New Radiator Still Coolant Loss
 

Just put on a new radiator yesterday. drove it home from my friends house let it cool and checked the level in the rad. it was low so i topped it off and went to town. got back home popped hood and it overflowed from the overflow tank. overflow tank was full. drained overflow tank so coolant was in between low and full mark. topped rad off again. drove to town today overflow tank level is normal but rad was 3-4 cups low. its losing coolant worse than the old one. i checked and there are no external coolant leaks anywhere. checked the oil and it was fine. i checked all my plugs and they were all normal color except the very back one which the electrodes were solid white. could i have bought a faulty radiator or possibly losing coolant through the valves or into the combustion chamber?

so i just topped it off again and left the rad cap off and turned the heat on and started the truck. it took 30 sec and it started overflowing out of the radiator. put cap back on and let it warm up and overflow tank started filling way up. could it be a clogged radiator?

Did you purge the system of trapped air after you replaced the radiator? When you "purge" it of air, coolant is going to be pushed out of the radiator since the cap is off. Did you replace the hoses when you put in the new radiator? What ratio of anti-freeze/water are you running?

Also sounds like it could be the HG leaking, so combustion gases are pushing the water out and/or water is leaking into the cylinders.

sounds like a headgasket. you're burning coolant in that last cylinder it sounds like.

Maybe you have a blown head gasket. My 88 was blowing water out the exhaust, none got into the coolant. Take the spark plugs out and shoot some air down each hole, water might come out one of them. Also, inspect the plugs, broken ceramic is a sign of water.

when we first put it in and filled it up we turned heat on and started it. it sucked in the coolant as normal and we topped it off one last time. im using prediluted 50/50 mix. all hoses were in good condition since i replaced them last year. how exactly do you purge it?

the old radiator was leaking so i used the stop leak tablets in it. but i wasnt losing as much coolant with the old as i am with this new one. that makes me wonder if its clogged

Try a ratio of at least 60/40, anti-freeze/water, respectively. Anti-freeze not only lowers the freezing point of water, it increases the boiling point. if your coolant is boiling, it will expand and shoot it into the overflow. You probably have a lot of air in the system, that could be why you "lost" coolant in the radiator but the overflow was the same.
Its possible you clogged something with those stop-a-leak thingies. IMO, they are crappy and just a band-aide.

To purge the system of air (22r/-e), take the radiator cap off and turn on the heat. Run the truck, best results with the front end of the vehicle up. Once the T-stat opens, you should get some air to be pushed out through the cap, and of course coolant will spill over. Add coolant as needed. It takes a while to get it.

Assuming we're not talking about a head gasket, what he said about getting the front end up is critical. These things suck if the radiator cap isn't the absolutely highest part of the cooling system. I had mine on my sloped driveway, with the front end up on ramps to get the air to purge completely.

Sounds like you still got air in the system.

They make a radiator kit for getting the air out of the system. Has a funnel with multiple fittings for various radiators. You put it on/in your radiator top hole, fill it up with coolant until it is full, with some up in the funnel, run the truck, let it burp/bubble itself to get all the air out and then it is good to go. Even has a nice little stopper you put in from the topside to keep you from wasting/spilling coolant when you are done. Done several this way.

:guitar:

What about the thermostat ?, try replacing it and see if that helps.

Take off the rad cap, jack the front end up and start the truck cold. Let it run till its at running temp, by then there should be quite a few bubbles comming out.

If there is a ton of coolant comming out there might be exhaust gasses pushing it out..

well, topped it off again last night ran it for about 15min and the overflow tank went up to the full mark and no further. checked it this morning and the level in the overflow tank did not go back down. checked the rad and it was half a gallon low. there was still alot of pressure in the system and the upper hose was still firm. i guess it is a headgasket issue.

I found a funnel that fit perfectly inside the mouth of the rad and did the same thing and it worked very well. Just kept adding until it didn't burp/drop any more.

ok so i jacked the front of the truck up and turned heat on. burped the system again. i noticed when i pulled the throttle lever the coolant would rise and spill out of the rad. after burping the system put cap back on and let it run. overflow tank filled all the way up but didnt overflow. i have come to the conclusion its a head gasket isssue. maybe i ran it hot but if i did my temp gauge didnt let me know.

My radiator would errupt like that when I burped the system. I just did the headgasket a few thousand miles ago. Could it still be airpockets, or it's definitely a headgasket problem? I havent experienced any coolant loss or headgasket-coolant-burning smoke problems.

checked the compression and all were low. first and second cylinder readings were 130psi, third cylinder reading 120psi, and last cylinder was 110psi. compression check was done when engine was at operating temp and throttle wide open. manual says minimum psi should be 128 and maximum psi should be 171. this sucks.