Yanmar 3YM30 - Blown Head Gasket

tomperanteau · #1 (**permalink**) 02-05-2012

How much would you guys pay?

We're in the middle of having ours repaired. The head had to be sent off from the shop to be planed and the head gasket ordered. We also told the mechanic to change the oil and service it while it is in the shop. That includes the impeller, etc.

The engine overheated when we were heading back into the marina. As Murphy stepped in, someone had bumped the key off and there were no alarms at the engine. The drive belt for the water pump just happened to break at that time. We discovered that she was overheating when we smelled her paint burning. I quickly turned the key on, hit the kill switch, and shut her down. Too late, the head gasket had blown.

After she cooled we found that she started promptly and ran great, but was blowing pressure into the cooling system. Yep, the head gasket was blown, but the rest of the engine was fine. After all, she only had 140 hours on a brand new engine.

So, we now have her in the shop and they have planed the head and are finishing putting the engine back together.

Question is how much you guys think something like this should cost us.

Faster · #2 (**permalink**) 02-05-2012

Ahh.. Mr Murphy not yet retired, I see...

Sorry to hear that, Tom. Not sure how to guess costs.. I imagine the shop bills out at close to $100/hr? Should be doable in not too many hours, but it always seems difficult to get out of those situations for any less than a boat buck...

Rockter · #3 (**permalink**) 02-05-2012

Tomper :

Yea, Murphy does have his moments. Key off, and belt breaking. Not your best day, I take it?

The modern aluminium heads are less tolerant of overheating than the older cast iron motors.

The crankshaft and bottom end should be OK, but you may have scored the bores if it got very hot. When the head comes off, have a close look at the bores.

You will not be able to see the pistons for scoring, but watch for bore adhesions and scoring.

I know what this feels like, man. I once got 12 miles on a partially re-built Honda motorcycle, with a brand new cylinder head wrecked. Yea, when they say to use a lint-free rag to clean the parts, they mean it.

Now I use a lint-free rag all the time.

.

JimsCAL · #4 (**permalink**) 02-05-2012

Hopefully its just the gasket and there's not additional damage. I paid about $700 to have a new head gasket put on a Universal 5411 a couple of year. That's parts, labor and tax.

tomperanteau · #5 (**permalink**) 02-06-2012

Thanks for the replies.

As it turns out the bottom half seems okay. They sent the head out to be planed and are putting things back together. We paid an initial $800 towards the bill, and that included the mechanic coming to the boat to disconnect and take it to his shop. I'm expecting probably $700 or so more, but I also asked him to give it a complete service while he had it in the shop. Oil change, impeller, etc.

He's at $85 an hours, so I hope it won't be too much additional.

tomperanteau · #6 (**permalink**) 02-11-2012

Okay, looks like an additional $900 total that includes the complete service. Probably a bit pricey, but it should be done right.

Faster · #7 (**permalink**) 02-11-2012

Quote:

Originally Posted by tomperanteau

Okay, looks like an additional $900 total that includes the complete service. Probably a bit pricey, but it should be done right.

The peace of mind over the next little while will be priceless and you'll soon forget that bill...

bljones · #8 (**permalink**) 02-11-2012

That's not bad for R&R and having the head decked, new gasket and servicing. Not great, but not bad. Something to think about is that if you can change a tire and read a manual, R and Ring a head on a 3 cylinder diesel engine isn't really all that much more complicated. The Yanmar shop manual is a decently written manual that even a novice with a basic understanding of mechanics can understand.

I'd be concerned about alternator output, if the engine ran for any length of time with the key off. We all know I am no electrical guru, but depending upon how the circuit is wired, it may be an issue.

smurphny · #9 (**permalink**) 02-12-2012

Murphy here, kin of the authors of this law and prime recipient of its consequences

That sounds like a pretty reasonable price. Look at it on the bright side; maybe you used up all your bad luck for quite some time. I'd say it was lucky that a lot more damage did not occur. Paint burning off? Wow. That's hot. Definitely verify that the piston walls are not scored, bearings too. With it in a disassembled state, it'd be a lot easier and cheaper to change out the rings and hone the cylinders now than to discover you're burning a lot of oil later and have to go through the whole exercise again.

tomperanteau · #10 (**permalink**) 02-12-2012

Thanks, guys. We were lucky for how hot the engine was when we finally shut her down. There were some plastic retaining rings on the injectors that had even melted and had to be replaced. They also did a valve job while they were in there, and didn't just plane the head. Not sure it needed it with only 140 hours on a new engine, but I guess it may have with all the heat. We just want to get it installed so we can get back out sailing!