Rep Power: 0

1998 honda civic 2 dr 1.6 auto with ac.....i have had this car for about 2 years now, about 3 weeks ago it ran hot but not all the way! made sure it had

coolant and such but ended up changing the radiator to a new one, ran good for awhile untill last week...it got hot according to the guage a few times but

came right back down to normal temp! to make a long story short i ended up having a water pump and timing belt kit installed and new cap....got hot

again so i did a new thermo, upper hose and electric fan relay, well the car still gets hot according to the guage but not so sure its really hot....the

machanics shop let me borrow a hand held thermoeter with a laser lite. ok so right now i have a new rad,thermo,water pump,timing belt,fan sensor and a

50/50 mix and when the guage reads 3/4 the actual temp according to this tool reads between 195-210 at the termo housing! but i can watch this guage

move up and down fairly quickly ? no water in the oil,no white smoke and it holds pressure!! i berped the system by running it for awhile with the cap off

untill the thermo opened and i could see the coolant moving then turned on the heater so that was flowing! let it sit for hrs and topped it off and made

sure that the overflow bottle was right, right now if i drive it on a hot day like today 105 outside with the ac on it will get hot under load going up hill, if i

turn off the ac it will cool down alot but not all the way...the fan will go on about 190 and stays on the whole time untill the temp gos back down.what are

the chances of having a bad water pump ? oh and the gas guage doesn't work right anymore so i go by miles....what am i missing ?? not loosing any water

etheir. thanks for any help on this matter, oh and it has about 225,000 original miles and runs nice and smooth! starts right up,no pinging

 
Rep Power: 518

Either your gauge is accurate or it is not.

Get a scanner that can read live engine data you can check while you drive.
The computer and the gauge don't share the same sensor. You could have one of the sensors bad causing gauge error.

If the live engine data does not agree with what your gauge is saying..... fix the gauge problem.
You should be able to verify the scanner temp reading with the infrared temp gun too. (Note limitations of the infrared method, it's most accurate on non-reflective dark surfaces)


If the scanner does agree with your dash gauge..... that would indicate a real cooling system problem.

 
Rep Power: 0

update..ok this 1998 civic that i been working on for my daughter! i could not get it to stay cool all the time so now it has this!!!!

new timing belt
new water pump
new radiator
new thermo
all new hoses
fresh surfaced head
new- h gasket
new cap
new temp sender
new elec sensor
have not changed the elec fan yet, it seems comes on and off when needed ?
took it for a ride and the temp still gos up to 1/2 to 3/4 on the guage useually at high rpm sometimes...when it does i check it with the laser hand held gun

and it reads 199 at the thermo housing and anywhere from 155 to 185 depending on witch hose i check! if i run it with the cap off with the idle about 1000

it will loose water out the top of the radiator ? with the cap on it builds pressure and holds, but when i hold the top radiator hose for a second it feels like

alittle bubbling ? i have run it with the cap off for 1hr, ran it with the cap on for an hr, the with the ac on and off, with the heater on and off ? then let it sit

overnight and the water didn't change, what is the best way to get all the air out of this system ?? i was thinking on the temp guage being bad but before i

did the h-gasket the machanic and i drove with the sanner plugged in and the gauge seemed to move according to the temp of the motor! right now if i

drive it, it will run about 1/3 on the gauge and sometimes go up as high as almost 3/4 and come back down 1/2 and slowly just a tad more and according

to the hand held temp gun it has got to 201 at the termo housing and all the hoses seem to be between 155 to 185 ? i am going to take it on the fwy and

see what happends and so far no water loss! and its a 90%water and alittle coolant just in case there was a leak i didn't want to waste anymore more

coolant...thanks for you time oh and the timing is perfect...

 
Rep Power: 518

Which temp sender(s) did you replace?



Have you done this again now since you replaced a bunch of parts?




Reading temp with infrared gun by pointing at the rubber hoses usually does indicate lower than actual temperature. The plastic on the upper tank of the radiator and the thermostat housing will probably give you closer to real temps.


199-201 sounds reasonable, I think the fan should turn on somewhere around that temperature.

HTH

 
Rep Power: 0

i replaced the one under the dist small brass one with 1 wire...took it for a ride and it did do alot better but still got alittle warm according to the guage! but it still shows 199 on the thermo housing and 165 on top of the rad plastic tank, i ran it w/o the cap when i got home for 30 min to get air out of the system because remember i had it completley appart,head,intake and all hoses off. i'm going to add water wetter and coolant today and hopefully call it good...but yes there is 1 sensor i did not replace and that one is to the right of the dist by the top hose where it go to the head, i think the book calls it a sensor and not a sender ?
but to make this clear after all these new parts are installed and running only hose water in case of a leak at the thermo housing it says 199 and the thermostat opens and fan comes on, radiator tank says 165, lasor on the head says 185 and with the cap off the water inside the radiator says 165-175 so i think that damn gauge is wrong...

