Blown Head Gasket in Kohler 18 hp V-Twin?

[JohnFornaro]

Howdy: I have a Soveriegn with a Kohler 18 hp V-twin engine. When I bought it from the guy, it looked like all it needed was a new inner tube in the front right tire. Turns out that oil comes out of what appears to be the right cylinder head gasket. I cleaned it off and tightened the head gasket screws. Lo and behold, the left cylinder has (6) head gasket screws. The right one only has (4) !! It seems that the leak is in the middle where the engine probably shoulda had 2 more head gasket screws. Any comments on this? If I replace the head gasket, will the problem go away, or is this an inherent design flaw? Where do you find the engine Identification numbers on this baby? Thanks for the responses. John Fornaro

[D-17_Dave]

I think on those twin Kohlers the # tag is a shiny sticker on the top of the engine close to the fuel pump. The sticker may be gone or just covered up. You need to find outr if the bolt holes are stripped out as this may be the cause of the blown head gasket and may hinder the repair. Also while you have the head off, check for too much cyl. wear by seeing if the piston moves up and down inside the cyl. Eccessive oil passing by the piston could have hydrolocked the engine and done lots of damage. Also does the piston move in and out?? It may be blown and the previous owner taken the head off and seen the problem and just put back a few bolts. Lets hope it's not that bad.

[Chris727]

I think I remember a guy at a local shop complaining about a Kohler twin on a zero turn, it also only had 4 headbolts and they had to use some kind of sealer as well as the new gasket.

[JohnFornaro]

Thanks for those snappy responses guys. I don't think I have deep engine problems (knock on wood) because it starts right up, and runs fiarly well. The spark plug on the affeted cylinder looks good also. To find the engine id, will I have to remove the hi-temp plastic shroud on top of the engine? Where is the fuel pump? If in fact I do have to replace the engine, which B$S ngine would be good to replace with? Thanks again

[Al]

Hi, I would pull the head. Take a straight edge and check the head surface for flatness. If you can slip a .002 guage under it, it needs to be resurfaced. Briggs OHVs only have 4 headbolts also. This engine should not have a head gasket problem. DO NOT PUT ANYTHING ON THD GASKETS, The gaskets should come with new head bolts. Do not use the old bolts. These bolts are "Torque to yield" and as in cars now can not be reused. I could be wrong on the 18 but the larger engines must have new bolts or nuts. The kit will have both. These Command 18 have been nearly bullet proof. If you have to resurface the head, repost and I'll tell you how to address this. Sorry you had trouble. Al Eden

[JohnFornaro]

Al: Thanks for the response. Am I correct in assuming that once I remove the heads, I need to replace the gasket? I should probably do 'em both, since the kit would have both cylinders, I assume. I'd rather not remove the heads, but I can't think of another place oil would come from....It drips right on the spark plug from a point directly above. Is there another way I could be getting an oil leak? Would an engine additive stop up the leak? I guess I'm a bit nervous contemplating the possibility of re-grinding the head surface. Thanks again.

[Dutch]

John, Is your 18hp V-Twin an OHV Command or an OHC Triad? There's a big difference between those two engines. If oil is dripping on the spark plug it sounds like the leak may be coming from the valve cover rather than the head gasket. The head gasket is below the spark plug. PS - The Command only uses 4 head bolts on each side.

[Roy]

Me thinks you have the infamous OHC Triad engine per dutch's question. The OHC engine has 4 valve cover bolts on one side and 6 on the other. If you have the OHC engine you most likely have a serious problem. My experience, Roy

[Al]

HI, If you have the TH or OHC engine, there are no head bolts or head gaskets. The heads and block are one piece. The cam/valve covers are more prone to leak than the OHV Command engines. If they are leaking, the oil will run down the sides of the cylinders and collect dirt. This will insulate the cylinder fins and cause overheating and failure. Also I checked and I believe only the 25 up Commands head gaskets come with the bolts and nuts for the engines with studs and the bolts are not reusable. Don't sell the Commands short, they are a heck of a good engine. There are some down in Texas running on natural gas on oil well pumps that run 24 hrs a day 7 days a week unattended. Maintainance people go in once a week and change the oil and ck them, then restart them. These engines have over 50,000 hours on them and are still going strong and go 24/7 without using oil. With the clean fuel they go a long time. Al Eden

[JohnFornaro]

