[AdamIsAdam]

I'm still burning off the pump gas.

I can't imagine sitting in the driveway at 3,000 RPM for 20 minutes. You're thinking less load = less heat?

[STEELCITYFIREBIRD]

Yep. It takes 20 minutes for the temp to climb on the highway?

[AdamIsAdam]

Well, at least 10 or so. Hard to tell these days because the car is running cool for go weather being cool.

The upper radiator mounts are solid. Radiator is firmly mounted.

I do like the idea of trying a clutch fan without a shroud just so I can remove the electric fan. If the electric fan & shroud are causing my problems, I should see lower temps on the highway, right?

If that happens, I'll go with a stock sized radiator. The question then is which one.

[STEELCITYFIREBIRD]

Try the 3k run in place.
Then go for a steady cruise in first or second gear @ 3k for a while and see if temps rise even quicker
By that time you should be ready for some good fuel.

All of these should be very telling.

I think your really leaving something on the table not seeing what you got going on inside the pump. From the pics I've seen, the hardware looks pristine. You have a new trick pump on hand still correct?

[lust4speed]

Adam, do you have the radiator sealed fairly decent to the support? Pontiac thought it worthwhile enough to supply rubber flaps on their AC cars not only sealing the radiator to the core support, but also totally sealing the area between the bumper and the support. Basically any air at speed could only go through the radiator. Without the baffles, a large amount of air entering the grill passes down and under the radiator.

Now it's bad enough that a lot of flow doesn't go through the fins, but the real grief is that this air mass creates a high pressure area under the engine - and that fights the air that is trying to get through the radiator, around the engine, and finally under the car. The more air forced under the car, the higher the pressure area, and the greater the restriction to air going through the radiator. This high pressure area under the engine is why the fans in our A-bodies need to run even at highway speed. Install an air dam to divert airflow away from under the car, and if done correctly, air will actually be sucked through the radiator because of a low pressure area under the engine.

I've installed large shrouds on the short radiators for two friends. We went with the 19.5" fan, 2797 clutch, and the corresponding big shroud. It's a little time consuming, and kind of freaky slicing into a brand new piece. All the cutting is on the bottom portion at the lower radiator hose. It ends up in the main portion of the shroud, and the bottom of the shroud is at the bottom of the tank. Just took a little fitting to get the sides of the shroud to sit fairly flush to the radiator. Side mounting holes in the plastic also had to be re-drilled. One of the cars was a '66 and the other was a '68 and both had small fans and no shrouds at all when we started. Their cars run cool, but what we don't know is they might have been okay with a good 18" fan and a new small shroud. Since they had nothing and we had to buy everything new, the decision was made to supersize the install. All I can say is that it is possible and you can't really see the hack job from the top.

[AdamIsAdam]

Originally Posted by STEELCITYFIREBIRD

Try the 3k run in place.
Then go for a steady cruise in first or second gear @ 3k for a while and see if temps rise even quicker
By that time you should be ready for some good fuel.

All of these should be very telling.

I think your really leaving something on the table not seeing what you got going on inside the pump. From the pics I've seen, the hardware looks pristine.

You have a new trick pump on hand still correct?

I returned that FlowKooler pump becaues of how far the blades were from the backing plate as seen here http://i300.photobucket.com/albums/n...2.jpg~original. I never even took the old pump off the car (I had a new backing plate that I was testing the pump against).

I have a spare OEM pump with the correct cast blades shown here http://i300.photobucket.com/albums/nn24/adamisadam/GTO/20150530_094111.jpg~original that came with the car.

But I didn't take my pump off the car yet. After all my troubles in June, I just wanted the car together and running for the summer and was afraid of opening a can of snapped water pump bolt worms . I guess it's time to look into that clearance issue soon. (Can I take the pump off without removing the timing chain cover? What's the deal with the sleeves?)

I guess running the engine at 3k while parked would be telling in showing if I have misdirected or blocked air, right? To lust4speed's point below, I have no AC air seals at all. My radiator is not sealed to the supports. It sits pretty tight to it, but since it's metal to metal, it's not 100% sealed. Plus the whole high air pressure issue with air dropping down under the radiator makes a lot of sense.

