TRIZ

iTrader: (14)

Background info: Completely stock 2001 civc LX, coupe.


I’m driving yesterday and notice my temp gauge in the car is just a sliver below H. So heres what I do:

- I freak out and drop the windows and blast the heat
- Park, check coolant and if the fans spin
-----Coolant level is between low and max, although closer to low
-----Fans spin only when you trigger them with the climate control in the cabin
- I check the tail pipe for white smoke, and unscrew oil cap to look for white residue- none. Cool, headgasket should be safe (never pulled the head on this motor- stock internals throughout)
- So I let it cool for a few hours since I had to study at the library
- I hop back in and temp gauge jumps right to the 1/3 level on startup
- I drive with the heat blasting, and AC on to keep temp gauge from going past H
- I get to my buddies place and park it in his garage and we do a number of things, as follows

- Plug in OBD2 digital gauge tool to check everything- all seems normal, even engine coolant temp- which is within normal operating range- it was at about 180 or so at the time we check, the car had been sitting for almost 20 mins.
- We double check coolant and that the fans aren’t dead
- Check the fuses in the engine bay… all good. Even swap some around, no bueno
- We stare puzzled into the engine bay. The internet suggested several things…
- We pulled the connector from the fan switch and jumped the two pins to make sure the fans clicked on- they did, saying the fans are good
- The top hose from engine to rad is hot, the bottom hose from rad to engine is cooler, good news. This is as it should be.
- Since we’re getting readings from the coolant sensor, we left that alone- it shouldn’t have any problems
- We decided it must be the thermostat and replaced it with a brand new one and gasket from autozone (we filled the coolant back up and got the air out of the rad too)
- Engine still gets really hot and the temp continues to climb… wtf right.
- So I had my buddy drive me back to my place to pick up these used engine coolant sensor and fan switch I had laying around for whatever reason (No, Never had any issues with my cooling system before- these were just spare, used, parts I have)
- I put both in, lost a little coolant, filled it back up, purged air from rad.
- Car still has an issue with heat- the fans don’t come on and the temp gauge in the car is at H.

I read that overheating is at 199.3 degrees, and everything under that is normal operating temp… but my rad had just a tiny amount of smoke coming from it at 195 degrees, so I couldn’t safely hit 200 to see if the fans ever kicked on… (The next day my buddy tells me that the smoke was a little coolant we spilled on the rad when filling it up- so I'm actually NOT burning coolant)

I dunno what else this can be. I’m riding my bike back to Autozone today and picking up a BRAND NEW fan switch.


^ not my bay, but a pic of where these sensors are at



KEYWORDS: Coolant, overheating, fan switch, FML

04 Honda Civic

iTrader: (2)

Thats ****ing crazy. Double check to make sure your not getting emissions gas in your coolant just in case it is the HG. I would have thought it was the ECT sensor for sure. Maybe its the cluster guage itself?
Is the coolant actually getting hot or is it just the reading?

TRIZ

iTrader: (14)

The coolant is getting hot, thats for sure. The upper rad hose is something you prob dont wanna touch when the coolant inside is nearing 200 degrees.

I'm wondering if its the cluster.. but at the same time, the fans arent kicking on and the relays seem to be clicking. Does the fan switch trigger the relay, which clicks and triggers the fans, or does the relay trigger the fan switch, which triggers the fans? If its the latter, it must be the fan switch, if its the first way then it must be the fan relay switch. (???)

Anyways, autozone has the fan switch (part# TU197) looks like a direct OEM replacement. $27.99. About to bike there, haha

04 Honda Civic

iTrader: (2)

Didnt see this -----Fans spin only when you trigger them with the climate control in the cabin
I am pretty sure the relay is what triggers the fan switch. At least that is the way it is in other cars I have seen around my friends shop.. but if you say the relay clicks its probably fan switch

CraigW

iTrader: (1)

The radiator fan switch should switch the coil of radiator fan relay, it's contacts should turn on the radiator fan motor.

Many of the relays out there in box have the same part # (printed on top)
swap the radiator fan relay with another of the same part # (mark which is which 1st with Sharpie)

madAd

Did you check your cooling system pressure?
If the relays clicking but the fan's not coming on, there is something wrong there. But, back around the 4th of July I noticed my rad. fan wasn't working, could've been 5 days before I even noticed. But it didn't work for a couple of weeks, and I even drove it to the Upper Peninsula and back, and it never overheated. Never even went above normal temp. I've replaced the motor since, but I just thought I'd throw that out there for ya to consider.

