Ok, 69 350ci. Pulled the timing cover to replace leaking crank seal. Original divider plate was toast, holes rust thru in 3 areas. Installed new plate, has appropriate distance to the impeller. While down I installed what i believe to be a cool mod. A 3000 cfm electric fan from a 97 v-8 Thunderbird, replacing a 15" flex and stock fan shroud. The electric fan and shroud fit our radiators almost perfect, little fabricating. Installed with relay and temperature control switch, comes on at 185deg and pulls alot more air than the flex and shroud. Problem i am having is the car overtemps at speeds when any fan shouldnt make a difference. I pull in the driveway at 220deg let it idle and the fan will bring it down to 200deg no problem and my engine thermometer reads 190deg. One thing I have tried to cure this is timing, 32 total adv, 16, 4. Nothing makes a diff. 160 deg thermostat,180 and no thermostat, No diff. Verified the thermostats are opening. It seems to me like a blockage somewhere. The lower rad hose is springed, upper is not. Rad is flowing, fairly new OEM 4 core. Also before, the engine never got over 205deg. Would air in the heater lines cause this? Only thing I did wrong from reading other post was I filled system complete with straight antifreeze, no 50/50. I pulled the pump off this AM to verify the divider plates sealed against the orings and the opening from timing cover tto the intake manifold was not blocked. Both checked out good. I doubt its a blown head gasket. Motor has been great along time, despite the leaks. And it does not have an engine mis or loss of power. Thanks, Any input, I appreciate.
Are the upper baffles between the core support and filler panel in place, along with the lower baffle panel?
Your total timing is 32, but what is your timing at around 2500-3000 rpm with the vacuum advance hooked up? Make sure the vacuum advance can is pulling at higher speeds. Should be drawing 40-50 degrees of timing at highway speeds with the vacuum advance hooked up. Of course, run full vacuum, not ported.
Not sure about straight anti-freeze, they always recommend a 50/50 blend. I would drain half of your radiator and replace it with water, that will give you a 50/50 mix.
As for trapped air, you can take out the thermostat and drill a small 1/8 hole in the ring. That eliminates hose collapse and air pockets. Some new aftermarket thermostats have this feature now.
Remove the electric fan, and use a stock 18" clutch fan. The fan tips should sit about 3/4 into the shroud. Not sure why people remove their factory setups. They worked when the car was new, they worked under GM warranties, they worked on millions of cars GM sold, yet people chuck it and go with an electric only.
The stock engine driven fan is way more efficiant than any electric fan providing the proper fan and shroud are used. Make sure you bleed all the air out of the system by running it with the rad cap off, you can usually see if there is any air in the system after the coolent circulates a few times.
Since it's a cruising speed I'm guessing the electric fan is inhibiting airflow across the radiator. Most people have the opposite problem of overheating at stop lights and what not. Are you sure the fan is pushing the air in the right direction? If it's not it might be fighting against the wind when you are cruising. Did you set it up as a pusher or puller fan? Did you remove the old fan as well or leave it in place?
Also from what I've read 50/50 anti freeze is good for cold temps, but antifreeze does nothing for cooling. 100% must be like syrup. Water cools better and anti freeze raises the boiling point. In the ponti manual it says at 15psi the boiling pt of water is raised from 212oF to 258oF. According to Boyles Law of ...just kidding, I think that's for a gas anyways. I just re did my water pump and I'm going with 20%anti freeze 80% distilled since I'm in Cali and it never freezes where i live. I've heard you can go 100% distilled if you add an anti corossion solution.
Some good info here: http://www.flowkoolerwaterpumps.com/cooling_faq.html "#7. Coolant composition. A 50/50 mixture does not help cooling it raises the boiling point. Run 100% distilled water with water pump lubricant or distilled water with about 15-20 % antifreeze. Both cool better than 50/50 and still lubricate the water pump to prevent corrosion in system. When the weather cools return to 50/50."
Ok, thanks for all the great input. I have the problem resolved. 30 miles of driving and stopping, went to 200deg couple times mostly hovered at 195. I made the coolant 50/50, added a bottle of water wetter (which works well, ive used before in AZ and noticed at 5-10deg diff)and timing. I believe my timing was too far adv. I put timing tape on the balancer during this maintenance and think its the wrong tape. As soon as I backed off pretty far from where i thought it should be, temperatures stopped climbing.
