overheating above 50 mph or uphill (highway). I already searched
 

Good day to everyone.

I already searched and made everything that I can... almost.

I live in +100 F area (a side to calexico, CA). The water temp never rises in city, even with the a/c turned on.
The problem is when I drive in highway above 50mph or in uphill, is when the water temp rises to hot.

So I decided to do this:
- New radiator
- New radiator hose (upper and lower)
- New thermostat
- New belts (all)
- New timing belt kit (pulley with new valve cover gaskets, etc)
- New water pump
- coolant flush (2 times with prestone flush)
- bleed coolant system.

I bleed the coolant system like 5 times (like the Fsm says), this is that I did sometimes.
- open radiator cap
- put the a/c in HOT temp
- start the engine, wait for the normal temp.
- squeeze both hoses.
- wait for the efans kick in at least 3 times.
- refill with antifreeze if needed.
- drive with the heater on during 15 minutes.
- check for coolant.

Even with new parts the water temp still rising

There isn't coolant in oil or oil in coolant, so I think that isn't the head gasket.

I haven't changed the radiator cap, it seems like.

I have notice that the lower radiator hose doesn't get too hot, even without thermostat. I decided to pull of the thermostat because maybe doesn't work well, but the water temp still rising without thermostat.

I checked the water pumps and both works well (new and old)

I dont know what to do.

Re: overheating above 50 mph or uphill (highway). I already searched
 

I don't see ECT sensor on that list a cheap part compared to what you've thrown at it to try and fix it.

Re: overheating above 50 mph or uphill (highway). I already searched
 

Coolant mixing or not mxing is not teh defining sign that the headgasket is blown.

And you threw all those parts at the problem without troubleshooting and you never changed the radiator cap?

Re: overheating above 50 mph or uphill (highway). I already searched
 

Like marc says... radiator cap... if its not holding pressure you'll have those symptoms.

Re: overheating above 50 mph or uphill (highway). I already searched
 

I forgot to say that I bought my civic hx an one year ago and the radiator cap seems like new.
Anyways in going to buy it and see what happen.
Thank you

Re: overheating above 50 mph or uphill (highway). I already searched
 

I had this issue when I put in a new fan. Even though the wires were blue and black I had to put blue to black and black to blue.... Did you change your fan? Did you re wire it? You might have the fan spinning in the opposite direction and when you're going fast with heavy wind blowing in, it slows your fan down. In my case it fried the fan motor, luckily I had two.

Re: overheating above 50 mph or uphill (highway). I already searched
 

The fan blows air to the engine direction. Its correct right?

Re: overheating above 50 mph or uphill (highway). I already searched
 

Does the car actually overheat?As in coolant is steaming out or boiling.

Re: overheating above 50 mph or uphill (highway). I already searched
 

Still overheating and coolant is boiling

Re: overheating above 50 mph or uphill (highway). I already searched
 

Get the radiator cap from dealer. They have better quality ones for same price as Autozone. If that doesn't fix and still having overheat, better do leak down test for head gasket. If it's boiling and losing coolant in radiator at high RPM usually means exhaust is going into the cooling system and blowing it all out while heating it up.

Also, easy check is to open the cap and let the car run. See the bubbles. Try revving and see how much the water level rises and how much bubbles it comes out.

Re: overheating above 50 mph or uphill (highway). I already searched
 

If the fan is stock then yes, it should be blowing into the engine. That's a pulling fan.

Do you actually have on an aftermarket fan? If you do, do you know if its supposed to go in front of the radiator or just in the original place of the OEM fan? And do you know if its and push(?) or pull(?) fan. (Push fan, blows air into the radiator when sitting in front of the rad.)

Has your fan motor blown on you?

But a pressure test will give you a definite answer if its your head or if its your components.

Re: overheating above 50 mph or uphill (highway). I already searched
 

Ducting.

Re: overheating above 50 mph or uphill (highway). I already searched
 

Have you checked the timing yet? I know a guy (me) who thought if he advanced the timing just a little (didn't own a timing light) so he'd get better mileage. Bad idea. It was OK around town, but over heated when traveling at highway speeds.

Re: overheating above 50 mph or uphill (highway). I already searched
 

Now also overheats at times when i drive with the a/c turned on.

The ignition timing its in 12* (red mark)

I installed...
new radiator cap
new thermostat (oem honda)
new coolant temp sensor (in the thermostat housing)

I removed the thermostat and tested again with same results.
The Fan is direct, turned on all the time and it still overheats.

I used the block tester and the fluid does not changed to yellow. (test for a blown head gasket)
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/faq-my-head-gasket-blown-overheating-3154674/


i dont know what to do...

Re: overheating above 50 mph or uphill (highway). I already searched
 

Since I bought, the car was loosing coolant, not to much but every 2 weeks I had to fill like >10 oz. of coolant, sometimes with water, yes it was wrong..
I never found the leak.

When I revving, the water level rises to much, and yes there are bubbles and seems like the coolant is boiling.

The fan pulls a lot air to the engine. I think that maybe it's a deficient Fan, but i dont know how to test for the CFM.

I tested like in the forum says and it its in 12*

Re: overheating above 50 mph or uphill (highway). I already searched
 

does it over heat while just sitting there or in town driving

Re: overheating above 50 mph or uphill (highway). I already searched
 

overheat while I drive.
driving in the town with a/c in the day (no over heat in night with a/c)
driving in freeway >50mph

I drive a lot from Mexico to Usa (more than 2 hours waiting time to cross), and the water temp only rises after long time with the a/c turned on. No overheat with a/c turned off.

Re: overheating above 50 mph or uphill (highway). I already searched
 

if you turn the heat on while driving will it cool off

Re: overheating above 50 mph or uphill (highway). I already searched
 

New radiator,water pump, no thermostat, direct wired fan. Negative test for exhaust leaks. The only thing remaining now for the engine to overheat is engine efficiency. If you have burnt-out valves or leaks in one or more valves, overheat is sure to follow. Adjust your valve clearance. Do a leak down test.

Re: overheating above 50 mph or uphill (highway). I already searched
 

You don't necessarily have to see exhaust gas in the radiator to know the head is toast. I had the exact same situation. I refused to believe it but it was actually the head gasket. It was just a tiny leak in the head but because when you drive, the pressure becomes higher, you only see the problem under load.

You are not leaking coolant into the cylinder. You maybe but very small to even notice it. You have small amount of exhaust leaking into cooling system which is causing bubbles and level rises on rev. Your cooling system is not circulating as it should because of that push from the leak. Coolants are going out most likely from reservoir cap. You can drive on freeway for about 20 minutes and stop the car, open the hood and check the reservoir. It should be boiling. It's not really boiling. It's just the build-up air in the system escaping from only one way out. You'll have a headache until you change your head gasket.

Re: overheating above 50 mph or uphill (highway). I already searched
 

Re: overheating above 50 mph or uphill (highway). I already searched
 

Re: overheating above 50 mph or uphill (highway). I already searched
 

Re: overheating above 50 mph or uphill (highway). I already searched
 

That's a blown head gasket, sorry man.

Re: overheating above 50 mph or uphill (highway). I already searched
 

do i need to bring the head to the machine shop?