Okay so this seems weird to me. I just finished building a 400 for my 1980 F-150 4x4 C6. The entire engine is brand new. I built it to the specs of that hotrod article everyone is always buzzing about. Everything came out great, it runs extremely strong, and sounds incredible. When I got it all back together, I filled the radiator with the standard 50/50 coolant mixture, and just left it alone to let the air purge out. It sat for a couple of hours before I topped it back off and started it up. Then as it ran, I continued to fill it, (as it was circulating into the block). Of course after a the thermostate opened (180 degree) it stayed full and I put the cap on tight. After the engine was broken in, I shut it down to check everything out, and it starting making rather loud girgling sounds, and a clinking sound, almost as if someone was rapping on the waterpump with a screwdriver or something. It only did it for a few seconds, but scared the crap outta me. I thought it was just more air in the system trying to get out, so I let it cool down, and filled it up some more before starting it again. Now I've run it quite a bit since, and still, everytime I shut it down, it makes a LOT of girgling sounds. I put brand new autogauge gauges in it, and the temp reads 180 - 190 degrees. So I know its not running hot, but it still girgles, sounds like the coolant is boiling inside the block. Anybody have a guess why I'm hearing these sounds? Am I just worrying about nothing? If its running cool... what could be wrong? Is it possible its still got air in it? Thanks in advance for your help!!!

SteveT

 

When you shut down, the heat from the engine has no where to go but the water in the block. Since your engine is not running you can hear what takes place - your thermostat opens letting coolant by.

 

What you are hearing is not un common. You may still have trapped air in the block. It may take several days to `purge it`. OR go for a long run to help it along. over the next few days you will notice the collant level droping when it is Stone cold in the morning.. fill to the proper cold level.

OLD TRICK >> I drill a 1/8 hole in the thermostat flange to allow `gass/air` to vent to the radiator side ..

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72 F-250
ICQ#6030753
http://clubs.excite.com/comm/area/pw/welcome/main.asp?cid=188005&auth=

 

just a tought. as you have been running the engine, have you turned your heater on so the coolant can circulate and get the air out of the heater core?

 

First, whenever I put in a newly rebuilt motor, I always put in a new radiator. Otherwise your just circulating old radiator gunk through a new motor. (Kinda like putting a used oil filter on.) Next, did you start filling the coolant with the top radiator hose off of the motor? This allows air to escape as the coolant is filling. Getting the air out of the heads is the hardest part because they are the highest point of your motor. Watch for white exhaust smoke to make sure you havent warpped a head. Compression gasses may be bleeding into the coolant passages! Hope not! Does your overflow tank fill up, or "puke" on the ground after you shut it off? I dont mean to scare you, but Id hate to see your motor completely ruined!

Nathan

 

First, thanks for the responses! There is no white smoke indicating a warped head. I had them shaved to insure straightness, so I know they were definatley straight when I put them on. I also have been keeping a close eye on the oil, for bubbles, or coolant getting into the crank case (nothing yet). Now, obviously if I heat it up to full temp, shut it off, and then open the radiator cap, it will puke all over the place. that would be normal, because the cooling system is pressurized... correct??? If I let it heat up to full temp, with the cap off, it seems to be circulateing quite well, and the level will slightly raise and lower in the radiator. If I bring the RPM's up and hold it there, the level will drop quite a bit (I would asume because its circulating into the engine faster than it is returning to the radiator). Then when I let off it will come back up to the top, and sometimes spill a little out of the radiator. It seems normal to me, but the noises when I shut it down seem odd. I had a pontiac before that I put new heads on and didnt get the right head gaskets for it, when I cranked it over, it would VIOLENTLY force coolant out the radiator, I couldnt even run it. So I would think if my 400 was having the same sort of problem, there would be a result more noticeable than what I'm experiencing.
??? When I put the motor together, there were cooling jackets holes in the head and intake, that the gaskets didnt have holes to match. I've seen other engines that were the same, so I thought nothing of it. Was that a bad move? Should I have cut out the gaskets to match? I've never heard of anyone having to do that before. This weekend I'm going to pull the intake and heads off my old 351M and see if it had cooling jackets that were also blocked off by the gaskets. Okay guys... thanks again.

Steve

 

I hear the same noises, I thought that maybe it was the pressures equalling out between the block, radiator, and over-flow tank. It seems louder at times than others.
Out of curiousity, what specs did you rebuild this 400 to?? comp. ratio, cam, etc....




SEANSTER 77' F150 XLT 2WD 400 C6
Edel.cam,intake
CARTER 625 AFB

 

Seanster, the compression ratio should be somewhere near 9.0:1 I used a CompCams extreme energy camshaft that has duration of 224 degrees intake and 230 degrees exhaust at .050. The cam has .524 intake lift and .529 exhaust lift. 110 lobe seperation. The heads were shaved for straightness. I ported/polished and port matched the heads, and intake. I used the matching compcams double coil springs, and matching lifters. It was bored .030 and I used speed pro power forged 8.5:1 pistons. It runs fantastic... and is amazingly strong. It really goes like hell, and believe me I have had a LOT of fast cars. I'm amazed with this motor, its incredible. I'm just really nervous about these noises. I havent been running it much... just been trying to figure out what problem there may be... if there is in fact a problem. When I run it up to full temp and shut it down, there is a thumping sound in the cooling system that is so strong, you can actually feel it in the floor boards!?!?!?! Just doesnt seem right to me!! I'm getting quite frustrated with it. Does yours make noises to this extreme? Any thoughts are greatly appreciated. Thanks!

Steve

 

Steve as far as the gaskets go all of the jackets won't line up with the gaskets. Your gaskets should have been marked on one end something like " this end toward front of engine ." Also your two gaskets are identical. Therefore when you put the gaskets on the lettering on the gaskets should have been up on one side and down on the other.

 

About a year ago now I rebuilt a 400 and had the exact same problem so I wrote a message about it here. Someone told me that they had put the head gasket on the passenger side on backwards and it made the coolant passage about half the size it should be. The symptoms were exactly the same, a kind of popping noise and the upper radiator hose would sort of shake. Sure enough I took off the passenger side head and the gasket was on backwards, I never would have figured it out if it wasn;t for this site. I hope this can help, Good Luck!

 

Thanks for the info guys... I'm fairly convinced that I must have a gasket in wrong. Tomorrow I plan to tear it down and check out the head gaskets, I'm really hopeing that I find one screwed up. It would be nice to know for sure what the problem was. I'll post back, and let ya all know how I make out. Thanks again for the help!!!!

Steve