1998 EJ6 (D16Y7 engine all stock parts) with 217k on the odometer and a problem that has me stumped. My coolant is vanishing causing overheats. I have checked all hoses and corrected a slightly loose lower radiator hose, and replaced a leaking rad cap.
Checked all hoses again repeatedly.
Replaced the malfunctioning fan thermo switch with an OEM one.
New OEM t-stat installed by me in January of this year.
Checked for combustion leak into the cooling system with a and it didn't indicate a leak.
No milky oil.
No white smoke out the tailpipe.

Anything else I missed or any ideas would be great? And yes I have the FSM.

 

When did you do the block tester test?

Have you pressure tested your cooling system and the radiator cap?

 

Some questions:

1. What is the rate of coolant loss?
2. Is water dripping from your exhaust?
3. When at operational temperature, what values are reported from the PCM and by direct resistance measurement of the ECT sensor? Are these values within spec?
4. What engine work has been done within the last two years? For example, has the IAC valve, intake manifold, exhaust manifold, or throttle body been cleaned/replaced?
5. You mentioned that the fan switch was malfunctioning. How did you come to that diagnosis?

 

Check passenger side carpet for wet spot toward the fire wall.

 

No leak at the heater core.
I did the block test about 6 hours before my OP.
How did I figure out the fan switch was malfunctioning? When the PCM outputs a temp of 214 (F) via my scan tool and the fan doesn't kick on but DOES upon jumpering the switch plug I reasonably concluded the fan switch was defective.
As far as engine work:
IACV cleaning and TB gasket replacement well over a year ago.
New exhaust to replace the cat converter from the EM (including gasketing) all the way to the very long mid-pipe that leads to the resonator
Replaced leaking oil pan gasket-speaking of which I need to go replace it AGAIN because it somehow didn't seat right and a small chunk blew out of it rendering the new gasket just as leaky as the old one it replaced.

I originally pressure tested the rad but neglected to RE-TEST after replacing the obviously defective cap and re tightening a loose lower radiator hose. After retesting today with loaner tools from the local Advance Auto it still wouldn't hold pressure but the pressure drop wasn't as great as before when I had a loose hose. I checked EVERYWHERE I could possibly see or think of and could not see, hear, or feel any leaks. Any ideas?

 

How old is the radiator,and is it a stock one?

 

Radiator installed new by a shop in July 2015 and yes it is.

 

Double check this before jumping the gun because I've never done this on a D/B engine, but I know for the F20/F22 engines people just use Hondabond to seal it, no gasket. I've used that with success on my old S2000.

I almost want to say that my friend and I did the same thing for his H22 but I don't honestly remember.

 

I promise you it has a gasket. The FSM indicates a gasket. The parts store indicates a gasket. The thing that mushroomed out over time and was leaking.....well that was a gasket.

 

I'm aware of that... I'm just saying that Hondabond may be a viable, decent alternative.

Edit: Although just from doing a google search on the pans, it looks like the F2*C pans have a flat surface while the D/B ones have some dimples. Probably means no go.

 

I had an issue with one of the small coolant hoses near the throttle body. One day it burst. Replaced it and eventually found the thermostat stuck closed. Changed the thermostat and haven't had an issue since.

Might be worth while to change the smaller hoses. It's not much to do.

 

Vanishing coolant and the system does not hold pressure. There is a leak somewhere.

Being you are not finding it, I wonder if your new radiator was a defective one. See if it came with a life time warantee. I know the one I put in that I bought from LordCo does, I think it's Spectra brand or something.

The only other place being all hoses and core is dry/clean is if it's pushing into the cylinders or oil but either I'm sure you would have figured out by now.

 

OP: with these engines the surest ways to detect a head gasket breach is coolant loss in radiator with coolant gain in reservoir. Other definitive test is to inject 100-150 psi of straight shop air (compressor. without leakdown tester),engine off, set each cylinder respectively at TDC and watch for bubbles coming out of radiator. These engines can pass every other test including block test. Your engine is experiencing coolant loss and overheating.. if you've performed a pressure test and no external leaks were seen then it's leaking internally (most likely through head gasket). With all those additional sighns it can't be anything else then a breached headgaskt. Head gaskets can breach in many ways: AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - Symptoms of a Blown Head Gasket

 

Seeing as how it was installed by a chain shop and the paperwork only said 1 yr parts & labor warranty I'm pretty sure it doesn't.


Son of a bitch. And yes I neglected to put that in the OP for some reason. I am losing coolant in the rad and it is presumably all going to the overflow tank and pissing out of it. What I was trying to figure out is where the hell the air was getting into the system and why it wouldn't hold pressure being as I couldn't put my eyes on any leaks.

EDIT: Will do a compression test to double check for HG leakage.

 

I have the FSM for the F series as well (my friend and his little sister both have F series accords which I tend to work on when I visit), and I already noticed that. Which is why I was kinda nixing the Hondabond idea from the get-go.

 

Do a dry and wet (two tablespoons of oil) compression test. If dry compression test shows low compression in one or more cylinders.. a wet test (oil) will isolate leak through cylinder compression rings. So, if a compression ring is leaking and has a low dry compression test psi number the added oil in cylinder during wet test will temporarily seal compresson rings and cause the (wet) compression test psi number to rise (usually 25 psi or more).

