'98 Camry Running Cold

Best guess is that the thermostat has failed. As your dad noted, they generally fail in the open position. Not an expensive job and after 8 years it is due for replacement anyway. Replace with Toyota or Stant brand. Some of the other aftermarket brands aren't much good.

As previous poster said, sounds like a new thermostat is in order. Not only does it make for chilly driving, the engine doesn't operate as well as it should with this problem. Don't follow Dad's advice about the cardboard.

You can check the thermo without the cardboard and without the risk of problems associated with it....Just feel the radiator hose as described in this link....it also mentions several other possible problems....and cautions against cardboard....

Regardless, the thermostat is the most likely culprit...

There were some high end cars (I think of Packards) which were able to close the slats in the grille in front of the radiator and thus augment the heat of the radiator water (and anti-freeze). But the cardboard is not a good idea. Go for the thermostat replacement.

Thank you all for your responses! I will replace the thermostat before doing anything drastic. I'm going to attempt it myself, while following directions downloaded from the Internet so wish me luck.

Thanx, Kari

Pretty simple job really....I've done several of them....only screwed it up once, and that was because I let the edge of the "stat" slip and I bent it under the housing, which caused a nice leak....As someone else mentioned, since you are trying it yourself, do yourself a favor, pay a few extra $$$ and get a genuine Toyota "stat." Odds are something else will work, but in the aftermarket stats I have seen, none of them have this certain little hole that TOY puts in theirs. Maybe that hole is unimportant, but after doing all that labor (which isn't that much), hate to see the job negated by an attempt to save $5- $7 with another brand. Thermostats, coolant and ignition parts in my opinion should all be Toyota brand. All the rest, aftermarket is fine.

Here in Canada, everybody does the cardboard thing, and I've never heard of a case of overheating because of it. Lots of those same people idle their cars for 15 minutes using remote car starters before they start driving, and, again, no overheating.

-- ... "`... then I decided that I was a lemon for a couple of weeks. I kept myself amused all that time jumping in and out of a gin and tonic.' Arthur cleared his throat, and then did it again. `Where,' he said, `did you...?' `Find a gin and tonic?' said Ford brightly. `I found a small lake that thought it was a gin and tonic, and jumped in and out of that. At least, I think it thought it was a gin and tonic.' `I may,' he addded with a grin which would have sent sane men scampering into the trees, `have been imagining it.'"

- Ford updating Arthur about what he's been doing for the past four years.

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Use a Toy thermostat, Ive had bad luck with aftermarket not being sized right or not working.

Pretty simple job really....I've done several of them....only screwed it up once, and that was because I let the edge of the "stat" slip and I bent it under the housing, which caused a nice leak....As someone else mentioned, since you are trying it yourself, do yourself a favor, pay a few extra $$$ and get a genuine Toyota "stat." Odds are something else will work, but in the aftermarket stats I have seen, none of them have this certain little hole that TOY puts in theirs. Maybe that hole is unimportant, but after doing all that labor (which isn't that much), hate to see the job negated by an attempt to save $5- $7 with another brand. Thermostats, coolant and ignition parts in my opinion should all be Toyota brand. All the rest, aftermarket is fine.

and, IMPORTANT!, don't ever replace the thermostat upside down ! Note carefully when you remove the housing which way the damned thing is facing. It really isn't a hard job, and with a decent socket wrench, it shouldn't take long. Check for leakage at the base of the housing when you're done, by running the engine for a few minutes. ...and DO get a genuine Toyota thermostat.

I think the main risk with cardboard is in leaving it in place when the weather warms - even for a day in January. Since there is no good reason to do it in this case, she shouldn't.

I had a '64 Volvo P220 wagon that had a windowshade-like device, operated by a chain inside the car, that would selectively block off part or all of the radiator. Engine cooling systems have improved since then.

The simples thing would be the thermostat failing in the open position as mentioned.

However, if replacement with a Toyota thermostat and Toyota coolant with distilled water (or the new Toyota Pink pre-mixed, do not add water) and you still have the problem, then it's either overcooling (which is not likely as you mentioned prior winters) or a leaking head gasket.

Hello again!

I just wanted to give a big thank you to everyone who helped with my problem. Yesterday evening, on my own, I replaced the thermostat!. It wasn't quite as easy as I thought, but I did it, there are no leaks, and my temperature gauge is now right where it should be -- just below the three o'clock position -- and rocksolid. The only problem I had was one of the bolts was blocked by what I think is the air conditioner unit. I had to borrow a wrench from my neighbor to get to it. But other than that everything went really well.

Thanks again, Kari... Toyota Mechanic Extraordinaire

Congratulations, Kari, and thanks for posting your follow-up - lots of people don't bother doing that and the folks in the newsgroup never get to learn what the problem really was.

Good going Kari, and thanks for the results of your surgery on the Camry. If you had the time or interest you might want to take the old thermostat and look at where the spring seals it closed. This is to shut off the water to and from the engine....and when the engine starts and heats up, the spring will open the seal when the temp reaches operating level, allowing the water to flow through the cooling system. If your old thermostat does not close all the way when cold, it means the water never reaches the high temperature it's supposed to. Unless you're concerned about the heater not getting the hot water going through it to warm you, there's nothing wrong with having a non-functional thermostat, except that your engine will operate too cold, and your gas mileage will suffer. Congrats on your job!

mack wrote: (...)

An engine that constantly runs too cold will build up acid in the oil, and will not last as long as a properly maintained engine. It needs to get hot to drive water condensate out of the oil, to prevent hydrochloric acid from forming. In the short term, or the Summer, a stuck-open thermostat won't hurt anything, but in the long term it's one of the cheapest ways to ruin your motor.

I tested my thermostat initially by dumping it into some hot water and found that it didn't contract like it was supposed to. Then I tried again by gradually heating up the water (as it says to do in the factory service manual) and found that it worked fine. Anybody have any theory about this? Why would it not contract under thermal shock?

Well I`m in Kanada and I DONT use a cardboard in front of my rad and I dont know anyone else who does. Even my daughter who lives inthe far north where temps go to -45 in the winter doesnt use a cardbaord rad cover.

Those days are gone now with the modern cars.I HAVE used cardboard rad covers 50+ years ago when a therm. failed "open " in the winter ,but couldnt work on the car to replace it until the temp moderated to warm.(No garage)

The rad is under pressure and it will work fine at 15lbs sq in. but when it is placed under a pressurized rad cap it wont open properly