running very warm but not extreme

[xirdneh]

The temp needle on my tercel moved from its normal running position (about 1/4) to a higher position (1/2). Just in case it was the gauge itself I bought a numbered gauge. The car runs between 190 and 200 degrees. I know thats too warm because the electric fan in front of the radiator comes on around 195 deg. I found out the thermostat opens at 180 deg. I tried running the car without the thermostat (same result). The radiator is only one year old. Timing is good too. For some reason the "heat control valve" on the exhaust manifold caught my attention. The spring was broke and the valve was flapping freely.
I wired it closed so the exhaust could flow freely and test drove the car. (same result)
I pulled the spark plugs. 1,2 and 4 were pretty normal looking (tan overcoat)
but no 3 was coated with a very bright white and somewhat thick deposit.
i'm thinking i may have a head gasket problem and can't help but think the "heat control valve" had something to do with it.
Has anyone had any experience with this?

[Carguylen]

May seem real simple, but is your fan running enough? My 87 was getting pretty warm, and I figured out that my fam was only staying on for 15-30 seconds at a time. I just unplugged the wire at the fan switch, and with it running, the car doesn't overheat. I know this is not good to have the fan running all the time, so I'm getting a new fan switch. Seems to have been the problem.

[MootsMan]

I was going to say, watch out for that fan running all the time. After I first started driving mine ( it was previously my son's car, I took over after he got a different car), I started it on Thanksgiving Day to let it warm up ( VERY cold day here), let it idle for probably 15minutes, came out and steam was billowing out from under the hood.....top of the radiator had cracked. Finally found out that the problem was that somebody had taken the relay out of the box and crossed a wire across the terminals, with the result the fan was running all the time....it finally just burned out.

I just installed a new temp. sending unit in the block of my engine, and now the gauge registers a little hotter all the time.

[ARCHINSTL]

I always keep an eye on the temp gauge ----because---
I became very aware of the fan and its switch when my Sister blew the engine on my '83, which eventually led to its trade-in.
She was accustomed to warning lights, and did not notice that the temp gauge needle had soared to the top. She drove it to my house with little, if any, water remaining.
When I returned from vacation, I replaced the fan switch and had the radiator repaired (split top). When I refilled it, I was using a hose, and must have put in a couple of gallons before realizing the quantity. When the car would not start, I finally noticed water coming out the exhaust pipe.... Sure enough, the head was dramatically cracked, and the pistons were pumping water.
1100 1985 dollars later (new head and other items), it worked for a while. However, the problem was not fixed, and was going to cost another 1000 or so. So, it was traded.
Tom M.

[xirdneh]

I always keep an eye on the temp gauge ----because---

Well I thought I had replaced the radiator last year but it turns out I did not. I lost track of which car had what (four tercels, three radiators in the last two years). So it turned out to be the radiator. But I did not figure that out until after I replaced the head gasket. I’m pretty sure the head gasket was bad because #4 cylinder was very clean whilst the others were typical with some carbon build up. (190,000 mile engine).
When the car ran hot after the head gasket replacement (frustration) I switched radiators from a car that was running cool and that was that.

i installed a temp gage in the good car and found that the car stays between
170 and 190 in very hot weather (stop and go or on the road) the fan comes on at 195. the standard needle gauge that comes on these cars should be between 1/4 and 3/8 for this range. if it gets to the 1/2 way point the engine is at or slightly over 200 deg. just a bit past 1/2 is 210-215 deg.

[MootsMan]

Before I put the new sending unit in mine, the temp. gauge consistently stayed at the halfway mark, or just a little below. Now, after installing the new unit, it stays slightly above half to two thirds of the way up. Is this something I should be concerned about ?? It's not running hot, as registering in the red area of the gauge, but it is showing hotter than it was before I changed the sending unit.

[xirdneh]

Before I put the new sending unit in mine, the temp. gauge consistently stayed at the halfway mark, or just a little below. Now, after installing the new unit, it stays slightly above half to two thirds of the way up. Is this something I should be concerned about ?? It's not running hot, as registering in the red area of the gauge, but it is showing hotter than it was before I changed the sending unit.

i'm not sure what to say about your temp gage readings. installing a gage with numbers might be the way to go. the one i installed is the mechanical type that has numbers spread out wide so its easy to read 5 deg increments. it cost abt 30.00. i engarged the hole in the firewall where the heater control cable passes through. it passes through above the gas pedal and about level with the top of the brake booster housing.
car should stay in the 170-190 range based on the car i have that runs best (out of four).
i've noticed that my bad car runs fine until it hits 200 deg. at that point i can detect irregularities faint pinging and slightly less power.