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1997 Civic Overheating

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tbrand

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1997 Civic Overheating

PostSun Apr 08, 2012 6:10 pm

The honeymoon is over, it seems.

After buying this car back, we drove it 10-20 miles a day with no cooling issues at all, for about two weeks. Yesterday, after driving around most of the day with no issues, the temp gauge started climbing. We weren't far from home, so I turned the heat on full blast and nursed it a little ways, but the gauge kept climbing, so I shut it down. After letting it cool down, we added 1/3 gal of distilled water, and drove it around for about 15 minutes, right at normal temp.

Today, we drove it 25 miles out to Easter dinner, and had no problems until we were almost home. The temp gauge started going up just as we were turning onto our street. Heater on again, and by the time we pulled into the driveway, coolant was boiling.

I've never really dealt with cooling before, so what's the diagnostic process? I have the FSM which has detailed R&R instructions, but diagnosis help is skimpy.

1997 Civic, 1.6L Automatic
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jeep_jeff

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Re: 1997 Civic Overheating

PostMon Apr 09, 2012 2:28 pm

Note: I am not one of the big experts on this board. I just recently got done dealing with some cooling system problems on my Jeep. I rank a little higher than armchair mechanic.

Did you check the radiator cap? There should be a rubber gasket on the inside, if it's got any cracking in the gasket, it isn't sealing, which would cause your coolant to boil off through the cap (this, as I understand it, gets worse as you drive it and heat the coolant more). This is also a $15-$20 part and is about the easiest thing to replace on any vehicle.

Any obvious leaks? Drips under the car? Any coolant spattered anywhere in the engine bay? (There are a few ways my Jeep can leak that only happen when it's driving, eg, a very specific fault in the water pump when it starts wearing out.)

This is not complete, but it's where I'd start.

EDIT: I was waffling over whether to suggest this, but you might want to check your oil. First, pop the oil fill cap off of your valve cover. Run your finger around the inside and see what you get on it. If it's amber or black and feels like vegetable oil, you might be fine. If its brown to white and has a thicker texture, stop driving, right away. (You are also screwed.)

If the oil seems normal, you might still want to send off an oil sample to a lab to get checked. Blackstone charges $25 for a basic test, and if coolant is getting in your oil, they'll spot it.

Also, I'd grab a bottle of premix coolant and throw it in the trunk with a funnel if you intend to keep driving it. However, if you do keep driving it, at least sort out the diagnosis soon (if it ends up being a head gasket leak, which the oil checks would tell you, you could be destroying your main bearings by driving on it). But, the serious case of the internal leak is least likely.

EDIT 2: As noted on the first line, I am not particularly an expert. This was all off the top of my head, so please, any one who does know better, correct me.
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tbrand

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Re: 1997 Civic Overheating

PostMon Apr 09, 2012 3:11 pm

I checked the oil right after it overheated the first time - not brownish or milky at all. If I had pancake batter in there, I'd be pricing out a B series swap. I'll double- check it before I install any new parts. OEM thermostat, cap, and coolant is $70-ish, so I may just do that, as I have no idea when they were last done.
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Thrashy

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Re: 1997 Civic Overheating

PostMon Apr 09, 2012 4:57 pm

Chase down coolant leaks first, I agree. Do you know if the water pump was replaced when the in-between owner fixed the timing belt? blown head gaskets are another common cause/effect of overheating on D-series motors, and would typically cause either the frothy/milky oil jeep_jeff is describing, or an oily sheen in the coolant. If it's leaking that way, you're also likely to have a lot of pressure in the coolant loop after the motor's been running. Either way, you're looking at a pricey visit to the mechanic, and possibly the need to have the head lapped, if the overheating caused warpage.
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jeep_jeff

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Re: 1997 Civic Overheating

PostMon Apr 09, 2012 5:22 pm

tbrand wrote:I checked the oil right after it overheated the first time - not brownish or milky at all. If I had pancake batter in there, I'd be pricing out a B series swap. I'll double- check it before I install any new parts. OEM thermostat, cap, and coolant is $70-ish, so I may just do that, as I have no idea when they were last done.


That's a good sign. Since that checks out, I'd be looking to rule out external leaks next, and maybe send in an oil sample. Again, hopefully it's an external leak somewhere. The problem I just fixed on my Jeep was a cracked head that was leaking coolant into the holes for the pushrods. My oil looked great, it wasn't leaking fast enough to cause any off colors or textures, but it did show up in a spectrograph. However, I was losing less than a pint (half-liter) of coolant every 500 miles (800 km), which sounds like a bit less than on your Civic (then again, I don't know where the line is for "oil is noticeably messed up").

Thermostat and radiator cap can't hurt, but I found flushing my coolant system to be a real pain, so I personally would nail down the problem before tackling the thermostat (to minimize draining and refilling the radiator).

