Possibly need new heater core
 

I have only driven my Civic here in Arizona and really only use my heater with passengers, but I almost never use my air conditioner, either. It was supposed to be 120° on Tuesday. It wasn't. I feel like having survived that, I do not need to worry for another year.

I always complain about my car being black. I wanted an HX. It took me several months to find Chorizo. I did not want to wait indefinitely (while driving my unreliable Forester) until I found a white or silver one. We talked about repainting or using Plastidip, but it never felt right.

Here I am, almost three years and eight months after I bought her and she started overheating on Tuesday.

No AC, just the window open, and I was driving 65. I turned on the heater full blast (oh joy!). Nothing. I stopped and adjusted my grill block. Nada. I felt I needed to slow down until I could get home and take off the air dam, but after I made it to my client, I checked my radiator.

I do not recall ever seeing the radiator fins.

I like to keep distilled water in my car, just in case, but I have gone through several bottles that leak and need to be replaced. I drove carefully to the nearest store and put at least twenty ounces of water in the radiator, planning on flushing today. I have not had any difficulty with the car overheating (it has been cooling off a degree or two each day since), but I have been topping off every day or two, and I topped off my fluids about three weeks ago.

I am definitely smelling antifreeze, so even when it is night, I open my window instead of using the vent.

Almost everything I read on-line says it is the heater core, with a few saying to replace the radiator. One time I topped it off I saw some water dripping a foot or two behind the radiator, but I have not seen that since, nor puddles, but they would evaporate quickly. There is a small damp spot on the carpet that I think smells like antifreeze, but so does the rest of the car. Neither the dipstick nor the oil cap show any water. There is antifreeze on top of the radiator, the top hose is crunchy, and there is antifreeze stain on the engine on the far side of the top hose, but I ran my car for about twenty minutes in the evening with the AC on full, headlights, and stereo. The engine was about as warm as it gets driving in the middle of the day (without headlights or AC). I pressure-tested the coolant system and it immediately lost pressure, but I could not tell from where.

Using KBB's "Fair" estimate, my car is worth $1,300. I looked at Civics on Craigslist and I would not look at anything for sale for less than $1,500, just the obvious problems seemed as bad as my car. I do not quite have that much and I have tax and student loan payments to make.

My Accord runs awesome, but I had wanted to fix the cosmetic stuff and have a pretty car while I drove my economical one. The best lifetime MPG anyone on this site got with a sixth-generation Accord with an automatic transmission was about 36, which is not a great deal better than I have done, although I drive 99% highway.

I kind of want to just top off the radiator each morning. It will get cooler and cooler, so that should be fine for a while, but one gallon of antifreeze each month being deposited all around Arizona does not sound like a very good idea.

Rockauto has the heater core for $40\59\70 (three different brands)
Pep Boys has Rockauto's $40 one for $90. Napa wants $111, and Autozone asks $121.
O'Reilly $122
Majestic Honda $251 (shipped)

It seems weird to spend ten hours replacing a $40 part, but I would not feel any better spending three times as much for the exact same part.

It seems weird to spend ten hours replacing a $40 part when the engine has low compression.

Some folks in my country would pour cornmeal and egg whites on the coolant to seal a leaky radiator. But anyway, would you feel comfortable getting rid of the heater core and just carrying a jacket around? I've already seen some that are used by cyclists that are very lightweight and can be folded to a pocket size.

You can bypass the heater core, or you can put in some "stop-leak", or you can start replacing parts on a car that's on it's last leg. Your choice.

I'd probably do the easiest one first and see if it "fixes" the issue.

BTW, are you sure you're not burning it? Or perhaps you have a pin hole in a rad hose?

Burning it? Failed head gasket? I just did not see milk on the dipstick or oil cap, not have I seen white\blue smoke. My Forester had a bad head gasket, which I fixed. That was tedious.

Eric the Car Guy does not approve of stop leak and I do not want to disappoint him. He was the only one to wish me Happy Birthday last year.

I don't approve of stop leak- it's not a band aid so much as a tourniquet. Yes, it'll stop the bleeding right now, but you're causing additional damage.

I'd rather block off the heater core for real than add stop leak and gum up the whole system.

You can blow a head gasket without ending up with water in your oil. In fact, the last one of these I saw was on a mid 2000s honda. Fill up the cooling system and check for bubbles at the rad cap when you briefly open the throttle up.

Take the two hoses I presume run to and from the heater core and connect them with a short piece of tubing. For diagnostic purposes.

