I have a 97 Honda Civic DX. The engine has 250,000 miles (approx). Recently, I was driving on the highway, and noticed that the water temperature was red-lined. Bottom line is I don't know how long it had been that way, but worst case scenario, it would be approx an hour. The car is now erractic, it overheats, misfires, and I am afraid to drive it for too long, for fear it might leave me stranded again. How can I tell if the head gasket is compromised, or blown? If the head gasket is blown, does that mean that the head needs to be straightened, or whatever the correct terminology is?

 

Do you have water in the Oil? When it is running & warmed up is the water or anti freeze in the overflow tank boiling? Is coolant coming out the exhaust pipe? As for your second question until you determine what the trouble is it is hard to say. You could have a cracked head.

 

Thank you, 90 Civic:
You have given me three things to look for. I will check those three suggestions out this weekend. Sorry, but my work schedule doesn't let me do much during the week. In the meantime, I hear that a compression test can help, but it seems to me that a low compression test could also indicate bad rings, or some other such failure, and not necessarily a bad head gasket. In any case, I will be doing the compression test this weekend. I will keep you posted on my results and progress. Please stand by for any needed assistance. And thanks, again.

 

Hello,
When as the last time the coolant was changed. Do you have any leaks? Do the fans work? Please give us more info so we can help you with the problem. Thanks, 2010civiclx

 

Low compression would cause a loss of power for sure, & cause erratic running. Check compression with all the plugs out if you have a low cylinder or two. Squirt some oil in those cylinders if the compression comes up then it is most likely rings if not valves or the gasket. But if you got this engine so hot you pegged the temp gauge & have no idea how long you ran it you most likely either took out a head gasket or cracked a head. Heat kills an engine you could of even collapsed rings. Right now with no more info it is a guessing game.

 

The usual symptoms are white "smoke" that smells like antifreeze from the tailpipe, misfiring in one or more cylinders, and one or more spark plugs discolored (unusually clean due to the steam-cleaning action of leaking water).

A simple test you can do at home is to get the radiator completely full and start the engine (cold) with the radiator cap off. Look for bubbles in the radiator when you rev the engine up. A severe case will blow coolant out like a geyser. If you only see a few bubbles it could just be trapped air, or it could indeed be a leak in the engine. There is a device garages use to analyze the gas and see if it contains CO2, which comes from combustion in the cylinders.

If you have a leak the next thing would be to take the head off and check the head and block for flatness. If the block is no longer flat the engine is very likely beyond repair. You can try having the head machined flat ("shaved") if necessary. Reassemble with a new gasket and hope for the best.

 

Do a leakdown test while watching for bubbles at the radiator fill.

This means pressurizing each cylinder with air and disabling the valves so that they are completely closed.

 

The last time the coolant was changed was shortly after the overheating incident. The reason for the engine overheating was no coolant due to a leaking hose due to a blocked radiator.

 

OK, so the weekend is here, and so I pulled all the plugs, removed the fuel pump fuse, floored the gas pedal, cranked the engine for about fives seconds each time, and measured the compression in each cylinder, and my readings for each cylinder from left to right are as follows: 190,185,190,187. These do not sound like numbers for a blown head gasket, or a cracked head. My mechanic had reported readings of 70,90,80,80. How could I have screwed my measurements so bad that I am getting more than double his measurements? Please advise. Did I totally screw up the readings, or did the mechanic lie?

 

BTW, my symptoms are that the car threatens to overheat again, and sporadically, I have no power. Not all the time, though. Occassionally, it backfires, though I took it out after making the compression readings, and it did not backfire once.