stangn99

My 1998 Civic has an overheating issue.
Its been going on for a while. i bought this car off my sister who also had this problem. Now I own the car and would like to have this fixed.

Since last year, we have basically been just cranking the heater to get the temps to drop. If you don't turn on the heater..it will reach Red in no time!

Here is the weird part. Sometimes..it doesn't overheat at all....I mean...i could drive the thing for 4 hours city + highway, and it won't overheat.

Other time, just sitting at idle, it will reach redline if you are not paying attention!
Other times in city driving..it will just bounce around all over.

I noticed that when it does overhaet...the FAN TURNS ON SOMETIMES ONLY! I popped the hood when the temps were close to red, and the Fan wasn't even turning!

I have already replaced the thermostat with an HONDA replacement (new), and also did a FULL BLEED! Yes...no air in system. It was done right, no leaks, no white smoke, no oil in coolant, no milky oil, yes coolant is full and no dirty, etc. etc. Just overheats.

Somtimes when overheating..even WITH THE FAN TURNING, it will still overheat. There has been times when turning on the heater actually didn't help much (on really hot days). So I would be forced to turn the car off and let it sit.

What should my next move be?
I searched and found out some people were chaning their Fan Switches with no results....where is the fan switch located? is it difficult to replace?

Would the radiator be bad? what causes a radiator to stop functioning properly?

Thanks for any help


Modified by stangn99 at 6:11 AM 5/31/2007


Modified by stangn99 at 6:31 PM 6/4/2007

jadziasman

My 1992 Civic VX was behaving like that. Not exactly the same but similar. A new radiator completely solved the problem in my case. It was clogged with corrosion or something else because coolant was not flowing through it quickly enough. Ebay sells cheap Chinese radiators for $42 shipped. It might be the solution to your problem but you should take the radiator out first and see if water flows through it quickly when you pour water into the inlet hose. The radiator outlet hose should be able to drain at least three gallons per minute without any pressure on the inlet side.

HondaHOVA04

The first thing you want to do is flush your coolant system. all the directions should be on the package...if not you just want to put the T pipe with the hose hook up on the back lower hose as shown in the pic.

You want to take your radiator cap off and have someone hold a bucket to catch the water that comes out. you want to make sure the car is off and that the heater core is open. (slide the air to hot). you want to flush everything out of the system...take notice to what comes out...you may want to drain your coolant before hand so you can see what the water pushes out.

once the water that is coming out of ur radiator is at least somewhat clear you have done the job.

now the KEY,after you drain all of the water out, is to make sure there is NO air in your coolant lines. You do this by putting radiator fluid back in and turning your car on. You want to leave the radiator cap off and let your car run untill it completely heats up to normal running temp. this may take a while.

Air bubbles will float to the top of your radiator...keep it full. The easiest way I have found to make sure you get ALL the air out is to jack the front end of the car up to make sure that your radiator cap is the highest point of the coolant system. this will ensure that all the air rises to the top.

some people will dispute this and say to open the bleeder valve after it has run for a while which is fine too. if you choose to do it this way. dont worry about jacking the car up. just run it untill its hot and keep the radiator full. when it the motor gets to normal running temp. there shout be a bleeder valve at motor end of the upper radiator hose. you will want to open this slightly untill you notice either air or coolant coming out. when you do not see anymore air then it means your lines are clear of air. make sure to put your radiator cap back on to do this.

*MAKE SURE YOUR HEAT IS ON WHILE DOING ALL OF THIS.

A few things to remember. There are only a certian number of reasons as to why your motor is not being cooled correctly.

A: There is air in the lines
B: Your thermostat is not opening or working correctly
C: There is a clog somewhere in the lines or your radiator
D: Your water pump went bad and is not spinning
E: One thing that will allow air to get in the lines is that your coolant resivor is empty and your radiator is pulling in air when it trys to pull in coolant. thus A

I have just described how to clean your coolant system. I would recomend that you replace your thermostat if you have not already. That is typicly an easy fix to a serious problem... If there is a clog in your lines or your radiator is bad you will see it when you clean the system. If problems still persist take it to a specialist and they will be able to tell you if your water pump is bad.

Hope this helps and dosnt confuse you tooo bad.

stangn99

Thanks for the instructions:

Before I did this however...i tried something

1. Turn on AC : BOTH fans should turn on...but only AC FAN WOULD SPIN!

2. Turn off car..let it cool.

3. Checked reserve coolant tank - dry as hell!

4. removed rad. cap and turn on car...let it get to normal temps and turn on AC. Again, only AC fan turned on. While the fan was spinning, i tried adding more coolant to the system - IT TOOK another 2LITRES!!!!!!!!! WTF?

5. made sure to get rid of bubbles and put everythign back together...took it for a spin..and no overheat!