Then consider a coolant leak into the cylinders. as Stubby79 suggests..

It was a cool 108° yesterday and I would have just used my vent were it not for antifreeze fumes. I had the same forty-five minute drive each way I did last week and my car was fine until I turned onto a side street, the engine started warming up quickly, but it had been uphill. Then there is a mile or two downhill, so my car was able to rest. I topped off the radiator after my appointment and drove home to try to do paperwork before my next client. My car was just fine on the freeway and highway, started running hot in-town, and started overheating when I was parking.

It seems I would be fine as long as I pushed my car into parking spots, but I just drove my gas guzzler.

I did not feel I could put off fixing it any longer, but I need to catch up on notes and start writing progress reports, so I am trying to focus on work and just driving the Accord.

I decided to take a minute and try to make sure that replacing the heater core would fix the problem. I had thought about bypassing it for diagnostic purposes, as Freebeard suggested, but I read:

5 Signs Your Heater Core is Busted - Clean Machine Car Wash

I ran my car for several minutes with the brights on and the AC on max. It seemed to be at normal operating temperature. Then I turned off the AC and turned the temperature all of the way up.

It blew cool. Not cold like the AC, but cool like in the shade in the morning, before the sun actively tries to kill me.

I am still going to try to focus on work and consign myself to driving the pretty car, but I feel satisfied I know what the problem is.

Definately sounds like heater core. I wouldn't bother fixing it unless you plan to address the low compression issue too. Might as well bypass it to stop the leak though.

No need to put antifreeze in when it's leaking like that. Just use distilled water. You're probably not freezing in AZ anytime soon, right?

Supposedly we never got below freezing last year, but it would be easy to drain the radiator and replace with 50/50. So, one of these and two hose clamps?

http://contentinfo.autozone.com/znet...56438/image/4/

Coolant has a higher boiling point than water. At least it keeps getting cooler outside!

There ya go. It will be just like driving an old Beetle with rusty heater cables.

My Beetle gave me exhaust when I wanted heat. Exhaust to air heater core is a bad idea.

That was what they call the 'fresh-air' engine, because it didn't supply actual engine cooling air loaded with oil fumes to the heater boxes. :eek:

I did not need to purchase clamps, I just used the ones on the hoses going to the heater core. Removing those hoses was incredibly difficult because the clamps pointed downward, but I could not do much with normal pliers. I tried finding longer pliers, but Home Depot only had needlenose pliers and I was concerned those would bend the clamps, but 90° needlenose pliers should have worked perfectly. The only long pliers I found were 45° behemoths. I thought they would be great because I could pull the hoses from an angle and have the drip pan underneath, but there was not nearly any room for that. I found some large pliers that were not as long as I wanted, but still difficult to maneuver in there.

Curiously, I had especial trouble with the passenger-side hose. It was short, connected to the bracket, with a cable that seemed to open a valve in the heater core. It was easy to remove the hose from there. Then the shorter hose came out. It seemed to take forever, but coupling the two hoses was easy.

I have not tested pressure yet.

A friend from Church told me to run the AC and see if both fans came on. Only the condenser fan ran. I thought I was finally okay to drive last week (before I finally bypassed the heater core) and Chorizo drove forty miles on the highway perfectly, even running the air conditioning the last several miles, to see how hot the engine would get, and if the cooling fan would run.

It didn't.

The temperature was fine, though.

The next client was several miles away, 45 MPH speed limit, and light traffic. Everything was fine until the mom rescheduled.

Then my car overheated. My phone died, too.

I went back to driving my Accord, but I still have not found a resonator. I have everything else.

I thought the thermostat was bad, but I had not realized how slightly they opened. I replaced it with a new one from the dealer anyway.

I used test wires to run the fan directly from the battery. I bypassed the fan switch with a paperclip and it ran. I checked all of the fuses with a tester and they are good. I followed the instructions in this video and learned my new test wires were already bad: https://www.youtube.com/watch?v=ire7vyDqelg

The relay clicked and my multimeter showed 0.5 Ω. In the video, the good one was 0.01 Ω and the bad one was 1Ω.

I bought a new one.

It was also 0.5 Ω.

The friend told me to make sure the relay box is putting out 12v. A mechanic on YouTube said you cannot put probes into the relay slots and suggested wrapping wires around each connector, securing them with electrical tape, and then using your multimeter on the wires.

My multimeter showed 0.

I was able to put my probes into the slots, but my multimeter still showed 0.

