A water pump cannot flow backwards - not even if you spin it in the wrong direction. It is a cetrifugal pump. It always flows from the center of the rotor to the outside of the rotor. It is slightly more efficient in the proper direction but it cannot flow backwards. The rotating rotor slings the water to the outside edges and this happens regardless of rotation direction.
It is possible your rad is plugged up... it is also possible that your water pump is pushing the coolant too fast to allow the radiator to effectively pull the heat from the coolant... it is also possible that your water pump does not move the volume necessary to allow the radiator to cool the coolant well.Big tube aluminum radiators tend to require added volume with out increasing flow to allow the coolant to spend enough time in contact with the tubes so they can transferr the heat effectively.You may need to try a different size pully to slow the flow down.Reverse flow pumps push water through the heads first then the block as opposed to the standard rotation pumps.So... it would still go into the engine at the bottom hose and out at the top hose.If the coolant flowed out at the bottom and in at the top,ford would have had to re-locate the T-stat to allow it to function well.
did you try to put the car in neutral when cruising on highway to see if the temp drops? if you had an old radiator there i would say it was the radiator for sure, but in this case if it does drop the pump might be spinning too fast like other members said here. in my car i cruise on highway at 180-185 steady when i'm in traffic it goes from 210 back to 185 running electric fan why don't you try installing your old radiator back just for the heck of it! if the problem persists you'll know the rad is fine. Just a thought!
Something it doesn't seem anyone else has covered, is it possible you have a blockage in the block? Thats all I can come up with on mine. Same problems, but only if I run the AC on the highway. I've been through the cooling system with the exception of tearing down the engine and cleaning out the water passages. My car sat for a while before the previous owner had it and set for a while before I got it. I think rust/dirt/crud must have settled in the block somewhere. Pulling the t-stat and flushing with a water hose had a never ending supply of brown water coming out the top of the radiator.
this is not true, the path of flow in the 302 is from the water pump through the block then through the heads then to the t-stat, then radiator. the reverse.pump is only refering to the direction that the pully needs to turn in relation to the driection that the crank pully is turing.
Ill chime in on this one this may or may not help, I have been running hot my self and have a similar set up as you. You mentioned rerunning the ground for an improvement in cooling and loosing two MSD boxes. Well last week I noticed when my Fan was running the voltage was right at 12 volts, if I hit the brakes, turn sig's or head lights it would drop as low as 11 11 1/2 volts. Two weeks ago a friend of mine gave me a bad chrome alternator he pulled from his car. Being a 100 amp unit I rebuilt it and replaced my 65 amp unit. My car now runs cooler and the fan is cycling at 195 in the driveway I need to adjust my fan thermostat for that but my voltage now stays at 12.5 or better. One of the worst things for electronics is under voltage or brown outs so it wouldn't hurt to recheck your grounds and insure you are providing enough clean power and amps for that fan. I've already lost one MSD box myself when a little thing like the horn wire shorted out and spiked the system now I always disconnect the MSD box.
Another update. I reconfirmed with March performance the water pump direction. I was told that this is a Standard Ratio pulley config. Which means standard for March (still high flow) They have standard High Flow and Performance High Flow. But still it is high flow. Add to that, it is a high flow water pump and then the high flow rad. They suggested I use a water flow restrictor to slow things down. In the mean-time, I had the rad removed and looked at. There is bits of silicone sticking out f some of the fins. They are going to acid dip the rad to hopefully remove any blockage resulting. As far as the MSD's blowing... The first one blew because they grounded out the main power wire from the battery. They were trying to tighten the connection and it grounded against the body. The second one went due to a bad ground. When they replaced the first box, they reused my ground location but did not fully make the solid connection. Only I would have know what to expect with it. Luckily Autozone will allow me to exchange the msd box and I have water restrictor plates on order from Jegs. If the rad repair doesnt fix the problem, then I'll try the restrictor plates, if that doesnt work, I'll go back to the old radiator and fan and start over.
Cooling problems is not caused by the water going too fast through the radiator...it is caused by water going too fast through the block and not being able to soak the heat. If you read about water restrictors this is what they clam...along with it is used in racing application only. "Restricting coolant flow leaving the engine lets you control the amount of heat absorbed by the coolant." A thermostat is needed on a street engine to reach operation temperature. The cooler the engine the more wear on rings and bearings.
a highe rtemp. thermostat will slow down flow by holding the water in the block longer to absorb more heat, a side affect of this is also letting the water stay in the radiator longer to cool down. You would get a more canstant engine temp. this way. When I worked at Autozone the we would reccomend higher temp t-stats for overheating problems.
With my scenario, once the thermo opens at highway speed, it would stay open no matter what thermo is in it. The mech informed me that the thermo in it while on our test drive was a 195 and yet it still held 205-210 while cruising.
I would take 205-210 at cruise. especially if you have gears in the back. I have 3.89s and it definitely keeps the heat up running at higher rpms, atleast before I put in the AOD. Plus I am in AZ. so whenever I can keep it under 220 is a good day
lol... The problem with that is that I intend on getting the AC running and the temp here is only 85 at best during these test runs. During the summer it will hit ambient temps of 130 at stop lights. (believe it or not I've tested it) If these changes do not make a difference in running temp then I will accept it and deal with the cooling problems when and if they occur when it gets hot again and/or I add the AC.
My mav used to run 205 - 210 deg.With the stock rad and a10:1 comp 30 overbore 302 and a fairly hot cam.Ran it that way for many years with no problems(and beat on it from time to time)Rad finally plugged up forcing me to put in a 3 row(copper/brass) since it was heating up at long stops.I cant make it run over 195 deg now.So you may have to get used to 200+deg but with an aluminum rad and a solid cooling system you should see 180 to 195deg normally.Good luck.
