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OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: 1963RedBrier ()
Date: January 21, 2018 07:54AM

My BIL & SIL gave my son, Mitchell, the car as a gift. It was bough new by my wife, Virginia. It has about 110,000 miles.

The first issue was that the radiator cap was completely broken. Easy fix.

Next we replaced the thermostat (the old one looked fine).

Watched some YouTube videos and the radiator fan does work, when jumped directly to the battery, but it is only registering 1.0 OHM! THE FAN NEVER SEEMS TO COME ON! Does the fan have to register 2 or 3 or more ohms to work correctly?

Third was replacing the radiator fan switch which plugs into the thermostat housing (the original one also looked fine). I jumped the radiator fan switch using a paper clip and the fan DID come on, but doesn't seem to come on when the switch is attached to the wiring harness.

My guess right now is that the fan is not strong enough (low ohms) to turn on or the cooling fan relay is bad.

The next step will be to replace the radiator fan, radiator, and possibly water pump, but I hate to keep replacing parts without diagnosing the issue! Any suggestions would be greatly appreciated! Thanks a million! Greg

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Phil Dally ()
Date: January 21, 2018 08:07AM

You don't want to hear this but those Honda four bangers are notorious for blown head gaskets.

No matter what free is good thing even if it needs a motor...have you done a compression check yet?

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: joelsplace ()
Date: January 21, 2018 08:15AM

"Third was replacing the radiator fan switch which plugs into the thermostat housing (the original one also looked fine). I jumped the radiator fan switch using a paper clip and the fan DID come on, but doesn't seem to come on when the switch is attached to the wiring harness."

This test told you the wiring, relay and fan are good. Take out the switch, connect a meter, put in water with a thermometer and heat it up until it switches. If it never switches it is bad. It will also tell you what temp it turns the fan on.

What makes you think it overheats? Some fan switches are set around 230 degrees.

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Chilly Willy ()
Date: January 21, 2018 08:46AM

Could be air trapped. Check for a bleed in the cooling system.




The Corvair, Keeping Nader Notorious winking smiley


Will
Northern California

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: joelsplace ()
Date: January 21, 2018 08:59AM

I don't know anything about Honda but does it control the fan with the computer and use the switch as an emergency backup?

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: MattNall ()
Date: January 21, 2018 09:16AM

joelsplace Wrote:
-------------------------------------------------------
> I don't know anything about Honda but does it
> control the fan with the computer and use the
> switch as an emergency backup?
========================================================

Without a wiring diagram... who knows? gg

Quickest way to check the cooling system....

Unplug the FAN.... Wire it direct to the Battery so it stays on....

Drive the car!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: jjohnsonjo ()
Date: January 21, 2018 10:20AM

My nephew had one of those and it kept overheating. MY BIL is a pretty decent wrench. After a couple of years of father and son projects to solve the overheating, which they never totally did, he got another car.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: rotted65 ()
Date: January 21, 2018 02:35PM

Almost all of those Civics are known to have bad head gaskets and warping the head is not uncommon. It takes a lot to make the fan come on, but should be on if temp is 3/4 or better The temp sensor is what tells the ECM to send ground and/or power to fan relay. Also IIRC there are 2 temp sensors/ 1 sensor for the ECM and 1 sensor for gauge. Check to make sure they are both working properly.

69 monza 110 PG gone many years ago
65 corsa vert 4spd gone
New toy 66 monza vert 4spd

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Timothy Shortle ()
Date: January 21, 2018 04:10PM

I would do a "block test" to determine if any HCs are present in the cooling system. Tell us more Greg. Is the car using coolant? Is the gauge reading too high? Is oil mixed with coolant in the lube system or cooling system?Cars with high mileage (100,000+), older cars (20+ years old), cars driven to abuse (continual use with faulty cooling system components i.e. broken radiator car and/or no cooling fan) are usually blown up in some way or another.

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Frank DuVal ()
Date: January 21, 2018 05:21PM

Quote
Greg
but it is only registering 1.0 OHM! THE FAN NEVER SEEMS TO COME ON! Does the fan have to register 2 or 3 or more ohms to work correctly?

Where did you place the leads to get this ohms reading?

BTW, E=IR and P=EI so P=E²/R or P=I²R so the higher the resistance, the less power delivered to the device, or consumed by the device for a constant voltage. Therefore, the higher the resistance of the fan motor, the less power it can deliver in CFM (or other work). Conversely, the lower the ohms for the same voltage means more current drawn by device, to the point of exceeding the circuit specifications, hence why a "short", close to zero ohms, blows a fuse.

The test of applying 12 volts directly to the fan was good. If the fan runs then, it is OK.

Jumping the switch with a paper clip also shows the circuit is working, like Joel said.

Is the switch getting hot? If coolant does not circulate, the switch might be in a cold spot. Got an IR temperature probe? HF, cheap.

Frank DuVal

Fredericksburg, VA

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Richard ()
Date: January 21, 2018 07:04PM

.



Edited 1 time(s). Last edit at 01/21/2018 07:12PM by Richard.

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: solo2r ()
Date: January 21, 2018 07:14PM

The fan operates when you jumped switch... move on!
That decade of Honda Engines do have an coolant air bleed screw...usually high up on a water housing. The fan switch will not work without coolant touching . As others have pointed out, Easy to overheat and blow headgasket.

