Yanmar 2GM20 oil exploding from dipstick hole

[Geek_Guy]

SB1,

Don't forget the easiest one. Especially if you have two engines. Swap the dipsticks. There seems to be an issue with some Yanmar dipsticks. Mine look fine, and even felt snug when I put it in but had the same symptoms you mention.

[boatbod]

A broken drill bit can often be removed by breaking it up with a punch.

2mm is pretty small to start with (ain't no eazy out that small going to work anyway) so you may have some troubles unfortunately.

[Wotname]

Originally Posted by sb1

....... Instead, I removed the mixing elbow, in the process breaking the head off one of the nuts. So I used a 2 mm drill bit to make a hole with which to use an "easy-out" to get the bolt shaft from the engine casing. Of, course, the drill bit snapped in its own hole. ......

Originally Posted by a64pilot

If there is any of the bolt sticking out you can sometimes get a vise grip on it, heat and PB Blaster and let it soak help.
I have also used a Dremel to cut a screwdriver slot in a broken off flush bolt too. Use an impact screwdriver, the kind you hit with a hammer, that knocks it hard into the slot so it doesn't strip and the percussion seems to help loosen the stuck stud.
I do not use easy outs anymore since discovering many years ago that when you break one of them off, you cannot drill it out, an easy out is as hard or harder than a drill bit.
Worst case, remove exhaust manifold and take to a machine shop.

SB1, I feel your pain .

All good ideas from a64 but unfortunately for the SB1, the broken stud is in the engine block so taking it to a machine shop will mean removing the engine - ouch.

Let's hope that the stud can be removed in situ.

FWIW, there might be a mobile stud removal guy in Cairns; if so call him!

The local guy down here does a roaring trade and from what I'm told, he has never been beaten - yet.

[Kahala]

It probably wouldn't cost that much to overhaul a 2GM20. It could be worse - it could be a Volvo!

[SeaSon]

Originally Posted by Wotname

SB1, I feel your pain [emoji2].

All good ideas from a64 but unfortunately for the SB1, the broken stud is in the engine block so taking it to a machine shop will mean removing the engine - ouch.

Let's hope that the stud can be removed in situ.

FWIW, there might be a mobile stud removal guy in Cairns; if so call him!

The local guy down here does a roaring trade and from what I'm told, he has never been beaten - yet.

Welder can put a tang on the stud top. The heat from the arc welding usually breaks em lose.

[CareKnot]

Originally Posted by SeaSon

Welder can put a tang on the stud top. The heat from the arc welding usually breaks em lose.

I will second that suggestion. Used to do it all the time back when I worked in a shop. I would use a little Blaster or WD-40 first. Let it sit overnight, then hit it lightly with a torch and a wire brush to clean up the surface before I welded it.

[sb1]

Thanks - you made me feel almost normal!

[sb1]

Originally Posted by Wotname

SB1, I feel your pain .

All good ideas from a64 but unfortunately for the SB1, the broken stud is in the engine block so taking it to a machine shop will mean removing the engine - ouch.

Let's hope that the stud can be removed in situ.

FWIW, there might be a mobile stud removal guy in Cairns; if so call him!

The local guy down here does a roaring trade and from what I'm told, he has never been beaten - yet.

Thanks for that. It's actually in the cylinder head so not quite so bad. I'll remove that as per

https://www.youtube.com/watch?v=qp056LYvdRc&t=643s

Cheers

sb1

[colin evans]

Hi all. Whilst on the subject of old Yanmars.
We have a beautiful old Yanmar 2QM20 in our sailing boat. It's done 2400 hours, never missed a beat & never let us down. The oil pressure shows rock steady on start up & after a period of about 10 minutes running drops back just a bit and then holds steady again. But after about 30 minutes regardless of the sea state the oil pressure gauge starts fluctuating wildly all over the place & then it settles again and holds as per normal pressure. It will repeat this time and again. The engine revs never change nor does boat speed or rythmn of the engine. I change the oil and oil filter religiously every 100 hours, fuel filter the same & anodes and impellar every 200 hours. Not sure whats causing this? Any suggestions? Thanks Col

[sb1]

Originally Posted by colin evans

Hi all. Whilst on the subject of old Yanmars... It's done 2400 hours

Oh dear. Mine are on 2500 (I think, because one of the hour meters is stuffed, so I'm going off the other one). Never mind, I love them despite how they abuse me. Sorry this doesn't help with your issue - hopefully someone has a solution!

