ok, so i did my zc swap and it runs great, but when on the highway, the motor cools down to below the median range, like it hasnt warmed up yet. i didnt replace it with a new thermostat, but i took the entire housing off my old zc motor (that worked completely fine) and put it on, and the same thing is happening? i never bled the cooling system, but i thought that only caused it to overheat, would that cause this problem as well?
TIA

 

If its cold outside and you drive one the freeway, the cold wind will make your radiator really cold, so your thermostat will say your engine is really cold. It happens to me during the winter.

 

i've heard that to get better gas mileage(during winter) you can put a piece of cardboard in front of 2/3 of the radiator, this will allow your engine to operate at normal temperature, and i've heard of people on h-t getting like 4 more mpg

 

I have always had the same problem with my car...it's almost like they over engineered the cooling systems. If you have the two small fans on the radiator try removing the smaller one on the drivers side. Just secure the power lines for it somewhere and you'll be runnin more in the middle. Depending on how hot your summers are I'd save the fan and put it in in the summer...but probably won't matter either way.

 

are your fans cycling or staying on all the time?

 

you probably did this already but see if you have enough coolant in your system...my car did that too on the freeway but when i was at a redlight, my temp went UP UP UP....not enough coolant in my system...just a thought

 

what is below the median range...most if not all 88-91 cars will show normal operating temp as just below middle but if its pointing down then theres a prob. Even my civic in -30 celceus will be right below middle. But does the temp gauge move around or it just sits stable at the one temp?

 

no no no, when i say median, i meant normal, and before i did the swap, it would always be normal ... i dont see how it could be the thermostat, being i took the whole housing off the old motor and put it on this one, and it worked perfect before ... also, im not having a problem with it running hot, just too cold and the fan (only one) is plugged in

edit: no, it's normal when at idle, yet when i get on highway, it goes down, which would leave me to believe it's the thermostat, but i replaced it

thanks


[Modified by xjoe, 10:59 PM 3/15/2003]

 

possibly coolant temp sensor check 4 codes , let us know

 

Removing his fan would be absolutely pointless. You do know that the fan only comes on when the motor gets very hot dont you? removing a fan is not going to have any effect on a motor that is running too cool.

 

My B16a in my car does the same thing. I've been told that it's most likely the Temp Sensor, because it'll act way stupid. COme days it'll show nearly overheating, others it will show it's ice cold. I replaced the thermostat recently, an had the same issues.

I'm tired of beating myself up on that problem, I'll just replace the $12 sensor!

 

When I had a ZC my temp would rarely move off the bottom of the gauge. The only time the temp would raise is if it idled in place.

 

I have an 89 CRX Si with 290k and it does run cold sometimes...... for example there is a skyway that I come through everyday on my way home from work, this skyway gets pretty cold and windy(those from the bay area CA may know where Cummings Skyway is between HWY 4 and Interstate 80.) I notice that 90% of the time my temp guage will drop down to a quarter or sometimes even less. But when I get back on the freeway, it raises right back to normal. Which leads me to second the thought of an over engineered cooling system. Just my $.02

 

Retard the ignition timing for a warmer engine.
Having researched this problem before, I was pleased today to realize that adjustment of the ignition timing has a much bigger effect on the Honda engine running temperature than in other cars I've owned. There is a critical position where rotating the alternator just a few millimeters in either direction has this big effect, while not affecting performance much. My 97 civic is in England and I also had my temp gauge needle at the bottom most of the time. Recently, I adjusted my ignition timing to try to find that band where your car seems to have that extra pep, but where you might also start to notice some pinging. I learned this trick while using Pontiacs to deliver food in Coralville, Iowa. I'd pulled in for gas one night and another customer heard my engine run on a bit with pre-ignition. He offered some good advice to turn the distributor just a tad in the retard direction. After that, I had a few cars running very well by listening for the pinging and then retarding ever so slightly. (In the case of a Chrysler Lebaron, it was very difficult to retard any without losing power noticeably, so I settled for some pinging and then used higher octane fuel, which made it run perfect.) Therefore, if you have a civic with properly adjusted spark plugs, and a rotor cap and arm that are clean, just rotate the distributor clockwise by a few millimeters (toward you from above, i.e. with the direction of the turning v-belts) and drive up a slope. I guarantee you will find the temperature rises. (N.B. I've given up tuning by ear because the Honda doesn't seem to ping easily.)