427 SO overheats and loses water

[chas427fe]

Hi everybody. I have been lurking in background and learning some things I should have checked into before buying. I purchased a B & B 1966 cobra with a 427 SO with Edelbrock heads and intake, Holley 750. Problem occurred on first ride when bolt from water pump backed out and stopped the water pump. It proceeded to go to 250 degrees and I pulled over. This happened in less than 5 miles. Drove part of way home after cool down but overheated again. Towed home and put nearly 2 gallons of water. Drove again for three more trips after putting lock tite on the bolt. Each time within 5 miles temperature went to 225 degrees. Would let cool down and would be 1 gallon of water low. Still runs like crazy but don't know what to think. I have followed the other thread but mine still runs great. Only on one occasion did it blow white smoke out the exhaust on start up. Drained oil after first occurance and oil was clean and no water in oil. There was a little grey sludge on the dipstick. I have limited mechanical ability and am reluctant to try to fix on my own. I live near Cincinati, Ohio so if anyone knows someone they trust to work on it that would be great. Also, it is supposed to have a 428 Cobra Jet crank, does this affect displacement? Thanks for any help. Chas

[mr0077]

I'm thinking it is a blown head gasket with a small leak between the cooling system and a cylinder.

[Jahred]

I'm voting for intake manifold gasket. I gotta guess they go out 10X more often than head gasket. Hopefully that white smoke was a fluke or just some oil getting blown out.

[Michael C Henry]

If you have the bolt on the cooling pump problem solved you can move on to other problem caused when temps went too high. If you think you may have a leak into the valley or else where start with a Stant pressure tester . Not verry expensive and can be stored in a neet litle case. Pump up pressure on a full cooling system and watch for pressure to fall. One thing I'm real concerned about is that little hose in between the intake manifold and coolant pump. I had a 460 have all sorts of problems caused by that hose . It has a blister on the inside. Not appearent from outside but the blister would grow and stop any circulation flow. When cool the blister would shrink .But when hot it would swell stopping circulation flow .Hot coolant would stack up untill the coolant temp at the thermostat would open violently. It would blow the coolant out of the recovery tank. Hard to tell what the temperatures at the cylinders got to. Normally coolant ( small quantity)would flow out of the manifold into the pump and back into the block keeeping all the coolant in the engine at near the same temperature untill the coolant temp was high enough to open the thermostat.

[mr0077]

And test the coolant for combustion byproducts...a radiator shop can do it for you, I'm not sure if there is a kit (like test strips) available at an auto parts house. That would eliminate the head gasket.
Reason I'm thinking head gasket is, when combustion gases get blown into the radiator, it will heat up fast. Another way to check for this is to let the motor idle with the radiator cap off...if combustion gas is getting into the cooling system it will burp gas bubbles.

[Michael C Henry]

I just saw a Stant radiator pressure tester kit for $68 at Northern Tool plastic case and all. You install the tester on a full coolant system and start the engine . The pressure should climb slowly as fluid heats up if it climbs verry rappidly you have a combustion leak into the coolant.That is not supposed to happen. If you are looking at a radiator that has a accses or filler cap .Fill the system with fluid and leave the cap off,start the engine and watch the fluid. It should be just fluid circulating .It will rise slowly pushing upward in cap area and spilling into the tube that should go to the overflow tank. If you see bubbles ,that is a combustion leak. On a cold engine there will be verry little circulation seen at the radiator untill the thermostat open . It should be a slow expansion. but there should be circulation in the engine. test the thermostat neck as it heats up should be s slow steady increase untill thermostat minimum temp is reached. temps should be almost the same front to back on the heads.

[chas427fe]

Thanks everybody. I will order the pressure tester and start testing it when it comes in.

[Michael C Henry]

Fe's large cylinders like temps at or above 180° I wouldn't go much above 190° . Once the coolant boils you have lost the control. Get the engine too hot and rings loose tension ,pistons and valves burn. Temperature is a balance more heat more performance and shorter life. I'm running a balanced type 180° hiflow thermostat. The big thermostat for Ford surge tank uses any Mopar thermostat. Ford has a thermostat with a large body and small opening valve. If the car is moving or a pair of fans are running I can keep it about there. I have a three position switch on the dash that I can manually turn on two or four fans. I also have two thermostic bulb sensors setting ontop of the radiator going to two adjustable thermostic switches that will automatically each turn on a pair of fans if it starts to get too hot as long as the master battery switch is on. The dash switch lets me get a head start if I know I'm getting into traffic or the like.
Temps like 160° would cause you to run a richer mixture and may cause the cylinder wall to get washed down. Carbon up and (or )fuel foul the plugs.

[chas427fe]

While I'm wating for the tester, I went out and started it up. I left the cap off of the filler tank. As the temperature rose it slowly rose and over flowed into the overflow hose. When the temperature got to 170 I put the cap back on and continued to run it. Total time 10-12 minutes. I reved it to 2000 rpm and held it there for a minute or two, blipped the trottle severeal times during this time. The temperature never went over 190. I did not see any bubbles, large or small in the water. Does this make sense?