WHY RAD FAN NOT SPINNING??? This is what I did:

Directly connected Neg and POS terms from the batter to the FAN terminals...NOTHING! it didn't even spin with the battery directly connected to it. So only the AC fan is working now, and I have removed the rad fan for now. It has not overheated at all yet.

I put a test light to the rad fan connected (from i think fuse box), and turned the ac on again....nothing. WTF? I'm so lost.

I'm looking at getting a new Rad Fan assembly first...and keep an eye on the coolant. I dont think it is a head gasket problem because I don't see any white smoke, runs fine, no oil in coolant, and oil looks perfectly normal....I'm just not sure where all that coolant went (also no leaks!)

I'm confused.

stangn99

"E: One thing that will allow air to get in the lines is that your coolant resivor is empty and your radiator is pulling in air when it trys to pull in coolant. thus A"

YES..i think thats what happend. The resivoir tank was complete empty. But i'm stumped as to where the 2L of coolant went off to?!?!

The funny thing is, I lef it idling for 20 minutes and the guage was at normal with only 1 fan working. I have complete removed the rad fan and only an AC fan is on there now....no overheating at all.

I'm not sure if this is an electrical problems, engine (head gasket), or cluster (which i doubt..cuz the car doesn't want to move when it gets close to red).

The problem is, the car is has salvage title (we bought it 3 years ago, and got tricked), and is a complete rebuild. But we have never had overheating problems until about a year ago.

mugencx

its your headgasket.

HondaHOVA04

yea it could possibly be your headgasket...i didnt metnion it before because you had good compression...when my headgasket blew on my b16 my compression was way down in one piston...if you notice any white smoke at all then it is your head gasket...make sure there is coolant in it and rev it hard and have someone stand at the back to look for smoke...any white smoke at all is a sure sign...

as for why your fan isnt kicking on, im not sure....most likely the problem is electrical...i know for my car with the b16 my fan wont kick on unless i rev it hard for half a minute or drive it around...for some reason it wont kick on unless i heat it past an idle...2L of coolant is a lot, if its not leaking out then it is most def getting burned off...

My brother and I did my head gasket and Ive been driving the motor hard since christmas without any problems...Its an easy job for any shop but will cost you if you outsource the work...

if the motor has overheated a few times you may want to bring it into a shop and make sure the head isnt warped...the aluminum heads that were dealing with dont take much to warp when heated past normal...if the head is warped then you are DEFINITELY buring coolant in the combustion chamber...

I do not know your current financial position but if you take it to a shop and they tell you it is warped, the personally, i would search junkyards for a replacement motor. should cost you anywhere from 400-800 depending on if it is a straight swap. then the shop you take it to will charge you typicly around 300. but in the end you should have a reliable daily driver again, that you dont have to feed coolant like gas...

barney gumble

sucks man, hope you get your car running at the right temperature
to overheating

stangn99

Oh man..thats no good.
I bought this car to save money, since I'm a little screwed financially! Oh boy.

I did get my gf to do quick/short rev to around 4k while I watched for white smoke. I didn't see anything at all. No smoke what so ever. I also didn't smell that coolant scent (kinda sweet smell from exhaust).

Wouldn't a blown headgasket cause a lot of loss in power? The car is naturally slow, but it doesnt seem like it has lost any additional power. It picks up fine, has no trouble reving up either.

I also got it emission tested last week - it passed with no problems.

I will keep an eye out on the coolant for sure. I'm in no situation to spend money on this car. As for the FAN, I am going to hook up a voltmeter to the terminals on the plug that connects to the fan. Once the AC is turned on, it should read 12V or so from the plugs (I think?) - since turning the a/c on would kick both fans on.

THANKS FOR ALL THE HELP.
I will post back my updates.

**Why can I only post 5 times a day? under my username, it says "trial".

Cboi

cuz u need to be a member for 2 weeks.. just be sure to keep the res at max till then also...

sirsmokesalot

I've got $20 on the waterpump

HondaHOVA04

it could also be your water pump, but im not sure how to tell...if all else fails you can just hook the fan up to a switch. the problem with a switch is making sure to turn it on when you start the car and off when you turn it off. it is better to just make sure it is working properly without having to do that but if you cant figure out why its not turning on then thats a solution.

stangn99

I'm not too sure how to test for the waterpump either. Its def. not leaking anything.

I hooked up a voltmeter to the plug that connects to the Rad. Fan and turned the A/C on. It read "0" nothing. I had the volmete set to DCV (is that right?). I turned on the heater...still... "0".

The fan is out of the car right now. I hooked up 12v battery to the fan directly and nothing. It won't spin.

I've been driving it without the rad fan with no problems so far. I will be checking the Resevoir tank for coolant tonight to see if anything has left. I'm expecting to see some of it gone.

