engine ran closer to Red Zone

[91tercelowner]

OK, so today I took that long trip across the state. I noticed it was solid in the middle between hot and cold.

Since everyone said that was ok, I was relieved.

When I got off the highway, there were some long stop lights. I noticed the indicated rose above the mid point.

Then, when I was at the building, there was a real long light where you had to wait for a green arrow, and the indicator headed real close to the red zone.

Keep in mind--yesterday (or the day before) I had checked both the coolant reservoir, and in the radiator itself. Both full.

I went in and had my business meeting, the whole time worrying if I would make it home ok.

Then, an hour later, the meeting ended. Before I started the engine, I lifted the hood. The reservoir was down to just at the low line. And the cap off the radiator, I couldn't see green.

Since I had 25 miles to drive, I dumped ice water from the trunk into the reservoir and into the radiator. It was all I could think to do. (It was ice from being in the trunk, I am in the northeast). I put in less maybe half of one of those large water bottles.

Then I drove home.

So, now I think there is a definite problem.

Thoughts?

[Daox]

Sounds like your thermostat is stuck partially open. Refer to your other post to see how to replace it, or just take it in some place.

[91tercelowner]

But how would the thermostat make the coolant itself be low?

[Paseo15psi]

Everything gets backed up in the block and the heater core. It doesn't recirculate and cool the engine.

[91tercelowner]

OK. Can you run this by me again?

Are you saying that the thermostat misfunctioning causes everything to get backed up? So the water/coolant were really in there, floating around, just not visible in the coolant reservoir nor at the top of the radiator?

Can you guys explain to me how the thermastat works, then?

Are you saying if I have it replaced, the problem will be fixed?

[4agetercel]

when the engine gets to a certain temperature the thermostat opens to let the hot coolant into the rad where it is cooled by the fan, when the coolant reaches lower temperatures the thermostat closes back up again. Does your fan come on?

[91tercelowner]

I never noticed about the fan.

I know the a.c. works, and the heater. If those are related to the fan that is...

So what you are saying is that if the thermostat closes while the coolant is floating around the engine while I am driving, that temp gauge will read really really high? And won't allow the coolant back into the rad nor the reservoir--which is why when I looked an hour later, it was empty/low?

So if I have the thermostat replaced--is that a zillion dollars? Hard to get to ? (No, I can';t do that myself, but need to be prepared to not be ripped off by a mechanic)

All this has nothing to do with the water pump, does it? How can we be sure that I don't need a new water pump (that went, in 98)

[4agetercel]

Yeah if your thermostat doesnt open then the engine keeps heating up resulting in the coolant to overflow through the resevoir. shouldnt cost too much to replace, i dont know how much it would be because i do my own work but all it is is 2 nuts that are on in the lower rad hose houseing, you take the houseing off , take out the thermostat and put the now one in and put the 2 nuts back on. easiest thing to do. so no it shouldnt be a "zillion" dollars. should be around half hour labour if even that much. If your water pump went in 98' then it shouldnt have gone again.

[91tercelowner]

What surprises me is that the guy who sold me the radiator didn't even check for or mention the thermostat, when I brought it back with this same problem last summer (it behaved since then, in cooler months).

Is there a way for them to test this?

And is there a specific way to actually tell when the water pump "goes" vs the thermostat?

(P.S., Thanks, guys, for making me an educated consumer--and less likely to be taken in by the "wolves" around here, i.e. the mechanics who will be happy to sell me stuff I don't need cause I'd never know any better.)

[4agetercel]

Well my Tercel has 406000klm and the water pump is still working after it has run with no coolant in the engine and overheated, so i doubt its the water pump, but if yu want to change it go ahead. thermostats are like 20 bucks and i doubt it costs too too much to install, so even if it doesnt solve the problem (which it should) it not bad to have a new one in the engine especially if it has never been changed.

[91tercelowner]

Well, I took it to two places and told them the problem and the likely fix that you guys suggested, about the thermostat.

The guy who originally sold me the new radiator told me that "in 99 percent of cases" the thermastat would not malfunction, it would completely go all at once and your engine would over heat. And that he had no way to check it except to take it out and dump it in hot water.

The second guy said changing a thermostat is a huge big deal. He didn't really believe me that this was the problem, checked my radiator--declared it low (despite the fact that I had just driven it, and so the level would not get back up yet) and before I could stop him, dumped lots of coolant in the radiator.

So, I am still stuck. Plus, given that this guy added coolant, when my coolant was probably still floating around in the engine, is it possible to have too much coolant in there?

I could have the first guy install the thermostat he said for $40, and hope for the best. but it makes me nervous that he does not believe me nor confirm the problem.

I was hoping for a mechanic that would say, Yes, that is correct and I can prove it.

[Daox]

Both of them are idiots then. Thermostats, especially on a 17 year old car are a common item to go bad. Theres no telling where they'll stick either. They are a valve that opens and closes. Sometimes they stick wide open, sometimes totally shut, sometimes (although less often) they'll stick partly open.

The process of checking the thermostat vs just changing it is just dumb as well. If the coolant is already drained, installing a new thermostat is literally a 5 minute job. The thermostat itself costs only $8 and the seal for it is a whopping 50 cents or so. Any mechanic who puts in a new radiator before checking the thermostat doesn't know what he is doing. Try another shop.

[4agetercel]

does the car heat up while driving or when it sits in one spot?

[91tercelowner]

Yup, idiots.

So the question is, given it is now a full and new radiator, is this still a 5 minute job?

The one guy refused--said its a huge big deal. The other guy will charge me $40 but he is the one who installed the radiator without checking the thermostat. I also found out he isn't a mechanic. But runs a shop that sells only radiators, which is kinda weird.

To answer the other question, happens while driving, and worse while sitting. Not so much highway, but traffic lights, etc.

[4agetercel]

well when it gets to operating temp and make sure the fan comes on and change the thermostat