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Discussion Starter · #1 ·
OK so I am wondering if this problem has been discussed before but I will begin with my longer situation with my 95 camry.

As some of you know, I purchased a second camry, a 95 coupe. It's been good to me and I finally got her back on the road today. I was just wondering one thing. Although now the fans are engaging and there is no overheating I noticed tonight (similar to my 96 which i will discuss shortly) that the radiator fluid in the reservoir bottle goes up and down in level dramatically. Tonight for the first time I actually noticed it pouring out the escape passage (attached to the top of the cap) and leaking out to the side, meanwhile my gauge read completely normal. Keep in mind the car was off at this point. so I started it back up and the levels went down as soon as my fans engaged. I drove it around and when I got back and shut off the car, I noticed the levels of rad fluid practically at the cap (all the while the full line is half way down the bottle) and I touched the upper rad hose and could feel it super hot with rad fluid boiling inside.

...Now my question is, although the car isn't overheating, is this something to worry about? I have been told by a few mechanics that fluid is supposed to boil and it's a normal occurrence, as long as the car doesn't overheat you're fine?!?! Too me this sounds insane...don't you dilute the distilled water with rad fluid for that purpose, to raise the boiling point?

Second part is my 96 is doing similar things, although it hasn't happened in months, it was doing that a while back and all the sudden stopped. However similar symptoms to my 95...rad fluid was bubbling in the reservoir bottle...I didn't ever feel it boiling in the upper rad hose like my 95...

Does anyone have any insight on what this could be? Maybe air bubbles in the rad system?!?! I'm just guessing but likely it's something else...
 

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Discussion Starter · #3 ·
I REPLaced both the thermostat and radiator cap on both cars . My 96 I had replaced about 6 months ago and had my 95 replaced about a week ago. Both were replaced with aftermarket rad caps. I used prestone rad caps on both purchased from part source here in Canada. Could it really be due to the fact that they are both oem original caps?

Btw would changing my thermostats from 192 degree to a much lower temperature help the problem at all?

Thanks for the reply :)
 

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Well, Your sure that there is no air in the system and that the radiator is full of coolant ( not just the overflow tank, the radiator itself ). And you have replaced the thermostat and rad cap (aftermarket), But did you check the sealing surface on the radiator side of the cap ?? There are 2 seals here, one outer ( the cap itself) and the Inner ( this is for the pressure relief valve on the cap). If the inner sealing surface is deformed from the defective old cap then the coolant will not get pressurized ( decreasing the boiling point) and will just push coolant out into the overflow tank.
The way it should work is like this, radiator when full and cold should have the overflow tank coolant lvl to the cold line, when the engine is warming up the system will start to pressurize, once it reaches above about 13 psi the cap will open and let the excess pressure out and flow some coolant into the overflow tank and bring the lvl up to around the hot mark and stabilize.
Then once the engine is shut off and the system starts to cool off decreasing the pressure until it starts to go into a vacuum, At this point it starts pulling coolant back in from the overflow tank past the cap and into the radiator thus bringing the lvl in the overflow back to the cold mark.
Now if the radiator cap is bad (not holding pressure) or the Inner radiator sealing surface is bad the system will never gain pressure and just push coolant into the overflow tank (no pressure = lower boiling point causing more coolant to be pushed out). Now when shut off and cooling down the radiator cannot pull coolant back in from the overflow tank (no pressure to begin with ends with no vacuum to pull it back in) = low coolant on your next restart and it keeps getting worse.

And don't install a lower temp thermostat, you will just create driveability problems and possibly inhibit system monitors from running.

Also, the ez way to bleed the cooling system on a 5sfe is to remove the coolant temp sensor, The one on the upper radiator hose housing at the rear of the cyl head, it will have a green connector and takes a 17 mm wrench or socket, dint loose the copper washer. Fill the radiator until coolant starts to come out of this hole then reinstall the sensor and top off coolant.
 

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抵抗しても無駄だ
2002 Solara SLE V6
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well ... you said it ... aftermarket rad caps and both cars boiling coolant :facepalm: ... perhaps even try using new OEM ones on one car for starters ?

boiling of coolant may mean the cooling system doesn't hold the pressure so the boiling point is shifted down significantly...
 

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Discussion Starter · #6 · (Edited)
So a quick little update...

I have driven the car about 130km or so today (70-80 miles) and I am noticing the fluid levels are fluctuating still a lot. Few things I noticed this morning was after driving it for about 20 minutes (with one stop along the way) I came home and with the car off, the fluid was actually pouring out slowly from the reservoir bottle top.

Anyhow I went to canadian tire to pick up a few things and when I came out, there was I'd say about 300-500ml of rad fluid on the road. I checked my reservoir bottle and it was pretty much empty at this point. I drove the car home, check the levels, now the level was back to about half way point (between full and low). I shut the car off and kept an eye on the reservoir bottle...within a few minutes it was back to the full line.

