[NothingSound]

I noticed that my 1997 Camry CE was running hot when I was on the highway, especially when I was climbing a hill. Not in the red, but about half way to it from normal. It would cool back down after the hill, but still ran a bit warm on the highway. On other 'minor' roads, around town and what not, the temperature stayed within the normal range. Most of my driving is done on the highway BTW. Around 100 miles a day round trip.

I noticed that if I took the vehicle out of overdrive while climbing the hill it would bring the temperature down. Almost to the normal position, but not quite. I told my mechanic about it and he said that it sounded like a blown head gasket, but other than the vehicle running warm there were no other symptoms of this. I searched around and found that it could be anything from a bad thermostat, a radiator cap, head gasket ......blah, blah, blah.

About a week and a half ago I was climbing a hill on my way to work, running above normal temperature as always and I noticed that dreaded antifreeze smell. To make a long story short, it was the heater core. I had to have the car towed to my mechanic where he replaced the core. I asked if he thought we should replace the thermostat at that time and he said no, your thermostat is fine. How he could know this without doing a hot water test was beyond me, but he insisted that wasn't my problem. I was hoping that my whole problem was the heater core to begin with, maybe clogged, my heat never was the best anyway, but when I was driving home that day it did the same exact thing, ran hot going up hills and above normal at highway speed.

I did a bit more research and everything I found pointed to a bad thermostat. Being the easiest and cheapest thing to fix I brought it back to my mechanic and insisted that he change it, which he did.

Well, that was it. The car ran spot on normal temp. Up hills, down hills, high speed, low speed.......perfect!
So you would think.

Yesterday on my way home from work I stopped at a light and all of a sudden a plume of steam started coming out from under my hood. I pulled into a gas station, opened the hood and after a bit of looking around, trying to figure out where it was coming from. Mind you, the car was running fine for 3 full days with no incidents. I ended up finding a crack across the top of the radiator about 6-8 inches long. There was antifreeze all over. WTF? When I first noticed the steam I immediately looked at my temp gauge and it was 100% normal. When I got back in the car it was still at normal. Being that it wasn't overheating I was able to get it to my mechanic. He was able to get a radiator on the spot and he put it in. I should mention here that the radiator he took out was only about 2 years old, if that. He put it all back together and we ran it for over an hour. I took it for a ride, we idled it, we revved it up in the lot......all of it. The car runs 100% normal. No overheating, no oil to water, no water to oil, no bubbles in the expansion tank, no seemingly high pressure in the hoses....nothing.

My contention is, if there were high pressure in the radiator wouldn't the cap have blown into the expansion tank before splitting the rad? The level stayed normal BTW. It seems to me that there are weaker points that would go before the rad. We replaced the cap BTW when we put the new radiator.

I drove the car home, about 60 miles and it ran fine. I stopped 3 times on the way to check everything out. All seems fine. No overheating, no overflow in expansion tank, no bubbles in exp tank and no seemingly high pressure in the hoses. I do notice that the lower hose stays very cold though, most of the time. My mechanic said that although that's not necessarily normal it may be normal for my particular car. The operating temp could not be better. It's as if the temp gauge needle is glued in place. It never moves from normal.

Well there you have it. I know this post is long, but I wanted to give all the details.
Could this be an underlying problem ie; head gasket, or just bad luck?
Any suggestions would be appreciated. I know I'm new here and only found this place through Google.
I've had a lot of experience with Toyota vehicles and hopefully I can help some of you guys out one day as well.
Foe now I'm going to bounce around this lovely place and see if I can expand my knowledge of Toyota vehicles.


BTW, the above mentioned vehicle is a 1997 Camry CE with 343,000 original miles.

 

[ihartmacz]

If the temp needle stays glued u may need a new sensor. Andy check engine light?


If it were the head, you'd notice in the way it ran and how it sounded.

 

[NothingSound]

If the temp needle stays glued u may need a new sensor. Andy check engine light?


If it were the head, you'd notice in the way it ran and how it sounded.

The temp needle goes down as the engine cools down but never goes above normal like it did before the thermostat was changed. Being that it worked fine before the new thermostat I doubt that it just happened to break at the same time the thermostat was changed.

The car runs great. Has power, no pings, great gas mileage / 33 miles per gallon.

 

[Stillrunning]

The car runs great. Has power, no pings, great gas mileage / 33 miles per gallon.

Problem solved.

