Topic: overheatin on the interstate

[hotrod]

ok, so heres my problem, the truck runs great around town and when wheelin. But after doin 65 or so on the interstate or whatever for 10 min the gauge goes way hot. not quite into the red but its hotter than it should be.

Truck specs:
83 22r
33's with 4.10s
msd ignition, new thermostat, new radiator, all new hoses, and radiator cap.

[DFWFO]

do you have an electric fan on your rad? at high speeds it may block the wind flo. how fast are you driving? check all fluids, maybe your water pump too. the water pump is a rubber wheel and may be rotted, at high rpms it might not be effective. Just a few things to look at

[hotrod [OP]]

stock clutch fan. Speedo says 55 but Im doin 66. Im gettin passed by every 18 wheeler out there

[emsvitil]

A thermostat that doesn't fully open can do that...........

It should start to open at about 190 degrees

At 212 degrees it should be open at least 8mm

[jimbo74]

what brand of new thermostat are you using? stant replacements from the parts stores are

[DFWFO]

is your clutch fan loud? yeah dont buy duralast or any cheap crap like that, their thermos suck, along with other parts

[Rocksurfer]

An old weak radiator hose can cause this, it will collapse at higher rpm's.

[jimbo74]

An old weak radiator hose can cause this, it will collapse at higher rpm's.

he said all new hoses

all new hoses

[hotrod [OP]]

its the dual slug toyota thermo. straight from the stealership. its got all new hoses on it too

[jimbo74]

how is your heater running? have you tried turning on the heater?

the outlet for the heater, is right over the thermostat and sometimes it tricks the thermo into not openning right

[Rocksurfer]

Did you replace the fan clutch?

[hotrod [OP]]

how is your heater running? have you tried turning on the heater?

the outlet for the heater, is right over the thermostat and sometimes it tricks the thermo into not openning right

havent turned on the heater. its hot enough in alabama! and i got the dual slug thermostat cause the smaller slug opens at a cooler temperature to allow hot water from the engine to stay on top of the thermo therefore keeping it open.

Did you replace the fan clutch?

i have not replaced the clutch yet. ya think it could be the clutch even though it only overheats at speed? . . . i think at one point in time i tried to stop the fan to see if the clutch was bad and i couldnt stop it. . .

[emsvitil]

At speed the fan clutch shouldn't matter........

[hotrod [OP]]

thats what i was thinkin. . . im stumped.

[DFWFO]

slow down? drink faster? maybe that might work

[Rocksurfer]

Quit driving in reverse down the Highway. 



Use coolant instead of water.




I bet it's something silly stupid.




What kind of radiator.



Maybe at speed the coolant is traveling too fast through the radiator which will not give the radiator enough time to cool the coolant.


On the other shoe a blockage in the block that is reducing flow.

[jimbo74]

did you bleed the system after you replaced all that stuff? there may be an air pocket i nthere

[Marlin]

It sounds to me like a plugged radiator. Take off the raidator cap and try pushing the engine dip stick down the tubes in your radiator. If it goes in hard or stops before hitting the lower tank, it is time to take it to a raidator shop.

Also try driving your truck at 65 mph and then come to a quick stop. Shut off the engine and run your hand oner the fins of the raidator looking for hot or cool spots. This would also indicate a plugged core.

Marlin

[jimbo74]

It sounds to me like a plugged radiator. Take off the raidator cap and try pushing the engine dip stick down the tubes in your radiator. If it goes in hard or stops before hitting the lower tank, it is time to take it to a raidator shop.

Also try driving your truck at 65 mph and then come to a quick stop. Shut off the engine and run your hand oner the fins of the raidator looking for hot or cool spots. This would also indicate a plugged core.

Marlin

he said the radiator is new

[hotrod [OP]]

its a brand new stock 2 row rad. from napa.

Maybe at speed the coolant is traveling too fast through the radiator which will not give the radiator enough time to cool the coolant.

why would it travel too fast through the rad?

[Rocksurfer]

Most of the time it is due to not using a thermostat (yes Jim I know he has one)   Just throwing out thoughts that may cause this to happen for the most part. Have you tried to flush the motor yet? At this point I'd give that a shot and see what happens, if it was run with just water for a long time rust will have built up in the block and very easily could clog a perfectly good radiator within a short period of time JIM! Hopefully you didn't get one of those Korean radiators they tend to run hot.

[fordh8r]

Although it's a new radiator, has this thing been in the Alabama mud since replacing the radiator? Could the core have a buncha mud stuck in it? How about real dusty trails? Heavy dirt build up on the core can cause it to run hot too. How's the timing on this? Retarded, advanced?  Do you get full advance at high speed? All things to check if any of these apply. 


Just a side note....mine ran like this with a blown headgasket with no other signs of trouble for about 3 weeks until it finally got bad enough to tell. 

[Rocksurfer]

Although it's a new radiator, has this thing been in the Alabama mud since replacing the radiator? Could the core have a buncha mud stuck in it? How about real dusty trails? Heavy dirt build up on the core can cause it to run hot too. How's the timing on this? Retarded, advanced?  Do you get full advance at high speed? All things to check if any of these apply. 


Just a side note....mine ran like this with a blown headgasket with no other signs of trouble for about 3 weeks until it finally got bad enough to tell. 

I was thinking timing and the headgasket was in the back of my mind but I didn't want to just throw that one out there yet until he tried some other things. Anyways for your minds sake now get a leakdown test to make sure the headgasket is ok.

[fordh8r]

I was thinking timing and the headgasket was in the back of my mind but I didn't want to just throw that one out there yet until he tried some other things. Anyways for your minds sake now get a leakdown test to make sure the headgasket is ok.

  That's why I eased into it...

[DFWFO]

Its not a head gasket problem, and DONT FLUSH YOUR MOTOR EVER!!! not with bilstien or any like that, you will lose compression and shorten the life or your motor. and an engine flush would have nothing to do with this problem.

[DFWFO]

where is the temp getting read from? check and make sure the wire is not touching the exhuast manifold or that the coil that goes around it itsnt touching anything either

[hotrod [OP]]

I was thinking timing and the headgasket was in the back of my mind but I didn't want to just throw that one out there yet until he tried some other things. Anyways for your minds sake now get a leakdown test to make sure the headgasket is ok.

i havent touched the timing on it since i got it. the PO put on a msd ignition. if i can get ahold of a light ill check it. its ran like this ever since i got it so maybe the PO messed with it for some reason.

[BLACKDOG]

Its not a head gasket problem, and DONT FLUSH YOUR MOTOR EVER!!! not with bilstien or any like that, you will lose compression and shorten the life or your motor. and an engine flush would have nothing to do with this problem.

Why isn't it a HG problem?    It could very easily be one. 

And yes, a coolant flush could very easily clear a clog somewhere in the passages.  That would indeed solve the problem if that was the case.

he said the radiator is new

And Marlin never said anything about it being an old radiator.  Crud from the motor can clog the radiator in a short time, along with an external source.

[hotrod [OP]]

whats the easiest way to check about a hg problem?

and the motors been flushed twice in the past 6 months, once when it blew the lower rad hose and then again when it got a new rad, thermo, and hoses.

[jimbo74]

check compression, check for oil in the coolant, water in the oil, see if the exhuast smells like burnt coolant