So my question...my mechanic says all of this is normal, so long as the temperature gauge never rises. He thinks we simply over filled the coolant levels when we replaced the thermostat and cap and it's simply dumping excess fluid out. He also said that rad fluid is "supposed" to boil and therefore I shouldn't be worried if the rad fluid is boiling inside my rad hoses and reservoir bottle, these are all normal occurrences...

Am I just being too overly cautious or should this be a cause for concern?
 

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抵抗しても無駄だ
2002 Solara SLE V6
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yeah, it's possible if it was overfilled. my 5s-fe spitted out some fluid too shortly after flushing and refill a year ago.
you should make sure though that system has no air in it. is the fluid up to rad filler neck after removing the rad cap ? don't do that when HOT, or at least use some thick rags around it.
 

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Discussion Starter · #8 ·
yeah, it's possible if it was overfilled. my 5s-fe spitted out some fluid too shortly after flushing and refill a year ago.
you should make sure though that system has no air in it. is the fluid up to rad filler neck after removing the rad cap ? don't do that when HOT, or at least use some thick rags around it.
I just came back from driving the car about 20 minutes ago. I will let the vehicle sit for a bit longer to let the engine cool then check if my radiator level is low by removing the rad cap. If I had to guess I would say it's still full or atleast close to it seeing as my reservoir bottle level seems normal now. If anything the car wouldn't keep all the fluid in the reservoir bottle if my rad was bone dry..I'd think it would serve it's purpose and push the fluid back to the rad..I could be wrong though.

I'll keep you guys posted.
 

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抵抗しても無駄だ
2002 Solara SLE V6
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i'm just worried if your aftermarket rad caps hold proper pressure. because if they don't then weird things will happen to fluid levels.
 

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V8'sRGone
95 Cam
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3 things:
A leak anywhere in the cooling system can compromise the whole thing as it may not be able to pull a vacuum and refill the engine block when the system is turned off and cooling down.

As for hot engines purging;
Water expands when heated. Thus a system full to the brim will likely force some coolant out during engine warmup.

When the engine is running the burning gas is creating BTUs that must be shed. The exhaust dumps the most BTUs, the radiator, and the block do the rest. BUT, right after you chop the key, there is still a huge amount of thermal BTUs to be shed but no exhaust flow of cooling system to do it so the engines temperature continues to rise for about 5 - 10 minutes and spikes. Often times this is when the reservoir gets coolant dumped into it as the pressure exceeded the caps rating and coolant is forced out of the block. Then the system begins to cool down.

As the engine cools, the density of the water increases, it takes less space, and if all things are correct it pulls a vacuum against the valve in the radiator cap pulling fluid back into the system from the reservoir.

A final note: ever notice how the fuel gauge and temp gauge remain pretty steady no matter what. I they have a means of averaging so they don't scare the hell out you! I know for certain the MZ's temp gauge can mask a 30 degree variance (+/-15F). Watch the OBDII data!
 

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Discussion Starter · #11 ·
Well today was an interesting day..so many different opinions to go with...

So one mechanic who I spoke to extensively today (not the one who thinks it's completely normal to have it boil) thinks it could simply be a lot of air in the system, causing the boiling point to drop significantly. He says he has a machine to do a complete radiator flush, which will also flush out other cooling components (water pump, etc). My question is, is this a safe procedure to try on the car? Will this likely be the problem?

Another update..I just drove the car for another 45-60 minutes and when I turned the car off and checked the levels they were normal. Like 76sport mentioned, within second of shutting my car off I kept an eye on the reservoir bottle and the whole system before my eyes began to boil. I opened the reservoir cap and a bit of fluid came out, so I put it back on...

This is some weird ass problem...is the car ok to drive as long as it's not overheating???
 

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V8'sRGone
95 Cam
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Its normal for fluids to go back and fourth between the res and the block. Its expected. Just because it dumps into the res does not mean its boiling over. If it routinely boils over you'll see the reservoir overfill and dump inside the fender. You would likely see the temp climb as the engine begins to over heat.

If this concerns you and you need an answer for your sanity, grab one of those laser temperature gauges and shot it at the water outlet before and after the thermostat. Depending on your elevation, glycol mix, and radiator cap, you might expect to see a reading of 224f as it boils over. Purging into the tank at lower temperature is more than likely just the water expanding as the block heats.

You could also by some OBDII scanning software/hardware too and glean some more data!
 

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Discussion Starter · #13 ·
Its normal for fluids to go back and fourth between the res and the block. Its expected. Just because it dumps into the res does not mean its boiling over. If it routinely boils over you'll see the reservoir overfill and dump inside the fender. You would likely see the temp climb as the engine begins to over heat.

