98 civic ex coupe. Car runs really hot. Replaced radiator, thermostat & gasket, water pump & timing belt, numerous hoses. Car doesnt leak & has had a leakdown test & pressure tests, passed with flying colors, also floorboards are dry so i know its not the heatercore. I replaced the coolant temp sensor, water temp sensor, fan switch and now the car is running hotter then it was with the old sensor and the radiator fan doesnt work like i did. We did bypass the fan switch and the fan does turn on. it gets almost to the red line before the fan turns on. Before it would only get midways and the fan would turn on. i checked the fuse and its fine. also when we refilled the coolant we made sure to make sure that we didnt allow for any air bubbles. the whole cooling system is basically new. The radiator fan relay also looks like its fairly new. I got this car last year. Im out of ideas. what am i missing

 

Maybe its a bad indicator.

 

You say you refilled the coolant, try flushing the whole system correctly, possibly an obstruction somewhere.

 

I think the car ran cooler when the old temp sensor was in it & the fan was functioning better, guage cooler with the other sensor. Does that make any sense to anyone???

 

Never let the engine temp get anywhere near the red zone. Otherwise, the engine will be permanently damaged.

Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push/turn the dash heater lever/**** to MAX heat. Fan need not be on.

3) Follow the directions in the diagram below

 

Wow you did just about everything.

Question I alway ask, does it do it only at idle or when you are driving or both?

I have a similar problem on my 96 ex, will do it only at idle seems like the fan is coming on late.

 

The process Ron is showing here is very important in the bleeding process. Are you loosing any coolant? I know you say it isn't leaking but was wondering if your level is going down at all.

 

2he i figured out the radiator fan problem. The relay was bad. I took the relay from the ac fan spot & put the cooling relay in the ac fan slot. With relay in the ac fan didnt work. So I know it needs the new cooling relay. But I litterally have replaced everything on the cooling system & its still acting up. So its at a shop now getting a hydrocarbon test & diagnostic. Hope its not the head gasket. So far its always been something simple on my car. Wish me luck

 

Let us know, that is the fear with my car as well, but I would think if my headgasket was bad it would of gone by now.

 

Not the head gasket. Apparantly there is another sensor under the distibutor that controls the gauge thats been giving me all this trouble. Nlt the head gasket just like I initially told them. I baby my car, I know my car & I know it was not the gasket.

 

How did you do this^ test? If you jumped the 2P switch connector and the fan ran, then the relay is fine.

 

I swapped out the relay switches with the ac & cooling fan. It wouldnt turn on as usual. We bypassed the switch & the fan was working as usual, but not on the car. Turns out another one if my sensors under the distributor needed to be replaced & that was causing my cooling system to go out of whack. Every other component of the cooling system has been replaced

 

So you are talking about the coolant sensor, that goes to the gauge was bad? Same think happened to me this afternoon, my gauge was creeping up, but seems like my fan is coming on late. Unless my coolant sensor to the gauge is bad on my car too?

Ron is it number 11? Also, to get to it do you have to removed the distributor?

 

motegicivic -- #11 is the temp sender unit for the cluster gauge. Removing the distributor would make replacement easier. But I don't think there's any reason at this point to believe your sender is bad.

 

Ron i created a new thread, I do not want to hijack this one anymore.

 

So ive posted before with the same issue and got a few idea but no answers to why my 98 civic ex coupe is giving me so such trouble with the cooling system. these are all the things i have replaced this year and still no success. Hoses, radiator, water pump, timing belt, thermostat and gasket, cooling temp sensor, water sensor and some other sensor thats under the distributor cap. The car passed a hydrocarbon test and a leakdown test 2 weeks ago. Please dont say the heater core because my passenger mat is dry to the touch and the car diesnt reek of coolant, although the car runs hot when i turn the a/c on. which i cant even do that anymore. the car has had a diagnostic and its been to 3 shops and no one can seem to fix the cooling system issue. lately the temp gauge would only go up if it is hot outside or the a/c was running (btw the cooling fan is turning on and cooling fan switch was reolaced as a precaution). now the car just seems to run hot no matter what. i never redline the car. as soon as i see the gauge go up i turn the heat on to pull the heat off the engine. also the car has plenty of coolant and no leaks. im at my wits end and there just has to be another idea out there on wtf is going on. help please or my pretty little civic is going to have to go. i dont want that. i want to add that my check engine light has never been on as well.

 

Could be some gunk or build up in one of the passage ways. When you replaced anything did you check to see if there was good flow though all the lines and block?

 

Does the cooiling fans come on??

 

Did you use a Honda Water Pump?

Like the other poster said, might be a clog, I would drain the coolant and check the hoses that go to the firewall, take them off and see if they are clogged.

You said the car runs hot no matter what, driving? and idling?

 

No I didnt check the lines bit I took it to a shop so I would assume they would do all that is necessary, especially since they are making $$$$. Yes, the cooling fan is working normally as well. its getting hot sitting there, driving, anytime anymore. Then sometimes its fine. I dont get it

 

I doubt they check the lines going to the firewall. Basically drain the system, pull the hoses going to the firewall. Could be a clogged heater core, I know water on the mat but still.

Also, refill and then bleed the system of air, properly.

 

Im bringing it back to the shop that worked on it since I basically paid them for nothing. I will have them check the lines gping to the heater core. If this doesnt work im not pouring anymore $ into this car. It wilL have to go. Ive easily dropped $1000 & its still not right. So frustrating!!!!

 

So originally you thought it was fixed right, thinking maybe the gauge was not reading right and had the sending unit under the dizzy changed.

Check the hoses, also flush it, and then bleed the system.

I can not remember did you do the water pump recently, if so did they use a Honda one?

Is this an orig engine by the way?

Another thing who did the the thermostat? I am wondering if it was put upside down, I know far fetched, but you never know.