Can I use the factor AC sealing kit P167 with my non factor radiator? Is this installed last, with the bumper and grill already in place? (now that I just had the front end entirely apart, painted and re-assembled)?

Also, if I decide to go with a stock sized radiator 15.5" core and shroud, will this fan work?
http://www.ebay.com/itm/271984291570...xe=exe,ext=ext

Originally Posted by lust4speed

Adam, do you have the radiator sealed fairly decent to the support? Pontiac thought it worthwhile enough to supply rubber flaps on their AC cars not only sealing the radiator to the core support, but also totally sealing the area between the bumper and the support. Basically any air at speed could only go through the radiator. Without the baffles, a large amount of air entering the grill passes down and under the radiator.

Now it's bad enough that a lot of flow doesn't go through the fins, but the real grief is that this air mass creates a high pressure area under the engine - and that fights the air that is trying to get through the radiator, around the engine, and finally under the car. The more air forced under the car, the higher the pressure area, and the greater the restriction to air going through the radiator. This high pressure area under the engine is why the fans in our A-bodies need to run even at highway speed. Install an air dam to divert airflow away from under the car, and if done correctly, air will actually be sucked through the radiator because of a low pressure area under the engine.

I've installed large shrouds on the short radiators for two friends. We went with the 19.5" fan, 2797 clutch, and the corresponding big shroud. It's a little time consuming, and kind of freaky slicing into a brand new piece. All the cutting is on the bottom portion at the lower radiator hose. It ends up in the main portion of the shroud, and the bottom of the shroud is at the bottom of the tank. Just took a little fitting to get the sides of the shroud to sit fairly flush to the radiator. Side mounting holes in the plastic also had to be re-drilled. One of the cars was a '66 and the other was a '68 and both had small fans and no shrouds at all when we started. Their cars run cool, but what we don't know is they might have been okay with a good 18" fan and a new small shroud. Since they had nothing and we had to buy everything new, the decision was made to supersize the install. All I can say is that it is possible and you can't really see the hack job from the top.

[FrankieT/A]

Originally Posted by AdamIsAdam

I returned that FlowKooler pump becaues of how far the blades were from the backing plate as seen here http://i300.photobucket.com/albums/n...2.jpg~original. I never even took the old pump off the car (I had a new backing plate that I was testing the pump against).

I have a spare OEM pump with the correct cast blades shown here http://i300.photobucket.com/albums/nn24/adamisadam/GTO/20150530_094111.jpg~original that came with the car.

But I didn't take my pump off the car yet. After all my troubles in June, I just wanted the car together and running for the summer and was afraid of opening a can of snapped water pump bolt worms . I guess it's time to look into that clearance issue soon. (Can I take the pump off without removing the timing chain cover? What's the deal with the sleeves?)

I guess running the engine at 3k while parked would be telling in showing if I have misdirected or blocked air, right? To lust4speed's point below, I have no AC air seals at all. My radiator is not sealed to the supports. It sits pretty tight to it, but since it's metal to metal, it's not 100% sealed. Plus the whole high air pressure issue with air dropping down under the radiator makes a lot of sense.

Can I use the factor AC sealing kit P167 with my non factor radiator? Is this installed last, with the bumper and grill already in place? (now that I just had the front end entirely apart, painted and re-assembled)?

Also, if I decide to go with a stock sized radiator 15.5" core and shroud, will this fan work?
http://www.ebay.com/itm/271984291570...xe=exe,ext=ext

Again on the highway, you don't need a fan or a shroud, you're approaching this the wrong way.
As for your FlowKooler, you should not have returned it, you should have adjusted the clearance and used it.

[John62]

For the third and last time, pull that water pump. The cast impeller shown in your picture is all you need. Use that pump if good, unless your current pump also has that impeller. Throw those divider plates in the trash. Get a new correct set from inline tube. Place the new divider plate on the pump and slowly work your way around the hole with a hammer or other tool till it almost touches, closer the better. Your old pump comes off with just the 8 bolts in the front. 3 are studs and must go in the same spot if the entire stud comes out and use some tape or dope as these 3 studs go into the water. Show us before and after and then go from there.

