Coolant Expelling from Overflow Tank

[Wozniak]

I have a Superformance Cobra w/Ford 460 (mild - 485hp) . The coolant temp increases to about 100 c when driving below 20 mph. The plastic coolant recovery tank below the metal expansion tank expels coolant, typically at stop lights, just after shut-down, etc. The thermostatically controlled cooling fans DO come on automatically. The vehicle has less than 1,000 miles on it. The vehicle runs at about 70c when driving 40mph+. The engine is equipped with an Edelbrock mechanical water pump. The car is brand new to me, so I don't know history.

Questions:

1. What should the pressure rating be of the radiator cap on the metal expansion tank? Where can I purchase a replacement?
2. What is "typical" running temp? ...is 100c higher than norm in traffic or at stop lights? (I don't know thermostat open temp)
3. Are there "high-flow" thermostats available for my application? Where can I purchase?
3. What do you suggest I look at to fix other than radiator cap and thermostat?

Any help / insight is appreciated,


Matt Wozniak

[Enginetime]

1.) Cap pressure at 16- 18 psi should be fine.

2.) Thermostate : 160 for hot climes, 180 for coller Drill a 5/16 or 1/4 inch hole on the coller of the thermostate to help bleed air out of the system.

3.) Your puke tank should have a line that goes to the top of your radiator to bleed off air.

Several reasons for coolent loss are: air in system, wrong plumbing, over filled system

Mark

[Wozniak]

Thanks Mark. The cap I have is 7 lbs !!!! I'll replace that first. Matt

[Bill Wells]

99 % of these SPF cars do NOT overheat, even with bigger engine applications than yours. when they do, it is a rare occurrence !

your fans should come on at 92 +/- C and shut off not too long later...dependent on how slow you are going , or if stopped. sometimes the temps will drift up towards 100C as fans work to bring the temps down, but seeing 100 C in non race conditions is highly unlikely. they usually kick off real quick once you get going from a stoplight. some folks have a manual override so they can control when they come on and go off, vs automatic on / off. i have an over ride on mine for security.

First 2 things i would check, and have seen it a dozen times :

1. are BOTH fans running ( i have seen a few cases where one shut down/broke/quit and the remaining fan cannot properly keep it cool ).

2. the MOST common occurrence is someone accidentally disconnecting the wiring to the fans and reversing one ( or both conceivably) when they hook them back up. cuz if the wire connector is installed incorrectly the fan will PUSH and NOT PULL...and therefor not properly cool. Check the fans to make sure they are both PULLING, ie sucking air from front to back, and turning the same way and not pushing air toward the front of the car.

my water temps run 75-85 C on highway , depending on ambient temps outside. it rarely climbs to anything above 95 -98 C in the harshest of ambient temps and slow driving. many SPF big blocks experience the same temp readings as i do, 460 and 514s alike.

not sure what my radiator cap pressure is , car is offsite now..

check your fans first as described above..let us know what ya find. it is real easy to reverse the fan wire connection / plug in and have one running the wrong direction as a result.

i had to replace a thermostat once, no big deal, but if ya replace it make sure you spend the money to get a high quality stat.

bill

[Rick Parker]

Matt:

100c is 212F so at low speeds it is "Warm" however once you get moving and get airflow through the radiator, it drops to 40C about 158F, so it seems as though it is functioning correctly. If you can get more airflow at lower speeds through a more efficient fan, perhaps one that moves more air it would probably help reduce temps at low speeds and idle. The high flow or "balanced" thermostats are made by a company by the name of Robert Shaw. They are brass and can be had through better parts houses. See if you can determine what fan you have and CFM it is rated for and act accordingly. You might also look at your radiator sizing, but I think the fan is the key in your application. Radiator caps are available through the Mustang vendors, 13lbs or 16lbs being the most common.

Good luck

Rick

http://www.stewartcomponents.net/Mer...ory_Code=Therm

[CobraEd]

OK guys,. . . . . I always hear about drilling a little hole in the thermostat to allow for some flow when the t-stat is shut. Thus eliminating hot spots in or near the heads. That is all well and good and makes sense except for on thing that I always think of when hearing this.

Don't ALL 289's, 302's, and 351W's have that little elbow bypass hose that goes from the passenger side of the thermostat housing directly into the top (input) of the waterpump. Isnt that specifically what that hose is for??????

Bewildered
Ed

[Enginetime]

The hole helps bleed off air in ford BIG BLOCKS, especially the FE series. Not nesessary in small blocks. He's running a 460.

[wtm442]

Matt Wozniak

My SPF 1049 had a "similar" problem when I bought it used from the first owner. The problem was self-induced.

Of course, I had to check everything before I took my first ride. The coolant was down a little, so I filled up the metal expansion tank. After a ride, I came back about an hour later and there was coolant on the ground, so I'd add more water. Same problem. It never overheated.

So I left it alone, and the problem disappeared. The metal expansion tank runs to a metal overflow container. When everything is right, there is some air space in the exansion tank, and there is some water in the overflow tank.

But that is not your problem . But my SPF also has a 7 lbs rad cap (CST T-7), and I have a small block. There also is a hose running from the expansion tank to the block. Yours may be different.

You could have trapped air in the block too, but I'm not that familiar with big block cooling.

You should call your local rep and discuss, especially if he installed the motor and transmission. Also, Bill Wells comments are absolutely correct. The last thing I would change is the radiator cap.

My water and oil track each other, and normally run at 80 C. The fans are supposed to come on at 95 to 97 C. You might want to throw the dash switch so the fans stay on all the time and let the engine warm up on the driveway. Then turn the fans off and shut the engine off and see what happens.

All of the other feedback is good stuff to try.

2000 miles for me and never overheated .....

Hope this helps.

[Wozniak]

Thanks to everyone for the advice so far. I have checked the following so far:

1. I replaced my 7lb radiator cap with a 13lb
2. I have verified that both cooling fans are operating
3. I have verified both fans are rotating in the correct direction – sucking
4. I have verified the fans come at approximately 95C

My next step will be to replace the thermostat with a 160F


Matt Wozniak

[ENTDOC]

I had a similiar problem that turned out to be loose head bolts allowing air into the system. It only overflowed after stopping usually. I retorqued the heads and problem went away. chuck