piss, that is about equal to the pressure coming out of each core tube.

Maybe I should try a belt driven fan and shroud...?

I don't know

35 years I have never had one beat me up like this one is

 

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I have a wild thought. What if you run a smaller pulley on the water pump and a larger one on the crank? Effectively speeding up the water pump and getting motor coolant through the engine.

BTW I agree with you the bucket, I was more interested in showing you how to do it. 

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You are welcome . Have been doing this along time myself . Hate problems like that sad apart about it is from my own experience usually winds up being something simple.  PS Please look at my fresh engine post again put some more on it.

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Had not thought about that Frosty. Could very well be.

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Did you cc the heads for true compression test?

Edited by indymanjoe

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hey guys, its taken a day to get back to ya.

Frosty, yes new flow plugs and divider plate, plate clearance set to a minimum

Two lane, your probably right its something stupid simple getting overlooked,    wtf is it   lol

Frosty, wouldn't over driving the water pump be like a band-aid? if it even worked.  please dont take any offense to that, I appreciate you throwing out ideas. that's why we're here, right?

Two lane, you mentioned something about a fresh engine post, I am interested in reading it. where can I find it? sorry if that is a dumb question

again thx for all your input, really

 

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Is it possible the lower rad hose is collapsing? should be a spring inside to prevent this. The rad hot from top to bottom suggest to me water is not flowing. Justa wag

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12 hours ago, DrJones said:

hey guys, its taken a day to get back to ya.

Frosty, yes new flow plugs and divider plate, plate clearance set to a minimum

Two lane, your probably right its something stupid simple getting overlooked,    wtf is it   lol

Frosty, wouldn't over driving the water pump be like a band-aid? if it even worked.  please dont take any offense to that, I appreciate you throwing out ideas. that's why we're here, right?

Two lane, you mentioned something about a fresh engine post, I am interested in reading it. where can I find it? sorry if that is a dumb question

again thx for all your input, really

 

No offense taken, it appeared, to me at least, that you water pump pulley was a little larger than stock so I was wondering if so that you might be slowing it down unknowingly. I don't know that it would be a band aid if it was unintentionally slowed down in the first place. I would suggest getting a stock pulley and measure its diameter and then compare it to the one on the car. If the stock pulley is smaller then you've slowed down the water pump.

Another thought, before you installed the new motor did you think to flush or replace the heater core? It's possible it could be partialled clogged from use/old age and restricting overall flow.

Edited by Frosty

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This might sound really dumb. but is your temp guage accurate ? just a thought  you know stupid simple thing LOL

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Frosty, your right about the pulley that is something I didn't even think about. The crank pulley is stock and water pump pulley that is on now is 4" diameter and factory (if I'm not mistaken) is 6-1/2", So I'm over-driving as it is.     Yes new heater core to

indymanjoe, Lower hose isn't collapsing, its got the spring. Also I never seen one collapse at idle but I guess it could if it were old and soft

On 3/6/2017 at 4:13 PM, DrJones said:

cap off the rad and water level about 2-3 inches below the top you can watch the water jetting out of the core tubes not dribbling but imagine taking a hard piss, that is about equal to the pressure coming out of each core tube.

Rad inlet is hotter than outlet by about 25 degrees so there is some cooling happening just not enough to counter what the engine produces

 bad pump??  even though its new, that kinda defies logic due to the fact you can watch the water jetting out of the core tubes. But maybe not moving enough volume

Two Lane, nothing is to dumb IMO,   I have two gauges on it now, factory dash gauge and a Bosch mechanical they are about 7-10 degrees difference between the two.

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I completely agree Pump could very well be problem. Mentioned before Have seen new ones that did not flow like they should was mainly due to too much clearance between the impeller and the pump housing itself. will not flow like supposed too if at all. Most of the pumps like from Autozone etc are remanufactured and whoever does them doesn't pay attention to the nuances or details. After all GM hasn't made them in 30 plus years. They pretty much just slap new seals and bearings in them and send them out door quick as they can...

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Read through your entire thread and these things can drive you crazy. A couple of thoughts:

1, Don't dismiss timing. If it is late it will cause any engine to heat. Are you sure that the timing mark is actually TDC? It would not be the first one I have seen that was off. If It has been verified to be accurate then is the distributor advancing the way it should. Check it with a timing light that has an advance gauge and see if it is advancing properly.

2, you stated that you have it running rich on purpose. This can cause problems especially at idle. A friend of a friend put an aftermarket injection on his hi-per Chevy. it would overheat terribly at idle until they put a laptop on it and dialed in the fuel. It dropped 20 degrees at idle with the proper fuel ratio. I see that you are using an end bowl Holley. Unless they have done something in the last 10 years to correct the problem they are notorious for running fat at low throttle openings. Until the throttle is open far enough to be drawing fuel off of the main jets it is drawing off of the idle circuit and they were always WAAAAAY to big for any kind of reasonable fuel control. It has been far too many years for me to reach into my memory to explain how to re-jet the idle circuit on one of those but anyone that is competent at Holley work should know about it. Think of it this way, any fuel that is not being turned into horsepower is being turned into heat.

Just a few more things to think about. Hope another point of view helps, Best of luck.

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Old Guy, when I say it is "rich on purpose" I don't mean it is so rich that it is blowing black smoke.. But more to the rich than to the lean side of things.  As far as the timing marks go, my timing cover does not have the casted marks and I didn't have a bolt on timing pointer. So what I did during assembly (heads off) is bring it to TDC then measured the degrees I could rotate the crank before the piston starts to move and then centered that, then marked the timing cover matching the mark on the balancer. I'm pretty sure I am with in 1 degree of being dead on TDC.

Back to overheating, I ordered a BRAND NEW water pump. I bit the bullet and bought a "FlowKooler" pump from Butler Performance. In my research these pumps come highly recommended. Tonight I'm hoping to have the time to install (honey do's pending) also picked up 165 thermostat. I'll update with the results after the install.

Fingers crossed............

Kooler2.jpg

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Good luck with the new water pump and thermostat Dr Jones. We are all interested to find out what happens next.

Dr Jones, I think I had a small epiphany. It just dawned on me that your overheating issues is with a Pontiac engine in a 3rd gen body. Bear with me.

When Pontiac built the third gens, other than the first couple of years, there are no open access to the radiator through the front grille. All the grilles are closed. So Pontiac installed a small plastic air dam under the car, in front of the front wheels/radiator that directs air up into the radiator from near road level. It's about 1.5-2.5 wide and spans the width of the car. It's not clear to me in your photographs if that air dam is there. Is that air dam still there? Is it removed or dangling? If it is missing or partially attached, then this may be contributing to you overheating since cool air is not being forced up into the radiator.

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Edited by Frosty
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