[chas427fe]

Tester came in and I started by pumping the system to 20 PSI, after 5 minutes no loss of pressure. Released pressure and started engine. after
4 minutes 150 degrees 2 PSI
6 minutes 175 degree 2 PSI
8 minutes 185 degrees 5 PSI
10 minutes 185 degrees 8 PSI
12 minutes 185 degrees 9 PSI
14 minutes 185 degrees 9 PSI
16 minutes 190 degrees 11 PSI
18 minutes 195 degrees 12 PSI
20 minutes 195 degrees 12 PSI
Gauge stayed steady during this. Engine ran at slow idle until I blipped it at 8 minutes and then it ran at 1200 RPM.

All this was done in my garage so there was no air circulation to help cool it.

Any ideas? Chas

[wtm442]

OK in the garage, but what about stop & go traffic - a real killer.

What thermostat - 180? 195?

Do you have electric fans with temp switch? If so, is it working correctly?

You may have had an air pocket after the first problem which made it look worse than it was.

[chas427fe]

I will test drive it tonight. Too late last night to go out. I don't know what temperature the thermostat is. The fan is controlled from a dash switch and I leave it on all the time, just so I won't forget to turn it on after warm up.

[chas427fe]

Took it out Thursday.. We drove it part in back roads and part on the interstate. Temperature hovered between 195 and 200. Came back dropped my passanger off and took it out again and combination of backroads and interstate. Had it up to 6000 RPM's and cruised some. Total miles were about 20 miles. No incident. Checked water level after 2 hours and it appears real close to what it was when I left. Dipstick had grey sludge on it. Took it out Saturday and drove it 30 miles each way to a car show. Got to the car show was a quart low on water. Drovw irt home, slower this time and it was low again on water maybe a pint. The dipstick again had the grey sludge onit both times i checked. When I removed one of the valve covers it was coated heavily with grey sludge. The valves and springs and the rest of the engine were clean, just oily. Drained the oil and no water in the oil. Oil pressure remained 75 PSI-85 PSI during all of this.

[chas427fe]

It appears that the water leak maybe the least of my problems. My mechanic pulled the heads and found 3 pistons scuffing the cyclinder walls, several of the valves were touching the piston tops (enough that the valves have small burrs on the top of the valve stems). We don't know where the water leak is but it is confined to one cylindr. He is sending out the questionable head to have it pressure and vacuum tested. Regardless it looks like the motor is coming out. The cylinders are already bored out to .030. I guess I am now confronted with what to do for a short block, since it is already bored out .030. It is a 427 SO but I don't know if I'm up to paying for another SO so does anybody have any suggestions? Thanks.

[HSSS427]

Get it sleeved? Mine has the passenger side bank sleeved and it hasn't caused any issues. However, I too had problem with heads leaking and dumping water into the cylinder from breached coolant passage. Probably worth having a reputable engine builder go through it while it's out. I wouldn't think you'd need a new short block, but I only play a mechanic on TV, and I slept in my own bed last night, not a Holiday Inn Express :-)

[jdog]

I agree, if the block's not cracked, have it sleeved. It will be good as new. Maybe better!

jdog

[Andrew Teal]

Chas,
Its hard to give up on a 427 once you have had one. I had some problems with overheating in stop a go traffic when I was frist work out the problems with my 427. I think as your drive and stop your ford overflow tank or recovery tank is loseing water everytime you slow down or stop. It doesnt take much of a fluid lose to run your temp up. I ran the overflow hose to a Morrose sealed tank, this stop my water lose problem.
The 428 crank has a longer throw than a 427, or 390 crank. Other words the 428 has a smaller {bore} hole and longer throw than a 427 that how you get 428ci . This might be why your hitting the values.

Andy

[Clois Harlan]

If you are taking your engine out have your mechanic check all your bearings for clearance (should be .0025-.003) works well for me. Anything less may cause overheating sometimes. I had my Cobra out last weekend in 100 + degree heat. Many stop and go lights for about an hour then on to the freeway home. My engine temp never got over 185 and we have some very long stop lights in Broken Arrow thanks to all the orange barrels everywhere.

Most likely if you have any wear on your cylinders it will only be on one or two of them and a sleve works very well. Maybe you can do a light hone of the others. You may want to have a little deeper relief machined in your pistons to accomodate for the increased lift of your crank or you can reduce the lift on your cam if that is an option. A good mechanic will know what to do. I have had trouble with over heating in the past with one of my older engines because of to much timing or air in my water or a number of other silly little things that alone would never be a problem but two or more together can cause you a little grief.

Don't give up on the FE it can be a very durable engine if it was built properly. Plus you have to love the torque and growl.

Clois

[Fake Snake]

Any rough price on the sleeve job?

[Poolw]

I have a 351 LA Exotic / B&B. It maybe dumb to say, but it doesn't have a schrod to direct all the air through the radiator. A schrod plus a two speed viper fan will slove your heating problems.