When I drained the coolant before replacing the thermostat I siphoned it out of the overflow tank, which was surprisingly full. I did that the hard way, the tank just slides out. I read the overflow tank fills when the engine overheats. I wonder how much of my missing coolant has gone there, but where has the rest gone?

Is this what your under hood fuse box looks like?

Part 1 -Under-Hood Fuse/Relay Box (1996-2000 1.6L Honda Civic)

Also you said your new test wires were no longer any good, what did you mean by that... were they burnt up, if so what guage wire did you use.

Help! I belong in DIY / How-to - Fuel Economy, Hypermiling, EcoModding News and Forum
 

TheEnemy! Thanks for responding! Yes! That looks just like my fuse box! I tried to figure out how to test the box, but I did not find anything. I might just purchase a cheap relay, get rid of everything but the terminals, but there must be a cheaper method.

I connected the test wire from the battery to the fan and it ran, but the wires were crazy warm, and the next time I tried to use them they seemed to be dead. I reconnected the fan to the battery and it did not start. 22 Gauge: https://oreillyauto.com/detail/dorma...00/honda/civic

These still work, they are 20 gauge: https://oreillyauto.com/detail/dorma...00/honda/civic

I finally picked up the last part to fix my Accord (and hopefully have turn signals again!), but there is a big hole in it. The Civic finally held pressure once bypassed the heater core and topped off with distilled water. I wanted to see if at least it would maintain its fluids. I drove over twenty miles and everything was fine, but suddenly she started overheating. I got off the freeway, parked, popped the hood, and topped off half an hour later before driving slower to my client's house.

The radiator fan never turned on.

I do not feel I have time to try to figure out Chorizo's electrical problems, so I took it to a Pep Boys near me.

They said the fan ran perfectly and they ran it for over an hour, but she never overheated. They said they did not fix anything, so they will not charge me, which is nice.

So that last run you were freeway speeds when it overheated.

I don't trust what Pep Boys told you, I haven't had much luck with their work in the past. Did you see the fan running? You said it had more than one, AC and it stayed cool with the AC on?

22 gauge is way too small, its best to use 16ga for the fan, 20ga.

I'm still thinking fan, could still be thermostat (sticking), slow leak only under pressure, weak cap, or even a bad pump, I saw one that would work for a little, then quit for a little. Is there any smoke coming out of the tailpipe, have someone follow you, and what color is it if it is.

My wife had one where the ECU quit giving the command to turn on the fan, unless the AC was on.

After doing a bit of research it seems that the most likely culprit is actually the head gasket is starting to fail, it has been talked about in a few forums as starting off with what you are experiencing.

https://www.civicforums.com/forums/3...reference.html

Yes

They replaced the timing belt on my Forester and a week later the engine suddenly ran roughly. They said I needed a valve lash and wanted $125 to replace the spark plugs and wires. I changed the plugs and wires in their parking lot and came home to ask the fine members on here what they thought.

The car drove worse after they messed with it.

I ended up going to a different Pep Boys, having their store manager look at my car, and he told me to go back and make sure the belt did not slip a tooth.

They said the tensioner broke, but it was under warranty.

If they tell you you need a repair and they are wrong, do they say "My bad?"

The clutch went out on my Civic when I was trying to leave town and my insurance took it to a third Pep Boys. They did a good job, but something was still strange about the experience.

Like these? All that I saw at O'Reily were the two sets I bought, although Fry's electronics has tons of them, but I had a horrible time finding ones for my multimeter. https://www.amazon.com/SE-TL4-36-Gau.../dp/B01L1JG32M

I will do that when I can.

I hope not! However, the engine has low compression, and rebuilding seems to replace the head gasket and do the rest of the work, but I would rather find an HX with fewer miles, or purchase a... Prius...

I was supposed to drive to Page, AZ to check out a job offer there, but I really did not want to. Instead, I walked to Pep Boys, picked up my car, drove thirty miles (in a much smaller loop, never 20+ miles from home), and she never started overheating, but it was almost nice out. I nearly enjoyed the walk. I think it was 86° when I left.

Still, I think the fan should have been on, but it was not.

I have spent as much time as possible trying to find another speech job down here that has more hours. Almost everyone says that if you can start the fan by providing direct power and by putting a paperclip in the switch, you need to replace the switch. This guy diagnoses the switch itself with wiring he bought from a junkyard for $6. I couldn't find the plug itself anywhere and it was late Friday afternoon, so I would not be able to try to find one until Monday. I was tempted to purchase one from O'Reilly or Autozone, but those do not always work, but if it is good and the fan still does not work, then I can return it.

