5.7/260 hp gm longblock overheating

[joeclark]

I have a overheating problem the first time out this year it ran great 2nd ime out it overheated (went up to 240) i shut it down right away I changed the thermostat.still overheats then i changed the impeller in outdrive still overheats took off waterpump and it looks good have a new one to put on but did not yet took off raisers they look ok went to take off manifold and bolts were lose will this cause it to overheat and miss when it gets hot ???? also did check dipstick but did not finf water in oil can lose manifold cause it to over heat ???????thanks

 

[Bt Doctur]

Re: 5.7/260 hp gm longblock overheating

Thermostat?????
Is there water reaching the therm housing?

 

[joeclark]

Re: 5.7/260 hp gm longblock overheating

i did not check that but when i changed it there was water in housing

 

[zbnutcase]

Re: 5.7/260 hp gm longblock overheating

Loose manifolds will only cause an exhaust leak, not overheating. Clogged risers will though...

 

[joeclark]

Re: 5.7/260 hp gm longblock overheating

i am going to put every thing back together and start from there can some one tell me what to check for and in what order. i don't know what else to do. i think if i go step by step i can find the problem .when i did change the inpeller it was in one piece. some one please help me

 

[Bt Doctur]

Re: 5.7/260 hp gm longblock overheating

A blown headgasket could inject hot gas into the cooling system and 240 is plenty hot enough to do that.Remove all the plugs, carb wide open, disconnect the + wires from the coil. crank engine from slave solenoid about 4 revs.record reading