emspilot

Ok, trying to figure out my wifes 95 Civic cooling problems. It's a D15B7 engine. First off, it has a new radiator, new thermostat, new coolant, water pump and timing belt are at ~50k miles. Engine has 145k on it.
After prolonged highway driving (45 min at >60mph) the temp gauge will start to rise, and will rise and fall, rise and fall like the coolant is not circulating, this will not happen unless it is subjected to a period of long highway driving, and then the car has to be driven slowly in town otherwise it won't happen, it stays nice and cool at high speed.... So I bled the cooling system, there were tons of air bubbles in the system (obviously the problem) after bleeding it did it again. Bled the system again, after 45 min of driving the overflow tank was FULL and there were lots of bubbles coming into the overflow tank. It took about an hour to bleed all the bubbles out of the radiator when I did it. So I'm thinking maybe I have a blown head gasket, but there are no other signs. There is no white smoke from the exhaust, no radiator fluid in the oil (just changed it to see), and the radiator fluid is nice and clear/green so I don't see any signs of oil in it. Any ideas???

Jafro

Pull the radiator cap off, run the car until it's fully warmed up, top off the coolant and see if exhaust is bubbling out of the coolant on the filler neck. That = bad head gasket.

Another couple of things you could do is a compression check and a radiator pressure test. You probably don't have these tools, but the average garage will.

emspilot

There are bubbles coming out of the radiator fluid after it has been running (idle) for about 30 min. That means 30 min from cold, AND 30 min after it's already warmed up.
If it was the gasket would'nt I see the other signs? Oil in the AF, AF in the oil, white exhaust?

Jafro

Not necessarily. Exhaust gasses are probably leaking through the HG during combustion, and coolant may not leak back into the combustion chamber. Just because exhaust is venting into the coolant system, doesn't mean that oil and coolant will mix either. The only oil that would make it into your coolant system in this type of leak would be blow-by from the rings, and it's such a small amount of oil that it would be hard to detect.

If you let the car sit, pop the overflow bottle open and there's a rainbow-like appearance floating on top of it, that's oil. You may not find chunks or obvious signs of oil.

You should get your radiator pressure tested. That would be the easiest way to tell if you have a bigger problem, but from what you've described already, it doesn't look good. If you have all the right tools (torque wrench and preferably some air tools) you could do this job yourself in a day for the cost of a set of head bolts and a gasket. That's under $100. A shop will charge you at least a grand. It's a lot of labor.

Green Fastback

last summer my D14A2 starts to do that,if you drive slowly(4.00rpm max)everything fine but if you drive high way or sinilar,its coolant returns from radiator never goes back to it.
Change termostate,fan swchtich,radiator cap,but almost the same and with radiator cap out theres the f**** bubles that show a little wleak somewhere,i hpoe is the headgasket.
i will open my engine this week-end,and then i will see whats happen,i think you better think do the same

emspilot

Yeah, I'm 95% sure it's the gasket. This AM I saw minute traces of oil in the AF.
Now my dilema is do we replace the gasket or the whole car. It's 10yrs old with 155k miles. Kelly value is only $1000. Seems silly to pay a shop $700 to fix the gasket.

dpkelly

You can think of it this way too:
New cars have car payments. Used cars don't. For a new car, you'd pay $700 in maybe the 1st 3-4 months and much more after that for about 4-5 yrs depending on your loan. Don't look at what it's worth, look at what you're going to pay in the future. New cars lose 20-30% after driven from the lot which is even way more than $700. 155k miles is not much. I'm at 237k on my '92 and it only leaks oil and still has good gas mileage. I'm planning to fix my oil leaks this summer myself come hell or highwater.

I'd get the tools and do it myself and learn about cars. I don't think you really need an air gun + compressor to do it. Torque wrench, breaker bar, extensions, basic ratchet set is probably what you'll need. Plus you have the opportunity to clean the engine out with it open. Maybe replace the rings if you feel adventurous. If you have problems, the forum is a good source.

emspilot

You have valid points. I do know about cars, I've done this work before on my CRXs and Integras before. That's not the issue. Time and money is the issue. With my schedule and my wifes it's hard to find the time to tear it down and be with only 1 car. (Kids and jobs and all)

Green Fastback

I dont know your car but for me,here in Europe my Civic still better with 10 years(year of 1995)than many new models,just one example Ford Focus 1.4 petrol engine:not faster ,not more confort,not more space,not more silent,not more style,so on but you know your life
My have know 230.000kms(about 150k mils)and its the first problem that starststo appear,do you know in these yaers how many Fiiat,Renault,BMWE i saw broken in the highway,here where Summer Time means 42 ºCelsius but you knows,change model but prefer Honda,Thats my adviçe

dpkelly

You could rent a car for a short while. Yeah I know the scheduling issues with kids and so on. So it sounds you know quite a bit. Even more than me - which isn't much.

Good luck whatever u do.