How do I know it works, but something else is wrong?

I searched for the part number and a discount dealership popped up. Majestic charged a little less, but with shipping, it was not much less than my nearest dealership. I called and they said they would have a shipment this morning, so I placed an order on-line, but didn't wait for them to fill my order, just said I ordered on-line, and asked if they had it.

It requires a 24mm socket, deeper than normal, so I bought one, and the fan still did not turn on. Not when I turned on the air conditioning, and not when the water started boiling out of the radiator.

I am pretty sure the fan should come on

It wasn't like this guy: https://www.youtube.com/watch?v=7UyhjT7nWY0

There was steam coming out and everything.

New Honda 180° thermostat, switch, and relay. Do you know what? i will put in a new fuse just for good measure. It is adding up, but still less than one hour of labor.

When the radiator was boiling, the radiator fan connector was only putting out .01v, so the O'Reilly guy said to unwrap the wire bundle and find the short. The guy from the other O'Reilly kept trying to sell me a fan.

Well, I had planned on waking up in less than four hours and driving 530 miles. We will see how that works out.

Fun. It is actually further than that...

Thank you very much for your input! Have a great day!

Do you get power to the fan (12v)? If Yes fan is faulty. If No supply is faulty. Switch grounds fan relay. If you get 12v at the switch with the switch open, relay coil in intact. If you never get 12v at the switch, relay coil is open circuit. Coil should be on a separate circuit from the fan fuse. If coil in intact either fan fuse is blown or relay is not making. A defective relay is a very common fault. Check the fuse box. There may be a similar relay in the box that you can temporarily substitute to confirm my diagnosis.

Is there a Pep Boys in Page, AZ? If not you need to move there.

I'm driving a water-cooled car for the first time in 50 years, and your travails aren't helping my confidence. For the time being, the Dasher runs cold. It needs a radiator shroud and/or grill block.

Did you end up trying to start the fan using a paperclip? My '97 Civic was having issues with the fan so we used a paperclip to make the fan run for a few months. One day for kicks, I tried plugging the switch back in and it worked fine. Maybe it hadn't been plugged in all the way or there was corrosion keeping it from working before.

If you're going to take your car to a shop, you're usually better off going to an independent one than a chain. Hop on Google and see which ones around you have great reviews. I'm lucky that the best reviewed shop in town is right next door for any jobs I can't do myself.

Your fan is fine. When you jumped battery power to it and it ran confirmed that.

I have seen more bubbles, in fact I saw one that when I revved the engine a little it hosed me down with coolant.

There should be a thermal switch on or near the thermostat housing, pull the connector and jump the terminals on the connector, this will be low current so a small wire will be fine. You will have to have at least the ignition on, (some run even with power off). If the fan comes on replace that switch. They can fail intermittently which can make troubleshooting a nightmare.

My experience with PepBoys was when they screwed up they blamed the customer and said it needed something else.

Edit: The head gasket can cause low compression, and with the proper tools and experience can be changed in an afternoon. We did so on Ugly a time or two. Though I suspect the engine is just worn out as well.

Good news everyone! I cracked my radiator!
 

I bypassed the fan with those 22g wires and the fan ran.
I jumped the switch (with a paperclip) and the fan ran.
I have replaced the thermostat, switch, and relay with new Honda parts. I have 12v into the relay box.

I did not understand how the switch worked, the cable supplies power, when the switch reaches temperature, it closes the loop, and the fan is supposed to run, so the second O'Reilly guy was wrong, the cable is fine.

Well, maybe.

I idled my car in the driveway for twenty minutes and checked the switch pins, thinking it was supposed to supply power, even though I should have realized that was not how it worked. I went to do an update and realized I should try again, but this time check for resistance, except when I came back there was a small puddle under my car and a crack in the seam at the top of the radiator. I do not know if it was there before, if there was too much pressure, it would have released from the heater core.

I turned off the engine, but kept the system on, and was about to short the cable, but thought to plug it in. Earlier today I just put in the clip and thought I would drive that way until I could figure it out, but knew I could do better. However, as I worked with it, I heard clicking.

That would be the relay.

I could not make it happen, so I tried my fateful experiment and attempted to accomplish the many vital tasks I need to complete before moving five hours away.

When I plugged in the cable, the cooling fan ran for just a moment. I pulled on it until the fan ran for several seconds, then unplugged it and used the paperclip.

