I have honda accord '95 , 4 cylinder (155K).

I guess i have overheating engine problem. After I have driven in highway for 20 min (80 mi/h), (temp gauge was always stayed 35%), I stopped th engine and under the hood I heard coolant boiling and gurgling sound. Some of coolant had spilled out from reservoir ( I had put to max level). My upper hose is very hot and lower hose is hot but not very hot as upper hose. Is this normal? Is my thermostat working?

When engine was cold, I opened the cap and let engine run. My coolant fluid rises up quickly and overflow from the top (really not moving like bubling). Had to put the cap on to stop it. After 10 min engine idling, I see water spitting out (sometimes flowing)continously from the tailpipe. Is my catalytic converter problem? If I drive around a bit, then I see no water coming out from tailpipe (completely dried and warm pipe) Did the heat dried it up?

To rule out head gasket problem and cylinder head crack, I did a OEM block chemical solution test on the radiator cap (checking for exhaust gas). It gave negative result (good). I also did compression test. All of my spark plug hole gave 185, 180, 180, and 195 psi. (for my car it should be 135 to 178 psi) I guess they are all fine good results.

Earlier a week ago, I had bleeded out the air pocket that my might have been locked close to thermostat area. This did not help at all. Yesterday, i drained out old coolant from teh radiator because I suspect Bar's radiator stop leak w/ water pump lube might have clog my coolant system. I also tried to drain the block, but only a little oil came out. This looks odd. I was expecting green coolant to come out. Is this motor oil or waterpump lube from Bar's stop leak? Do you know what is going on here?

I refilled radiator with deionized water, bleeded, and idle the engine a bit and drove around with heater on. I stopped teh engine and cooled off for a bit. Then again I removed teh radiator cap and added some water, let engine idle for a bit. This time I let the water come out of the cap and see if it moves. This time I could see water bubling and moving up and down. Is this normal? Is my coolant circulating around? Is my thermostat working?

Next, I drained the water from the radiator and block (again a little oil came out). Then I refill with coolant w/a antifreeze, bleeded out, and drove out for a long drive highway 20 mins w/ on and off. stopped at my destination and checked under the hood and heard no boiling/gugling sound. Later that late evening on my return trip with no heater on, I heard boiling sound (but no resevoir spill off, only went level up to max.)

Today, I drove a short distance ( 2 miles), my engine light came on. Stopped at grocery store. Then after half an hour, I drove back with heater on, no engine light was seen. I was expecting that engine light stays on unless you delete it or disconnect battery. My temp gauge never went above 35% even when I had boiling engine hot. Is my gauge normal? I never heard radiator fan coming on while driving or idling. I am really confused? Pls. I need help. Appreciated your comment.

 

The upper hose carries the hot coolant to the radiator and the lower hose carries the cooled coolant (it is still hot to the touch) back to the engine. So it does sound like your thermostat is working.

Your description of the problem sounds like a head gasket issue to me. The compression test would not pick up a small head gasket leak. The block testing solution should detect the problem.

Maybe try a leakdown test on each cylinder?

I would also inspect each spark plug to see if one plug looks worse than the others.

 

Which engine light? Yellow or red?

 

That stop leak stuff is murder.
Some weird symptoms though...
1 - at 80mph you're running your engine at over 3000RPM, if your cooling system is having problems already that could theoretically cause issueees
2 - 35% isn't totally abnormal though, I'd say mine sits at 40%, maybe 45 at the most. Perhaps a secondary ECT gauge with an actual value on it? Your engine is supposed to operate at 212 degrees F, which is really very very warm. I'd consider finding some kind of temp gauge.
3. oil in your coolant, as PAhonda said = possible head gasket.
4. short the underdash connector and check what that engine light code is.
5. water from tailpipe is not that abnormal, my muffler just flipping fell off and it was full of condensation.
6. perhaps fill the overflow tank less?
just a bunch of ideas there

 

Thank you all for your help.

My engine light that came on one time was "yellow" not red. I don't think I can have red because LED looks yellow.

Last night, I did jump the 2P connector and read engine light code: 1-2 (continuosly repeated). Online search says something to do with primary O2 sensor. I called the workshop and their computer says EGR valve. Confused!

I also got transmission D4 blinking code: 1-3; 1-4; 0-8 continous repeated) Does anyone know what are these problems?

