[fiesta62]

hi, i have done everything to try and keep my car cooler at idle, it gets up to around 200 at idle, not critical i know but car pings at around 190 , so i need to keep temp 190 or less, car is a non ac, i read that the AC 68 gto used a 5-11/16 inch water pump pulley, my 67 has a factory 8 inch water pump pulley, 67 and 68 used the same water pump, so i figure i could put the 68 pulley on my 67 to speed up the pump, i would be going from 8 inch down to 5-11/16 inch, has anyone done this with any success ?......and if anyone has a 68 5-11/16 inch pulley let me know i would like to try it....thanks

[68 Firebird]

Yes that helped my car with cooling. Think my waterpump pulley
is 5.5 and my crank is 7.25. Remember the ratio was like 133% compared
to stock 90%.

Basically went from non AC setup to an AC setup for improved cooling.
That and a Hayden HD fan clutch and a 7 blade fan from a TA with auto and AC!!

Good Luck

Gerry

[fiesta62]

great that's what I hoped, now just got to find a 68 pulley, lots of 8 inch ones around but the 5-11/16 are scarce but they do come around I missed a few on ebay recently....

[68 Firebird]

I bought mine from March systems. They do aluminum pulley systems.
Was able to buy just the WP pulley and I painted it black for a stock
appearance.

Think it was about 70 or so bucks

Gerry

[chrisp]

What type of fan are you using ?

[fiesta62]

Originally Posted by chrisp

What type of fan are you using ?

well i had the 17. 5 inch factory clutch fan on it, but then took it off and installed the larger ac shroud with a 19 inch flexalite fan....i didnt see much improvement if any, so just this week spent a lot of time sealing off all gaps around shroud....and bought a new derale 6 blade flex fan, its there deepest pitch they make and they say it will pull the most air over rad at idle, i just finished this yesterday and also installed a 160 thermostat....today is the test drive, fingers crossed

[chrisp]

If heating up @ idle / sitting still a clutch fan is no good as not 100% engaged , use a 7 blade 2 1/4" pitch flex fan Hayden 3718 now sold as Parts Master 3718 . That will give the most air movement . No whirl noise either . Make sure you are not running lean . Only my opinion , but has solved a few hot @ idle engines .

[fiesta62]

Originally Posted by chrisp

If heating up @ idle / sitting still a clutch fan is no good as not 100% engaged , use a 7 blade 2 1/4" pitch flex fan Hayden 3718 now sold as Parts Master 3718 . That will give the most air movement . No whirl noise either . Make sure you are not running lean . Only my opinion , but has solved a few hot @ idle engines .

i have just fitted the derale 6 blade 17019....pitch is 2-3/8 inch, and it 19-1/4 in size so its 1 inch bigger than the hayden u mentioned....though i see hayden is 7 blade so not sure how that compares with the 6 blade....anyway will test car today to see how derale goes, car is not lean, actually its a bit rich if anything.....thanks

[fiesta62]

tested car with new fan....ran at 170 to 182 when moving great !.......pulled over sat for 5 to 10 minutes and temp climbed to 210....soon as i got moving it started dropping again, problem is it pings over 190, buggered if i know we have done everything

[pugslyx234]

Been reading posts could it be carbon-ed up in the heads/pistons creating hot spots which would cause pinging just mez 2 %

[fiesta62]

Originally Posted by pugslyx234

Been reading posts could it be carbon-ed up in the heads/pistons creating hot spots which would cause pinging just mez 2 %

dont know about that, engine was rebuilt by previous owner about 25000 to 30000 miles ago....our next trick i think is to go a even smaller water pump pulley....

[68blackbird]

I tried all the things you have stated, 400, #16 heads aluminum rad, water pump, clutch fan, timing, jetting. I tried everything. Converted to run on e85, it does run cooler on e85 but still goes to 205 at idle. Added smaller water pump pulley and larger crank pulley. And it's better. But with all the above changes the car will not stay at 185 in all situations. I have not had the heads off the car to verify. But I have concluded that my pistons are to far down below the deck for proper quench. All this to say, before you continue to drive yourself crazy and spend more money. You might want to pull one head just to see where you are with the deck height. At least if you find your pistons 0.040 in the whole you know what's going on with the engine and anything you do is a bandaid.