Check the condition of your hoses while you're at it. That's one thing I forgot. They shouldn't have cracks or show other signs of wear (I don't remember the exact list of properties off the top of my head; I'll check my oil soaked Chilton when I get home).
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jeep_jeff

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Re: 1997 Civic Overheating

PostMon Apr 09, 2012 5:24 pm

Thrashy wrote:Chase down coolant leaks first, I agree. Do you know if the water pump was replaced when the in-between owner fixed the timing belt? blown head gaskets are another common cause/effect of overheating on D-series motors, and would typically cause either the frothy/milky oil jeep_jeff is describing, or an oily sheen in the coolant. If it's leaking that way, you're also likely to have a lot of pressure in the coolant loop after the motor's been running. Either way, you're looking at a pricey visit to the mechanic, and possibly the need to have the head lapped, if the overheating caused warpage.


That's a good point. If it's the gasket, there's a reason. If you just replace the gasket, you'll be doing it again the next week. My brother's first car was an Accord, and he ended up replacing the head gasket more often than he filled up his gas for the month that he owned it.
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tbrand

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Re: 1997 Civic Overheating

PostMon Apr 09, 2012 9:28 pm

@ Thrashy - I was told the water pump was done, but I don't see any papers proving so. The car has actually had two owners between us - the guy we sold it to, who got it running again, and the guy we bought it from. I think most of the repairs came from the first guy, whose contact info I no longer have.

Today I filled the radiator/reservoir again, and put the new cap on, and took a short drive. Came back, and there was lots of spray under the hood, but nothing appeared to be leaking, and the reservoir was over the MAX line. Crap - I'll have to be more careful about that. It makes me wonder though - if I had a leak, and it was overfilled, wouldn't the coolant just continue to leak there?

I rented a pressure tester, and I'm not sure if it told me anything. It seemed to be designed for a larger radiator opening, and it sounded like air was leaking out right at the filler neck. I'll double-check all the hoses tomorrow, see if I can see any leaks.

Given that I've been filling up with distilled water instead of the $20/gal Honda coolant, I'm sure my ratio is off by a lot. I know I'll have to drain the coolant eventually anyway, just to put the proper mix back in. Whenever that happens, I'll do the t-stat, if it didn't turn out to be the problem.

How about the fan? Should I be jumping the fan motor straight to the battery, to see if the motor burned out?
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Thrashy

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Re: 1997 Civic Overheating

PostTue Apr 10, 2012 8:14 am

tbrand wrote:How about the fan? Should I be jumping the fan motor straight to the battery, to see if the motor burned out?


Worth a shot; I do seem to remember that in the troubleshooting flowchart for my car.
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TurboBrick

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Re: 1997 Civic Overheating

PostTue Apr 10, 2012 11:04 am

Does the upper radiator hose get hot when the car reaches normal operating temp? If not, the thermostat is sticking. (while the car is not running) Put your hand under the pump and feel around if it's weeping from there.

I had a pinhole leak in my heater hose that was underneath the intake manifold on my Volvo. I found it by listening to the psh...psh...psh sounds of water droplets evaporting off the hot engine block right after driving it. There was no way of seeing where the leak was, just listening and running my hand up and down the hoses looking for signs of coolant. Also, check the carpet at the driver and passenger footwells in the car, in case it's your heater core that's leaking.

Remember that antifreeze does two things in addition to the obvious- protects your cooling system against corrosion and raises the boiling point of the coolant.
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tbrand

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Re: 1997 Civic Overheating

PostThu Apr 19, 2012 5:44 pm

Update: The cooling fan still seems to not want to work. I tested the it straight to the battery - turned on fine. I swapped the AC condenser fan relay with the cooling fan relay, and the AC fan still worked, but not the cooling fan. That just leaves the temp switch as the culprit, yeah? In addition, the radiator developed this little issue today. I had every intention of keeping the cooling system OEM, but a Denso radiator is $300 - gak!

http://www.youtube.com/watch?v=SUnHxf6V ... el&list=UL

I hate to be that guy, but what sorts of stopgap measures have you had success with in this arena? The funds just aren't there yet to do it the right way.
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Thrashy

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Re: 1997 Civic Overheating

PostFri Apr 20, 2012 11:00 am

I'm not sure it's worth staying OEM there, not for that price at least. A generic parts-store replacement rad will run you less than a third of that -- hell, you could get a Mishimoto all-aluminum replacement for less!
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tbrand

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Re: 1997 Civic Overheating

PostFri Apr 20, 2012 4:04 pm

So, a Mishimoto all-aluminum for $190 wouldn't be a bad deal?

Also, I got in touch with the PO, and he said he's not sure that the water pump was done after all. That, along with the fact that the freakin' AC condenser wasn't plugged in or mounted, makes me wonder how good of a job this shadetree mechanic did with the internals. I mean, why would you have the head off, do the timing belt, and NOT do the water pump? It's twenty stinking dollars!

Fortunately, I happened to buy a t-belt/water pump kit when I planned on fixing it myself, so that won't cost me anything but time. Just annoying.
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