Tylerars24

My pickup is having an overheating issue. It does not overheat when the RPMs are below 3000, but it seems as soon as it is above 3100RPM it starts to overheat. What I find strange is that it happens whether I'm going 75-80 on the highway, or in first gear-low range. The temperature drops off pretty fast when I drop below 2500.

I have an electric fan.
I have replaced/flushed the coolant.
Replaced the thermostat.
I can manage it reasonably with the heater.

The guy who owned it before me put in an aftermarket radiator a year ago, stock replica as far as I can tell.

I have searched and can't seem to come up with something that matches my symptoms.

Thanks

Jay351

What kind of radiator is it? Is it a crappy replacment?

I see you have a body lift, where the radiator drop brackets installed?

stormin94

Sounds like you might be low on oil, or using the wrong kind of oil. Also, make sure the fins on your radiator are CLEAN, and not dusty, or muddy. You also might be running too lean, or you have a bad thermostat. Check all of these things.

paxil4x4

blown head gasket

Tylerars24

Thanks, for the replys.
I doubt its the head gasket, oil is clean, no odd smoke. The motor runs pretty strong IMO.

Not sure if the radiator drop brackets were installed, it was installed before I got the truck.

It could be the oil, I am about due for an oil change anyway. I''ll start w/ that.

mt_goat

Might possibly be the lower radiator hose collapsing. When the engine is reving high the water pump is going faster too, this can cause a suction in the return hose to be high enough to collapse the hose shut. I remember replaceing my lower hose once with a cheap aftermarket hose form Pepboys and it had a steel coil inside to prevent the hose from collapsing.

highway

sounds like you have some type of flow restriction either the radiator or the hoses.

highway

Tylerars24

Mt_goat, how do i got about figuring out if the lower house is the culprit?

Highway, I was thinking it was probably a restriction somewhere.

Thanks guys.

mt_goat

Good question...I'm not sure, but you might try having a friend rev it up over 3000 rpms while you look at the lower hose. Of course you want the thermostat to be open at the time, so do the test while the engine is hot.