I had a 4.7 doing the same thing, it was the radiator had clogged up at the bottom. So, when you hit highway speed it could not cool down fast enough. The reson i a putting a comment on a old post because if anyone seaches and pulls this up at least they can find a resolve.
An expert who has achieved level 3 by getting 1000 points
An expert that got 20 achievements.
An expert that got 10 achievements.
An expert that got 5 achievements.
Re: 2004 overheating at highway speeds
Check rad cap & check your rad hoses for one that may feel soft & collapsing & restricting flow under higher speeds. Sometimes you can see it **** in when you rev engine in park. Especially lower hose.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
you might have air in the cooling system, or water pump might not be functioning right, I would try burping the system first too see. with the car off and cooled down pull the radiator cap off and start the car, let it run for about 30 minutes should force all air out of the system, keep a eye on the coolant level while doing this.
A couple more things to check. First - are you sure it really IS overheating? I assume you think so, or you wouldn't have gone to the lengths you have to correct it. The reason I ask is sometimes the temperature sensor itself will go bad causing erroneous readings. That not the case, then think about this.....does the vehicle seem to be running okay at highway speeds, but not in town or in stop and go traffic? The fan clutch on the radiator fan can cause issues if it is too tight or too loose. A too tight clutch can overload the engine causing overheating. A too loose clutch can cause the fan to slip too much causing improper air flow through the radiator at slower speed and at idle. Since you aren't losing coolant, I agree that it probably isn't the head.
Need more input. If it over heats all the time, you could have a bad thermostat,, collapsed hose, stopped up radiator or radiator low on water. If it overheats at slow speeds but cools down when you ge to highway speeds, you may have a problem with th the fans and/or sensors.
When does it overheat? At idle, or at highway speed? Is the coolant level where it should be? Overheating at idle or highway speed may be a faulty thermostat. If it overheats only at idle then it is likely a cooling fan fault. To determine if the fan is working start the engine and switch the A/C on, the fan should come on, if it does not, then you need to have the computer "scanned" to see if it can detect the reason for the fan not coming on. If the fan is switching on, then you need to have the water pump checked to see if in fact it is pumping coolant (this could also be the cause of overheating at highway speed) If you are overheating only at highway speed you may want to have the enigine checked for a blown head-gasket, or faulty radiator.
When driving down highway only, it overheats? When running steady, I take it you mean, sitting idling? If it's only overheating at highway speeds, and all else has been checked out & is o.k., I'd take a close look at rad hoses for soft spots (easy to squeeze) that may be causing hoses to collapse at highway speeds & restricting flow of cooling system. Another thing to try is, turn your heater on high fan & high temperature when it starts to heat up & see if temperature gauge goes down (cooler) at all. If it does, then rad not doing it's job properly.
Check your rad hoses. They will tend to collapse (**** in) & cut down on flow at highway speeds, more than city, due to increased demand & flow on cooling system. If they don't feel relatively stiff, I'd change them. You might even see them **** in while sitting and revving the engine a bit.