Overheating issues after replacing radiator, 1994 ST Hatcback, 7A-FE Options

[Noahwhite2014]

Yup, need some help, not sure whats wrong now. It will be long, but I'm trying to include every detail possible for the best possible help

So one day i was driving home, and my AC went warm. I was confused as it hadn't done that before. So i began to pay attention to my gauges very closely, everything was normal, temp gauge was just a hair before the middle. About 5 minutes later, when i was near home, still paying attention to my gauges, i heard a felt a pretty loud pop. Didn't know where it was from, and I didnt think it was my car as in my neighborhood we usually have construction going on, so i figured it was someone who just dropped something heavy nearby. And then about 100 feet further down i smelt coolant, took a look at my gauges, still normal, no overheating. And then pulled into my driveway about 200 feet after that. I popped the hood and steam started coming out from the sides of my hood. As i opened the hood i saw brownish splash marks everywhere and a Crack in my radiator about 10" in length with a gap between the crack of about 1mm.

Well i figured, 21 year old radiator made of plastic. Had to crack sometime, and it just happened to be while it was pressurized and i was driving. So i ordered a new radiator (Spectra premium radiator). I already had hoses (gates hk23rb kit) as i had planned to replace the old hoses which were beginning to show excessive wear. I was also planning to flush the cooling system when replacing the hoses so i let the fairly dirty coolant go... When i drained the coolant after the radiator had cracked, it was very brown and murky and had quite a substantial amount of rust in it. Drained everything, turned the heater to completely hot, put the output to feet and put the blower fan on max. Flushed with water till it was clear (couldn't get it perfectly clear even after 10 minutes AFTER it had gotten mostly clear).

The radiator came in last night, I put it in, replaced the hoses, and flushed the whole thing with distilled water one more time, Then i poured in the factory toyota red coolant... My dad told me he mixed it with distilled water at a 50/50 ratio so i trusted him and poured it in. I hadn't used the toyota stuff before so i assumed at the 50/50 ratio it was supposed to be that red. Then about 3 minute later, i found out he didnt mix it with distilled water. So i poured in the same amount of distilled water as i did coolant, of course i couldnt fit all the distilled water in, and me being the idiot that i am, i started the car to burp the system so i could get the rest in there. I didnt think to drain the coolant and remix and pour it back in...

So after fully burping the system, i thought the car was fine, i opened took it for a drive, filled up the distilled water to the top after it cooled down, topped up the overflow tank, and everything seemed fine. Then this morning i took my car to work and on the way it began to overheat. As soon as i saw it hit 3/4 of the gauge (didnt see it sooner), i turned the ac off, put the heater on full, and put the fan on max. The temp immediately dropped back to half, and i was able to make it to work. After work i topped off the rad with distilled water and sealed it back up. And drove to a friends house, he lives a decent way up a mountain, and on the way up, the car temp, climbed quickly. I pulled over, shut the engine off, popped the hood, and let it cool down. Started it up and drove up to his house. Spent a decent amount of time there. Then drove home, As i got on the freeway my temp gauge went up to 3/4 so i turned the heater on etc and the temperature went to the middle of the gauge and was steady. The only time temps would climb is when going up slight hills when the car was at 2700+rpm or on flat ground at 3000+ rpm.

Any idea what could be wrong?

Coolant has no air in the system
Don't have any apparent leaks, and the coolant doesn't drop in level any more
The coolant is a bit dirty now
Thermostat did still open after i replaced the radiator and hoses
Replaced the radiator cap with one from Napa, its rated at 13psi


Side note, When getting rid of the air in the system (car was on jacks so the front end was up in the air, Used a spill free funnel, and watched for all the air bubbles to go away like on every video i watched on youtube. I noticed The coolant rising and falling a lot more than it did in the videos. Could this be my water pump? And all the rust is the pump itself completely degraded..?

[Bitter]

Are you pushing out a lot of bubbles? Did the old coolant smell burned or like cleaning fluid? Do the bubbles smell kind of like exhaust?

It sounds like either you have an air pocket trapped or are pushing gases into the cooling system. Does the heater always blow hot? Do you hear any gurgling?

This post has been edited by Bitter: Feb 22, 2015 - 10:13 AM

[Noahwhite2014]

Are you pushing out a lot of bubbles? Did the old coolant smell burned or like cleaning fluid? Do the bubbles smell kind of like exhaust?

It sounds like either you have an air pocket trapped or are pushing gases into the cooling system. Does the heater always blow hot? Do you hear any gurgling?

Didn't smell like exhaust. It only smelt burnt when all the coolant was spewed over the exhaust manifold. But when I drained it, it smelt like rust and coolant

Heater is always hot after the car is at operating temp, when it starts to overheat when going up hill, it gets really hot. Can't hear any gurgling and I don't see any leaks anywhere either

[Bitter]

That's a tough one. When it's overheating can you pull over and check the overflow bottle to see if it's forcing coolant out into the bottle?

