2003 Honda Civic EX Temp Issues

[Pooplips]

So my Honda is acting up. While driving the temerature guage whill shoot up sporatically. I have topped off the coolant in the radiator and the issue goes away.. for awhile. I did some reasearch on probable causes and the most common was to change the thermostate. Cheap part no big deal, so I did that and purged the air out. Its has been fine for a week or so and is now happening again.

I took it to the mechanic and they pressure tested the system and found no leaks or other issues.

Today teh temperature guage shot up again. So when i got to work i let everything cool off for about 3 hours and checked the coolant. The reservoir is full but the radiator is not. After doing additional research this morning I feel like its pointing to a head gasket issue.

Would a head gasket issue show up during a pressure test? My inclination is that it would. Is there anything else it could possible be?

[Pooplips]

I just topped off the coolant and to me it didnt take much at all. Less than 1/4 of a jug approx. Very confused at this point.

[Syonyk]

"Less than a quarter jug" going straight into the radiator and not the overflow bottle is a lot of coolant.  It's probably only a 2-3 gallon total system capacity.

Yes, the symptoms you have are consistent with what a bad head gasket will do.  I'd normally say just replace the thermostat & see what happens, but if you're losing coolant, it's going somewhere.  Either you've got an external leak (when the engine is hot, carefully poke around the engine bay with a flashlight looking for a steam spray or mist), or it's going into the engine, which is usually a head gasket.

[Joggernot]

I also have a Honda.  When mine temperature spiked, one of the fans had died and required replacement.  Loss of coolant means its going somewhere.  Gotta check it for leaks and head gasket.

[Dan_at_Home]

Also check the carefully check all the coolant hoses thorough out the engine area and inspect for any cracks or signs of slow leaks.

[Pooplips]

Thanks for the replys.

[guitar_stitch]

Plastic radiators can crack along seams and lose coolant via steam.  You won't see it and it will pass under a pressure test when cold.  :-/

[Greg]

Try replacing the radiator cap.  It's what controls how much pressure builds up in the system, and when the coolant flows into the reservoir and when the system sucks the coolant back from the reservoir into the radiator again.

If the cap is bad, pressure may not hold, filling the reservoir and running slightly hotter than it should.  Also, it can allow air not coolant to be sucked back in on cooldown resulting in air in the system.

Plus, cheap part.

[Pooplips]

Try replacing the radiator cap.  It's what controls how much pressure builds up in the system, and when the coolant flows into the reservoir and when the system sucks the coolant back from the reservoir into the radiator again.

If the cap is bad, pressure may not hold, filling the reservoir and running slightly hotter than it should.  Also, it can allow air not coolant to be sucked back in on cooldown resulting in air in the system.

Plus, cheap part.

Thanks for the suggestion. I will def do that. I dont think I have a leak. I think somehow the reservior is not allowing the coolant back into the radiator. The reservior is always filled to the max-max and you can tell its over flowing based on what i looked at last night.

[ncornilsen]

How does your oil look? I imagine your mechanic would have checked that.

A headgasket -might- show up on a coolant system pressure test. I've had them be marginally blown, and the coolant system pressure test showed nothing, but a cylinder leakdown test DID show air leaking into the coolant.

Before you go spend the cash on a headgasket or more leakdown tests, get a UV dye kit, and put it in the coolant. (DIRECTLY into the radiator. DO NOT put it in the overflow. Try to minimize the amount that spills into the overflow hose.) Do a few laps around the block till it's warm.  Use a blacklight, and see if you can find a leak. Check the plastic tanks on the radiator (I had this issue.) If this turns up nothing, it may still be a headgasket.

[HipGnosis]

So my Honda is acting up. While driving the temerature guage whill shoot up sporatically. I have topped off the coolant in the radiator and the issue goes away.. for awhile. I did some reasearch on probable causes and the most common was to change the thermostate. Cheap part no big deal, so I did that and purged the air out. Its has been fine for a week or so and is now happening again.

I took it to the mechanic and they pressure tested the system and found no leaks or other issues.

Today teh temperature guage shot up again. So when i got to work i let everything cool off for about 3 hours and checked the coolant. The reservoir is full but the radiator is not. After doing additional research this morning I feel like its pointing to a head gasket issue.

Would a head gasket issue show up during a pressure test? My inclination is that it would. Is there anything else it could possible be?

The system is made to be full all the time, except for the reservoir.   The coolant expands as it heats up.  The expanded coolant goes to the reservoir.  The coolant should go from the reservoir to the radiator and engine when they cool.  Yours didn't do that.  You need to fix that before you do anything else.

[ncornilsen]

So my Honda is acting up....

The system is made to be full all the time, except for the reservoir.   The coolant expands as it heats up.  The expanded coolant goes to the reservoir.  The coolant should go from the reservoir to the radiator and engine when they cool.  Yours didn't do that.  You need to fix that before you do anything else.

