trouble stay cool.. (truck and me!)

[BiggSixx1970]

Alright guys, I've been fighting this beast for weeks now I just can't keep my truck cool, It just keeps overheating and I don't know what to do..

This all started a few weeks back when I decided to replace my original hoses and flush out my radiator, replace the thermostat, this went good without a hitch, new hoses look good.. Well I noticed my water pump started weeping, oh joy, but that was easier than expected.

I replace the water pump in what felt like minutes, filled the old girl back up, fired it up to take it for a test run and it started over heating. My radiator didn't appear to be flowing right.. I wanted to replace the old radiator anyways because it was kind of beat up and had a couple pinholes and some corrosion.. Soo, I have a friend with a couple spare radiators at his place a 3 core and a 4 core, that he was going to use in is 455 '70 buick skylark. It drops right in, easy as pie, once i figured out some size variables with attaching my hoses I filled her back up and went for another test fire..

It overheats again this afternoon

The rundown.. I replaced all of my heater/radiator hoses, replaced my thermostat, replaced my radiator and upgraded to a 4 core, and replaced my water pump, and flushed the engine the best I could yet the old straight six still is overheating.

Do I need to bleed the system? If so how do I do that? I primed the system the best I cold by making sure the hoses were full, I also stuck a garden hose inside my water pump and blasted a bunch of water back into the water-jacket.. I just don't know what to do now, or where to start? I was thinking about putting in another thermostat in case the new one is bad. It's a 250 straight 6, if anyone needs pictures I can take some. I just don't know what to do now, I'm reaching the limits of my mechanical know-how

Thank you all for your time! Ya'll are awesome

[Andy4639]

My first suggestion is fill it up and then get the front of the truck as high as you can u may have a air bubble in the system and it want cool down until you get all the air out.

Do u know the radiator was good since it was sitting around your buddies shop. there could have been debri inside it that is clogging the flow up.

[BiggSixx1970]

Originally Posted by Andy4639

My first suggestion is fill it up and then get the front of the truck as high as you can u may have a air bubble in the system and it want cool down until you get all the air out.

Do u know the radiator was good since it was sitting around your buddies shop. there could have been debri inside it that is clogging the flow up.

It is a used radiator that he bought from a guy that has a small shop, the guy he bought it from said it was good, but you never know, to my upon first inspection it looks just fine, it's clean, has new petcock. When it was in my friend's possession, it just sat in a corner on the floor of his shop waiting to be used, shouldn't have anything more than a little dust inside it maybe, before I hooked it up i ran water through it the best I could

[Tom Vogel]

Is that a new radiator. If not, make sure it is profesionally rotted out, not just "flushed" at home as it were.

[Jon01]

I've found air pockets in several different vehicles.
My scout was the worst as the way the upper host/t-stat housing is set up it's actually higher than the radiator cap.
Easiest way to push an air pocket out in my experience is to take it out and flog it good. That will push the pocket out 90% of the time.

[BiggSixx1970]

Originally Posted by Jon01

I've found air pockets in several different vehicles.
My scout was the worst as the way the upper host/t-stat housing is set up it's actually higher than the radiator cap.
Easiest way to push an air pocket out in my experience is to take it out and flog it good. That will push the pocket out 90% of the time.

The thermostat housing is on top of the engine, I'm at my girlfriends right now, but from what I remember the thermostat housing is probably the highest point on my engine.. Don't quote me on that cause i'm not lookin right at it though. I mean, I thought about taking it out and pullin her hair (truck not the girlfriend, lol) but i didn't want to fry the bearings in my new pump or overheat anything too much

[PanelDeland]

My first suggestion is to get a thermometer and check to see if it's actually overheating.You may have a sender/gage/light problem since everything else is new.Also take the cap and have it checked.Watch when it's up to temp to see if the water is actually flowing.Also,look thru the fins and make sure air can flow thru them.

[BiggSixx1970]

Originally Posted by PanelDeland

My first suggestion is to get a thermometer and check to see if it's actually overheating.You may have a sender/gage/light problem since everything else is new.Also take the cap and have it checked.Watch when it's up to temp to see if the water is actually flowing.Also,look thru the fins and make sure air can flow thru them.

Ya know, It doesn't really seem to even be getting 'that hot' in the radiator, it warm, but it's not as hot as the temp gauge says. I have a gauge, no light. I was thinking about replacing the sender too to be safe.. The engine does appear to be getting hot though, judging by the smell of the grease warming up on the outside of it

[trac209]

Originally Posted by BiggSixx1970

Ya know, It doesn't really seem to even be getting 'that hot' in the radiator, it warm, but it's not as hot as the temp gauge says. I have a gauge, no light. I was thinking about replacing the sender too to be safe.. The engine does appear to be getting hot though, judging by the smell of the grease warming up on the outside of it

If you have a "hot" engine and a warm rad you have something wrong deffo. A blockage or bubble in the system someplace not letting the coolant flow properly. Start by confirming the temps before you proceed
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[Ol Blue K20]

You didn't accidentally put a reverse rotation pump in did ya
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[BiggSixx1970]

Originally Posted by Ol Blue K20

You didn't accidentally put a reverse rotation pump in did ya
Posted via Mobile Device

Not to my knowledge, I just got the one of two options at the o'reilies's a couple blocks from my house, $20 for a reman, $26 for new, I got the new one

[nos81z28]

Is your fan clutch still good?

[cdowns]

if u put a thermostat in wrong it will ovraheat

[BiggSixx1970]

Originally Posted by cdowns

if u put a thermostat in wrong it will ovraheat

Haha, no sir, I didn't put it in upside down, Put it in the same way as I took the old one out. I'm a rookie but I know not to do that >.>, thanks though!

[BiggSixx1970]

Originally Posted by nos81z28

Is your fan clutch still good?

There is no fan clutch, there is also no shroud on the 250 Inline engines, There is lots of airspace around the engine and the water jackets relatively thin walled so they didn't use fan clutches or shrouds until you got a v8, to my knowledge

[BiggSixx1970]

Got her fixed! Had more air than coolant inside the engine.. Air gap under my thermostat that was insulating it from the fluid temp not allowing it to open up. Thanks guys! She's stayin' nice and cool, no shroud, no fan clutch, just straight fan and a new big block radiator!

[Andy4639]

Cool is Hot which means Cool!