Those plastic rads are junk. The fact that it cracked but did not blow the cap pressure relief just means that it blew at less than the 13-14psi setting on the cap. Replacing the rad cap once in a while is good maintenence. The only way to check your temp sensor is to verify actual coolant temp using a thermometer or replacing it. I think you're fine.

 

[NothingSound]

Problem solved.

Those plastic rads are junk. The fact that it cracked but did not blow the cap pressure relief just means that it blew at less than the 13-14psi setting on the cap. Replacing the rad cap once in a while is good maintenence. The only way to check your temp sensor is to verify actual coolant temp using a thermometer or replacing it. I think you're fine.

Thanks for the response.

So you think maybe just a coincidence?
Maybe the radiator was weakened from running hot before the thermostat was changed?

I'm just a little paranoid driving so many miles and I can't afford a new car right now.
I've taken great care of this Camry and want to get what I can out of it, but I don't want to be breaking down every week.

 

[Dave's]

I have a '92 and an '01. Both temp gauges never move after reaching operating temp. My guess is you're ok now. The t-stat can cause an engine to over-heat if stuck closed or run too cool and/or vary the temp if stuck open or it opens too soon. Plastic rads are known for failing easily if the engine heats up too much causing not only heat stress but pressure stress from the increased temps. If you had to tow it when the heater core went then I'm guessing it got hotter than normal at that time. (maybe didn't max out but climbed pretty high.) Can't say for sure your problems are over but chances sound good that they are.

 

[NothingSound]

If you had to tow it when the heater core went then I'm guessing it got hotter than normal at that time. (maybe didn't max out but climbed pretty high.)

It definitely was running hotter than normal at that time.

What about the lower hose being so cold all the time?
Is this normal? Others have told me it's a good thing
because that's where the engine gets it's coolant from.

Any thoughts?

 

[Kep]

If you want to be certain about a head gasket leak there are chemical tests that can be completed on the antifreeze to determine if there are exhaust gas components in the coolant. In your account I did not read anywhere where he had done any tests. He just seemed to guess and replace parts (unless he offered and you declined the tests). I think I would start looking for a more thorough mechanic.

You said that your temp gauge is "glued" in place. If it doesn't show cold when the car is cold then you have a sensor or gauge problem. A mechanic can put an analouge gauge on the engine to get an actual temperature reading. Are you sure that your mechanic did not? (There are also laser temperature gauges that don't need a connection to the engine. Maybe he used one of those?)

The fact that your radiator blew shortly after your heater core disturbs me. Both going does seem to imply high pressure in the system. I don't think that typical overheating shouldn't cause high pressure if the radiator relief valve is operating correctly. Has the radiator cap release pressure been tested? Yes, there is a gauge to check these (I think that they come with a pressure tester for the cooling system). It may be cheaper to just change it out but then you'd never know if it was actually the problem. If you don't mind doing it yourself ask some of your local autoparts stores if they loan out something that could test the radiator cap. Some may have one.

The lower hose should be cooler than the top hose. I don't know how large of a temperature drop the radiator will produce. It would be affected by the air temperature but, even in the winter, I would think it would at least get warm if the coolant was circulating correctly. A truely cold return line is an indication of a blockage. Normally a failed thermostat. If you take off the radiator cap and run the car until it warms up you should see the water moving in the radiator (on & off).

Kep

 

[NothingSound]

If you want to be certain about a head gasket leak there are chemical tests that can be completed on the antifreeze to determine if there are exhaust gas components in the coolant. In your account I did not read anywhere where he had done any tests. He just seemed to guess and replace parts (unless he offered and you declined the tests). I think I would start looking for a more thorough mechanic.

He did not offer any such test.
He's not the one that guessed, I did.
I suggested that he change the thermostat.

You said that your temp gauge is "glued" in place. If it doesn't show cold when the car is cold then you have a sensor or gauge problem.

When I said "glued in place" I met when it's at normal operating temp. Not like before the thermostat was changed. That's when it would read high going up hills. Like I said before, it reads cold when engine is cold and goes up as the engine warms up. Once it reaches normal it doesn't move either way. I doubt the sensor went at the same time the thermostat was changed.

The fact that your radiator blew shortly after your heater core disturbs me. Both going does seem to imply high pressure in the system. I don't think that typical overheating shouldn't cause high pressure if the radiator relief valve is operating correctly. Has the radiator cap release pressure been tested? Yes, there is a gauge to check these (I think that they come with a pressure tester for the cooling system). It may be cheaper to just change it out but then you'd never know if it was actually the problem.

