OVERHEAT ? pls HELP . chevy 454 c20 81

[sammysamm]

was driving today and truck started blowing steam from the bottom of cooling fan or hose of cooling fan. only when truck heats up. but not really drivable now without steam shooting or water/coolant dripping from the cooling fan/pump area in center of fan wheel.


could i have no coolant and need to refill? i can post a video of problem to help. please help me and ask any questions you need to diagnose further. truck has no problems until now and i have done basic maintenance.

car starts and runs fine.. and i have no problem other than steam blowing out coolant leak. (makes car undrivable tho... and im worried the engine will over heat or more damage will be done by driving it.

[75_chevy]

Is it leaking from a hose? Replace the hose
Is the radiator cracked? Fix or replace it

[JohnnyPopper]

Keep as much water in it as you can till you find the leak.

First sounded like the pump, has a weep hole on the bottom side, but it usually doesn't steam when your leaking from there. Unless you're really low I guess.

Find it, fix it, do it when it's cool so you don't get burned.

[sammysamm]

LEAK.it is coming from the pump area for sure but looks like the bottom side? of the pump or the hose that connects to the pump. its is possibly very low with fluid. i have not filled or checked radiator in over a year.


Im going to post a video and please check it out and see what you think. give me a few hours. thanks for the help guys.

if it was a hose that broke how would i know? at first when it broke (today .. it sprayed everywhere in engine compartment. looks to have started from the fan center area hose connector.(water pump) im not sure if i can trace the exact leak area but i will try.

[sammysamm]

Is it leaking from a hose? Replace the hose
Is the radiator cracked? Fix or replace it

more to my post above..


radiator is not cracked. water pump or area near fan center may be cracked if thats possible . im thinking its most likely a hose. they have not been replaced since 1981.

can ANYBODY post a link to how i refill radiator.(sry)  its my first time doing so. is it ok to use water for now until i find problem source and solve.

yes im waiting until engine is completely cool until i touch anything. i see the cap that says STANT radiator under pressure 15lbs on top of radiator. do i just fill it? 

ps my thermometer or gauge in truck does not read overheating it reads middle of gauge (permanently) .. maybe thermometer is adding to problem or not working as well. but it seemed to be working fine last week.

thx

POSTING pics/vid shortly

[75gmck25]

Plain water will work fine for now while you are troubleshooting, but its won't take long to start developing rust inside if you continue to use plain water.   GM recommends 50/50 antifreeze and water to cover all temperatures, but even a light mix of antifreeze will reduce rust formation.

Remove the cap and fill radiator to the top with water.  Then start the engine and it will suck the water into the engine and you will see it drop down.  Continue to slowly add water until its just barely at the top of the radiator neck, and put the cap back on.  Fill the overflow bottle up to the cold mark and let it warm up.  Then check for leaks.

Your sending unit gauge wire may be grounded or broken.  There should be a green wire connected to the sending unit, which is screwed into the driver's side head.  The sending unit is tucked up under the middle section of the exhaust manifold where its hard to see.  Original sending unit wires have a black heat protective sleeve over the last several inches to keep from being burned by the manifold.

You may also have a bad guage, since a broken or grounded sending unit wire usually makes the gauge go full hot or full cold.  Sticking in the middle is not common unless there is no power to the gauge.

[sammysamm]

ok im going to try in a few hours. thanks. so the over flow bottle has a leak and cannot be filled. a little hole worn on bottom edge near battery.

it has  been like that for a while.

how much of a problem is that? guy at jiffy lube said i can run truck fine as long as radiator is ok. without an overflow bucket. i guess i will need to buy and repair that soon as well.?

[JohnnyPopper]

It will run fine without the bottle, but it's good to have in place.

What it does is collect water that pushes past your radiator cap when it's real hot, and then when the radiator cools, it creates a vacuum that draws the water back out of the bottle.

The idea is that you have right amount of water at all times.

Try some JB weld on the bottle, you'll be good to go.

Did you find the Leak? Sound like the small hole right under the water pump shaft. If that's it, you will need a new pump.

[sammysamm]

johnny ---  yea thx for help. i think you said it right..  "Did you find the Leak? Sound like the small hole right under the water pump shaft. If that's it, you will need a new pump. "

im checking the hose area.(radiator hose)  it might be a crack in old hose.

it will have to wait untill tmrw to be looked at and i will come back and check in here.

thanks for help so far.

hopefully a new pump is not needed. i will post photo and video soon to better describe/diagnose.

[sammysamm]

First sounded like the pump, has a weep hole on the bottom side, but it usually doesn't steam when your leaking from there. Unless you're really low I guess.

Find it, fix it, do it when it's cool so you don't get burned.

OK. i opened radiator stant cap and the radiator was bone dry . right to the bottom. i filled it half way with water and ran engine for about 20 mins and did not see any leak yet.  IS IT POSSIBLE that radiator was just empty and low and steam caused it to spray out last remaining liquid?

i will buy some coolant today and fill the radiator up full and run the truck again to see if leak is still there.


it seems like it only leaked 1 time when the truck was hot (ran on highway for 30 mins) and i have not yet seen it leak again.

how long should i run the truck to get it hot enough to see the problem occur. also i think i may need to replace the thermometer/heat on gauges just reads in the middle no matter what . (seems like it does not work correctly.


i will check back soon. thanks for help.

[sammysamm]

https://imgur.com/a/UjXpjPO


PICS video above in link

[sammysamm]

https://imgur.com/jMhGKK1

[JohnnyPopper]

Thanks for the pics and video, was afraid I was going to see you lose your finger...

That spot isn't normally where you see a leak.

With the Stant cap back on, run it, with water topped off and see if you can duplicate it.

It might be that you ran her dry and she just steamed out wherever there was a place too weak to hold it in?

And yes, something is not working with your gauge. Do a search on this site, there's a lot of help with gauges.

Others might weigh in... 

[sammysamm]

ok so bad news. leak is for sure coming from pump area. it is leaking from directly behind the fan belt . i circled it in red. the pump must have a crack or something behind the fan belt. i have a video i can upload. of it. the pump is leaking just from behind the fan belt area.

you can see steam shooting from it.

looks bad and im guessing i will need to replace water pump/fan/.

probably just going to take it into shop. ps my finger was way far away from the engine at least 1ft. lol

[sammysamm]

from what it looks like im guessing the seal is old and worn out on the water pump. it seems to be leaking from that area. eg. in the space between the pully.. fan pully and the water pump .

tell me what u think. i can film video or any pics u may need to better diagnose. 

thx