This morning, I started the car and no engine light came on (I had not deleted or disconnected teh battery) Good sign! While engine running, I also noticed that I forgot to connect the EGR valve connector yesterday when I removed for coolant bleeding for easy access. So, maybe the problem is solved for temporary.

Maybe I have to solve teh head gasket leak by seal solution for temporary until I can afford to fix at workshop. If it gives more problem, I may have to flush coolant completely by removing thermostat and using backflush with garden hose.

BTW, does anyone knows how to replace thermostat step by step procedure? It is really hard to get backside of the engine for easy access of thermostat.
Thank you again.

 

Your car only has a yellow check engine light.

When checking codes, a long blink = 10, short =1. So long short short =12.

Reset the codes by removing the 7.5 amp backup/radio fuse in the engine bay fuse box. Drive the car and recheck the codes when your CEL turns on.

The transmission codes point towards a bad engine computer, so it is worth the time to recheck the codes.

To change the thermostat, I drained the coolant. Removed the air intake tube. Then I had enough access to remove the 2 or 3 bolts holding on the thermostat cover.

If you go to the common diy thread on top of the gen tech help forum, you can go to the online manuals link. From there, the hondatech site has a 94 shop manual you can download for free. The 94 and 95 accord are identical and this will help you a lot.

 

Good. That one's called the "check engine light." There are a couple of red engine lights too.You may be taking out the wrong plug. There's a rear balance shaft maintenance bolt/hole back there that will drain a bit of oil if the bolt is removed.

X2 on downloading the manual. It has nice pictures of these things.

 

Thanks all for your help again.

About 3 days ago,after coolant flushing w/ deionized H2O and replaced with fresh coolant 50/50, I added K-seal stop leakage in radiator and head gasket (for suspicious of tiny undetectable leakage). There was no change in result after driving around.

I still get boiling coolant sound after driving long time in freeway (20 min) with no heater on. I was told by mechanics that i have more water than antifreeze (65%/35%). This might be the cause. So I need to add more concentrated antifreeze, is that right? It is very hard to get 50/50 coolant because when you flush, there is some water remaining in the block.

I bought infrared thermometer today and measured my overheating engine. The temp on cylinder block/head was 242 F. On ECT switch B upper hose nozzle area was 206 F; on ECT switch A at thermostat nozzle was 185 F. If everything is ok, my radiator fan did not come on simply because the switch A never detected temp above 200 F, is that right?

Engine coolant temperature sending unit. Is on the side cylinder head facing the passenger tire. It is the closest sensor to Temp switch B. It only has one wire going to it. It controls the temperature gauge in your car, so its signal (resistance) varies. In order to measure its resistance, does the engine have to be running? also for switch A and B? can we disconnect the connector without unscrewing from the nozzle area and test the resistance? This is to test my temp gauge and radiator fan.

Thanks, and appreciated your help.

 

Some blocks have a drain bolt on them on the bottom or the front but I generally only drain at the radiator.

I don't think the disparity between the antifreeze and water is causing you problems when hot, I would think it causes problems when cold because it decreases your protection against freezing temps as the percentage of straight H2O increases. Would your mixture be a problem when hot? I doubt it. This isn't really an authoritative source but it jives with what I'm thinking:

HowStuffWorks "How Car Cooling Systems Work"

I don't agree with the mechanic at all. Everyone knows the cooling system is pressurized and I see that affecting it's boiling point more than anything. Maybe there's an issue with the cap? Maybe the system isn't able to hold pressure because the cap is defective?

But I agree that most of your symptoms seem head gasket related especially the overflowing from the neck.

 

Antifreeze will raise the boiling point as well as lowering the freezing point. So there IS some truth to what was said. I normall buy concentrate and add 7 pints after rinsing with DI water. Then fill remaining space with water.

The pressurization will raise the boiling point more than the antifreeze concentration will. But they both add together to get the boiling point you need. What have you done to rule out the headgasket leak? Leakdown test?

Check the cap like MessAround says. A bad cap won't let it pressurize properly. A scratch or gouge in the radiator neck will allow the same leakage even with a new radiator cap. Down the radiator neck is a smaller opening with a bit of a raised edge on the rim. THAT is where the pressure is sealed; operating against the intermediate-diameter rubber gasket of the cap.