2G Overheating, coolant pressure

[Dihtung Glava]

Hi, so I've been passionately searching this forum for the past week, ever since I bought my '99 2G 4G63T(out of a 1g) swapped eclipse, looking for a thread that would pose a similar problem to mine, but I haven't found one, so I'm writing my own now.

It all started when I first bought the car and drove it home. Pushing it up a nice curvy hillside road, the car blew almost all of it's coolant out of the overflow bottle and overheated towards the top of the hill. I stopped, got some water from a nearby restaurant and carefuly continued. I kept my eye on the temp gauge the whole time and, as it was staying in the bottom half, I thought I was in the clear. I let it hit boost a couple of times when I finaly drove into my town (which was probably stupid, I know) and it overheated again, just as I pulled into my driveway. All and all the trip was about an hour and 30 minutes, with the first overheat happening around 25 minutes in...

I found the radiator cap wasn't holding very well, so I got a new one the next day. This one, rated for higher pressures, holds nicely. The problem is now the entire cooling system is under a lot of pressure. The top radiator hose is rock solid after a couple minutes of driving and the coolant overflow bottle is constantly beeing filled, not so much when cruising, but if I floor it, it'll fill up in a couple minutes. So I'm guessing the coolant (which is about 50% water since I last filled it up) is constantly boiling or, there's just way too much pressure in the system, or you know, both.

So If anyone had something similar happen, what did you need to fix/replace?

 

[chrysler kid]

You can run anything, but I reccomend the cheap green stuff as well

Currently running peak asian blue in my gst, ive had issues in the past running a HOAT coolant type, the new style coolants seem to like to seep past worn o-rings, and they dont seem to run any differently despite the bigger price.

Run the cheap stuff, it will be in the old school green coolant type at your autoparts store.

Sometimes switching to a name brand universal coolant will still be a HOAT style, if you feel it with your fingers you can feel the greasy qualities of it, and thats the style i had had issues with causing coolant seal leaks in older high mileage vehicles. Typically the water pump pipe o-ring

 

[mjm0157]

I dump the cheapest green shit from Rural Kings in mine, their Providence house brand 50/50 (6 bucks a jug). Normal green antifreeze is what it had in it in 1992 when it was new and hasn’t hurt it yet over the course of 31 years. I only put coolant in it when I put it away for winter storage, then if I don’t tear it apart that same cheap green coolant stays in it until the first time I go to the track for the year, then it gets all drained out and replaced with straight distilled water as that’s what the track rules call for (that’s any drag strip you go to, and someone always blasts coolant everywhere when they break something, then they get to be the asshole that shut the track down for an hour because they have to clean coolant off the track) and that’s what stays in it until it’s time to put it away again. Never bought any fancy coolant for anything I own, just the cheapest thing I can get that’s the proper specification. Coolant is coolant as long as it’s the right kind for the application, brand makes absolutely zero difference unless paying for a certain name helps you sleep at night.

Some people argue that the glycol is necessary for lubricating the pump, but I do hvac for a living and in the buildings I work at they either run strait water, glycol mix, or brine. The only thing required for a pump seal is a fluid, they are not picky. Some seals are not rated for glycol, but all pump seals can be used with water.
Buildings will use glycol/ water mix if outdoor air coils have the potential for freezing. Glycol is often avoided due to its overall cost. Glycol is less efficient at moving heat than just water, so with the use of glycol/ water mix things have to be sized accordingly. Piping will be bigger, coils, pumps etc. not to mention propelyene or ethelyne glycol concentrate itself for over $2k per 55 drum. Another down side to glycol is it can become corrosive, there is maintenance required.
In cases where glycol cost is prohibitive brine is used, ( ice skating rinks) brine is salt water that has so much salt dissolved in it it cannot accept any more salt ( fully saturated).
Now while we dont want to use brine in our cars, it is actually possible. ( it is disgusting and looks like muck

Personally I like to use plain water for the first few start ups and getting car on the road. So much easier to drain the 5 more times you have to pull it apart. Then after its sound add green coolant. I find home depot is one of the cheapest places to buy oil and coolant.

There are gimmicks sold like “water wetter”. If you are looking to add cooling efficiency to your system dont waist it on this because there is no better coolant than water. Just dilute with water…… or go with the bigger three row radiator and some good fans!

 

[Mech Addict]

Your observation about water transferring heat better than ethylene glycol is true, but overlooks the role of boiling point elevation. The fluid can attain a higher temperature at a given pressure (or reach a given temp at a more reasonable pressure) than water alone. This has other mechanical benefits, but a higher temp fluid will also have a higher rate of heat transfer to air passing through the radiator.
And obviously anti-freeze for cold weather.