After driving for over an hour and then going up a steep hill or idling in traffic the temp gauge will go up a little, but will come down when the heater is turned on and blowing. I have never heard the radiator fan come on except once when I was trying to teach a friend how to drive manual. The fan came on when the car was OFF but the ignition was on the on position (I guess that's what you call position III). The fan was only on briefly until the car was started again and the lesson continued.

I just read in another thread by the senior mod (and seeming auto expert) that you should never continue driving the car once the temp goes above half. Well the default position for my temp gauge when the car is up to temp is just about half so to me that seems a bit overly cautious? At any rate, most of the time when the temp goes up it goes to about 3/5 to 2/3. There was one time it went to about 7/8 or just below the white line when I was climbing the winding hollywood hills with two passengers and luggage. You can't get out of 2nd gear and much of it is spent in 1st gear. I stopped a couple times to let the engine cool down when the fan blower wasn't able to lower the temp gauge while climbing. I opened the hood while the engine was idling at one point and the temp gauge had come back down to normal, but the radiator fan was not on. Rusty94cx suggested it is probably the radiator fan switch. I like this diagnosis given that the temp gauge only goes up under extenuating circumstances or idling in traffic after a long trip and the radiator fan hasn't been coming on when it seems like it ought to be.

I contacted a guy advertising his services on CL and he said he would put in the new radiator switch I bought and he also said it would be wise to change out the thermostat and flush the coolant at this time as well. The other civic overheating thread that just popped up advises to use an OEM thermostat. I bought a Stant thermostat from Advance Auto Parts. I shouldn't use it?

Is it really likely I have done harm to my engine going up those hollywood hills? At the time I didn't feel any excessive heat from the engine anywhere when I opened the hood. But I didn't exactly know where to look/feel.

 

Do not forget the part how your car was severely neglected for many many years. Don't try to compare your situation with the other overheating thread. I think I would be safe to say that everything that can be replaced, should be. If the other thread advised using OEM parts why then would you not do the same?

Everything that the mechanic is going to fix is a job you can do yourself in less than an hour.

 

I am not much of a DIY person, but I do understand it is encouraged when posting on these forums. Severely neglected? Why do you say that? It basically had one owner--the guy before me bought it with 8000 miles in 1994. It was his daily driver up to when I bought it. for 242,700 miles it didn't seem neglected to me.

 

I stand by my quoted statement. Overheating is one of the most efficient ways to kill a Civic engine. Avoid it at all cost. Otherwise, you'll need to replace the engine or car after it nickel and dime's your wallet into submission.

Does the engine loose coolant? Have you checked the reservoir and radiator levels?

Start by replacing the thermostat and thoroughly bleeding the cooling system. The latter also may solve the radiator fan problem. If you want to take your effort a step further, also replace the radiator and cap.

 

The radiator is new. The coolant level I check often and it never moves at all. It's always at the same level. When the guy sold me the car he topped off all the fluids, including the coolant reservoir tank above the max line. I bought a turkey baser and drained the coolant in the reservoir to a little below the max line. Before and after I've never seen the coolant level fluctuate when I check on it.

So you think even though it didn't go to the red line I damaged my engine? I mean, given what you know about my car thus far and what I've posted on this forum does it seem likely damage has been done?

 

I can't say whether your engine is damaged. My point is that overheating always has the potential to cause engine damage.

At this point, based on what you said, I'd start by replacing the thermostat and bleeding the cooling system. During the bleed, note whether or not the radiator fan turns on, though it might not if the weather is very cold outside.

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Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below (hint: the bleed bolt is located where the upper radiator hose connects to the engine):

 

Thanks RonJ!

To clarify: bleeding the system is not draining it it's just getting air bubbles out?
Should I put a pan of some kind to catch coolant that comes out? (How can I determine where the coolant will fall on the ground so I can catch it?)

 

No draining needed if you only need to bleed. The purpose of bleeding is to get all the air out of the system. Placing a pan below the radiator and engine area below the bleed bolt should do the trick.

When you replace the thermostat, you may want to drain the coolant from the radiator in advance to reduce coolant spillage. However, this is not absolutely necessary.

 

Disregard. Mistook you for someone else. Apologies. That aside, follow the advice given in both threads. The cooling system is one of the easier systems of a car that you could work on. You'll surprise yourself.

 

Okay, no worries.

Yeah, the bleed seems like something I'll be able to do; I dunno about the thermostat, tho. My friend and I botched a brake job on my last VX that ended up costing me more money in the long run because I ended up having to bring it to a mechanic to fix it right and got berated for wrongly leaving the brakes in a dangerous setup. So since then I've sort of felt better to leave it to the experts. But these forums seem like they are really helpful with a lot of experience.

 

You can successfully replace your thermostat if you take advice from members here.

Here's a diagram to get you started. Drain coolant from radiator (if you wish to avoid a bit of a coolant mess); remove a couple of bolts on the thermostat housing; remove old thermostat; install new OEM thermostat with new seal; torque thermostat housing bolts to spec; top off coolant in radiator and reservoir; and bleed cooling system. Done.