Hi guys
I recently purchased a 1999 honda civic.
was running fine..till yesterday..
i noticed the car would start to overheat a little.
so i touched the bottom hose and it was relatively cold comared to the top one.
So i thought the thermo must be stuck.
changed it out. filled with coolant ,bled the air. the car was fine.
test drove it up and down the freeway for an hour great.
So today i decided to take it on a road trip for LA to vegas
I got half way -150 miles with the car running great then car started to overheat again but worse than before
i was stuck in the middle of the desert with the thing.
so i removed the thermostat all together and refilled and bled the air.
no difference. kept over heating so i turned around and headed for home, doing multiple cooling stops all the way back to let the motor cool and not fry the gasket. luckily for me it was all downhill all the way home and i managed to keep a steady speed without working the motor too hard.
i noticed each time i stopped to let it cool that the reservoir would be full up and the bottom hose would be cold. very strange!!
anyone got any idea what happened to the car?
is the water pump gone out?

 

Could be a possibility. How many miles on it? Last time you changed the timing belt?

 

yea i would try checking the water pump. I'm still having problems with my 93 del sol. Lots of upgrades but still stock radiator. On hot days when i'm driving faster than 65 mph it starts to overheat. Its not the thermostat and no air in the hoses. Any ideas?

 

Clogged radiator, radiator cap failing, air in or entering the system.

Does it overheat at idle? Does the fan come on?

 

radiator cap is new.
radiator- when i squeeze the bottom hose the liquid in the radiator purges out of the filler hole (and the rad looks new) so i dont think its that.
i think you may be on the right track with air entering the system somewhere.
I know when it was boiling hot i stood back away from the car, and with a stick i prized off the filler cap and it was like a volcano of steam and water shooting out, so would that mean the system is pressurised ok?
Fan does not come on.

to the del sol guy- i think these civics/del sol are a bad design by honda because they have a half size radiator in them. I don't think its adequate size for high speed driving or desert driving...correct me if you think I'm wrong

 

del sols acually have a 2 row radiator... don't know if it different between the sub models...

 

fill the car with water and start it cold with the rad cap off. if it starts to bubble within a min or so it is probably a head gasket. also you said you fan is not working? un plug your cooling temp sensor and short it out with a paper clip or a piece of wire to make your fan run constintly. then if it dosent over heat with that shorted you need to change that sensor . they are 17 bucks on ebay

 

50cool50...u may be right about the radiator. I love this car and it didn't start doing it until it reached high heats outside and it only would raise when i was going over 65 for a steady period of time. But even still the aftermarket radiators don't look much bigger...although i don't know much about them. thanks for your help tho

 

does anyone know what the largest size picture is that can be posted?

 

 

my coupe with a b16 in it doesnt overheat now with a dual core radiator or before with the stock 14 year old radiator.

 

well maybe since mine is a b18 and turbo it's producing more heat? idk...how much did ur dual core radiator cost? any recommendations on brands?

 

Mine is doing the same EXACT thing... I replaced the fan switch, and all the only thing that I can think of is I havnt bled it since an iacv replacement, new tb, and fan switch which all relate and are withing close proximity to the t stat... Im praying its air.... my friend whos a very competent mechanic is fearing the head gasket... Im doing a compression test this weekend, but im throwin in the towel with hondas if this is a head gasket... and mine is exactly the same, lower hose was luke warm, cap exploded off, no boiling in the overflow tank... and I have a brand new dual row radiator and slim fan so its not that, save yourself the money... in my case, either the t stat failed (unlikely, its a year old), I have air in the system, or the gead gasket is done...

 

Sounds like a head gasket to me. I had the same symptoms. Aint too hard to replace. Bout 80 bux max for head gasket, and 20 bux to resurface head. The only thing is its time consuming.

 

Sounds like a prob i had. '98 civic ex. changed the water pump

 

and of course the thermostat and hoses....do the whole job at once so i dont have to mess with it again...

 

Altho my fan was working...have you changed the relay...like the fuel pump and horn are commonly the same part number you can try that.

 

so have you checked everything in the cooling system proficiently? The hoses, t-stat, water pump, radiator, and cap? If you've checked everything and your convinced its none of those things than it is probably your headgasket. The most affective and sure way of checking it is buying a kit at a parts store. It uses a color dye to tell if the headgasket is bad. You can do the common test of running the vehicle with the radiator cap off and see if air is coming up but thats not always a sure thing because the air coming to the radiator could possibly be distributed by the exhaust, not the headgasket. For everything else, another sure way is to use normal cooling dye. Empty some of your coolant out of the radiator, put the dye in, and let it run a bit and see if you can see any dye coming out of your hoses, t-stat housing, water pump or parts of the radiator. That kit is also sold at part stores. It comes with the dye and the flashlight and glasses needed to see the dye

 

Here are the kits. They are very much worth the money. This way in the future you wont have you guess whats wrong with you or a friends car...you actually diagnose whats wrong with it

 

Before you go replacing the headgasket, this might be a good place to start. The fan is a rather crucial part in that system. However you did say that the bottom rad hose was cooler than the upper, it may be your coolant temp switch.

 

My ek is doin this same exact thing, if i drive slow the temp stay normal but as i get on it temp goes all the way to H, n im hoping its not the head gasket