[AdamIsAdam]

Originally Posted by John62

For the third and last time, pull that water pump. The cast impeller shown in your picture is all you need. Use that pump if good, unless your current pump also has that impeller. Throw those divider plates in the trash. Get a new correct set from inline tube. Place the new divider plate on the pump and slowly work your way around the hole with a hammer or other tool till it almost touches, closer the better. Your old pump comes off with just the 8 bolts in the front. 3 are studs and must go in the same spot if the entire stud comes out and use some tape or dope as these 3 studs go into the water. Show us before and after and then go from there.

ok. I'll do pull the pump. Not this weekend, but soon. Where are the backing divider plates on inline tube's site? I don't see them? Why not use the one that's on the car now?

[John62]

If yours are good you can reuse them, if not here is the Epay number.190643520255 they are the only one that make the correct reproduction. The S.S. repro's you show in your picture don't have the notch and do not fit without cutting and grinding.

[John62]

Originally Posted by John62

If yours are good you can reuse them, if not here is the Epay number.190643520255 they are the only one that make the correct reproduction. The S.S. repro's you show in your picture don't have the notch and do not fit without cutting and grinding.

I say this with the assumption you have the early style divider plates used up thru 1968, hard to tell in your pictures. I hope my comment did not sound mean. Until you can verify the water pump is flowing correctly nothing else you do will make up for it.

[AdamIsAdam]

Originally Posted by John62

I say this with the assumption you have the early style divider plates used up thru 1968, hard to tell in your pictures. I hope my comment did not sound mean. Until you can verify the water pump is flowing correctly nothing else you do will make up for it.

My engine block is a mid 70s 400cid ('76 as I recall). So I take it those dividers aren't correct?

I do recall reading that the divider i bought wasn't good do I returned it with the pump. I just wanted a spare on hand in case something went wrong when I opened up the current one.

No worries on the tone. I appreciate the help. I'll stop crying now.

[John62]

Sounds like you have a nicely built motor so everything will need to be at its best. You likely have the second style divider plates so the one I showed on epay is not what you want. Your motor in a newer build? so all you should need to do is get a water pump gasket and pull your water pump [11 bolts not 8 like the early model] and check clearance.

[lust4speed]

Seems like I had to re-use the tin pieces from the original hardware with the replacement flaps. Can someone confirm this? If the kit doesn't come with the tin, then it might not be much more work to start from scratch and fabricate something from light aluminum. The original design and backyard quality of the pieces leads me to believe that Pontiac discovered they had a problem at the last moment, and this was an effective piece-meal repair effort to correct it -- but it did work, and Pontiac included it on the early A-bodies with air. As a test, you could stuff foam insulation making a seal around the radiator to core support. The sealing of the bottom of the bumper to the core support is going to take some additional ingenuity. Some day I want to fabricate a custom air dam that not only seals the area from the bumper to the bottom of the core support, but then continues back and finally angles down four to six inches to help block airflow under the car. I was thinking that instead of the dam being near the front bumper, I'd put it back farther just in front of the front wheels. This should help prevent any problem of scraping it going up driveways. Anyway, think it would be very worthwhile to try.

Your photos on the Photobucket site shows the 11 bolt pump - so just the one plate sandwiched between pump body and timing cover. Leave the timing cover and it's dedicated bolts in place and just remove the pump bolts necessary to remove the pump body. When you are positioning the plate back on the timing cover, make sure that the plate seals up nicely to the two rubber seals. This is another area that pays dividends with not having any coolant bypass its correct route. You can also use some Ultra Gray or Right Stuff to seal up any questionable areas inside the pump cavity.

As far as swapping out radiators, that's a tough one. I have a friend that has purchased several custom radiators for his 66 GTO, and from my perspective all have been about the same for cooling. His latest purchase is a large cross-flow aluminum with a custom aluminum shroud and two high capacity electric fans. The assembly is fully polished out and cost him a fortune. He still doesn't run any cooler than my old-school brass desert cooler radiator with the factory A/C stuff along with the 2797 fan clutch. It's not that my old radiator is better, but all properly working large radiators are pretty close in their cooling ability, and my overall system is just more finely tuned.

