overheating update
 

okay, i guess i forgot to mention this before, but the truck will not ever overheat while it is in park or idling. it will get up to temp, the tstat will open and the fans come on. it is only overheating while the vehicle is moving....

what could cause this??? transmission?
i figure....
the tranny is getting really hot, heating up the engine from the back to the front, and thats what causes the engine to overheat, and then the front and top of the engine heats up and finally the tstat opens up??

it makes sense to me....

Lower rad hose is collapsing when engine starts to rev. It's happened to me. Matt

is your timing really advanced?

i dont think the trans could heat up enough to make the engine heat up... You got air bubbles in the cooling system? maybe you need to burp your coolant lines.. that would explain a spike in temp's at certain times, when the air bubbles are @ the sensor...

a lean air:fuel ratio and really advanced timing will make an engine run hot...

pc

Sounds crazy,but I'd bet your fans are causing the air to "dam up" in front of the radiator.Try turning the fans off while cruising at speed.I know it sounds nuts,but it happened to me.

11 degrees initial timing, about 35degrees total.

the fans have nothing to do with it. it didnt do this before i got my gears.

eric, i tell ya what.. lets swap your engine/trans into my truck and see if it still happens.. :gi:


btw.. what happend to the girl intrested in a job? she change her mind?

come bring me the app. i havent had a vehicle to drive over there to pick it up for her.

Have you checked the lower radiator hose yet? If not check it!

how do i check it? it looks to be okay

I would replace it with the lower radiator hose with the spring inside, that prevents it from collapsing.

Looks can be very deceiving!! If you have not replaced the hoses in the last 3yrs or so i would do it!!

Hey how do you guys burp the air outta the cooling system? Later Mike

rock the truck thats what i do and it works! later shane

new upper and lower rad. hoses put on with the new engine last april. new heater hoses installed about a week ago

Rev the engine while looking at the lower rad hose if it colapses its eather the spring in the hose or a pluged rad.

Or just a plug in the system somewhere, or else something else isn't right. At idle, it won't overheat, because it doesn't have enough timing to do it, but under load it would. It also could be, you're running too lean, but usually, running that lean would show as your headers glowing red.
Eric, do you think your block is bored more than .030 maybe? Maybe it's bored over like .080, and the cylinder walls are so thin, it's boiling your ****.

[good to know mine came with a 2 row and still has it in there.]

355 sbc,10:1CR, Holley aluminum heads, Lunati cam(235/240@.050 - .490" lift),full MSD ignition

Eric, you are trying to run that engine combo with lower gears using a 2 row radiator? Electric fans or not that 2 row ain't gonna cut it especially with even lower gears than before. And it was in the truck when you bought it in '01? I'm surprised it cooled it before the gear change. The 4 row is more for big block applications but the 3 row just might be what you need.
With the lower gears installed the engine is steadily running at higher rpms than before requiring a cooling system change. It cooled ok before the gear change and that's the only change made? The engine is building more heat than that 2 row rad can handle now at hightway speeds. There may also be some blockage in that rad making it worse.
I had a 2 row rad recored with 3 row for $125 for my 78. Since then I bought a brand new 3 row rad for my 85 for $150. They're not that bad. Shop around.

Electric fans?
Gotta fan shroud on it?
That new lower rad. hose have the spring in it when you installed it?
Sometimes they don't come with a new spring......they want you to reuse the old one.

i spoke wrong, the radiator IS a 3 row.

when i changed the rearend out, i also changed the tstat because the old one was stuck open and always running really cool. i've changed it twice since then and it still over heats.

the elecctric fans worked fine before and shouldnt be giving me trouble now. they come with a built in shroud.

no, the block is bored .030 over for sure.

the lower hose doesnt have a spring in it, but i have revved it to about 5500 while watching it and it never moved.

Okay, let me put it this way. I'm driving about 70-75 on the highway, turning about 3500 rpms continually. the guage reads about 180-190. at any random time it will shoot up to 210 and then head over to 260 and stay there for maybe 10 seconds AT THE MOST. then it will drop back down steadily to about 180-190. the whole time it is rising, it smells like antifreeze.
the same thing happened one day while i was getting off the highway coming to a stop. so it doesnt just do it while its revving up.

but no matter what i do, i can let it idle for 30 minutes and rev it up in park and the thing will run perfect.

ive got a real stupid idea but hey at this point maybe anything will help... Are you using the same brand of thermostat fromt he same supply house over and over when you change them... it could be possible they have a defective bunch of springs in them or something.... ive bought electronic ignition modules from a local parts guy three different KEM brand pieces and all three were bad it turned out to be adefective lot of them.. id try getting a genuine delco thermostat and get it at a totally different supply house... if thats the problem id go back and tell the guy you originally bought them from...
i know its a shot in the dark but hey strange things happen sometimes

Either you got a bad one or its upside down. Put a new one on.

also have ya flushed out the cooling system lately?? could be some crud in there ?? im just grasping at straws now but hey

the one that stuck open orignally came from o'reillys. i replaced it with a highflow 180 mr. gasket from jegs(the same one Ryan raves so much about). it overheated with it so i replaced it with another one from o'reillys and it did the same thing and is the one i have in there now.

so 2 tstats doing the same thing.

and no, i havent flushed the system lately.

Replaced it 3 times? I would guess that is not the problem. If you smell antifreeze you have a leak some place. Try looking at the sensor/ sending unit. It sounds like you could have more than one problem but maybe if the leak is fixed the problem will go away. If the sensor was faulty/ leaking you could have erroneous readings.

the sensor is good. havent changed it since i put it in originally in april. its not leaking anywhere around it.

with my luck i probably blew a head gasket!! :ww:

edit. my truck wont start now because the battery is acting like its almost drained AGAIN.

my friend bought a 96' BMW 328is the other day. i like it a lot. i think i might sell my truck and buy something like his car......