Well, I'm starting to think it may have finally happened. With 328,000+ miles on my stock B18C1 engine, I'm starting to think the head gasket may have finally given out. I've been losing coolant for several months now, with no visible leaks. I thought maybe it was a bad radiator cap (been on the car almost 10 years now) so I just replaced that with new OEM Honda cap. Still losing coolant. One day the coolant got pretty low, and while sitting in a drive-thru line the temp needle started creeping up above where it normally sits (just below half). As soon as I started driving again it dropped back down. I topped off with 50/50 coolant/water that day and the temp needle hasn't gone above normal since then.

Today I was pulling out of my neighborhood and noticed a large puff of white smoke coming out behind the car. Great. Back in January my distributor went out, and in the process of troubleshooting I ran a compression test (first time doing the test on the car in 12 years of ownership) and it seemed to be fine. I'll be doing another compression test soon, though.

Anyway, is the OEM Honda MLS head gasket still considered the best option for a stock engine? What about ARP head studs, any point in doing that on a stock high-mileage engine with zero modification plans? Helms does not specifically say to replace the head bolts, so I could re-use them, right?

 

If the the OEM gasket lasted that long, I'd stick with it. Why mess with success?

 

Oem gasket is still the best, and studs are a superior fastener so I would vote for that. Although you can reuse oem bolts too.

Commonly on dc2 they will have radiator tank cracks near the upper hose connection and occasionally a hose on the throttle body or fitv. Anytime I have seen a mls head gasket leak on a Honda it was a byproduct of overheating from other issues. If you do take the head off carefully check the deck surface and head for flatness. I find that the natural stress relieving that happens throughout years of heating up and cooling down tending to make the decks a little wavy. Also, a static compression test will not show any clues with a slow leak issue like you are having. I would say with that amount of mileage its time for a nice overhaul of the engine. Long live the b18c

 

Oem is fine. I used Oem Hg when I was making 400hp. The Oem head studs are fine too just make sure you loosen them in the proper order sequence and do the same when tightening them.

 

Everything he^^^^^^^^ said is spot on. Additionally,if you want a final confirmation, pull the plugs out in the morning(after an 8 hour or so sit)and you will likely see coolant in one of the cylinders. If not ,look for rusted out spark plugs or "washed" piston tops....

 

Unfortunately don't have the time or money for a complete overhaul. How much does it usually cost for the smallest amount of head milling possible? The car has never actually overheated so would the milling really be necessary?

 

I keep smelling coolant inside the car, but haven't found any signs of leaks on the floor or anything. But still I wonder if there's a problem with the heater core, which I replaced in 2008.

 

Check all the hoses ect before spending the time and money on a headgasket.

OEM is the only way to go. People typically deviate from OEM when trying to change compression via different head gasket.

If the oil cap isn't milky the head gasket is most likely Ok.

 

See that's the thing, I replaced every single coolant hose on the entire engine back in November 2008 with new OEM Honda, because I was chasing some coolant leaks back then. Surely they wouldn't have gone bad in less than 5 years.

 

Have you already ruled out your HG? You can go to your local autoparts store and buy or rent a coolant pressure tester to test for external leaks. Leaving the pressure tester on the car for a few hours will also force coolant pass the HG if it is indeed leaking.....

 

I agree, pump it up to 15-18 lbs ands let it sit. Poke around for leaks, take the plugs out and see if coolant seeps into the cylinders. You shouldn't smell coolant inside the car unless you spilled some on the radiator recently. Sometime you can smell it for a few days if that happens.

 

I just looked under the oil fill cap and took out the spark plugs. Also checked the oil on the dipstick. Oil level is perfect. Didn't see any foamy substances but then the car has been sitting for over 22 hours now. Not sure if that matters. Spark plugs #3 and #4 have been a little more difficult getting in and out the past few years, but I'm guessing the threads in the cylinder head are a little dirty. They almost feel like they're cross-threaded when removing the plugs, but they're not.

Looking at the plugs, #3 and #4 looks like they have a little oily residue on the threads themselves, but the ends actually inside the cylinders look fairly normal to me. Couldn't smell any coolant on the threads. Looking inside the cylinders, the tops of #3 and #4 pistons look a little wet, while 1 and 2 look more dry, or maybe just slightly wet. Tried to take pics but 1 and 2 are harder to see.



Cyl 4


Cyl 3


Cyl 2


Cyl 1


I would actually love it if the radiator itself were leaking. That's an *easy* fix, and actually the radiator in the car now is a CSF (I think?) brand that cost me less than $100 and was installed almost 10 years ago. But I recall the failure of the OEM raditor's plastic tanks back in 2004 where there was coolant sitting around the edges of the top tank, and on this radiator I haven't seen any of that. I guess I need to inspect it more after driving it.

