rhscare

Well heres whats going on. Ive battled this issue for a while with this car and it seems to come and go. Basically when I am on the freeway, mostly at ANY amout of incline, and sometimes on surface streets, the car overheats. And bad. Like, I need to pull over because its topping out bad. Yet as SOON as I come to a stop the needle just drops back to normal as though nothing happened. Last year I blew up my thermostat housing so I replaced that, a new thermostat, drained and bled the system and still had the same problem. This was when I was living in Vegas and it tended to only happen as it got hotter outside. Now I am in Hawaii and it still happens on inclines. All I can think of now is the waterpump. Here is my setup.

Koyo
E-Fan
I dont have the undertray either, which I heard could be a factor

What do you guys think? Waterpump? Any advice would be great. Thanks in advance.

J-Rat

iTrader: (2)

What thermostat did you use? And yes, you need an undertray.

classicauto

iTrader: (3)

Do you still have your air pump?

If not, are you using a dual alt. pulley to keep the two belts on the waterpump?

rhscare

Still have the airpump, and as far as thermostat...it was a prestone, without the jiggle pin. This was before I read so much about using the OEM thermostat. I was gonna swtich it out but seeing as I was having the same problem as before, when I still had the OEM one, I figured it was something else.

My5ABaby

iTrader: (7)

The undertray does help, especially at higher speeds.

Just because you had an OEM thermostat before that didn't help doesn't mean it was good. Your previous thermostat could of been crappy. I had an OEM in mine and was having heat issues. Replaced it with another OEM and it's been fine since.

rhscare

Well I suppose I could try replacing the thermo with an OEM one and the cap with a Mazda one instead of prestone lol. But I dont see how those two things would lead to this problem. Like I was saying its mostly on an incline, and if I turn the heater on, often times it will drop back to normal, and if I come to a stop the gauge drops back to half. I dont really understand that part because when I pull over and pop the hood, you can hear coolant boiling. Not like spilled coolant, but boiling in the hoses and everywhere else. Some days its tottaly fine, others I have to head back home cause of the overheating.

Oh and another symptom is the upper rad hose will become hard as a rock if that helps. I mean you cant even squeeze it a little. Granted its hot, but that fact aside it becomes solid and stays that way until its had PLENTY of time to sit and cool.

classicauto

iTrader: (3)

Well, if the T-stat you have was wrong or opening too late the temp would rise high on the gauge, then it opens and flows the super hot coolant to the rad...then your gauge drops back down a little. If you had a perfectly functioning OEM one, it would release the coolant from the block before it got that hot.

As far as the upper rad hose getting super hard...well if the rad cap you are using has a spring with too much pressure - then your system will be over pressureized and the hose will be hard. This could be caused by other problems but if you've got some generic rad cap on there I would rule it out first.

rhscare

What about the little hose going from the rad to the overflow. Its looking pretty old and I have been meaning to replace it. If there were pinhole cracks or holes, would that cause a loss of vacuum enough, or add enough air to the system to create all this?

RETed

Okay, can we eliminate the obvious?
The fan is spinning the right way, right?

Is anything original in the cooling system?
You already mentioned the Koyo and the electric fan...
Water pump still original?
Water pump (and alternator) belt?
Are you running an air pump?
If not, are you running a double pulley / belt system?
Radiator hoses replaced?
Radiator cap(s) replaced?

Do you smell coolant (sweet) when driving the car (hard)?


-Ted

classicauto

iTrader: (3)

no.........you've gotta look at the simple things like I said before. First off - replace all the cheap generic junk like your rad cap and T-stat with good OE ones.

Second make sure your belts are tight (you saidyou still have an airpump - the belt is on it right? regardess of whether or not its on there - you NEED two belts on the water pump)

Third.....I might ask how big you e-fan is and whether or not it has a shroud....that can have a large effect on th effciency of the fan.