So what am I doing. I have a 455 on the stand in the garage 9.25 credit with iron heads and the pistons are out of the deck .004. It will run pump gas all day and stay cool.

Rich

[fiesta62]

hi..well i am now thinking about installing the later 69 water pump, its a better design, so i am looking at various suppliers, some do kits so hopefully i can find everything needed, my mechanic feels the 67 water pump design is not good and at this point we dont have many options left except maybe installing aluminium radiator but for now we lean towards a better water pump....

[68blackbird]

Originally Posted by fiesta62

hi..well i am now thinking about installing the later 69 water pump, its a better design, so i am looking at various suppliers, some do kits so hopefully i can find everything needed, my mechanic feels the 67 water pump design is not good and at this point we dont have many options left except maybe installing aluminium radiator but for now we lean towards a better water pump....

can your mechanic tell you where the pistons are in relation to the deck?

Rich

[fiesta62]

not at this point he isn't wanting to go there yet

[abefromen]

Originally Posted by fiesta62

spent a lot of time sealing off all gaps around shroud....

May I ask what you used to do this?

[fiesta62]

i bought some black rubber strip 2.5 inch wide by about quarter inch thick, i ran it down each side on the inside edge of shroud and bolted it into place, i actually did all sides at once which was a mistake , when i tried to fit shroud it would not fit snug, i found that its best to do one side at a time and check, so remove fan, fit shroud into place, then position one strip down one side, mark it, take off shroud, bolt strip into position, refit shroud to check its all fitted right, then repeat for other side, these side strips slip fitted between rad and side support brace. Across top i used black sponge rubber tape about half inch thick it stuck to the shroud and also when shroud bolts on the sponge also gets compressed so is clamped into place.
at each top corner of the shroud i bolted about 8 inchs of rubber strip , i bent it down to bolt down the side about 4 inchs across top and 4 inchs down side these pieces pressed tight against the rad core, this worked fine and sealed off the top corners, as you will see sponge has nothing to stick to here, so sponge stops about 4 inchs in from each corner and is mostly hidden by the fan gaurd.
then when sides and top was done i jacked up car and bolted bottom strip of rubber from under car, this rubber pressed hard against the bottom rad tank
i also got some black silicon and filled in any gaps between rubber strips and shroud
yep lot of work but now its solid and air tight ! and nothing shows just a few bolt heads on the outside of shroud which i painted black it looks great, my friend suggested just glue sponge rubber all round which will compress and allow fitting of shroud more easy and he may be right , my method is a lot of work, but made to last ! i attached 2 pics

[rexs73gto]

I don't see anywhere where you have taken the water pump off & made sure the distance between the pump & the divider plates are as close as they should be. The distance between the pump impeller & the divider plate should be no more then .30ths. You should make sure the distance is no more then the .30 & no lees then .20ths. The factory never had these kinds of problems with or without A/C. If you pull the pump apart & make sure the clearances are correct you shouldn't have any more problems. This type of concern has been talked about on this site many times. If you follow these simple steps you won't have any more problems with over heating. Step 1 make sure the fan is pulling in the air. By that I mean that the fan clutch if you have one is locking yp & pulling the air in when the car is getting hot. Make sure the clutch is locking up. # 2 make sure the T-stat is working correctly. If it's old replace it. More then 4 years & it's old so replace it. # 3 make sure you have a proper amount of coolant. A 50/50 mix is more then enough. Pure water cools better but it also causes lots of rust. So keep the coolant where it should be. More then 50/50 will make it run hotter then it should. # 4 make sure your radiator is clean & clear. The more junk in the front of the rad. will slow down the air flow & make the car get hot. Make sure the fins of the rad. are clear & straight & don't have a bunch of fins bent over. If you do use a fin comb on the rad to straighten them out. # 5 Make sure your rad. cap is working & not blowing it's seal to soon. if it lets go at a low pressure it will let in air into the system & cause your car to get hot. Again if it's old more then 3 years old ,, replace it. # 6 & the most important make sure the clearance on the divider plate of the water pump is where it should be. If it isn't your car will get HOT. Slow speed is the hardest on your car because the coolant isn't moving as fast. If the distance between the divider plate & impeller isn't correct your car will get hot. Now if you follow these simple rules your car will not get hot. The factory did it this way & it worked just fine in all climates for many years. It only stopped working after someone changed things when it needed repair. Put it back to the way the factory had it & you'll be fine.