If this concerns you and you need an answer for your sanity, grab one of those laser temperature gauges and shot it at the water outlet before and after the thermostat. Depending on your elevation, glycol mix, and radiator cap, you might expect to see a reading of 224f as it boils over. Purging into the tank at lower temperature is more than likely just the water expanding as the block heats.

You could also by some OBDII scanning software/hardware too and glean some more data!
Ok so let's add a couple things to the equation. As you had mentioned the car still seems to be pushing fluid from the reservoir bottle back to the rad. In some instances when the fluid I guess gets super hot it begins boiling over and slowly pouring out the cap of the res bottle back into the fender engine bay area. As of four days ago my fans were not functioning and therefore the car was overheating and the Gauge would go closer to the red (3/4 the way). So I'll assume since I'm no mechanic that the car is NOT overheating since replacing the fans and the fuse, it engages the fan operation normally.

Is it possible that the system simply is pelt pushing air out of the system being it's over filled and eventually this will all go back to normal operation? Seems after doing a rad coolant change in my 96 it did this very same thing and eventually over time the problem vanished..

Am I nuts or is this definitely an issue? As of now if the needle stays at the half way mark as it should be I'm not worried driving it..but can any of this do any damage with hot rad fluid leaking to the engine bay area??
 

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V8'sRGone
95 Cam
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Ok so let's add a couple things to the equation. As you had mentioned the car still seems to be pushing fluid from the reservoir bottle back to the rad. In some instances when the fluid I guess gets super hot it begins boiling over and slowly pouring out the cap of the res bottle back into the fender engine bay area. As of four days ago my fans were not functioning and therefore the car was overheating and the Gauge would go closer to the red (3/4 the way). So I'll assume since I'm no mechanic that the car is NOT overheating since replacing the fans and the fuse, it engages the fan operation normally.

Is it possible that the system simply is pelt pushing air out of the system being it's over filled and eventually this will all go back to normal operation? Seems after doing a rad coolant change in my 96 it did this very same thing and eventually over time the problem vanished..

Am I nuts or is this definitely an issue? As of now if the needle stays at the half way mark as it should be I'm not worried driving it..but can any of this do any damage with hot rad fluid leaking to the engine bay area??
I'd think the balance period would be like a one time event. My concern here is I'm not going to say its OK and then have you burn your engine up. Any other details to share?

As of four days ago my fans were not functioning and therefore the car was overheating and the Gauge would go closer to the red (3/4 the way). Blue is clear and makes sense.

I assume . . . the car is NOT overheating since replacing the fans and the fuse, it engages the fan operation normally. << How do you know they work properly? You need a temp gauge so you know the water temp.

Why did it blow the fuses and get the fans replaced?
 

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Discussion Starter · #15 ·
As of Right now the car continues to boil after car is turned off and can be felt in upper rad hose and sometimes the reservoir bottle will boil almost to the top of the bottle.

I had my fan replaced because it was completely seized and not spinning. From my understanding the fuse was definitely cut. It was about 20 min after starting the car that the fan still didn't engage so we jumped the fan fuse to ensure it was working. Too ensure safe measure I managed to get a new original relay from Toyota for it too. Popped that it in and the fan started going on intermittently as per normal operation.

The car is still driving fine and the needle remains at the mid point. My fear is if I don't tackle the problem before winter with freezing weather, it may not do this andthen creep back up next summer. I'll keep persisting and keeping an eye on what the car is doing.
 

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1) You need to find a new mechanic if he thinks boiling coolant in a properly operating system is normal.
2) Reread in my last post how to bleed air out of a 5sfe.
3) Did you check the inner sealing surface on the radiator side of the cap as mentioned in same post ? And test the cap? And is it the correct cap? 2 different styles are often mixed up. Both look almost the same but the inner valve is a different height ( if you have the deep style radiator the short cap will fit but the valve does not seal properly)
4) You may want to have a good mechanic ( not the one your dealing with now) check for CO2 in your cooling system ( leaking head gasket or cracked head)
5) Figure this out before #4 is positive.
 

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抵抗しても無駄だ
2002 Solara SLE V6
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also if we talking about possible HG issues, two tests are very helpful in looking into it:
a) cooling system pressure test, very easy with a proper equipment, any mechanic can do that quickly
b) compression test on all cylinders (easy on 5s-fe, very hard on 1mz-fe)
c) look for signs of leaky head gasket: coolant color getting brownish, engine oil getting milky on the dipstick and milky/buttery residue under oil filler cap. bubbling in coolant return tank is a sign of leaky HG too as exhaust gases seep to cooling system through bad HG.

and please get finally a new rad cap from dealer, it's only $15 bucks over the counter or so...

and last thing, get a coolant tester (4 or 5 ball type thingy with a straw) from local auto parts store like Autozone and check what kind of mixture of coolant you are having, maybe it's too much water in it and boling point is too low, because of that ?
 
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