My mistake all. It's definately a valve cover gasket, not a head gasket. 6 bolts on the left cylinder, 4 bolts on the right. It is an OHC engine; the oil is running down the sides of the cylinders and collecting dirt. Inattention to this problem will lead to engine failure, fer shure. This is what I cleaned off, and I don't relish doing this a lot. So the salient question is then, Will new valve cover gaskets solve the problem? I shoulda known that head bolts don't turn by hand with a 3/8" ratchet driving a 10 mm socket. Perhaps I should just crank 'em down a bit harder on that side? It seems clear, however, that Kohler has engineered a design flaw in this particular engine, in spite of the excellent track record of those engines down in Tejas. There should not be a 50% asymmetry between the two halves of a two cylinder engine. This is disappointing, but not the fault of the guy I bought it from. Thanks for all the input

[Dutch]

quote:

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Originally posted by JohnFornaro
My mistake all. It's definately a valve cover gasket, not a head gasket. 6 bolts on the left cylinder, 4 bolts on the right. It is an OHC engine; the oil is running down the sides of the cylinders and collecting dirt. Inattention to this problem will lead to engine failure, fer shure. This is what I cleaned off, and I don't relish doing this a lot. So the salient question is then, Will new valve cover gaskets solve the problem? I shoulda known that head bolts don't turn by hand with a 3/8" ratchet driving a 10 mm socket. Perhaps I should just crank 'em down a bit harder on that side? It seems clear, however, that Kohler has engineered a design flaw in this particular engine, in spite of the excellent track record of those engines down in Tejas. There should not be a 50% asymmetry between the two halves of a two cylinder engine. This is disappointing, but not the fault of the guy I bought it from. Thanks for all the input

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Don't confuse the 18hp V-Twin COMMAND OHV engine with the 18hp V-Twin TRIAD OHC engine. They are completely different. The "Texas" engines Al refered to are COMMAND engines. There have been major issues with the TRIAD engines. Use the Menu Search function with the word "Triad" to read about what others have experienced.

[JohnFornaro]

Dutch: I'm definitely not confused about which engine I've got. I may not have carefully read the report on the Texan engines. In my quote, however, I repeat, it's an OHC. Doesn't say Triad on it, but it may indeed be one. Perhaps I am a bit wistful about not having the reliability of the Command engine, but that cannot be helped at this point. Later on, I'll do a Triad search. Thanks for writing. Back to Al. I have had a fellow splitting firewood for me the last couple of days, and I went out this morning to cart some of it to the wood crib before the ground thawed and I messed up my lawn. The right valve cover is leaking something terrible; The guy I bought it from had obviously wiped it clean before selling, and I didn't notice it at the time. Live and don't learn is my policy, and now I've got to deal with the issue. So, I checked out your (Al's) website...rather good. Do you sell these valve cover gaskets? Because that's what I need to try next. Incidentally, is it ok etiquette to inquire about various member's tractor oriented business? Al, if you would, PM me with price, shipping, etc. Kohler TH18S; Spec: 54511; Family:TKH574U1G2RA; S/N: 2810302011. I couldn't believe it; earlier I couldn't find the ID tag. This morning, there it was, big as you please. Doo-dee-dee-doo...Doo-dee-dee-doo...Doo-dee-dee-doo...Must be a dark shed.

[KVANDY12]

John don't kick yourself to bad on not finding the motor #s I did know where to find them on b/s motor I bought till one of the fellows told me where to look. Ken

[roma3112]

JOhn here is a theread that i started over a year ago, i had one of the "triad" engines in my tractor until it started to go south, luckilly i got some fine folks here and @ simplicity to help me out. http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=42725 I cant say enough for the folks here ESPECIALLY AL Eden. In my case AL went over and above Everything i could have expected from a buisnessman. I only wish Boston and Iowa were closer so I could have went to thank him in person. Al will steer you right if a valve cover gasket will cure it Great, if I were you I would pay close attension to the oil mine started to show signs of metal flakes the second year I had it. Good luck with the problem I hope your solution was less drastic than mine was.

[JohnFornaro]

Thanks for the note Al. I'll keep you posted on that gasket replacement. I talked to a Kohler rep at a distributor in Richmond VA about my problem. He sounded knowledgable. Apparently, if you tighten the 4 bolts too much, you actually warp the valve cover enough to cause leakage. I didn't discuss my opinion of the engine's design flaw (6 bolts on the left, 4 bolts on the right) with him. At one point in our conversation, he assured me that that engine was "technically advanced for it's time", or words to that effect. I never know how to respond to marketing phrases of that sort. What I do know is that not every product from every manufacturer is perfectly designed or built. One of our jobs as consumers is to figure out the reality that pertains to the marketing phraseology that is bandied about so professionally. That's why I love forums of this sort. It is a time and money consuming job however. Now on to Topic #42725 per Roma's suggestion.