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: cfmann ()
Date: January 21, 2018 08:23PM

if you haven't changed the oil all to recently an oil analysis from blackstone labs could tell you a lot more about the general health of the engine. i.e coolant seep in oil, pointing to head gasket (maybe)...

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Coupedevair ()
Date: January 22, 2018 04:32AM

Hi 63.I feel you on the overheating.I just got through fixing an over heating problem after hours of burping the system flushing radiator caps and cussing.
Finally took the car to a shop for my son to find out it was a cracked head .I thought it was head gasket.Im pretty sure the hondas have a bleed valve.Air in system will cause overheating .I would ensure there is no air in the system and let the car heat up with the cap off to operating temp.watch for bubbles.I had a toyota t100 that I covered all the bases too ended up being a warped head.If you see bubbles its not good.

Mike H
Located in Northeast TN
1964 monza 900 110 under construction!
1965 monza convertable 110
1966 sedan 140

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: azdave ()
Date: January 22, 2018 04:43AM

I got a 90 Honda wagon a few years back that the PO said always overheated and he was done trying to fix it after trying new fan, radiator, head work, etc. . I was buying a different car from him and he said I could have that one too for $100 just to get it out of his way.

The head was off and I could see fresh green anti-freeze in the water jacket around the cylinders. What no one before me noticed was that about 1" below the top edge the water jacket was mostly filled with silt and sand-type debris, probably corrosion by-products from someone not running anti-freeze many years before. Almost the entire water jacket area around all 4 cylinders was effectively blocked so no water would ever circulate properly. With some slim screwdrivers and a shop vac I cleaned it all out, re-assembled and got her running great. Even with the A/C on in the Phoenix summer heat there were no further issues. I put it on eBay a few months later and got $3200 for it. The buyer flew out from Chicago and drove it home.


Dave W. / Gilbert Arizona
66 Corsa 140 4-speed w/factory A/C
66 Corsa 140 4-speed w/factory A/C
66 Corsa 140 4-speed
65 Corsa 140 4-speed
66 Corsa 455 Toro V8
65 Monza 455 Toro V8
65 Monza 110 Convertible
65 Monza 4DR 140 PG w/factory A/C
65 Monza 4DR EJ20T w/5-speed




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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: Mel ()
Date: January 22, 2018 06:34AM

Phil Dally Wrote:
-------------------------------------------------------
> You don't want to hear this but those Honda four
> bangers are notorious for blown head gaskets.
>
> No matter what free is good thing even if it needs
> a motor...have you done a compression check yet?


X2 sad smiley

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Update!: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: 1963RedBrier ()
Date: January 22, 2018 12:34PM

It's 65 degrees in the Washington DC area today and my son and I just ran a compression check on the Civic. The car was cold and not warmed up. Results are left to right:

1 - 171

2 - 171

3 - 145

4 - 144 (this one was wet with oil)

The overflow tank was bubbling on the first two tests, but we did them backward from cylinder 4 left to cylinder 1.

There does not appear to be any coolant in the oil, or oil in the coolant. The car runs fine idling in the driveway. No smoke or steam out of the exhaust.

Our next step will be to find if there is a coolant air bleed screw (as solo2r suggested) and try to burp the system. After that will direct wire the fan (as MattNall suggested) and take it for a spin around the block to see if it overheats. Thank you all! I'll make updates as time and weather permit...

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: joelsplace ()
Date: January 22, 2018 01:40PM

As far as running it up to temp with the cap off: Lots of vehicles will overheat without pressure in the system. There are always hot spots that need pressure to keep coolant in contact with them.

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: 1963RedBrier ()
Date: January 22, 2018 02:08PM

Update #2: Topped up the radiator and the overflow tank. With the Civic idling in the driveway, the temp gauge reads between 1/4 to 1/3, and I'm getting minimal to no heat with the fan on full blast. The coolant in the overflow tank is bubbling away and steaming slightly, but the car is not overheating. I loosened the new fan switch to burp the system and ensure coolant is touching the new fan switch and now it is. The upper radiator hose is HOT and the long lower radiator hose is cool to warm but easy to grab and hold onto. The fan still is NOT coming on! Next will be to direct wire the radiator fan.

Is there any reason the Civic couldn't be driven with the electric fan on all the time?

I mistakenly left the radiator cap off when I restarted the car and of course the coolant splashed all over! Is this an indication that the water pump is good? Or, BAD?

Thanks! Greg

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Re: OT: Help with son's 1995 Honda Civic Overheating Problem!
Posted by: MattNall ()
Date: January 22, 2018 02:28PM

1963RedBrier Wrote:
-------------------------------------------------------
> Is there any reason the Civic couldn't be driven
> with the electric fan on all the time?
>
> I mistakenly left the radiator cap off when I
> restarted the car and of course the coolant
> splashed all over! Is this an indication that the
> water pump is good? Or, BAD?
>
> Thanks! Greg
===================================================================

No problem driving with the Fan Hot wired to run all the time..

You are going about this all wrong..

1 Fill radiator put cap on tight.. start engine

2 check for liquid at highest point... temp switch??

3 Look for liquid rising in coolant tank...... some bubbles are OK NOW.... but not later...after you've driven, check got bubbles still.... if you still have bubbles....blown head gasket / cracked head! Ask for SEALER name here!!

4 Shut off and do not touch anything!

5 return in 2-3 hours and check ONLY Coolant "reservoir / expansion tank"

6 Refill coolant reservoir to 1/3 -1/2 FULL NO MORE!!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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