need help 3400 v6 engine cooling

jordanbmx

jordanbmx

Club Member
3400 gm engine, start the car, it running for 2 minutes tops, coolant gauge starts to go above normal, heat is ice cold. Pushes all antifreeze into the overflow and out of the lid. Loosen the radiator cap and it sucks it all back in, add what coolant was lost from leaking out of the overflow lid. Car has heat, temp gauge goes down and runs normal. Car has lost no power at all what so ever. Intake gaskets were changed about 20k miles ago. Internet search says head gaskets but their is no anti-freeze in the oil, no performance loss or odd exhaust smoke. Im stumpted. Ideas?
 
My girls car did that and I flushed the heater core and its been fine since. I used a garden hose and sprayed it till the water coming out of the bottom radiator hose was clear.
 
you've got a plugged heater hose or core. take off both heater hoses and like randy said flush till you get clear water. if not you'll need to swap out the heater core. if you end up needing a new core hit me up, I can get a a brand new one at a discount thru the wife. -Bill.
 
head gaskets..... just went thru this ....after putting intake gaskets on it ,the customer overheated it one to many times ,
although if the coolant goes low i usually have to bleed the system, you cant just pour coolant in it and throw the cap on like old schools.
if it pushes coolant out of the over flow there is somthing causing it (pressure) or bad (radiator cap)


.i did intake gaskets on a car ...i did not diagnose the problem someone else did, they just wanted intake gaskets done
finished job , car ran fine ,heat was mint, everything seemed ok, 10 mins later they call and say its still overheating,
they bring it back and it has no heat and the overflow is overflowing.
of course its my fault!!!!!!!!i had to tear it all back apart even further it sucked , but its pretty easy to do
the reason the heat goes away is because the exhaust pushed air into the cooling system and the heater core gets a air pocket and cavitates

they make a tool that looks like a turkey baister, you put a solution fluid in it and put it above the radiator tank with the cap off and squeeze it. the fluid will change color if there is carbon monoxide(exhaust)present
 
Do i need to mention that about 2 months ago i put a bottle of barsleak in it, for a leak i couldnt find. then a little rubber crossover hose finally gaveway, (that was my small leak) now i have that stuff flowing thru the system
 
im pretty sure the 3400s had head gasket issues. are either of the radiator hoses over pressuriezed? what is the coolant system pressure when running at operating temp?

you may have a blocked hose or core but i sure wouldnt rule out head gaskets.
 
We have had the head gaskets replaced in every one of the 3400's in our fleet as well as my personal vehicles.
 
straightshotperformance said:
head gaskets..... just went thru this ....after putting intake gaskets on it ,the customer overheated it one to many times ,
although if the coolant goes low i usually have to bleed the system, you cant just pour coolant in it and throw the cap on like old schools.
if it pushes coolant out of the over flow there is somthing causing it (pressure) or bad (radiator cap)


.i did intake gaskets on a car ...i did not diagnose the problem someone else did, they just wanted intake gaskets done
finished job , car ran fine ,heat was mint, everything seemed ok, 10 mins later they call and say its still overheating,
they bring it back and it has no heat and the overflow is overflowing.
of course its my fault!!!!!!!!i had to tear it all back apart even further it sucked , but its pretty easy to do
the reason the heat goes away is because the exhaust pushed air into the cooling system and the heater core gets a air pocket and cavitates

they make a tool that looks like a turkey baister, you put a solution fluid in it and put it above the radiator tank with the cap off and squeeze it. the fluid will change color if there is carbon monoxide(exhaust)present
Click to expand...
This^^^ just had it happens on a venture van. Same exact things happening that you described.
 
Well, flushed the heater core, radiator, and engine. Filled radiator back up with coolant, started the car and let run and run and run, one bleeder screw is broken and one isnt. The temp gauge was alittle above normal but no heat. The car is parked for the day. Having my gf take me to work and tomorrow morning im gonna buy a new bleeder screw from the dealer in hopes that being able to bleed the air out of the system will fix my issue.
 
i have had terrible times with air bubbles in GM cooling systems... sometimes they will sneak to the heater core and stay... jack the car up so the radiator cap is at the highest point, take the cap off (when cooling system is cold) and warm the car up... rev it with quick burps of the throttle as well... sometimes the bleeders dont take every air bubble out.
 
Had the same symtoms on four different GM cars that used DexCool antifreeze...had to replace head gaskets on eachIMG_0820.JPG
 
head gaskets do seem to be fairly common, sometimes they are run with problems like you speak of and then you start to see cracked head issues.
 
well i put the new bleeder screw in, bled the system. knock on wood its fine now. drove it to work and around... no issues. The the drivers window track broke. anybody want a 2001 monte carlo lol
 
You must log in or register to reply here.
Back
Top