[JohnFornaro]

Having just read Topic # 42725, I feel that my earlier remarks are absolutely accurate. Remarks about us being consumers and all that. It may be that, in the marketing community, the term "technically advanced" means "ha ha, gotcha again". Right now, I'm going to fix that dag-blab gasket, and see what happens next.

[Roy]

John, While you have the valve covers off check the fuel pump cam lobe to make sure it is not disintegrating and putting metal fragments into the engine oil. My Triad OHC had that problem. My experience, Roy

[SimpleMan]

Something else you may want to consider doing is putting some clean out plugs on the blower housing of that motor. I've got one of the 'infamous' OHC/Triad engines myself. Had some concerns with it for the first while, but those seem to have been corrected. I am noticing some slight valve cover leaking myself, and plan to adress this issue this spring. What I did do though was purchase some 'clean out plugs', which are available from Kohler. Now when I do get some crud on the fins, I just remove the plugs and blow everything out with an air compressor. A whole lot easier than the old way of having to remove the shrouds.

[roma3112]

Gord Is there any part # associated with the "clean out plugs" that you got from kohler? I am thinking about getting some. tahnks

[SimpleMan]

The part in question can be purchased at Jacks Small Engines. here's the link. http://www.jackssmallengines.com/kohler_guard.cfm It's the top item, under the "Blower Housing Plugs" section. They work great:) Gord

[JohnFornaro]

Here it is March 31st, and I'm telling the rest of the story. Finally got around to replacing the valve cover gaskets around March 9th. I photographed the original #1 Valve Cover. It includes the fuel pump, with the cam mentioned by Roy. The inside of the cylinder head looked OK by me. That is, the inside was very clean, with no signs of metal fragmentation. Arg...Could someone show me how to insert jpeg's here? Unfortunately, the Valve Covers themselves did not strike me as engineering marvels, rather more like the work of a junior mechanical draftsman, executed by a sloppy manufacturing department. In the photo, you can see by the play of light and shadow, that they're not all that flat. Worse, they're not even made of aluminum, but rather a non-metallic substance...kinda like a stong fiberglass. As it turns out, poor materials, poor design and poor manufacturing conspired to produce a leaky valve cover gasket. To make matters worse, there is a pin which serves as a fulcrum for the rocker arm of the fuel pump. (See arrow in photo) From this angle, you should not see the pin, because is is trapped by the fiberglass. The pin is inserted from the other side, where it is kept from working loose by the side of the valve cover itself. As I was inspecting it, I noticed that the pin seemed to be protruding fairly far, so I tried to squeeze it in with my thumb, to no avail. So I tried tapping it with a hammer, which caused it to punch thru the other side, shown in the photo. I was concerned that it would work itself loose, with possibly catastrophic results, but I reassembled the engine with the new gaskets, and figured that I could at least run it for a few minutes without damage. To my consternation, they still leaked. So now I had a leaky, malfunctioning valve cover. My good deal on a Sovereign looked worse and worse. Back on the phone with the rep. Original valve cover #28393-06 was superceded by #28559-03 which was superceded again by #28559-06. $50. Took a week (March 19th) or so to get the replacement valve covers in, but they looked much better. Note how there is a groove along the entire perimeter covered by the gasket. This turned out to be the design improvement which makes the inferior material work, at least in the short run. In this photo, you can see the pin retaining geometry better. The arrow points to where it was punched out on the previous cover. So now I am up and running with no leaks, but still considering whether I should invest in one of Al Eden's Command Repower kits. Someday I will write about mechanical design...maybe when I retire. If I can stop spending my retirement fund on replacing parts that should have been made right the first time! LOL

[Al]

Hi, We just had a TH in with leaking valve cover gaskets. We pulled the engine and the blower housing off. The cylinders were coated with about a half inch of oil and muck. We pressure washed of the worst and had to scrape and wire brush the rest off. I would check for this. Also ON ALL OF THE NEW OHV ENGINES VALVE COVER TORQUE IS CRITICAL. On the stamped steel ones, overtightening pulls the steel under the bolt down and then the gasket is loose between the bolts. Same thing happens with auto engine valve covers and oil pans. REMEMBER MORE THINGS ARE DAMAGED FROM OVERTIGHTENING THAN UNDERTIGHTENING! Torque specs are Important. I understand you can't undo what someone else has done and I don't mean this to reflect on you or anyone else. Just addressing a critical issue. Al Eden

[UCD]

John You have to be a paying member to be able to upload pictures and/or to post pictures here.