I have a problem with water blowing out of the new intake. I get it full and running great then the same plastic plug blows out.. the one in the back left side blows off and spewes eveything all over again.. what's up with this.... ???. New intake and made sure that all the parts and piees were ok so I'm jjust not sure what to do here. please help again guys and gals.. thanks for all your input too. I can't imagine why they would even put a rubber/plastic plug where it is and it comes with a brank new clamp but lyou can actually pull it right off. I did put silicone on it this time but it blew off anyway... at with end now.... thanks

 

Ok, Tried the new rad. cap.. still the same problem. This time it actually blew the rubber cap apart. I had just water in it to flush it out and ran it for about an hour with the new rad. cap in place and I know for a fact that the old intake did not have that 3/4" port coming out of the back like this. I pulling y hair out over this one ..lol and as always thanks for help.

 

Here is something you can try.
Get hold of a cooling system pressure tester, and just connect it to the radiator with no pressure applied. Start the engine and watch the pressure tester gauge.
If the pressure rises some when heating the coolant,that is normal. If it rises quickly , you could have a head gasket problem where compression is getting into the cooling system.
Compression pressure can reach 150 psi
Cooling system pressure should relieve around 15 psi
There has to be a reason for it blowing off.
Were any head gaskets replaced? If so , were the gaskets compared to be exactly the same and installed correctly?

 

No headgaskets were replaced or anything like that just all of the sudden bammm running greaat for months then this happens where the intake manifold started leaking then I removed it and put a new manifold on it. Now even looking at the pictures at the auto parts store looking at I can planly see that plug in place and not blowing off. I just can;t understand that...
so this morning I went from that plug into a tee for the front of the manifold so this should tess me quite a it

 

How about a little more info ?
Where did you notice the leak first? EXACTLY ?
Was the reason for the leak determined? Did you find anything wrong with the original intake manifold to answer why it leaked?
The reason I am asking these questions is ; you may be repairing the result , which is the leak, but may have missed the cause for the leak. Is this a possibility?
As stated earlier, there has to be a reason that plug is getting blown off. Where is the pressure coming from ?
Did you attempt to run the engine with the radiator cap on, but loose and what was the result?

 

Did you ever find a solution to this problem? I’m dealing with the same issue. Whenever I’ve had to put a little more gas on the peddle, it blows off and leaves me stranded.

 

There are a few reasons for the pressure to build up and blow off the cap.
Just replacing it does not find the cause . The method to determine the cause was listed in a previous post.
If the equip is not available , pretty sure it can be rented, but you still need to know what to look for and be able to determine why the pressure is blowing the cap off.

We don't know if the engine ever overheated, which if it did, could have warped the head, blew a head gasket or worse caused a part of the engine to crack when cold coolant was added. A good shop should be able to pin down the cause .