[fiesta62]

Originally Posted by rexs73gto

I don't see anywhere where you have taken the water pump off & made sure the distance between the pump & the divider plates are as close as they should be. The distance between the pump impeller & the divider plate should be no more then .30ths. You should make sure the distance is no more then the .30 & no lees then .20ths. The factory never had these kinds of problems with or without A/C. If you pull the pump apart & make sure the clearances are correct you shouldn't have any more problems. This type of concern has been talked about on this site many times. If you follow these simple steps you won't have any more problems with over heating. Step 1 make sure the fan is pulling in the air. By that I mean that the fan clutch if you have one is locking yp & pulling the air in when the car is getting hot. Make sure the clutch is locking up. # 2 make sure the T-stat is working correctly. If it's old replace it. More then 4 years & it's old so replace it. # 3 make sure you have a proper amount of coolant. A 50/50 mix is more then enough. Pure water cools better but it also causes lots of rust. So keep the coolant where it should be. More then 50/50 will make it run hotter then it should. # 4 make sure your radiator is clean & clear. The more junk in the front of the rad. will slow down the air flow & make the car get hot. Make sure the fins of the rad. are clear & straight & don't have a bunch of fins bent over. If you do use a fin comb on the rad to straighten them out. # 5 Make sure your rad. cap is working & not blowing it's seal to soon. if it lets go at a low pressure it will let in air into the system & cause your car to get hot. Again if it's old more then 3 years old ,, replace it. # 6 & the most important make sure the clearance on the divider plate of the water pump is where it should be. If it isn't your car will get HOT. Slow speed is the hardest on your car because the coolant isn't moving as fast. If the distance between the divider plate & impeller isn't correct your car will get hot. Now if you follow these simple rules your car will not get hot. The factory did it this way & it worked just fine in all climates for many years. It only stopped working after someone changed things when it needed repair. Put it back to the way the factory had it & you'll be fine.

hi rex...everything you mention here we have done, i mean everything, i now run a deep pitch derale fan so no clutch to worry about, new thermo 160, new cap 13 psi, coolant correct, shroud sealed, towel in front of grill gets sucked in so pulls good air, rad is original harrison has been serviced and tested fine, it has been recored too with a 4 core hi flow...i also installed external oil cooler for the tranny so no hot oil in the rad....now for water pump, my mechanic knows the workings of these pumps and the flow cooler pumps , he took my pump apart and welded a plate onto the impeller to close the blades in for better flow, and also fitted a smaller pulley to spin pump faster and move the coolant faster we went from 8 inch down to 6 inch and that alone should have made a big difference but its still gets hot at idle, my mechanic does say the design of the 67 pump is useless and we have discussed installing a new timing cover and then fitting the edlebrock pump which is a much better design, but as thats a lot of messing around i just bought a stewart electric inline pump, it fits onto the bottom rad hose and pumps 55 gallons a minute and works with the original pump together i think the water pump issue will be no question anymore, if i still have problems my only option then we think is to try aluminium rad but i really hope thats not needed

[GT182]

E85 here in the States is one contributing factor to over heating most don't take into consideration. I ran 5 gallons of 100LL aviation gas mixed with a couple of gallons of 87 octane E85 and my cooling problems were drastically redused by 99%. No overheating at idle. Especially if you sit for 5 minutes or more. Some of these red lights here where I am, at really busy intersections, will stay red for up to 10 minutes. No fun to sit there and watch the temp creep up.

Also remember, as I've and others have said before, these cars came out of the factory with 190 or 195 thermostats. No problems with overheating at all back then. Plus they were running real gasoline not this E85 crap. A 160 is not good to run as it doesn't get the engine hot enough to get the moisture out of it and the exhaust system. Also, these new and rebuilt water pumps have the wrong impeller on them. Of all that I've seen these days, all have cast impellers with the vanes shaved flat. You do not want to run them. They are their own problem seeing they'll cause cavitation when moving the coolant. Stay away from them.

I haven't heard from Cardone yet but they have built the correct cast impeller for the 8 bolt pumps.... I have one in my 66 GTO so I know they've been manufactured. I'll be checking with them this coming week to see if they've found them in the warehouse in Dallas, so we can get the correct part number for them.