Engine runs cold

Logbear · Post by **Logbear** » Sun Nov 28, 2004 1:22 pm

With the cold days now a problem has come up that has been common with my past Tercels. The water temp stays cool. Going along at freeway speed it does sort of warm up, but I would think that I could make it really warm in the car. I have always put something in front of the grill to block some air flow to the radiator and that helped. Is there a real fix for this problem or should I just cut a little piece of vinyl flooring and plastic tie it to the grill. If I'm stuck in stop and go or city driving it does warm up nice and the fan does come on when it get about mid-range on the temp gauge.

Teddy1 · Post by **Teddy1** » Sun Nov 28, 2004 3:56 pm

logbear,

You didn't specify where you live, so I am going to assume you DON'T live in the actic tundra. I do not have any experience with these cars in FRIGID weather, so, I cannot guess how they perform in it. My cars have been through -20's successfully.

The 3A-C equipped Tercels are NOT in the habit of running cold, actually. For emissions and efficiency reasons (mileage, primarily) they actually tend to run a little on the WARM side, considering how little power they produce. Instead of running cold, what they SEEM to like to do, is, FLUCTUATE WILDLY between quite warm, and too chilly (I have addressed this in my Tercel Wagons by using a different thermostat, a Weber carb with NO emissions gear, timing changes and etc.).

The wagons were also given WOEFULLY inadequate radiators for extended duty in hot climates, but this doesn't seem to be an "issue" for you (the smaller sedans/hatchbacks seem to get along just fine with their radiators).

If you are using the stock radiator, water pump and thermostat, and your coolant mixture is currently 30%-50% antifreeze and 50%-70% water, you should NOT be seeing unusually cold engine temps.

Let me ask some quickie questions, so that I can help you figure out what's going on.

1. Are you allowing the car to warm up in the morninings, for at least 5 minutes, before driving? This initial warm up is ALL IMPORTANT with the 3A-C... cast iron block, smallish oil galleys, steel mains, steel pistons and aluminum heads...

2. Have you verified oil/coolant capacities?

3. When was the last time you checked the condition of your thermostat? (it may be stuck OPEN, which is certainly preferable to being stuck CLOSED). If the 3A-C's thermostat is removed (or stuck open) it will DEFINITELY run cold. Even during summer!

4. When was the last time that you backflushed the cooling system?

5. Do you still have the stock radiator?

6. Does your car still have the stock carb setup, with all emissions gear?

7. Have you checked timing? Even slightly advanced timing will make this motor run WAY cooler... but also tends to increase the ping/knock substantially (which is unfortunate, considering what a low compression engine it is).

-Teddy

Lateer · Post by **Lateer** » Sun Nov 28, 2004 4:21 pm

That sounds to my mind a hell of a lot like a thermostat that's stuck open.
Toyotas all run their heater so hot that you can't have them on full blast most times.

I'd drain the coolant somewhere safe (ethylene glycol is toxic, after all) and have a look at the thermostat.

The manual on here should help with that.

Teddy: What Weber did you have? I'm currently running a 32/36 DGAV 3B and someone has removed the auto-choke...

ludehawk · Post by **ludehawk** » Mon Nov 29, 2004 11:14 am

along the same lines... mine is running very cold recently as well... to the point it barely gets warm and stays that way... even after 6 hours of 80mph driving....... I'm thinking a froze - open thermostat is my problem as well

Logbear · Post by **Logbear** » Mon Nov 29, 2004 11:14 am

Teddy, in answer to the questions. I live about 40 miles north of Seattle. This morning 27 deg F.

1) This morning I warmed the car up while I made coffee. It got just warm enough to melt some of the ice off the windshield.

2) I just checked and added a bit of coolant yesterday. Oil is fine.

3) I haven't checked the thermostat. It sounds like I should.

4) I haven't backflushed the cooling system.

5) Yes stock radiator.

6) Yes stock carb and all emissions gear.

7) It's been a while since I checked the timing.

I think I'll start with checking the thermostat. What is the backflushing procedure?

Teddy1 · Post by **Teddy1** » Mon Nov 29, 2004 12:35 pm

logbear,

I would like to point out that since you live just North of me, we might as well get together and check your car out.

Backflushing the Tercel's cooling system requires the installation of a $10 coolant backflush kit, like the Prestone branded one, or the Napa one, etc. The backflush kit consists of a molded high temp plastic "T" fitting, which splices inline with your heater core (from within the engine bay). The PURPOSE of the backflushing kit is to allow for high pressure water to be pumped from your garden hose, through your cooling system, to remove sediment and dereriorated/corrupt coolant. I like to open my radiator cap as well as the drain cock on the drivers side of the block during backflushing (this procedure is started with the engine cold).

It is STILL a mystery to me why most manufacturers (with the exception of Mercedes, on some models) do not integrate backflush facilities into the cooling system right from the get go.

I am going to HAVE to assume your thermostat is stuck open, logbear. Including gaskets and a tube of high temp RTV, you are looking at about $12 from Napa.

dug320 · Post by **dug320** » Tue Nov 30, 2004 12:14 am

It is without question the thermostat.

Before you decide to put in a flush kit, think about how are you going to legally dispose of the antifreeze.

Antifreeze is toxic. Take your car to a place that recyles/reuses anitfreeze.

Antifeeze does not wear out! The rust inhibitors and ph buffers do become less efficient over time. Dirt and rust can plug the fins on the rad.

In any case the antifreeze will continue to work.

takza · Post by **takza** » Tue Nov 30, 2004 5:30 am

Best place for the flush kit is that top horizontal heater hose.

