Engine teardown- how far?

[bigd14]

The eternal question of how much work to do “while you are in there” is haunting me today.

I purchased the 34-2 this past fall knowing that the engine (2011 Volvo Penta D1-30 with ~750 hours) had suffered several overheating episodes, including during an aborted sea trial where the engine temps suddenly increased accompanied by smoke from the engine compartment which seemed to be some of the paint from the head vaporizing. A local marine engine mechanic went through the entire cooling system on the sellers dime, removing impeller bits and replacing the HX core and gaskets. He pronounced the engine fit and told me he wouldn’t hesitate to take the boat anywhere. Indeed it starts and runs just fine, with normal temps and no coolant loss (now that I have removed the hot water heater from the circuit which was leaking coolant). However; there are several oil leaks through the valve cover gasket and injectors that I suspect were caused by the overheating incidents that I need to fix with new gaskets.

Now, the main question: since I will have to remove a bunch of the cooling and fuel system components to replace those gaskets should I go one level deeper and replace the head gasket as well? It seems relatively easy once I get the engine dismantled to that point and I do have a complete new head gasket set and new bolts and a torque wrench and workshop manual. But I am afraid of opening a Pandora’s box as I venture into unfamiliar territory. What dangers lie ahead? I am not an engine guy so all I know is what I read in the workshop manuals and YouTube.

So, is replacing the head gasket because I am worried about potential damage from the overheating episodes worth the extra effort, or is this a don’t fix what ain’t broke situation?

 

[Frank Langer]

Doug, would it be worth a phone call to the mechanic you mentioned in your post, to see what he suggests, and perhaps if he's in the area, if he could help you if you get stuck on the project?
Frank

 

[Pete the Cat]

The eternal question of how much work to do “while you are in there” is haunting me today.

I purchased the 34-2 this past fall knowing that the engine (2011 Volvo Penta D1-30 with ~750 hours) had suffered several overheating episodes, including during an aborted sea trial where the engine temps suddenly increased accompanied by smoke from the engine compartment which seemed to be some of the paint from the head vaporizing. A local marine engine mechanic went through the entire cooling system on the sellers dime, removing impeller bits and replacing the HX core and gaskets. He pronounced the engine fit and told me he wouldn’t hesitate to take the boat anywhere. Indeed it starts and runs just fine, with normal temps and no coolant loss (now that I have removed the hot water heater from the circuit which was leaking coolant). However; there are several oil leaks through the valve cover gasket and injectors that I suspect were caused by the overheating incidents that I need to fix with new gaskets.

Now, the main question: since I will have to remove a bunch of the cooling and fuel system components to replace those gaskets should I go one level deeper and replace the head gasket as well? It seems relatively easy once I get the engine dismantled to that point and I do have a complete new head gasket set and new bolts and a torque wrench and workshop manual. But I am afraid of opening a Pandora’s box as I venture into unfamiliar territory. What dangers lie ahead? I am not an engine guy so all I know is what I read in the workshop manuals and YouTube.

So, is replacing the head gasket because I am worried about potential damage from the overheating episodes worth the extra effort, or is this a don’t fix what ain’t broke situation?

Short answer is no. Do not remove the head gasket unless that is indicated (shows leaks internally or externally--apparently your mechanic claims to have checked this). Putting a new head gasket in as a preventative thing is, imho, is not indicated until you are that far into the engine for a clear reason related to your suspect that the gasket is leaking or some other deeper repair to valves or pistons. No matter how fine a mechanic you are or out recently your torque wrench has been calibrated, you could break a head bolt or stud and there is always a danger for something to go wrong in the retorquing sequence. Some engines require all new head bolts when removing the head (though many mechanics skip this for understandable reasons) because they stretch when torqued and retorqued and the expand and contract (and become brittle and more likely to shear) through heat cycles--so my more experienced mechanic friends would tell you to leave them alone. The constant expansion and contraction of the engine takes its toll on the lifetime of the studs and bolts as well as the gaskets. My advice is leave well enough alone. If the engine was not run out of oil, it can get quite hot before permanent damage is done.
The valve cover gasket should be fairly easy, but I am wondering about leaks around the injectors; yikes. You are sure the head was not damaged? I would try just tightening them or replacing the copper crush washers if that did not work. Are you sure the oil around the injectors just did not come from the leaking valve cover? There is no oil (other than the diesel) that should be appearing there under any circumstance. FWIW.

 

[bigd14]

Thanks Ray! This is what I needed to hear. It’s likely the oil I am seeing around the injectors is just leaking from the valve cover gasket. I have a complete gasket kit that includes crush washers for the injectors so I will just replace them and the valve cover gasket, adjust the valves and stop there. Shearing a head bolt sounds like a very bad day!

 

[Drewm3i]

If you are worried about the head gaskets, check compression for uniformity and/or have a leak down test performed.

My bet is the leaking valve cover gasket is running oplil down near the injectors--so I would simply replace the valve cover gasket and try again.

As a former mechanic, I would not go disassembling an engine unless I had to--and I have had to do so only a couple of times. Feel free to PM me if you feel like you need more help.

 

[bigd14]

I would not go disassembling an engine unless I had to

Thanks!