So I've read through every post on every forum I could find but I wanted to start a thread just to get some input before I tear into my motor. I have a 1998 CX hatchback with a completely stock d16y7. It appears that I've developed a small head gasket leak. Here is the scenario. After driving for over an hour or so, the temp guage will move very slightly if I'm sitting too long at a light, even with the fan and heat on. It has gone up to a little past half a couple of times. It doesn't always do this, but often enough to cause a little concern. It's recently gotten colder in the mornings where I live and I notice that on startup, white smoke pours out of the tailpipe for about 6 minutes, until the car is warm. If I am losing any coolant, it is a minimal amount and there is no mixing of oil and coolant that I can find. I have also recently developed an intermittent startup misfire. It will misfire for about 10 seconds on startup about 50% of the time. I am fairly confident that I have a small head gasket leak but I wanted to get some input from you all. Please let me know what you think and thanks in advance for your help.

 

Is the "white smoke" burning coolant or just normal steam on a cold morning?

Have you replaced the thermostat, checked the coolant level in BOTH the reservoir and under the radiator cap, and bled the cooling system?

Regarding the cold misfire, are there any CEL codes? When was the last FULL ignition system tune up?

 

The white smoke appears to be much thicker than the usual cold morning steam, but it does go away after warm up.

I have not replaced the thermostat. It is possible for it to be that intermittent? I drive 45 miles on the highway at 75mph twice a day and the only time the gauge raises is when I am at a stop for too long. Coolant level is correct in reservoir and radiator. I attempted to bleed to coolant system but while doing so, the coolant very very slowly starts to come back out of the radiator. The level will rise, rise, rise then an air bubble will come up. Do you suggest continuing with this procedure until no more air bubbles come up?

The car threw codes for Cyl. 1 misfire and random/multiple cylinder misfire. Plugs, cap and rotor have been replaced. Wires have not been, to my knowledge.

 

All seems pretty normal to see when attempting to bleed the cooling system and yes keep doing this, you want to get all those pesky bubbles out. Try squeezing the lower radiator hose to get things going. Water pump maybe?

 

At this point, I see no reason to jump to the conclusion that the head gasket is blown. How hot have you let the engine get on the cluster gauge?

Replace the thermostat (Honda), top off cooling system with coolant, bleed cooling system, and replace plug wires. Then go from there.

 

When looking at the gauge, if the bottom mark was 0%, the lowest squiggly line on the symbol was 50%, and the red portion was 95-100%, the highest I have seen it go is about 65-70%.I have never seen it go past 3/4 of the way to hot. I'm sorry but that is the only way I can think to describe it.

I will give the thermostat a shot and bleed the coolant. However, I don't have fast access to an OE Honda part and I'd like to do this soon. Do you think the Stant Premium or Beck-Arnley thermostat will be good enough to determine if that is the problem or not?

Thanks again for all of the help.

 

This^ is a very good description actually. I just wanted to know whether you had severely overheated the engine, which does not seem to be the case.

I personally am not familiar with those brand thermostats, but Beck-Arnley is a very good company from what I've read.

 

Thanks for the help, I'll try to give this a shot tonight and report back tomorrow morning.

 

So I have an update. I replaced the thermostat and bled the coolant. Through a little more observation and reading I have come to the conclusion that the head gasket is my issue. Here's my theory. As the motor cools and sits overnight, cooling is leaking into the combustion chamber on cylinder 1. Upon startup, it misfires for a few seconds and smokes out of the tailpipe. The smoke definitely smells of coolant. After all the coolant burns off, the motor runs fine and doesn't smoke at all. Does this conclusion seem plausible or am I overlooking something?

 

To test your theory, pressure test the cooling system and look for coolant entering cyl 1, and also do cylinder compression and leak down tests.

Did you replace the old plug wires?

 

You can get a block tester kit from O'Reilly's auto parts for $35, and return it for a refund excepting $8 for the fluid. My test fortunately came up negative. However my radiator was 15 years old, thin, blocked, and falling apart. I got a new oversized radiator from Ebay for $56 and installed it myself, with a screen in the front, along with a Beck-Arnley thermostat, and did a system flush with distilled water and new coolant. I highly recommend getting a gauge that shows you the exact coolant temperature. I use an Ultragauge, that also shows other useful parameters.

 

Sorry for the delay but the problem is fixed. It was a leaking head gasket on cyl. 1 like I had guessed. I replaced the head and gasket and now all symptoms are gone. Upon removal of the head, the black coating on the gasket was worn off between the combustion chamber and coolant passage whereas all other cylinders were in tact. Also, the piston on cylinder 1 was very clean, as opposed to the other 3 which were carbon-caked. Thanks for all the help everyone.