That doesn't hold true if a bad headgasket is injecting gases into the coolant system, or if a leak is a partial path through which the pressure is relieved/air is sucked in through a leak. Generally a leak will be accompanied by a slow drop in the reservoir level, nor will a leak cause excess coolant to be pushed out into the reservoir. I still recommend a cylinder leakdown test after replacing the radiator cap. But I wouldn't spend any more time on the reservoir setup than replacing the rad cap before I did a cylinder leakdown test.

[the_fella]

If you're sure there isn't a leak somewhere in the system, this sounds like a blown head gasket. There are kits you can get at the auto parts store to test for this.

[thurston howell iv]

Have you checked the water pump? I had the same issue over the winter. It was freezing and the car temp would spike. Every time I looked I could not find the leak. Replaced t-stat and hoses to be safe. Was fine for a bit and then started acting up again

Anyway, turned out to be the water pump ($17 off of ebay) - I should have replaced it when I did the timing belt but it was fine... Nevertheless, the replacement only took a little bit of time and all has been well since. Temp is rock solid.

[Pooplips]

It very well could be the water pump. I never knew it was recommended to change that when changing the timing belt.

I dont believe it is the radiator cap. When I went to check the coolant last night after letting the car sit for the weekend, I could clearly hear that here was a vacuum being maintained on the system. Could it be possible that somehow the coolant can not make it back to the raidiator from the reservior because of a clog in the line?

I am going ot try and inspect that next. Is there a way i can check to verify if it is the water pump?

Thank you everyone for all the help.

[zolotiyeruki]

It very well could be the water pump. I never knew it was recommended to change that when changing the timing belt.

The reason it's recommended is because
1) it's a decent interval for replacing it, and
2) it's a significant amount of labor to change the timing belt, and it's only another 10 minutes worth of work to replace the water pump while you're in there.

I just did my timing belt and water pump, and here were the steps (I forgot some the first time through, hence the negative numbers):
-2) drain coolant, disconnect battery
-1) remove hood (it makes everything else so much easier)
0) remove windshield washer tank (it makes everything else so much easier)
1) remove alternator and belt
2) remove cruise control and wiring harness that passes over the valve cover
3) remove idler pulley and A/C compressor belt
4) remove power steering belt
5) remove power steering pump bracket
6) remove valve cover
7) remove upper timing belt cover
8) remove bolts from water pump pulley
9) remove middle timing belt cover
10) remove crankshaft pulley bolt, pulley, timing belt guide, and lower timing belt cover
11) loosen timing belt tensioner
12) remove passenger side engine mount
13) remove timing belt
14) remove water pump

Steps -2 through 13 are all prerequisites to removing the water pump

[BeerBeard]

If you're over heating it's possible to lose coolant through the top of the reservoir, but you should see it around that area and smell it burning while driving since it typically splatters over hot components.

If that's the case, you're probably pumping gases/air into the cooling system via a very small crack in the head gasket. You'll need to do a cylinder leak-down test not a compression test or coolant system pressure check.

[Papa Mustache]

I have a '99 CR-V with ~290K miles and we've owned it since new.

We've been down this road a few times with leaks. The original radiator lasted 160K miles and the original water pump lasted 215K miles and conveniently started leaking at about the same time it was due for a timing belt.

I replaced the thermostat along the way once or twice looking for the same overheating behavior.

In the end it was the radiator leaking along the seams between the core and the radiator tanks (plastic section of the radiator at top or bottom).

The first time I used a $125 off-brand radiator from an internet supplier. It lasted 13 months. One more than the warranty and the retailer was not helpful. I replaced it with one from NAPA for ~$150 (wholesale price). It lasted eight years I think and started leaking along the seam between the top tank and core again. I went back and they gave me a replacement for free b/c it had a lifetime warranty.

Guess what? Got a leak again. Not sure where it is yet but I think it is on the driver's side which could also be a water pump leak. It is slow.

If I don't keep it topped up then the car gets hot when it idles for several minutes b/c there isn't enough coolant in the engine to keep everything wet. The cylinder head gets the hottest and that's what runs low first when the system is leaking. It could crack or warp if the engine overheated excessively so I keep an eye on the temps. I never let it get very hot and fast idle the engine (foot on gas pedal) if it is running hot in traffic until I can top off the radiator.

I think this is a good plug for OEM parts. The original radiator lasted 160K miles. The replacements much less and thus more trouble than they are worth. I can get the OEM radiator for $350 online from a Honda dealer. The local dealer thinks their parts are made of gold and won't play nice so I don't do business with them. Last water pump replacement was an OEM pump too.

Another tid-bit - I discovered the current NAPA replacement radiator didn't have the overflow tank nipple drilled out so the radiator doesn't move water in and out as necessary - it just - leaks? Might account for the missing antifreeze this summer. Prob won't lose much this winter with colder temps.

Hope this is helpful info for you.

[Pooplips]

Thanks for the reply. I will look into it.

[Syonyk]

I generally prefer OEM parts for things that are a pain in the rear to replace.  If it's quick and easy (distributor cap, spark plugs, etc), I don't care as much.

Unless I was broke at the time, in which point I'll get the cheapest thing I can find and hope it works. :)