Cooling System Issue after running EFI Swap

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
Hello all,

Well it has been a while since I have posted due to some life changes but I am back now and I have a question regarding my EFI swap I had done in the summer of 2006.

So I have a 1978 302 that I had converted to EFI. I had gotten it started and driven it around town since I had completed the swap but there had always been an issue. It sounded like there was a marble banging around somewhere on the front of the engine when ever the engine was on. It was a random noise occuring every 5-10 seconds on average. Spare this, the car ran and started beautifully.

This fall, as usual I had turned the car to run it for about ten minutes to charge the battery and run the fluids. While it was running, the "marble" noise suddenly increased, became constant, and coolant started pouring from the front of the engine around the bottom of the water pump. I shut the car off immediately.

I am now focusing on fixing this issue and this is what I have found so far:

-The coolant had a noticeable about of orange, rusty tint to it.
-The thermostat housing, which I had cleaned out during EFI swap, had an excessive amount of scale in the section on the front of the car.
-The EFI intake manifold immediately beyond the thermostat has a rust residue that appears to have been carried by the coolant.
-After removing water pump, it seems to spin however it sounds like it has a low spot where it rubs against the thin metal plate for a 1/8 of a full revolution.

This evening I took off the water pump and plan on replacing it. I now have the following questions that I hope you can answer.

-What caused the increasing "marble" noise and then catastrophic leak?
-Have I been running the wrong water pump since the EFI swap?
-Was the failure a result of the EFI or just time for it to go?

If you could all provide your experiences I would appreciate it.

Thanks,

Mike
 
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It is possible that the water pump that was on the car may have been incorrectly rebuilt or the impeller (thing that circulates the water that looks like a fan blade) may have been bent.

The best way to find out if the water pump between the 1978 302 and the EFI water pump are the same is by asking the parts place what the stock number of the two pumps is. I do this from time to time with parts between the Fox Body Mustangs I have and other Fords I have.

Rotation of the water pump could be an issue but I know I had a "reverse rotation" water pump in a 1985 E150 van I used to own because the fan clutch said right on it REVERSE ROTATION with an arrow on it. It was really neat, I thought I would pull a flex fan off of another van and put it on the 1985, When I got done I was standing in front of the van with the engine running and the air was blowing out of the engine compartment, through the radiator, and was blowing on me instead of the engine.

When I pulled a later EFI timing cover off of a later model motor that is in a 1968 Cougar XR-7 I have, and I compared it to the 1970 or 1971 timing cover I was putting back on the car, the only difference I could see was the mechanical fuel pump access hole was cast closed. I know the 1970 or 1971 water pump and the EFI water pump were different but I was going back to the V-Belt pulley system too and needed the older water pump to make it work.
 
The pee-hole in the water pump is there to let you know when the front bearing goes in the water pump, to the best of my knowledge. When it starts to go the water gets by the bearing and leaks out of the hole. This I have had happen on both steel and aluminum water pumps.

Oh yes, another thing, did you replace the timing chain when you did all of this work? If not, could it be slappin the back of the timing cover? My step-brother did some work on his 1967 Mustang wa-a-ay back in the 80s. When he tightened the upper timing gear retainer he didn't torque it, he just tightened it. It sounded like a rattle in the front of the motor for some time, and then the top gear loosened up enough to break the pin in the camshaft off and mess his motor up.
 
Oh yes, another thing, did u replace the timing chain when you did all of this work? If not, could it be slappin the back of the timing cover? My step-brother did some work on his 1967 Mustang wa-a-ay back in the 80s. When he tightened the upper timing gear retainer he didn't torque it, he just tightened it. It sounded like a rattle in the front of the motor for some time, and then the top gear loosened up enough to break the pin in the camshaft off and mess his motor up.

I did not touch the timing chain. Reason being was that since there was no problem with it prior I decided not to mess around with it. Thanks for reply.
 
The best way to find out if the water pump between the 1978 302 and the EFI water pump are the same is by asking the parts place what the stock number of the two pumps is. I do this from time to time with parts between the Fox Body Mustangs I have and other Fords I have.

That is a good idea, I will try it out. Thanks.
 
Did you use the original timing cover on that block, or switch to a later part from an EFI 5.0? I recall reading that there are certain combinations which should be avoided (some other more knowledgeable folks have posted the details here in the past). If you have an unintentional parts mis-match, you might have cavitation within the front of the cooling jacket.

That might not produce the "loose marble" sound, but it could possibly contribute to pump impeller problems.
 
Did you use the original timing cover on that block, or switch to a later part from an EFI 5.0? I recall reading that there are certain combinations which should be avoided (some other more knowledgeable folks have posted the details here in the past). If you have an unintentional parts mis-match, you might have cavitation within the front of the cooling jacket.

That might not produce the "loose marble" sound, but it could possibly contribute to pump impeller problems.


When I did the swap I did not touch the waterpump or timing change cover. So everything had remained the same since I was running the carb.

Your suggeston about certain mismatching combinations is interesting though. I would love to hear anyone elses opinions or thoughts on this.

Can anyone else chime in? I would appreciate your opinions.

Thanks,

Mike