As far as why the fan swap. The electric fan with its shroud sits inside, the engine side of the Rad,(pull) so its not blocking anything at cruzing speeds. All the upper and lower baffles are on. The 97 ford V8 Thunderbird fan with the shroud notched 3/8" on each side fits perfect over our 67-69 OEM radiator cores. It draws alot more air thru the cores than the stock shroud with a flex. Clutch, im not sure. Never ran one, but I doubt it pulls more. Bottom line is it adds more HP, I know some will disagree to that. Not much maybe 3-5, but noticable to me. Whole deal total cost was 90$. Salvage yard fan,Jegs temp control switch and relay and my time. Ehh.. and a headache figure out rising temp.
Some people prefer straight electric fans to a clutch fan. But a clutch fan uses ZERO hp. As the engine revs, the clutch disengages above 3000 rpm. There are different versions available, thermo or rpm, but in general they disengage and freewheel as rpms rise, unless the engine is piping hot.
One disadvantage to any mechanical fan is of course the noise. Some fans are noisier than others, depending on the blade angle, flexibility of the fins, and stagger of the blades. Factory GM units used stiff steel blades on their clutch fans, but each blade had a curved lip at the tip, and staggered blades, to eliminate almost all noise. The fixed blade designs, GM or aftermarket, are rather noisy.
It's splitting hairs, but the 0-5 hp a clutch fan may use at 4000 rpm, well consider that an electric fan puts a drain on your electrical system, which puts a load on the alternator, which then of course uses a few horsepower to turn.
A popular do-it-yourself mod that people used to do was rig up a switch, off the gas pedal or carb throttle lever, to cut power to the alternator at wide open throttle. But over the years, some tests in magazines have proven that while you may save a couple hp by allowing your alternator to freewheel for a few seconds, your also taking power away from an MSD unit and/or spark plugs, so they recommended not bypassing your alternator for those few extra hp you may save.
Great to hear you may have solved your problem. I use Water Wetter (two bottles) and straight water in my system.
I have an overheat problem too, one issue is it's a Pontiac from the 60's, they've been known for cooling issues, god knows I'm having mine too. I would never change to an electric fan, just to gain 2-5 HP, I would of changed the radiator to an aluminium rad. and use a clutch fan, that's my next option. The car isn't designed for electric fan's, if it ever fail's Goodbye engine, especially a hot running Pontiac, I'd trust the belt's because there is more than one there, both don't always break. As far as Water Wetter, heard about it, and some say don't use it, it does nothing at all, I've talked to some on Highperformancepontiac and they swear it does nothing and use proper 50/50 antifreeze. I was also under the impression Water Wetter worked it's best with only distilled water, with antifreeze it worked so-so.
I used to have overheating problems...car used to run mostly around 230-240....got it lower and lower over the years , by fillers , water pump, timing, carburator etc..(and actually got rid of an electric 'helper fan' , placed in front, it was just blocking more than it helped)..but last item was a new 3 core alum radiator by Champion...now car runs 185-195 from colder time of the year to the hotter times. Personally I dont like the electric fans (have had on other vihicles) as they tend to "whine" too much.
I actually did test the Water Wetter stuff about 10 years ago, when I still had a 4-row radiator factory style radiator (went to aluminum a long time ago). I too suffered from "heat creep", and it would go to 200 degrees, then after driving for awhile, sitting in traffic it would go to 205. Then sitting longer it would creep to 210, then 215.
I bought 2 bottles of Water Wetter, and let the car idle in the garage for about 20 minutes. Same conditions I've always had, all I did was add the Water Wetter. The stuff actually worked. Temps never went above 205.
The down side was that I used to swap intakes a lot, and didn't have the intake crossover cut. That meant I had to drain fluid to get the intake off. I'd reuse the fluid if I could, but I realized that special fluid was not the answer, and that it would get expensive with all the intake swaps I did. But the stuff actually worked.
Went to an aluminum radiator, full vac advance on the timing, always stayed with the factory clutch fan, and the car runs at 190 all day now. I had an electric in front of the radiator, but later removed it. It worked great at the dragstrip, in between runs, to cool the engine down. But I don't race the car anymore, so I removed it.