ABOUT THE SWITCH: I thought about that..but wasn't sure how to hook it up. Should I directly connect it to the battery, and somehow add a switch to connect/disconnect?

thanks for all the help/tips

stangn99

Thanks!
I was wondering why I it kept saying trial.

Here is a quick drawing of how I think the connection would work. Please let me know if this is wrong...and sorry for the lack of knowledge.

instructor74

man stop guessing if you are using coolant and have no signs of a leak it has to be a head gasket. Do a compression test look for a low cylinder or 2. When you pull your spark plugs look at the end are 1 or 2 of them clean and the others look normal? That is another sign of coolant use. After running the car and letting it sit for a few hours if you open the rad cap is there pressure pushing out? Again another sure sign of a bad head gasket. These are all things you can check at almost no out of pocket expense. I just did my head gasket this weekend and had good compression on all but 1 cylinder and had excess pressure in the coolant system after the car had sat for a few hours. Total cost of the project under $75 but I get a discount at the part store and have access to a shop to do the work in.

slvrcvc93

Well i have had this problem but ill let you know where to start first not the water pump it moves with the timing belt and if you have ever held one the fins on the pump are attached to the pulley chances of it breaking are 1 in a million on a stock motor. First you need to turn on the car and you normally wouldn't do this but smell the exhast doest it have a sweet smell ???? if theres no white smoke it should still smell funny. the compression test is a good idea but on a older car not exactly perfect because all the cylinders on a single cam might show low compression but it still will have signs. also make sure the floor board in the passenger floor are not getting wet can be leaking inside but you would have noticed by now. The fan switch is about 10 to 15 dollars so if your fan is not turning on id start there cheapest and easiest soulution its the one on the thermostat housing also you can put direct power to the fan just to make sure its working also also easy to check. if not you will have to check coolant temp sensor its the one on the actual head. If i were to put money on anything though it would be on the head gasket belive me even for a novice on a single cam not an entirely impossible job good tools a book and anyone who has some knowledge on cars you can get the job done for 100 dollars some bear and about 2 1/2 to 3 hours of work and that's giving you leeway time people who have done it before can be done and turned on in about 1 hour.

EL Vap133

Get a paper clip and bend it so you can loop the fan switch plug. This will make the fan run constantly. If it runs then your fan is good and you might have a lazy fan switch.

stangn99

All the spark plugs look to be fine.
That was the first thing I did. They actually look too good for plugs that haven't been changed in about 3 yrs.

When I open the Rad cap after about 2 hrs of sitting, there is hardly any pressure coming out (if any).

Like I said, I will check the coolant level again once I get home. Should I check when the Engine is running and HOT or off and COLD? or does it matter?

Thanks for all the tips man.

instructor74

do the compression test after the engine is warm pull all the plugs out. Remove the fuel pump fuse I have pulled the ecu fuse and that worked for mine. Most gauges crank the car let the needle pulse 5 times take your reading repeat for the other 3.
Even with out pressure in the coolant system it still could be leaking. The first head gasket on my car never kept the coolant under pressure after running. the second one in this car kept pressure all the time.
good luck

stangn99

I did the exhaust sniff, and didn't smell the sweet scent. I took a whiff right about after 1 minute of the car running. It does smell a little different from my other car though (which is a different make)...but not a sweet smell. There is def. no smoke.

I'll double check the scent tonight to make sure (i don't have the greatest sense of smell).

I've tried putting 12v directly to the fan...nothing.
I've already concluded the fan is dead..but have not purchased another one yet. I don't think there is any power coming out the plug that connects to the Radiator Fan (did a test with voltmeter). Also checked the fuses and they are all fine. I think i'll get a replacement fan and hook up a switch to it.

I'll see how that goes and will post back in a few days. I'm going to keep and eye out on the coolant first...if its not disappearing again...ill worry about the fan (since it doesn't seem to be overheating without the Radiator Fan anyway). A/C fan does work fine though, and does turn on when temps rise.

Thanks again for all the help!
We'll see what happens in 2-3 days

stangn99

I will need to get my hands on a compression tester first

I will def. do this though though....

Thanks again.

importfan0103

it stopped over heating right..... he added two liters and overflow was empty my bet, dont take this the wrong way, u bleed it the wrong way and the xtra coolant is just cuz u didn't put enough in in the first place. keep the res full and the fan probably just dead, u said u checked the voltage from the plug and it read nothing but remember it only sends power when it need the fan to come on its not going to have pwr all the time most likely as u said the fan is dead. it sounds like u fixed it man

1992cxcivicEG

thermostat and water pump replacement...

hatch96y7

put ur fan back in place run 1 wire from ur pos side of the battery to ur red wire i belive in top of the fan it should turn on.

muhaMan

thoroughly check your radiator hoses!! mine had a VERY SMALL hole in it and it was shooting coolant all over my motor.. that caused some frequent overheating