I have another friend that had a custom aluminum radiator built to his specifications and its core is a full 4" thick 5 core. The thing is massive, and it actually runs hotter than a normal radiator because he can't get enough air through it. Just one of those ideas that looked good on paper, but didn't work out that great.

[STEELCITYFIREBIRD]

My point on the mounting is; metal to metal mounting is going to wear into the rad tanks where they contact the rad support, and flex the rad core @ the upper anchor points.Either of which will lead to leaks, the rad coming loose, and rust stains at the contact point with the rad support as that nice new paint wears off.
Rads should be rubber mounted @ tanks or suspended, with a large contact area on the horizontal core struts, or a combination of both.
If your interested, I'll get you a link to some of the inexpensive trick mounts used on circle track cars with these type rads.

Get inside that pump.
As the problem is likely water flow related as rpm's increase, (your pump is "burning tire", making a whirlpool, instead of propelling water)
Your rad and fan seem to have plenty of capacity. As your temp pulls right back down once the rpms come down.

Hope you get it all sorted out, hey it could be much worse, your temp gauge could look like a compass telling you your headed due East!

[68azbird]

Originally Posted by STEELCITYFIREBIRD

My point on the mounting is; metal to metal mounting is going to wear into the rad tanks where they contact the rad support, and flex the rad core @ the upper anchor points.Either of which will lead to leaks, the rad coming loose, and rust stains at the contact point with the rad support as that nice new paint wears off.
Rads should be rubber mounted @ tanks or suspended, with a large contact area on the horizontal core struts, or a combination of both.
If your interested, I'll get you a link to some of the inexpensive trick mounts used on circle track cars with these type :

X2
All radiators expand and contract to some degree. Solid mounted radiator will eventually Crack somewhere.

[AdamIsAdam]

I now have in my possession a 18 inch clutch fan, a new Hayden severe duty clutch, and a standard 18 inch fan shroud for my car. Parts ready to be installed, time permitting.

Interesting observation on today's drive. It's pretty cool out today, 50s and windy and cloudy.

So aside from the usual observations, 180° around town, 200°-205° on the highway, I noticed that my fan is not coming on while on the highway now, but every time i pull over to check it out, the fan turns on. Why, you ask? Elementary, my dear friends. I deduced that the cold moving air is tricking my thermostat into false, cooler readings. Every time i slowed down below around 45MPH, the fan came back on.

Anyway, I'll going to yank it and bolt up the clutch and fan without the shroud and see how it is on the highway. If it's cool, I'll begin cutting up my shroud to fit my non OEM radiator.

If you look at my pics, you'll notice for some reason my lower radiator hose neck is higher than stock which won't allow the shroud to bolt right in. Someone suggested having the neck lowered on the radiator. Might improve water flow too.

I'll keep you posted of results.

[bendutro]

Originally Posted by AdamIsAdam

So aside from the usual observations, 180° around town, 200°-205° on the highway, I noticed that my fan is not coming on while on the highway now, but every time i pull over to check it out, the fan turns on. Why, you ask? Elementary, my dear friends. I deduced that the cold moving air is tricking my thermostat into false, cooler readings. Every time i slowed down below around 45MPH, the fan came back on.

Are you referring to the thermostat or the temperature switch that controls the fan operation? Where is it located?

Originally Posted by AdamIsAdam

If you look at my pics, you'll notice for some reason my lower radiator hose neck is higher than stock which won't allow the shroud to bolt right in. Someone suggested having the neck lowered on the radiator. Might improve water flow too.
I'll keep you posted of results.

I fail to see how the slope of the rad hose and the influence of the fitting height will have any appreciable effect on the flow.

Thanks for continuing to post your results, I hope you're converging on a good solution.

[AdamIsAdam]

Ya, I was referring to the fan temp sensor. Poor typing. Watching the Mets game.

As for the radiator, look at the pic I the first post. The radiator is pictured upside down, so the 11 o'clock position on the picture is actually the lower hose. Look how it's about 3" from the bottom of the radiator. Isn't that bad for circulation?

[JSPONT]

My electric fan controller gets plumbed into the crossover so it reads the water temp, not the radiator temp. I can control what temp. the fan comes on now.