Aftermarket Head gasket failure.
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Last summer I smelled the telltale glycol smell in the exhaust on startup so realized I needed to do head gaskets.
I ordered a top end gasket kit from the Honda dealer but was informed they no longer sell the kit, only individual gaskets. The dealer brought me in an aftermarket kit by KP of Japan, at considerable savings. I though no more about it and proceded to do the job. I worked for 7 years as an engine builder a number of years ago so I am very careful about details. Checked the heads on a granite surface plate for flatness, checked the block with a true straight edge, used a calibrated torque wrench and assembled everything with clinical care. This week I smelled coolant again! When I removed the heads yesterday I miked the crush ring of the gaskets and they were all within 1/2 thou of 0.041" all the way around, but the grey graphite material was all swoolen and decomposed on the block side where the water passages are. I have bought OEM gaskets for the re-repair! I am wondering about the cause of the failure. Are these gaskets just of inferior materials? I used a product called "Water Wetter" with the coolant as I have done in my competition bikes for years, but they don't have head gaskets, just "O" rings. Could this have eaten the gasket material? It never overheated, but the left side had a weep of coolant right through the gasket material for about an hour after first start up, right at the top, but then it stopped. I did not use new head bolts but the old ones were cleaned and lightly lubed. I second guessed myself for a long time, but after dissasembly I'm sure the repair was carried out correctly. The heads are still flat to .0005", (this time I used the new $15,000 laser measuring system here at work) I might add that the valve cover gaskets that came with the kit never fit well, and always leaked, even with new honda bolt rubbers and correct torque. Any thoughts?
Tim Johnson
1984 GL1200I 1975 GL1000 2002 GasGas trials. 1956 Norton Dominator |
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#1
07-25-2012, 09:52 AM,
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I used Honda Gaskets, Coat the threads and under the heads with moly 45. replaced the oil orifice O ring
used the same cover gaskets, never had a problem.
The only stupid questions are the one's that are not asked.
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#2
07-25-2012, 04:15 PM,
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I never use anything but Honda head gaskets on my bikes, but, I'm wondering if you overlooked the hose that runs from the coolant reservoir tank to the radiator? Quite often that hose will end up with a crack on the bottom which almost imperceptably leaks onto the hot engine or radiator creating the anti freeze smell but it leaves no visible traces of coolant because the hot engine/radiator evaporates it before you can see it. I know you mentioned that you smelled it in the exhaust but the cooling fan could be pushing the smell the back of the bike. This hose is not under pressure so it does not gush coolant when leaking and it can leak intermittently depending on the transfer rate from rad to reservoir.
Ed (Vic) Belanger - 1954-2015
Founder of gl1200goldwings.com |
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#3
07-26-2012, 04:55 AM,
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No, the head gaskets have definately failed. The overflow hose will be checked this evening though.
As you noticed in my original post the gaskets had deteriorated where they were in contact with the coolant. Tricky; yes, I used the honda moly paste (both times) It really is great stuff, I don't think there is anything comperable available off the shelf. The OEM valve cover gaskets fit so much better. They are so much softer than the aftermarket ones. Thanks guys.
Tim Johnson
1984 GL1200I 1975 GL1000 2002 GasGas trials. 1956 Norton Dominator |
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#4
07-26-2012, 07:04 AM,
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I have only heard bad things about aftermarket head gaskets. I'm sure some are fine but this is such a huge job (IMO). When I did mine last year I went with mother Honda gaskets. I didn't want to do the job again if I could help it
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#5
07-26-2012, 08:03 AM,
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