Another thing I noticed is that when removing the radiator cap after the car has been sitting a long while, I hear pressure releasing and making bubbles in the coolant in the overflow tank.

 

So I got a coolant pressure tester, hooked it up and pressurized the system to about 16 PSI. The pressure definitely started dropping immediately, and fairly quickly. Did not see any liquid leaking anywhere. Removed the spark plugs, no change in how quickly the pressure was bleeding off.

I could hear what sounded like air leaking near the radiator neck itself, where the tester adapter and cap were attached. Could that mean the neck of my radiator is allowing pressure/coolant to escape, or could the tester itself be bad or defective? Everything seemed to be hooked up good and tight.

 

I think there may be a connection problem or the tester itself is faulty. If the pressure drops that quick there should definitely be a leak. Spark plug #2 is covered in rust and is one typical indicator of a leaking HG. I would focus on that hole....

 

You mean 2nd from the left? That's plug #3.

I actually tried 2 different pressure testers. One didn't come with the right adapter for my car, but I hooked it up to the adapter from the other kit, and both showed the same pressure drop. It dropped from 16 to below 7 PSI in a matter of minutes - not seconds, mind you, it did take a bit for it to drop. The adapter itself is all metal construction (except for the rubber seal) and appears to be high quality. The kit with the correct adapter cost over $150 to loan it out from O'Reilly.

But still, haven't seen any milky foamy substances anywhere. Do you think I should run a leakdown test?

 

Yes.
The leak down test will likely be inconclusive. Given the appearance of the one spark plug,the overheating, the mysterious coolant loss, and the wetness in the cylinders,I think you simply have to make a reasonable assumption that the HG is bad. That would be my final opinion if it were my car,and I'd pull the trigger. I have seen one or all of these combinations/clues over the past 17 years as a technician....



(also a HG leak this small rarely results in oil/coolant mixture. The coolant is burning up in the cylinders. You are likely experiencing a rough idle in the morning that goes away after a few minutes)

 

hmm yeah I have noticed the engine stumbling a bit on cold startup, for a few seconds, and then it finally gets up to the usual cold idle RPM of 1500-1800 depending on ambient temps. But I assumed that was the FITV which has never been serviced or cleaned on this car. You think it's more likely a HG breach?

 

So I drove the car to work this morning. After getting going, I did not smell any coolant inside the car. In fact I never smell it inside the car while driving, only after it's been sitting several hours. I even drove with the heat on full hot, but did not smell any coolant smell through the vents. Car drives normally, accelerates normally, and also still gets the usual 28-30 MPG fuel economy. The engine burns 1 quart of oil AT MOST in 6,000 mile oil-drain intervals.

After I got to work I popped the hood and looked around. No evidence of coolant leaks anywhere. No smell of coolant whatsoever. With the engine running I also did not see any white smoke or any other smoke at all coming out of the tail pipe, but of course that was just with the engine idling.

I'll run some more of these checks with the system under pressure tonight. Might also go back to the auto parts store and see if they have another kit just to rule out this one being faulty.

Still got me stumped...

 

Mine burns the same amount of oil.
Half quart- 3,000-5,000k miles

 

Bump goodluck i thought i hacd the same problem till i found a hairline crack on my radioator dodged a bullet

 

I just swapped out the pressure testing kit with another kit, and will test again tonight after the radiator has cooled down. That should determine whether the pressure was leaking because of faulty radiator, or faulty tester/adapter. Might also put the tester on my wife's car to check it out.

 

also check for bubbles in the reservoir when the car is running and the smell of exhaust in the tank. or take the rad cap off when the car is cold and bring it up to temp and see if it bubbles in the rad which would result in a small breech in the headgasket.

 

Well I'm thinking maybe my fears may have been premature. I swapped out the pressure tester for an identical kit today, and tried it on my wife's car first. Held pressure perfectly. So now I put the kit on my car and took it up to about 16 PSI, and it seems to be holding pressure perfectly.

I thought that the car was still losing coolant after I replaced the rad cap, but now I'm thinking maybe it was just some air in the system, which worked its way to the top of the radiator and made the coolant level look lower. Today the coolant level was the same as yesterday, reservoir tank is the same as yesterday, and it seems to be holding pressure just fine.

So, hoping all is good.

 

Okay so the system held over 15 PSI pressure for nearly an hour. I also just ran the engine with the radiator cap off and saw no bubbles at all. Also while the system was pressurized I sprayed all coolant hose connections with soapy liquid, and again saw no bubbles. Removed all spark plugs with system pressurized, saw no loss or change in cooling system pressure.

Sooo... pretty sure there are no leaks and no blown HG... right?

 

Well at least there is no major leaks or catastrophes. It's a very uncommon issue for a well maintained b18c to have any unprovoked head sealing issues.