Overheating and boiling coolant in reservoir and more!

[turkaljd]

My 93' Camry (3vz-fe) just overheated yesterday and the coolant in the reservoir was boiling to the point that it completely evaporated even after i turned the engine off for about half an hour. i have noticed some small leakage before in my garage, but nothing tremendous. I refilled the system completely full and filled the reservoir. Again, it boiled over violently causing me to pull over and wait another half an hour to cool down.

In addition to this the engine has a very rough start to the point of almost stalling unless i press on the accelerator.

It has done this before (rough starting when the gauge reads temps above the red line, but without the violent boiling) but i just added more coolant to bring it up to full and it worked normal for like 6 months, up till now.

After i finally drove it home, the coolant in the reservoir was completely full but it was still letting some steam out of the relief tube. While driving it the temp gauge went from normal temp to maximum above the red line and then back randomly the whole way. Also the heater was on maximum but it was blowing cold air.

I hope this is just a broken thermostat or leaking hose (in the best case) however. Would excessively high temperatures cause the engine to behave in this way (the near stalling starts and almost stalling on stops) or is this indicative of a blown head gasket, something I'm hoping it is not as it sounds like a lot of work to replace.

[71Corolla]

Sounds like it is more than just a bad thermostat, but it could be. You need to repair any leaks, (including checking to see if the water pump seal is going) replace the thermostat, bleed all the air out of the system and go from there. You also need to make sure the hydraulic fan system is working properly, which means for starters checking the fluid level in the power steering system.

BTW, routinely overheating the engine is a sure way to blow your head gaskets.

[turkaljd]

Originally Posted by 71Corolla

Sounds like it is more than just a bad thermostat, but it could be. You need to repair any leaks, (including checking to see if the water pump seal is going) replace the thermostat, bleed all the air out of the system and go from there. You also need to make sure the hydraulic fan system is working properly, which means for starters checking the fluid level in the power steering system.

BTW, routinely overheating the engine is a sure way to blow your head gaskets.

I periodically check all of my fluid levels, and yes the fan is working just fine. Locating the leak is proving to be difficult as none of the hoses are wet but the splash shield are, i'm going to need to do some more digging in there.

I don't routinely overheat the engine, the last time this happened the temp gauge was all over the place, but the coolant was not boiling. However it still did have a rough start where i had to hold the gas down until it stabilized. It was kind of low on fluid so topping it off fixed the problem (i don't know what that did for the rough starting though), until 6 months later (today) it boiled over on me.

I should add that it was starting rough for the past couple of days and then this happened (the traumatic overheating) where it would almost stall at warm engine temperatures after i let it cool down for half an hour and adding fresh coolant/water.

[71Corolla]

Could be a failing water pump, when was the last time it was changed? I've seen a cooling system do strange things when the impeller separated from the shaft and did not always spin. The fact that you sometimes have no heat in the car is something you need to look at and find out why that is happening. Whatever is causing that, you don't have consistent coolant flow going into the heater core.

The best way to diagnose is to do a coolant pressure test to find any leaks. If that does not get you anywhere, then a leak down test will tell you if you have a head gasket issue. What you don't want to do is starting doing a water pump and thermostat job without knowing if there are other problems like a blown head gasket.

[turkaljd]

Originally Posted by 71Corolla

Could be a failing water pump, when was the last time it was changed? I've seen a cooling system do strange things when the impeller separated from the shaft and did not always spin. The fact that you sometimes have no heat in the car is something you need to look at and find out why that is happening. Whatever is causing that, you don't have consistent coolant flow going into the heater core.

The best way to diagnose is to do a coolant pressure test to find any leaks. If that does not get you anywhere, then a leak down test will tell you if you have a head gasket issue. What you don't want to do is starting doing a water pump and thermostat job without knowing if there are other problems like a blown head gasket.

The heater issue only occurred today just before the fluid started boiling. The pump was never changed so that indeed could be one of the problems.

However, how does the near-stalling on warm starting fit into all of this?
That why i'm very concerned it could be a head gasket leak. ( I hope it is not as that seems, after looking over the service manual, like a ridiculous amount of work to replace)

I should also mention that all of the parts on the car are original from 93 except the radiator.

I read a post that someone with similar problems replaced the outlet cap (on top of the engine with the tube to the reservoir) and his problems were solved (it wasn't holding pressure in the system). I'm thinking about trying this first, as the cap is relatively inexpensive and cant hurt to try.

[71Corolla]

Originally Posted by turkaljd

However, how does the near-stalling on warm starting fit into all of this?

It's hard to say. But without a properly functioning cooling system you'll have a really hard time diagnosing any driveability problems.

Definitely do the simple and inexpensive things first, new rad and pressure cap and go from there. Whatever you do, only Toyota parts here.