Why would the wiring work with the paperclip, but only with the switch when pulled?

I am not excited about the crack in my radiator. It only released a fine mist.

For now.

Hello Xist,

Can't offer much help on your wiring issue, not being equipped with any Honda knowledge. Only suspect would be a bad wire to clip connection inside the plastic connector that plugs into the thermoswitch.

As for the split in the radiator, welcome to the "Gee, I fixed problem X, only to find the next weak point in the system" club. My condolences. My situation was a leaking thermostat housing. Replaced that, got a split in the radiator. Replaced that, blew the lower intake manifold gasket (that was old and leaking anyway). You can "buy some time" (not a lot of time) by depressurizing your cooling system. I have tried two ways, and can think of a third and fourth.

First way is to loosen the radiator cap to the first notch - the point where it releases the internal pressure seal and allows pressure to get to the overflow tank. Messy, as the outer seal above the inner seal also comes loose, so you get some overflow out the radiator neck, too. I've tried this for a commute or two, and lost a lot of coolant to slosh.

Second way is to get one of those "lever-release" type radiator caps, and either wire the lever up (if there is room for it with the hood shut, I did not have room when I tried it) or shim the lever base up so it depressurizes the system. This is what I did, it sort of worked. Kept spitting the shims out, though, so I probably only somewhat reduced the pressure. The radiator still dribbled from the crack, but it wasn't bulging at least, and did not "blow out".

Third way is to get or make a "blank cap" that has no inner seal, just an outer one to the radiator neck. You might be able to just drill out the itty-bitty "return valve" in the middle of the radiator cap's lower seal. This return valve is what opens when the cooling system pulls a slight vacuum upon cooling down and allows drawing coolant back in from the overflow tank. A small hole is all you really need to dump pressure.

Fourth way is to get a super-low-pressure radiator cap. This isn't as good as no pressure, but it is likely more available and requires no other mods. 6 PSI seems relatively available, which is ~10 psi less than most factory caps.

The idea is to run your cooling system open to the atmosphere via the overflow tank. This will reduce the stress on the split in the radiator, causing it to bow out less, grow slower, and not spit as much coolant. You'll lose the boiling point raising effect of a pressurized system, so this won't work for high load or extreme heat situations. It should limit the leak rate enough that you can "limp along" to a point where you can replace or repair the radiator. Do keep an eye on coolant level and temp, though. Don't want to turn a simple radiator leak into a cooked engine.

Note: make sure your overflow tank does not have a tightly sealing cap, else it might blow off. If you cannot find where it vents to atmosphere, check it a few times during driving to make sure the cap hasn't blown off. If it does, you may need to make a larger vent hole in the overflow cap, that you can later plug with a screw after you replace the radiator and go back to running a pressurized system.

I once split a radiator top hose. I removed the radiator cap, topped up with water. then drove 10 miles to the nearest dealer. Never lost a drop of water. Bought my new hose, drove home. Same result. Changed dose, topped up, cap back on and back to normal. Without the cap there is no pressure. Coolant still gets up to 212 degrees.

A "Standard"-quality radiator is $56 shipped from Rock Auto. That would need to wait until my second paycheck from the new job, but should be fine.
Maybe the crack was already there, a couple of times I found coolant on top of the radiator and when I first pressure-tested it, I heard hissing from around the opening, but it did not seem to be the worst problem, so I did not try to track it down, although I did not notice anything of the sort the second time I tested the pressure.

Making progress yay. Yeah I know it sometimes sucks but now that you know these problems they can be fixed.

Does the switch have one or two connector pins on it?

If it has one it will control ground, and if so something is loose and not making contact. It could be corrosion as well. If so when you pull on it you pull on whatever is loose and it makes contact.

If it has two it would likely (since you already replaced the switch) be a bad connector. if you can take a picture of the end of it looking into the slots I might be able to help you jury rig it, maybe even fix it. But most likely it will have to be replaced which will require splicing in a new one and the part stores are often proud of their connectors. I payed $20 for one on my Jeep recently.

I do not know if you can really see it, but it is round with four holes, two being for the clip, and two being for the leads. I should be able to bring in my old switch or ask them to grab one of theirs and see what they can match to it.

Or call Honda and at least get a part number.

https://s21.postimg.org/txb4be7av/Fa...h_Bypass_1.jpg

I cant really tell from that photo, how do the wires look on the back side, any kind of fraying or still solid with the insulation?