'98 Camry cooling issues. (LONG)

[dcbc991]

Hi all. I own a '98 Camry with the 4 cyl engine and auto trans. Currently it has 143k miles on it.

Over the last few months, I've noticed that the car seems to be running a little hot. When stopped, the temp gauge will climb north and get within a 1/4" of HOT. But when the car is moving forward, the temp will return to normal. Never do the fans ever kick on.

Now today while driving, steam began rolling out from under the hood at the overflow tank after about 10 miles of driving. The temp gauge read NORMAL. After shutting off the ignition, bubbling coolant and steam immediately flowed into the overflow tank. Then after about 5 minutes, coolant retreated back into the radiator as it cooled down. I released the radiator cap to check coolant level and noticed a small spring was actually resting inside the radiator! (What the heck is that doing there??) So I fished it out.

I noticed that the top radiator hose was very hot to the touch, but the lower radiator hose was actually cold! So I assumed this meant I had a failed thermostat stuck in the closed position and perhaps the spring I fished out was just part of a broken thermostat. But later I removed the thermostat to inspect it and it was perfectly in tact. I also tested it and it opened at 195 degrees, but barely so.

So I bought a new thermostat, which turned out to be a 180 degree instead of the 195 degree that came out of it. Before installing it, I tested it and it opened up much better than the old one. After installing the new thermostat and allowing the car to reach operating temp, the lower radiator hose is still cold while the top gets very hot. Oddly enough, the temp guage now reads that the car is running cooler as the gauge is just south of the midway point.

So now what could be the problem? A bad water pump? Maybe the impeller of the water pump is free-wheeling and therefore no circulation is occuring?

Any suggestions welcomed (and sorry for the long post).

[carsrus]

The spring thing you found in the top is your rad cap. You need a new one.

The bottom hose should be a cooler, but not completely cold.

[dcbc991]

Thanks for the reply. OK, I'll check the radiator cap and report back. I'm still wondering if I'm not getting any circulation because that lower hose should only be a few degrees cooler, not cold.

[fenixus]

also make sure that your cooling fans both kick in sometimes even at idle. if not check fusebox and check/replace fan fuses and knock on relays to make sure they didn't get stuck. if i remember right, fan fuses are 30A female MAXI fuse type (big plastic square on top).
i had one fan fuse broken, engine temp was only a little higher at idle, but i could tell the difference by touching rad (very hot! instead of "normal hot"). later on i replaced also thermostat and htr fuse (had heating trouble).

oh, get a new cap from dealer, they are cheap. going aftermarket is not a good idea on this one.

[Stillrunning]

Agree that your first problem was a broken rad cap. Hot expanding coolant went to the overflow. The reason it got worse after shutdown was that engine temps increase for a short time before they begin to cool. I'd replace with 195 stat though not the 180 as that will affect engine operation, and that's why your gauge is showing cooler temp. If you've been topping up system with plain water that will lower boiling point. Always top with 50/50 premix. If you buy aftermarket stat look for position of small bleed hole that may replace jiggle valve and install in 12 o'clock position to allow air to flow through system. Did you make sure you vented all the air out when refilling? Jacking up the front of car may be required. You can look for coolant flow with rad cap off as engine warms, but do not open already hot system and do not look directly over rad cap opening. Visable flow will occur when stat opens.

[dcbc991]

Ok, the radiator cap was definitely part or cause of the problem. The bottom half the cap is completely broken off:



The spring was laying inside the radiator. Which means that the other parts are circulating inside my engine and could wreak havoc on my water pump and such.

After installing a new cap, the lower hose is pressurized now where as before it didn't seem like it. But the lower radiator hose is still cool to the touch.

So now I'm thinking that I must have a bad water pump?

I've never seen one for this model, but is it possible that the fan could be free-wheeling and not moving any water?

And like I said, the fans never seem to kick on. I'll check those next.

It's getting close to changing the timing belt again anyway, so I'm thinking this might be next weekend's project. While I'm at it, just change out the water pump and the oil seals as I have a small oil leak. Perhaps take the radiator off and have it flushed at a local shop.

Thanks everyone here for your input. It's greatly appreciated.

[Stillrunning]

Originally Posted by dcbc991

Which means that the other parts are circulating inside my engine and could wreak havoc on my water pump and such.

I doubt parts will be able to flow past rad's cooling fin passages. I wouldn't worry about it. If the temp gauge is operating correctly and showing no overheating then don't worry about temp of lower hose. The fans will kick in when they need to. If lower hose is cool then there's not sufficient heat to trip the switch. Slow flow in the rad will cause coolant to cool more than fast flow, that's another reason for a stat.