[turkaljd]

definitely, i will post back as soon as i try the caps out or make any other progress.

[corolapete]

Hope its not but it sound like a blown head gasket. I had that same symptom on my other car but the car was not a toyota. The way you describe it happen the same thing to my other vehicle.

[fenixus]

seems that you have two problems with cooling system. intermittent no flow of fluid (water pump or lots of air in system?) and low pressure (a leak somewhere as car is loosing fluid) causing boiling point to be shifted closer to water boiling temperature.

I would first do a coolant pressure test with at least front spark plugs out. watch where the coolant squirts from, this will be your leak, fix it asap.
if coolant shoots out of spark plug tubes (with spark plugs removed) then you have blown the HG. if it doesn't then it's a chance that new WP and rad caps fix the problem.

check how your oil dip stick looks like. if oil is milky and not clear then it's mixed with coolant (bad HG). if you have buttery residue under oil filler cap then it may point again to HG problem (not always though).

steam coming out of return tank vent tube and boiling coolant is not a good thing. start testing it, maybe it's not too late already.

no heat and temp gauge jumping up and down may be related to air pockets in cooling system, so bleeding is a must too (after fixing the leak).

good luck!

[71Corolla]

^^ Good advice.

One thing I learned from working with the hydraulic cooling fan is the system does not behave like any other I've worked with. By that I mean, because the fan is infinitely variable, you don't get the cooling/heating cycle temps like you do with an electric fan. With the electric, the coolant gets to a certain temperature, the fans kick in, the coolant temp drops, fans stop, coolant temp rises. Repeat.

So what ends up happening is the coolant temperature stays more consistent, so some parts of the cooling system will always be near the boiling point. Because of this, if you don't have a properly pressurized system, the coolant will boil more easily. I found this out when bleeding the air out, the coolant would readily boil in my Lisle funnel and keep doing it over and over, something I had not seen in any other car I had owned. It made it look exactly like a bad head gasket, when coolant boils you see bubbles, I was starting to think my head gaskets were blown. Out of paranoia I did a combustion leak test, was negative. I also did a leak test and also a crude leak down test, negative. I have no leaks, and no coolant loss, all is good but damn did it look like there was a problem.

Best of luck hope it's nothing more than a minor leak or bad rad cap. A head gasket job is a lot of work to say the least, and can get expensive.

[DarkSideMoon]

I'm going through a very similar problem. Two things to note- after you think you've solved the problem, you will get absolutely nowhere unless you bleed the air out. Get a good funnel, and seal it up at the fill neck cap. Start the car, and rev it to about 2k rpm, watch, add coolant as needed, ect. Vary the rpms, let it go down to idle, all the time making sure there is still coolant. If it starts to overheat at any point, obviously turn it off. Secondly, resist the urge to put any sort of stop leak product in. My first radiator died, and the gunk is still floating around after 2 flushes, clogging my radiator cap open periodically. Also, proper (OEM) caps are very important, and if it is the water pump you'll have a very hard time seeing the leak as it drips down very far away from the pump. I'd watch it with the car running.

[turkaljd]

thanks for the advice everyone. i'm going to get new caps some time this week and do a flush and fill of the cooling system. Hopefully this will turn up something and perhaps the source of the leak that is not so evident.

However one major concern I have is; can this be also causing the poor starting and near-stalling without being a head gasket failure? As I have mentioned, it had the rough starts before, but filling the coolant up full took care of that (strange? or would hot temps cause this). I just rented a compression check gauge and leak down test hose that I am planning on using it sometime soon, hopefully this will put my concerns to rest (that is that it is not a Head gasket failure).

Should i do the tests before or after i get the new cap and fill and bleed the system?

[turkaljd]

oh and by the way, i did take a quick look at the oil dipstick to check the fluid, i didn't notice anything by i'm going to inspect it more extensively today.

[azcat90]

Originally Posted by DarkSideMoon

I'm going through a very similar problem. Two things to note- after you think you've solved the problem, you will get absolutely nowhere unless you bleed the air out. Get a good funnel, and seal it up at the fill neck cap. Start the car, and rev it to about 2k rpm, watch, add coolant as needed, ect. Vary the rpms, let it go down to idle, all the time making sure there is still coolant. If it starts to overheat at any point, obviously turn it off. Secondly, resist the urge to put any sort of stop leak product in. My first radiator died, and the gunk is still floating around after 2 flushes, clogging my radiator cap open periodically. Also, proper (OEM) caps are very important, and if it is the water pump you'll have a very hard time seeing the leak as it drips down very far away from the pump. I'd watch it with the car running.

THANKS! You are the radiator guru.

[DarkSideMoon]

Haha thanks! It is the result of several others here walking me through my overheating issues. 6 months of troubleshooting led to learning way more than I ever thought I'd need to know about my cooling system.