TRIZ

iTrader: (14)

SO I went and got the part at autozone.. biked there, 11miles round trip.

Drove the car to my buddies place and we triple checked everything again. Nothing new. So I'm thinking its time to install this fan switch I just picked up

I pulled off the power connector to the fan switch, let the temp hit 200 and used a multimeter to check if the circuit was completed when it "switched" over. I thought it was going to switch at 200, but it switched at 205! Odd, but it works. So I dont need to install the fan switch!

So I decided to put my old cluster in and see where the needle sat... sat right where it should. ****, the needle on the cluster I was running was off!!! I had replaced it about 2 weeks ago and maybe never noticed???

CONCLUSION>>>> All my ***** right, the friggen gauge needle was off. Why? Because whoever I bought it from had pulled the temp gauge off while the thing was on and it wasnt put back at the same position, hence the off reading. I-EYE-YIE!!! I pulled it off and put it back on a few times trying to get the right position and I believe I got it. So all my ***** back and together in working order.

unTuned

haha god. the whole time i was reading the first 3 posts i was thinking 'noone has mentioned that maybe the cluster needle is screwed' i was going to ask if you had switched or messed with it. that sucks...all that worrying for nothing. at least you know your systems running good..haha.

04 Honda Civic

iTrader: (2)

I mentioned it, but you said that your coolant infact WAS getting hot? Im kinda confused lol Glad its all sorted though.

TRIZ

iTrader: (14)

Its supposed to get hot. Up to 200 is totally normal. When its at like 215, somethings not right, when its at 220 or 230 somethings totally broken N needs fixing.

I didnt notice that it was ever at H... which is odd. So i kinda dismissed the cluster issue. Oh well... at least its fixed. This is pretty much the entire guide on what to check when your overheating tho.

TRIZ

iTrader: (14)

Its supposed to get hot. Up to 200 is totally normal. When its at like 215, somethings not right, when its at 220 or 230 somethings totally broken N needs fixing.

I didnt notice that it was ever at H... which is odd. So i kinda dismissed the cluster issue. Oh well... at least its fixed. This is pretty much the entire guide on what to check when your overheating tho.

gearbox

iTrader: (95)

yeah i was gonna say either waterpump or broken cluster, esp since you replaced the cluster recently. and you should not need the fan to turn on to save the car from overheating. some cars you do, but on our cars even a hot day you will rarely see the fan turn on and even then its only for a short time if youre at idle alot.

mclean987

iTrader: (1)

my 2002 d17a2 overheated because of bad heater hose all the coolant leaked out and it was at the H for like 10 mins before i noticed thats when the car shut off itself. i changed the heater hose and filled with honda coolant and let all air bubbles out but it still overheats, it takes like 20 mins though so my question is how do i know if its fan switch, radiator or thermostat or headgasket ? the thermostat hose isnt as hot as the other so im thinking its thats so im going to buy new radiator cap later and take out thermostat out and see what happens, any ideas? what do i change first ?

gearbox

iTrader: (95)

pretty sure driving that long with no coolant killed the engine. at the very least you need new headgasket, possibly a whole new engine if the block or head is warped.

mclean987

iTrader: (1)

yep thats what i thought, women !

mclean987

iTrader: (1)

what else would it have killed? should i bother taking out thermostat or changing radiator cap and fan switch and thermostat switch ? if those were bad it would show up on ecu obd2 scanner right ?

gearbox

iTrader: (95)

i dont think those would go bad just from getting no coolant on them. they will not show up on obdII but when you get the engine fixed you can check to see that they are working. but i really dont think anything happened to those sensors and parts.

TRIZ

iTrader: (14)

HOW TO CHECK WHAT YOUR OVERHEATING PROBLEM IS:

Your top hose should be hot as the coolant leaves the engine, trickles through the rad as it cools, and back into the engine on the bottom... Top hot, bottom cool. If this works, and there are no leaks from your radiator, then its fine.