 
Rep Power: 0

honda lists 2 differant things.....a temp sender 1 wire, aqnd a temp sensor with a plug. looked up on google and thats worthless! i replace the 1 wire so should the other be replaced too ?? here is 1 artical i found that is stupid....

What does a Coolant Temperature Sensor do?

Updated Answer
Manual Labour
the coolant temp sensor( cts) reads the temp of the engine and adjust the fuel air mixture depending on the temp. if its cold out the sensor will adjust for more fuel to ease the start of the engine.


ADDITIONAL:

The Coolant Temperature Sensor measures the temp of the coolant, not the engine. The sensor controls the thermo fans on/off. depending upon temperature.

 
Rep Power: 518

There can be more wrong information found on Google than correct info.






On YOUR engine, on the end of the head, near/under the distributor:

The sensor with the single wire operates the temp gauge on the dash.
The sensor with 2 wires is for the computer.


The radiator fan has its own temp sensor (switch) on the thermostat housing.

Sounds like it.
Got scangauge?

 
Rep Power: 0

thanks ezone i got that now but, according to that gauge it was all over the place driving home lastnight about 8pm so now i ask where do you guys suggest i install a external water gauge on the head ??? this is getting really old and frustrating....

 
Rep Power: 0

thinking on this i was going to replace the other for the computer but if the 1 wire is for the gauge that doesn't make sence! should i drill and tap a new hole in the head for the machical gauge ?? or do they make an external temp gauge that just plugs into the original temp sender ?? that would be too easy!!

 
Rep Power: 0

IF she has a cracked block wouldn't that show up in the oil ? or build too much pressure ? by the way yesterday i added a bottle of water wetter and then drove it about 25 miles, much to my surprise when the gauge started to climb i pulled over to check the temp with the gun and the motor was 185 and the thermo housing was 199 and the fan came on but what surprised me was when i went to take the cap off because the upper hose felt like very little pressure the cap came off easy with very little pressure ? before the ww i had to keep releaseing pressure to take the cap off...

 
Rep Power: 518

Have you driven around with a scanner (or scangauge) showing what the computer is seeing when the gauge is reading hot? (data comparison)
I mean, verified that it is not really overheating and your dash gauge is really the problem?

Did you use a factory temp sensor?
How about replacing the original gauge itself if it is the problem? (I just looked up a DX temp ga, only $25 retail...IDK what car you have though.)

If you are going to add another temp gauge, I'd try to use the original threaded hole for the original sensing unit first choice. If it won't fit there, I'd have to see what else is possible, and that's tough to do when the car isn't in front of me.




I think I'd rather have the Scangauge myself, there's a lot more data and functions available right at your fingertips with it.

 
Rep Power: 518

So reading at the thermostat housing is the most accurate place to get your reading. The others aren't quite accurate, therefore misleading.

If you had tried to remove the cap before the fan ran, would it have had pressure on it? Maybe. The fan was cooling down the liquid that is in the radiator.

Oh wait, you are running water, aren't you? Maybe go to 50/50 and see what that does?

 
Rep Power: 0

the new temp sender is from napa, and before i did the h-gasket the machanic and i drove the with a top of the line scanner plugged in the whole time and the scanner seemed to match what the gauge said ? my daughter just called me after the car sat all night and the coolant level is right at the top where i put it...the overflow bottle is where it should be.. the only other things that come to mind is mybe the radiator got clogged some how but it looks new inside and its only a couple months old, or the new thermo isn't right but it opens right at 198 or the new water pump isn't flowing enough, when i ran it with the cap off and the coolant level low but above the ribs when the thermo opened it flowed good ? i just dont get it!!

 
Rep Power: 0

yes i have been reading the temp at the thermo housing and so far it has not gotton any hotter than 201 in the middle of the day at 98 outside with ac on...

 
Rep Power: 518

But what's it like NOW? Does a computer scanner reading agree with the gauge now?

And that's when the fan kicks on, right?



When does it appear to run hot?
Sitting still at idle, or driving down the road?

 
Rep Power: 0

well its been a couple of days and she says that its running pretty good but only turns the ac on off the fwy! i got a new aftermarket electric gauge that will hook up at the stock sender...i will see what is happening now i hope! no i have not driven the since the new h-gasket because the machanics shop got busy and he needs it, he only let me use it when it dead at the shop.are those HF sanners any good ? they have 1 for 40.00 and 119. for codes and turn off the engine light but they get a 20% re-stocking fee for returns.

 
Rep Power: 518

I couldn't tell you anything about them. I have the factory HDS scanner software and the older Honda PGM tester available to me.