The cap was tested after the heater core went and it was fine. However, I insisted on a new cap when they put the new radiator. I took it for a ride just a little while ago and everything appears to be fine. I wish some of my previous cars ran as good as this car does.

The lower hose should be cooler than the top hose. I don't know how large of a temperature drop the radiator will produce. It would be affected by the air temperature but, even in the winter, I would think it would at least get warm if the coolant was circulating correctly. A truely cold return line is an indication of a blockage. Normally a failed thermostat. If you take off the radiator cap and run the car until it warms up you should see the water moving in the radiator (on & off).

That was checked yesterday when I was at the mechanic and had it running in the lot. There appears to be good circulation with no blockage. The lower hose does get warm when the thermostat opens and then cools down again I guess when it closes.


Thanks for the response.

 

[NothingSound]

Keep this in mind folks:

Before the thermostat change the engine was running warm going up hills on the highway.

After the thermostat change the engine ran at 100% normal temperature.

If it were the head gasket causing the hot temps while going up hills wouldn't it still do it even after a thermostat change?

 

[Dave's]

If you're really concerned about the head gasket then there's the chemical tests and compression tests available as noted. But if you're not seeing white smoke from the exhaust after the car is warmed up, you're not losing coolant or oil, and the oil isn't 'milky' on the dipstick, I wouldn't worry too much. Just keep an eye on things every day or two for a few weeks. A t-stat that's not working properly (and BTW there's fully closed and fully open and everything in between depending upon engine load, outside temps, cooling effiecancy, etc) can cause the temp to climb under load (uphill) and then drop when cruising. With a brand-new clean rad and coolant, I'm not surprised it's doing a great job at taking the hot incoming coolant and chilling it before it goes out the other hose.

 

[Kep]

+1 on Dave's

All else seems satisfactory. :thumbup:

Kep

 

[NothingSound]

If you're really concerned about the head gasket then there's the chemical tests and compression tests available as noted.

I just ordered this:

Combustion Leak Test Kit

Hopefully it will put an end to whether it is or isn't a head gasket problem.

I'll post the results once I get the kit and perform the test.

 

[WhiteRabbit]

hmm, how does it work?

 

[NothingSound]

hmm, how does it work?

From the little bit I was able to read on the internet about these kits,
you put the included fluid in the tube and then suck coolant in to the tube.
If the fluid turns blue, you're good. If the fluid turns yellow, there is engine combustion present.

 

[ECale3]

the plastic portions of the camry's radiator is notorious for cracking without good reason. Mine's done it too. Unless you're still having other problems you're most likely in the clear.

 

[NothingSound]

I just ordered this:

Combustion Leak Test Kit

Hopefully it will put an end to whether it is or isn't a head gasket problem.

I'll post the results once I get the kit and perform the test.

I just took the test using the above mentioned test kit.

The results were negative for the presence of combustion in the cooling system.
I took the test three times following the instructions perfectly.

Question is.....does the test really work?

 

[Kep]

You put the blue fluid in the receiver and jam it into the radiator fill tube while the warm engine is running. I don't know how long you're supposed to let it run but if there are exhaust fumes in the coolant they bubble up into the fluid and it turns yellow. You can buy the bottle of fluid for under $10. Maybe NothingSound will give us a report.

Kep

 

[NothingSound]

You put the blue fluid in the receiver and jam it into the radiator fill tube while the warm engine is running. I don't know how long you're supposed to let it run but if there are exhaust fumes in the coolant they bubble up into the fluid and it turns yellow. You can buy the bottle of fluid for under $10. Maybe NothingSound will give us a report.

Kep

You can buy the fluid by itself for around $5.00

It says in the instructions to keep squeezing the bulb for a minute
while the radiator is circulating. I did it for around 2 minutes and the fluid remained blue.

 

[Kep]

There was a local mechanic here in Houston that swore by the stuff. I haven't tried it on mine yet but I am pretty certain that what you did was fine. It might be interesting to hold it by the tail pipe and suck up known exhaust into it. It will have gone through a catalytic converter so it might not work but if it turns yellow it will satisfy you that it is working.

I was fabricating the test container for myself and just bought the fluid. Then I found a leak in my overflow reservoir and (I hope) that solved my problem. I still plan to try it but I have put it on the back burner for now.

Kep