Let your car cool for several hours, pop the hood, make sure your ac and air is off and turned all the way down to off. Start the car... look to make sure the fans arent spinning. Turn the AC on / defrost and make sure the fans spin. If they dont.. your fans are bad. This is the case why ppl overheat only at stops or when idling parked.

Check your fan switch by removing the fan switch connector and connecting a wire between the two prongs.. if the fans click on, its good.

Its your thermostat if all else fails.

This assumes your head gasket is fine (to check if its bad: make sure nothings leaking all around where the head and block meet, and that there is no white smoke coming from the tail pipe, and no white residue on the underside of your oil fill cap and inside your head from what you can see when removing the oil cap), and that your gauge cluster is fine (coolant temp levels should be at 0 or "C" upon start up and only after about 10-15 mins or so start to rise only to less than the 1/2 way mark... if it raises to more then that OR if it starts off higher then 0 or C then you gotta problem with the cluser- meaning the needle is not positioned right (someone f'd with it) or its not connected correctly (you botched the re-wire job when your swapped clusers).. yessir)

That sums it up.

mclean987

iTrader: (1)

thanks mate, i have never changed my cluster but i realized my radiator is bad and leaking so im putting a brand new one in now, the top hose is hot and bottom hose is cold so this backs that up, i have no leaks, smoke or anything so im thinking engine/headgasket is still good, after i finish radiator we will see im keeping my fingers crossed, i think my heater core was blocked or something aswell because the heater in car wouldnt work, i just looped it because i dont need heater

mclean987

iTrader: (1)

so i hook up the fans straight change radiator and cap, thermostat and radiator hoses and blede out air bubbles and the temperature guage goes higher than normal but car doesnt overheat, the top hose is very hot and the lower tone that goes to thermostat isnt its kinda cold, its a brand new thermostat so is there a thermostat switch or something that controls it ? males it open and close? the ecu isnt throwing any codes either, i was thinking does overheating engine mess up water pump?

TRIZ

iTrader: (14)

I dunno man... Your over heating and your heater doesnt work? That sounds like more than a coinscience, but I dont know anything about the heater core system. :/

gearbox

iTrader: (95)

well if his heat isnt working, the heater core is clogged. it just isnt letting coolant to that part of the system. or the water pump isnt circulating it properly.

GreenMachineDX

Water pump!!!

mclean987

iTrader: (1)

im thinking its water pump aswell tha nks guys really appreciate it, the heater core must have been clogged because when car was overheating the heater didnt work at all in car and it should, i have since bypassed the heater core because im in florida and dont need it, im gonna change the water pump and pray it works otherwise its head gasket time, im gonna change ect aswell and see what happens, thanks again

mclean987

iTrader: (1)

i can drive like 10 miles or 25 mins before temp goes above normal but it doesnt go all the way to Hot and lower thermostat hose stays closed

gearbox

iTrader: (95)

well bypassing the heater core isnt the best idea either, it does provide extra cooling, even with the heater turned off. it has quite a bit of extra "space" to circulate coolant. thats why they say when you first start the car in very cold weather, you should always turn the heater on right away. if you wait til the engine is hot, then turn the heater, you will have ice cold coolant going from heatcore to the engine which can crack the block.

pjb3

The other problem with bypassing the heater core is that you will not have defrosters even if you can live without the heater.
I may be wrong but I doubt it is the water pump. The only way a water pump would fail to circulate coolant is if the impeller or pulley was slipping on the shaft and that would be very rare. Most water pumps fail or are replaced because of a leaking seal that allows coolant to leak were the shaft enters the housing.

mclean987

iTrader: (1)

i removed the thermostat completely and it still overheats, so now it can only be water pump or headgaske, how can i test if water pump is bad? how do i know if its head gasket and not water pump because the oil and water isnt mixing and car isnt smoking driver perfect for 20 mins

gearbox

iTrader: (95)

are you losing any coolant at all from the overflow tank? if you are, its headgasket. if its losing coolant and not leaking any, then youre slowly burning the coolant in the engine. not enough to make a smoke show or affect how the engine runs, but enough to make a difference.

mclean987

iTrader: (1)

i am not losing coolant through the overlfow only when it starts overheating after 20 mins of driving and pressure gets too high then it sprays out of hose that goes to overflow im guessing the pressure has to find somewhere to come out, i might be slowing burning coolant or water which is what ive been using through the engine but i have no way to tell?