Tercel running too warm-hot

It's possible it's the wrong thermostat. I may be mistaken, but on my

84 Tercel (now long gone) I THINK you also had to line up some little hole on the thermostat in the right direction....maybe toward Toyko? ;>) when you installed it.

But seriously, I do seem to remember something about seating it properly. I'd buy a new thermostat and insure you get it installed properly.

A P.S., if you haven't done it recently, it can't hurt to replace the radiator cap, also.

What makes you think that it wasn't running too *cold* before?

As long as you aren't pegging the gauge or have any obvious signs of overheating (pinging, steam, odor, power loss) - maybe you're OK.

-- Mike Harris Austin, TX

If you just had the work done and the temperature gauge is noticeably higher - something was done wrong. You should not run without the thermostat - can lead to worse gas mileage and more oil contamination. First step, have them re install a genuine Toyota thermostat.

If you just had the work done and the temperature gauge is noticeably higher - something was done wrong. You should not run without the thermostat - can lead to worse gas mileage and more oil contamination. First step, have them re install a genuine Toyota thermostat - doesn't cost much and it fairly quick and simple to access.

Who did the work? If the shop is reputable and competent, they can diagnose the problem themselves. Some possible causes are:

• incorrect thermostat opening temperature

• thermostat installed incorrectly (upside down)

• someone damaged or disconnected a cooling fan wire

• someone damaged the coolant temperature sensor wire or connected it loosely

• incorrect coolant mixture

• air not purged from the coolant

• bad radiator cap

• if the coolant was flushed, something clogged the radiator or one of the coolant passages during the flush

It's way too hot going up a hill. I want to hook up the air conditioner soon.

If the water pump wasn't working well, and it still was twice as cool as now, I would think the job was done improperly.

voice from the past

I'm going to get one.

Now that I'm certain there aren't any rusted-through bolts that are going to twist in half, I think I can do it myself. I'm in no mood to argue with the mechanic.

Man! I can't believe that Prestone is twelve bucks now...

What I learned from experience is that while you're saving your brand-new coolant to put back in, use something to deflect the water coming out of the radiator to the pan or you're likely going to get dirt and grease washed off the car, spoiling the fluid.

voice from the past

Since you are going to do the job, I'd bite the bullet and use the OEM Toyota Coolant. The Red Stuff...

Sounds like your mechanic messed up something....you might as well do the job right...

I've thought about the upside-down thermostat...

What do you think of the Prestone spigot you put on your heater hose and flush out the block from there?

I flushed it the old-fashioned way before I realized the rattle I heard was the water pump, before the repair work. It was running kissing-the-cold-line cool right before the replacement parts were put on. Now regular temperature is about 1/3 warm. It was 1/2 today, being 100 degrees outside. It would definitely go to hot if I went up a hill today.

The mechanic said the thermostat didn't come with a gasket, but he took care of it. I purchased the parts myself for the lifetime warranty. If I was given the wrong parts, I think I should be the one to take it apart and fix it.

voice from the past

That sounds like the old thermostat wasn't working correctly to let the engine get up to the proper operating temperature.

Sounds normal, i.e. the new thermostat restricts the radiator water flow and therefore the engine quickly heats up to normal temperature. All of my cars normally have the temperature gauge at about the middle once they've warmed up.

Not clear how you know that. If the thermostat is working properly then it'll open up the radiator flow and keep things from overheating. The 3/4 reading you mentioned before sounds a bit high but it's hard to tell without knowing exactly how the gauge is calibrated and what the actual temperature was. The gauge in my '87 Nova (Corolla clone and mechanically very similar to your Tercel) frequently gets up to about that level but it has never gotten into the red zone or actually overheated.

Those t-taps are OK but can be another potential source of leaks. Make sure the cap and clamps are on tight.

If the engine was running at the cold line, the old thermostat was probably stuck in the open position.

1/3 to 1/2 way up the temp gauge is normal operation. If it holds there when running up the hill, then everything is OK with the cooling system. If it creeps much above that, then I'd make sure the coolant is circulating properly and the radiator fins are not clogged with debris.

I'd let your mechanic take a look at it to get his opinion as to whether it is operating properly. If the temp holds at 1/2, then it sounds OK to me.

I was once told by a mechanic that a thermostat was for cold starts only; that the engine can warm up in cold weather without having to warm the whole resevoir. I never heard of a thermostat being functional beyond the initial engine warm-up.

I want to get the air conditioner a fuse and see if it works, get it charged, and hopefully have a cooling system powerful enough for it.

voice from the past

Either the mechanic does not know what he or she is talking about or you misunderstood the explanation. The thermostat functions all the time, whether the engine is running or not. A "cold start" refers to an engine that is not warmed up to operating temperature and does not really refer to the ambient temperature.

The engine and emissions control systems operate more efficiently when they are warmed up to operating temperature. During a cold start, the thermostat keeps the coolant that is in the engine block from flowing through the radiator so everything warms up more quickly. As the coolant warms up, the thermostat opens to allow more flow through the radiator.

If the refrigerant in the AC is discharged, then the compressor will not engage, even with a new fuse. This is a safety feature built into AC systems to prevent damage to the compressor.