[Wotname]

Originally Posted by sb1

Thanks for that. It's actually in the cylinder head so not quite so bad. I'll remove that as per

Cheers

sb1

Yes, of course, my bad.

I guess I was trying to explain that isn't wasn't as simple as taking the exhaust manifold into a machine shop. Now you get to take the head in...

Hope it works out for you.

[Wotname]

Originally Posted by colin evans

Hi all. Whilst on the subject of old Yanmars.
We have a beautiful old Yanmar 2QM20 in our sailing boat. It's done 2400 hours, never missed a beat & never let us down. The oil pressure shows rock steady on start up & after a period of about 10 minutes running drops back just a bit and then holds steady again. But after about 30 minutes regardless of the sea state the oil pressure gauge starts fluctuating wildly all over the place & then it settles again and holds as per normal pressure. It will repeat this time and again. The engine revs never change nor does boat speed or rythmn of the engine. I change the oil and oil filter religiously every 100 hours, fuel filter the same & anodes and impellar every 200 hours. Not sure whats causing this? Any suggestions? Thanks Col

Given the details you posted, I would suspect it is gauge problem.

Is it a mechanical or electrical gauge?

If electrical, maybe a crook sensor or wiring (dodgy connector) or the gauge itself. Old wiring is famous for intermittent faults .

You gotta start somewhere so perhaps run a new wire (temporary) straight from the gauge to the sensor. You could start measuring voltages etc but if electrical theory isn't your thing, substitution with known good items is way easier.

[a64pilot]

You know if I was to pull the head, I would have the valves done and new seals fitted, that ought to buy you at least another 20 years until the seals dry out and need replacing.
When your have the head off inspecting the cylinder bores can give you a very good idea where you are in terms of how long before an overhaul will need the be thought about

[CareKnot]

Originally Posted by a64pilot

You know if I was to pull the head, I would have the valves done and new seals fitted, that ought to buy you at least another 20 years until the seals dry out and need replacing.
When your have the head off inspecting the cylinder bores can give you a very good idea where you are in terms of how long before an overhaul will need the be thought about

This is very good advice. I would strongly urge to to take it. It goes without saying that you should include an oil analysis too.

[sfnz]

Originally Posted by colin evans

Hi all. Whilst on the subject of old Yanmars.
We have a beautiful old Yanmar 2QM20 in our sailing boat. It's done 2400 hours, never missed a beat & never let us down. The oil pressure shows rock steady on start up & after a period of about 10 minutes running drops back just a bit and then holds steady again. But after about 30 minutes regardless of the sea state the oil pressure gauge starts fluctuating wildly all over the place & then it settles again and holds as per normal pressure. It will repeat this time and again. The engine revs never change nor does boat speed or rythmn of the engine. I change the oil and oil filter religiously every 100 hours, fuel filter the same & anodes and impellar every 200 hours. Not sure whats causing this? Any suggestions? Thanks Col

same engine and same thing happening, looks like the oil pressure regulator (naturally an obsolete part as I have tried to get one !!!) the 3QM though slightly different valve design fits and has the same pressure setting however...yep that's obsolete as well, have been thinking of trying a 2GM one but they have 10psi more pressure, to check it, unwind the oil filter and then the big nut (32mm from memory) that is on the shaft that the filter threads on , with that lose the threaded part screws out and that's your oil pressure regulator, do you have a manual for this engine ?