Hi

I know Ive seen this problem on here before, I tried searching several different terms and either didnt get what I needed or found an insufficient answer. So Im F'in sorry in advance.

I have a 94 civic beater. Bone stock. Im also in Texas and its been like 106 everyday. The damn thing is overheating at idle, after its been running for about 30 minutes. I checked the thermostat, new cap, checked flow and flushed the system, checked the timing, checked for a blown head gasket, the fan runs great....everything checks out fine.

Everything points to the radiator not being enough for the heat here. It acts fine when its 99 or 100 degrees outside. It only overheats when its this hot and there is no airflow onto the front of the radiator. So I'm thinking get a radiator with a two row core.

A couple of things hold me back, one I used my radiator from a D series a few cars back on a B series swap and it worked fine. Two is that Ive seen this problem mentioned several times but without an answer, so Im wondering if there is something Im missing.

The only thing I can think of the would possibly be causing this, other than the radiator is too weak, is a faulty distributor that could be advancing my timing.

Any wisdom on this bullshit?

 

Have you tried running it without the thermostat?
Add some Redline water wetter to lower the temp?

In the summer you can get away without a thermostat. My mpg hasn't changed much either. In the winter here in the northeast you will need to put the thermostat back in or my car will never get warmed up.

 

The new cap you bought, did you get it from the dealer or from autozone or something? Ive heard lots of issues from people buying caps from places other than the dealer and they suck... its worth spending the little extra $$

 

had this problem before.

when you start moving again. air flows over the radiator and the engine temp starts to cool.

The problem is the temp sending unit that activates the electronic fan. When the coolant gets too hot it triggers the fan to go on. You'll see wires that go from the fan to a unit that screws in near the thermostat housing.

Its either the temp sending unit/sensor. or the fan is dead.

you can test the fan by connecting it to the battery.

I dont know how much the sending unit is.

The jimmy rig i set up, on my beater, was to connect the fan straight to an Accessory fuse. so when the car is on, the fan is always on. with this you may need to change the fan every 100k or so.


Thats what i did with my 92' beater civic. 350k and counting.

 

My guess would be the thermoswitch, which is what Alfred5279 is referring to. If you check the timing at full warm idle, and it's correct (matches up w/ red, usually easier to see at night) than it shouldn't be a factor in the overheating. Even if your timing was set at max advance/retard, the car would be able to keep from overheating (at least at idle), assuming the cooling system is working correctly.

If you search for thermoswitch on this forum, you'll find threads with pics of the thermoswitch on your car. I believe the torque is 17ft-lbs. After replacement you'll have to bleed the system, leave the cap at the first stop (not all the way closed) and idle the engine until the cooling fan comes on twice (watching temp. gauge just to be safe). Then add coolant if necessary to the rad. and in a day or two add to the overflow bottle which will be low. - think you already know all that, but in case someone else doesn't...

edit: found the pic, you can thank Civic2Scooby (and the plastic is blue on that one 'cause it's a Spoon, otherwise it's usually brown)

[SPOILER="thermoswitch"][/SPOILER]

 

bullshit

first most radiator caps are made by motorad in the aftermarket or gates ... both are highly reputable companies

secondly if he's constantly overheating the cap is not the first place to look


i'd try some water wetter or maybe you just really do need a new radiator but i find that hard to believe. you say the fan works but is it kicking on when its supposed to?

 

There are more reasons than that to keep your thermostat installed. Thanks but thats bunk bro.

The fan is coming on at temp though!


It did the times I measured. The thing is, it will still get hot while I'm standing there looking at the fan running. Damn thing. I guess Im biting the bullet and getting a 2 row radiator.

 

Could be a clogged radiator. I know you have to change it out every 100k or so. I've changed mine at least 3 times. its got 300k+.

bought a new one for around 65-80 bucks. new. made in china

County Radiator
orange, ca

 

h: h: h: I didn't realize your fan was coming on at temp., I really did read your post I swear (well, skimmed). An old thermo could still click the fan on but take much longer than it should, but if it works at all that's enough to keep it from getting close to the red (as long as the rest is working correctly).

Your theory of the distributor being at fault seems more likely now, but still seems like the system should be able to cope. If the rad. doesn't have too many bent/clogged fins, I'd try water wetter like rebeld suggested.

edit: and you can get new ones on ebay (from what seems a reputable store), for 5th gens at least, for ~$40 including shipping.

 

Well Im sure the thermoswitch is healthy because I measured the temp at fan activation and it was at proper temp. The radiator wasnt clogged, I flushed everything (and during that process saw that everything flowed just fine anyway). I determined that the distributor was ok so I concluded that the OEM radiator just couldnt keep up with this weather and the heavy traffic. I installed a koyo 2 row and the car has behaved itself. I drove ALL day on side streets running errands (In HOT weather), trying to get it to overheat by driving hard. The best I did was still under half. :thumbup:

Expensive radiator but it will save me from an afternoon of labor and cash had the headgasket blown (plus a machinists fee and possible cylinder damage!).