Warning.....DON'T leave the plastic flushing tee in there...replace it with metal or some serious plastic...I had one crack a few weeks after I flushed it...the heater hose puts some sideways tension on it...fortunately I caught it in time.

Breakage could result in engine damage.

I use the extended type antifreeze...good insurance against doing the heater core thing.

If you are hooked up to a sewage treatment plant...I THINK...that putting the old antifreeze down the toilet is a second choice legit disposal method...the treatment plant can clean it up. Can't find a recycl-disposal place around here.

They also charge to get rid of old tires...so you find a lot dumped along the backroads.

warbstrd · Post by **warbstrd** » Tue Nov 30, 2004 8:18 am

mine ran like crapola when the thermostat was stuck fully open. i knew it was the thermostat because when i touch the heater hose it was barely warm. after running the car, open the hood and touch the heater hose. if the hose is hot going in the firwall, but cold coming out its a heater core problem and a temp sensor problem. BUT more than likely its a stuck thermostat. oh and get the more expensive thermostat by i think Barg Warner (??spelling???). i bought the cheaper one the first time and it lasted about 6 months, it too got stuck open(good thing it didnt get stuck closed), and it looked very cheesy made. the more expensive one was heavier and looked exactly the same as the original thermostat.

Typrus · Post by **Typrus** » Tue Nov 30, 2004 9:34 am

Sounds like what is happening to my Terc. It's the thermostat, I'm sure. While you are getting that replaced you might as well get your system flushed. It can't hurt after all. Heck, it's probably a good idea. I changed my fluid and flushed the radiator when I got the Terc and it came out all puke-colored (rust-infused green coolant) so I then proceeded to re-flush with some rust inhibiting stuff. Thus far the new coolant has remained nice and bright green.
So that brings in a few questions.
How much are those Weber carbs? $400? $500?
Does anyone know where to find an aluminum radiator that fits our cars?
How long will the water pump go before needing a replacement?
What are these problems that can arise with the heater core? How do you diagnose and treat them?
Does anyone know if there are headers made for these engines?

Here is something I would recommend to everyone who ever has to start their car in 45 degree or lower temps;
<a href='http://www.jcwhitney.com/autoparts/Prod ... 73/c-10101' target='_blank'>http://www.jcwhitney.com/autoparts/Prod ... c-10101</a>

It is called a tank heater, what it does is heat the coolant as it circulates it thru the engine block. It is temperature regulated so it gets the block up to (I believe) 160 degrees. Makes for easy starting, rapid heat in the cabin, no 5-minute idle-time needed, allows the engine to run more efficiently (a hot block runs better than a cold one) and for a modest $30, why not?

Those are the most efficient of the "block heaters" which also include;
Heatpads attached to the oilpan
Heat elements attached to the block by magnets
"Dipstick" heaters
Freeze-out plug heaters
Tank-heaters

We use a tank-heater on our 7.3L Powerstroke diesel and it works great. If you put the heat output selector on window then plug this in, a bit of heat will rise from the vents keeping away the brunt of minor frost on the windshield.

Lateer · Post by **Lateer** » Tue Nov 30, 2004 5:21 pm

The Weber on my Tercel was a dodgy job, which I'm currently correcting in small doses as funds and time come in.

That heater block sounds just like the ones we use in the Fire Service for the trucks that are stationed up in the hills, so they start when we need them to.
Got a manufacturer for them?

And I'm looking at getting the core cleaned on my radiator, after I talk to the lab manager here at the School of Chemistry about disposal of antifreeze.

Typrus · Post by **Typrus** » Tue Nov 30, 2004 5:27 pm

Zerostart.
Yeah, they are an intelligent way to go. Protect your engine, thus your billfold.

Lol. I dunno where to dispose of my anti-freeze so for now its in a bunch of HDPE plastic containers awaiting proper disposal. Funny thing- they make plastic milk jugs out of HDPE!

Lateer · Post by **Lateer** » Tue Nov 30, 2004 11:13 pm

Yeah, they do.
It's one of the few plastics you can put in contact with food and not have it degrade, or end up in the stuff you want to eat.

HDPE also holds its shape very well.

takza · Post by **takza** » Wed Dec 01, 2004 5:45 am

Typrus wrote:
What are these problems that can arise with the heater core? How do you diagnose and treat them?

Most heater cores are a BIATCH to get to and replace...espec if you have AC.

Usual symptom is a sweet smell coming from the heater vents...solution is to replace the heater core.

So to avoid the problem or postpone it:

* reverse flush the system with the Prestone flush kit, but replace the tee when done.

* use extended life antifreeze and maybe change it too soon...and maybe use the booster additives now and then.

* use a rad cap in good condition

* DON'T casually flush the coolant system with chemicals....unless you have a cooling problem...you are mostly just asking for trouble. Have heard that using distilled water as a fill is a way to slowly remove lime...dist water is slightly acidic. Have also heard of using some vinegar as a mild cleaner.

Guest · Post by **Guest** » Wed Dec 01, 2004 6:13 pm

Just got through replacing the thermostat. Sure enough the old on was stuck open. Thermostat and gasket from NAPA $8.69. I already had some blue RTV. The hardest part of the job was scraping the old gasket off the engine. The lower nut is kind of hard to get at, but once I got it loose it came off easy. I saved the coolant and reused it. It looked clean and green so I poured it though a fine mesh screen in a funnel back into the radiator. Now after just a few minutes of running, the temp gauge goes up to just below midpoint (it used to stay right down near the "C" all the time), and heat, real heat that feels warm comes out of the heater.

I suppose now that the engine actually reaches normal operating temperature I should do a little tune up. I'll be watching to see if my fuel economy gets better.