overheating

[rckclmbr]

what are all the causes for over heating?

bad thermostat, electric fan not coming on, water pump out, clogged system,

ok well i have taken care of all these.

what else might be the problem?

[Digger87xj]

plugged radiator, blown head gasket,

if it is a 87-90 xj, the coolant recovery bottle and cap...

[red91]

you left out fan clutch.

[rckclmbr]

the coolant recovery bottle and cap are new. it is a 90 by the way. how would i check the radiator and blown head gasket?

It over heated the length of 4 blocks. i had to jump start it so it wasn't hot from before. i just drove around 2 blocks and parked it. when i got back coolant was spewing from that bottle

[Digger87xj]

you left out fan clutch.
yep fan clutch will do it too

[Digger87xj]

the coolant recovery bottle and cap are new. it is a 90 by the way. how would i check the radiator and blown head gasket?

It over heated the length of 4 blocks. i had to jump start it so it wasn't hot from before. i just drove around 2 blocks and parked it. when i got back coolant was spewing from that bottle
sounds like the head gasket is in fact blown. the easiest way is to do a leak-down test on each cylinder. that involves applying commpressed air to the cylinder at top dead center and seeing if it bubbles out the recovery tank.

[rckclmbr]

if i had a blown gasket wouldn't i be getting some white smoke/steam from the exhaust. i know when i blew it in a taurus i had a fully functional smoke screen behind the car for miles. right now i am running ritch and getting black smoke.

[rckclmbr]

ding ding ding and the winner is red91inwa. it was the fan clutch. after i had replaced everything else and it was still over heating i put a new fan clutch in and its all good now.

but i do want to say that that was the biggest pain in the a$$ ever. i never knew it would take me so long to get 4 bolts out.