[Noahwhite2014]

Yes it does overflow into the bottle

[Lamont]

This sounds like a blown head gasket pressurizing the coolant system.

[Noahwhite2014]

This sounds like a blown head gasket pressurizing the coolant system.

How can I check that?

[Lamont]

This sounds like a blown head gasket pressurizing the coolant system.

How can I check that?

You can have a mechanics shop test your coolant for traces of fluorocarbons that will be present if exhaust gasses are leaking into your coolant. The test isn't expensive.

[Smaay]

the head gasket is not going to suddenly blow. I highly doubt its that.

make sure all the bubbles are out. Dont worry about your mix ratio. thats fine.

[mkernz22]

Check your thermostat too. If it's stuck closed then it will cause overheating.

[Bitter]

the head gasket is not going to suddenly blow. I highly doubt its that.

make sure all the bubbles are out. Dont worry about your mix ratio. thats fine.

But a head gasket can be previously weakened or damaged by overheating in the past, then finally overheated once more and it goes. Who knows what happened before the radiator cracked, maybe it's always had a poor head gasket and just took the shock of the bad radiator and that overheat to cause it to start leaking.

It sounds similar to what happened to the 3.8 Taurus my dad had a long time ago, bought it used from a family friend. Her father had over heated it once, but it ran fine for a few years when we bought it and was fine around Chicago for months. We took it on a long road trip into Michigan climbing some hills on the highway and it was just barely pushing past the half way mark, but it was hot out so we didn't think anything of it. On the way back home it began getting hot just accelerating, then just cruising under light throttle, then it got hotter and was pushing out coolant. Blown head gasket(s), had to tow it back home.

[Cabilo]

Worst case scenario is a cracked cylinder head.

[Bitter]

Check your thermostat too. If it's stuck closed then it will cause overheating.

That is possible, it could be sticking or not opening completely and blocking coolant flow when the engine is needing the extra cooling capacity. A quick fix if that's it.

[Noahwhite2014]

The thermostat on the 7a is hooked up to the lower rad hose right? Also anyone know the price at the dealership? (Or is an aftermarket one from like Napa or oReilly okay?

Also for the entirety of me owning the car it has never past halfway on the temp gauge, not even on a hot day. The day the radiator cracked it didn't overheat either. Now that I think about the crack I believe it was because of old plastic tanks, and weakening from chemicals... The previous night, I was spraying brakleen on some parts I was holding, while the engine bay was open and completely forgot how far those cans shoot (and the amount it shoots out) and it got all over my rad support, radiator, and front bumper. First thing I wiped was the bumper because I didn't want to ruin the paint, then the radiator support and then the radiator.

Thanks for the help guys. If it does happen to be a head gasket, I have my schools metal shop that can machine the head back to spec if warped. And I have all the tools at my disposal to replace a head gasket. As for a cracked cylinder head... Lots of 7As in the junkyards here.

[Noahwhite2014]

By the way, how can i test the efficiency of a radiator?

i honestly don't know if the radiator is even good quality because I've never bought a radiator before...

this is the one i bought:
http://www.amazon.com/Spectra-Premium-CU17...r/dp/B000C7S0F8

[Noahwhite2014]

Replaced the thermostat with a stant superstat rated at 180F

The old thermostat looks like crap, Super rusty, and the small washer part with the small spring could move about 1mm before it would be stuck.

After bleeding the air from the cooling system, it runs great so far. Can rev it to 6k with no change to the needle. Driving up hills at 4k rpm doesn't affect the temp at all. On the freeway i can do 3k rpm with no problems!

Hopefully this holds true tomorrow when i drive when the sun is out.

[Terzin1]

Replaced the thermostat with a stant superstat rated at 180F

The old thermostat looks like crap, Super rusty, and the small washer part with the small spring could move about 1mm before it would be stuck.

After bleeding the air from the cooling system, it runs great so far. Can rev it to 6k with no change to the needle. Driving up hills at 4k rpm doesn't affect the temp at all. On the freeway i can do 3k rpm with no problems!

Hopefully this holds true tomorrow when i drive when the sun is out.

It's been a few months, how has this been holding up?

[Noahwhite2014]

Replaced the thermostat with a stant superstat rated at 180F

The old thermostat looks like crap, Super rusty, and the small washer part with the small spring could move about 1mm before it would be stuck.

After bleeding the air from the cooling system, it runs great so far. Can rev it to 6k with no change to the needle. Driving up hills at 4k rpm doesn't affect the temp at all. On the freeway i can do 3k rpm with no problems!

Hopefully this holds true tomorrow when i drive when the sun is out.

It's been a few months, how has this been holding up?

Absolutely perfect
the hottest day so far in traffic heavy up an incline didn't even cause my temp gauge to go up past half