However, (in the same scenario above) if the compression doesn't change during wet test then that points to the intake and/or exhaust valves leaking compression or head gasket breach as source of compression loss. With compression loss through a head gasket it's usually in two adjacent cylinders because the breach will occur at the spot located between the two offending (low psi) cylinders. Best way to rule out intake and or exhaust valve leak is via a leakdown test.Leakdown scan also reveal compression loss through rings and head gasket (bubbles in coolant)..really, it's the best overall test for evaluating the health of an engine.

 

Alright so if I'm reading you (and my ASE A-1 section in my textbook) correctly the coolant bubbles could be caused by valve leakage and not a HG issue?

 

Valve leakage does not involve the cooling system.

Often the only symptom of a slow leak in the head gasket is loss of coolant (often pushed into the reservoir tank) and eventual overheating. You may find that the cooling system pressure rises rapidly after starting with the engine cold. Normally, it should not rise much until the engine warms up. This can be tested with a radiator pressure tester or feeling the pressure in one of the hoses with the system closed up.

 

Oh joy. Going to see how much it costs to get the head checked, cleaned and machined if necessary. Already know new bolts are about $40 shipped and a HG set from RockAuto is $90 shipped. Any chance I could get away with just a new head gasket as I know the EM , valve cover, plenum, spark plug seals, thermostat housing gaskets are all good?

 

Honda FSM doesn't state to replace the head bolts. If they are noticeably stretched you will have to but to date I have never seen a stretched honda bolt.

I think the threads in the block do the stretching.

 

Best to use OEM (MLS) head gasket. Rock auto usually doesn't have OEM parts. Try HondaPartsNow or other online Honda OEM store. Headbolts are around $2.10 each (x 10) and as Tomcat said not necessary but, many people feel is good practice at little expense to do so. Cleaned, checked (for level,cracks and valves leak-tested) and milled should be around $60-$75.Not sure what your budget is but, if you can afford to do so a valve lapp and valve stem seals may save headaches in the future if you are keeping this car long term. Check the block for level with straight edge and feeler gauges. Not likely the block is warped but, if it is..your freshly leveled cylinder head is of no use on warped block. DO NOT USE SCOTCH-BRITE PADS TO CLEAN MATING SURFACES. Carefully use blade and solvent (brake cleaner). These (two-part) are great videos for any headgasket replacement:

 

Was going to go with a Fel-Pro MLS HG set from rockauto is the OEM one really that much better/different? Also the $40 I quoted was from HondaPartsNow for the head bolts. Getting the valve seals, new IM gasket, head bolts, and head gasket brings it to ~$106 with shipping which is doable. I plan to keep this car long term and yes I already know not to use a pot scrubber to get gaskets off thanks for the reminder though. I have professional tools as I'm starting ASE Automotive Certification coursework in the fall and going to be doing this full time as a career. Snap-On Torque Wrenches, GP impact sockets, IR electric impact, gasket scraper, etc.

EDIT: Got a quote from a local trusted machine shop (the one my preferred shop sends all their machine work to).

$65 to get the head checked/cleaned/milled
$85 for the valve job provided I supply the seals

Last question....can/should I save ~$32 and NOT get new head bolts or are they a must?

 

IMO: best to get valve (lapp) job and new valve stem seals while the head is already off. Did the machinist tell you the valves have some small leaks?

You can re-use the head bolts as was already mentioned (stated in FSM ,,iirc). However, as already mentioned, some people (including the guy in video) feel it's good practice to use new ones. I used new ones when I replaced mine three years ago and (maybe just a placebo effect) felt good about it.

I've never used a Felpro gasket but, many have. I can't comment on the difference in quality but the diference in price is under $10. OEM is around $32 on HondaPartsNow,

 

Haven't taken it to the machinist as this is my DD. I work 30ish minutes from my apartment and can't really afford to have the vehicle down any longer than absolutely necessary, hence the reason I asked about various costs and different suppliers. RockAuto gets me parts FASTER and CHEAPER than HondaPartsNow or HondaPartsCheap both of whom charge an arm and a leg for shipping and handling but those parts are Fel-Pro not Honda OEM.

Triple-checked the FSM and it does not say to use new head bolts and I found ordering through HondaPartsDeals.com I can get all the parts (minus the new head bolts) for around $73.

 

...AND I THINK I FOUND IT!!!! I just went out and intending simply to dump all the excess out of the overflow container back into the radiator checked again for ***** & giggles in the dark. Turns out that when I checked every hose, etc, etc I missed a particular spot on a particular hose. Put on my headlamp and noticed around the clamp on the water valve (hosing leading INTO heater core) there was white residue. Pulled the long plastic air tube away from the air box and looked directly downwards and lo and behold there is a tiny I mean damn near miniscule portion of perforated hose on the other side right above the clamp.
Hose #6 in https://www.hondapartsnow.com/Page_Product/PartDetail.aspx?Vin=1HGEJ6671WL042373&Filter=()&Su bCategoryUrl=water-valve&Diagram=

And by the clamp I mean on the side that clamps to the valve on hose #6 NOT the side that clamps to the heater core inlet.

Which was impossible to see in daylight as was the residue while the plastic air tube was there. I also saw little white driplets of coolant on the rear motor mount (mount just above the PS rack). Again no way to see that in daylight as the stupid plastic hosing was blocking any good view and it was too bright out. Debating whether to throw UV dye in to be absolutely sure or just buy both hoses from the local auto parts store and hope this fixes it.