MTU 8v183

I ran a yacht with them. We put about 700 hours on them within 14 months. They had 700 hours when the one motor grenaded on survey seatrial for my customer. It was majored......they ran good, smoke a little at cold start and slow speeds......smooth at cruise on good on fuel burn and pretty quiet engines.......but parts are EXPENSIVE.....we had to do exhaust manifold gaskets on one engine, $12,000. We had to do something else on one of them and that was uber expensive also around $16,000, I think it was turbo's, injectors and pump..............raw water pumps are around $4000 to rebuild, they do last a very long time, and they have a S/S impeller so no impellors to change.

Which version, TE92 (657hp @ 2300) or TE93 (756hp @ 2400)?
In a 1992 boat, I would guess the former, which is fully mechanical and better than the latter, in several ways.
Just as an example, the whole heat exchanger is a bronze masterpiece in the 92, while they did some corner cutting and used aluminum in the 93.
Good reliable engines, but as already mentioned, proper maintenance ain't cheap.
Btw, as I recall the original raw water pump is bronze also internally, which is actually even better than s/steel.

Out of curiousity, do you know why one block was replaced?
These engines can be fully rebuilt, and I never heard of cracked blocks or whatever.
Oh, and talking of rebuilding, be aware that the official MTU maintenance schedule states that their "1DS" rated engines (i.e. pleasure boat rating, which is true of both the 92 and 93 models) should go through "W6" echelon every 6000 hours or 8 years, whichever comes first. Where "W6" means complete overhaul, no less.

Now, in practice not even MTU official dealers dare suggesting complete overhauls every 8 years, which in most pleasure boats means MUCH less than 6000 hours.
But the equivalent schedule for "1A" rated engines (i.e. the unrestricted continuous versions of the same blocks, rated for only 2000 rpm and with a much lower output) is either 12000 hours or 18 years.
And all MTU engineers I spoke with recommend to not mess too much with this timing, no matter how low the hours.

In other words, also for the engine which was not replaced, even if still far from 6000 hours, a full overhaul is by now way overdue, after 28 years.
Whoever didn't take the opportunity to overhaul also the other engine while replacing one, I can only guess that either was not properly advised, or had a limited budget.
Either way, a BIG cost, to be considered in the negotiation.
Good luck.

I had a customer that had a cracked block. Recent service, replaced all injectors, injector pump etc. on 12v183 that was about 5 years old. Enroute to NY from FL, they stopped one night in Charleston, injector leaked and filled cylinder up, block cracked when they tried to start it. New engine was $250k.

W6 service, if it's a complete overhaul....around $40k. But call an MTU dealer to confirm, access to the engine can add or subtract a decent amount of $$$.

I would have guessed even more that $40k for the full overhaul, but it's quite likely that US prices are a bit more reasonable (or better said, less unreasonable...) than here.
But unless the e/r accessibility is outstanding, I'd prefer to pull the engine out and have it done in a fully equipped shop.
Working in better conditions can only give better results.
Which is also the reason why I wouldn't have missed the opportunity of the other engine lifted for whatever reason.
Nothing like an empty e/r to clean/check/fix everything!

@Capt J: do you possibly remember if that V12 with the leaking injector was a TE92/1000 hp or a TE93/1150 hp?
What I said for the V8 applies also to the V12: the earlier one had a much better reputation than the latter.
After which, in fact, MTU phased out the 183 block completely.

PS: the throttles can be a helpful hint: very likely mechanic with separate levers on the 92, and electronic on the 93.

They were 1150 hp. Boat was a 2001 68' Azimut. I managed 2 of them that were 2 hull numbers apart, and ALL electrical and location of everything electrical was in totally different places. One of them, they built the joinery over all of the pull down ceiling panels!!!!!!

If coolant is dropping without the motor running it could be going 2 different places. You could have a bad heat exchanger and it's leaking into the saltwater side of the heat exchanger and overboard, shut the seacock and take the raw water hoses off of the heat exchanger, add coolant, get a pump and pump it up to 12 psi......look at/into saltwater side of heat exchanger and see if it's ending up there........or you could have a bad head gasket or cracked head and it's getting into a cylinder which can be absolutely catastrophic. You need to get a MTU mechanic that knows 183's out to check it.

Are you positive the level is dropping while the engine is not running? The cooling circuit gets pressurized while the engines are running, so that's when any leak is more likely to materialize.
And for the same reason, you actually can't check the level before and then right after running the engine, because you should wait till the engine is cooled down before opening the cap - and the level is affected by temperature anyway.

In other words, in order to be sure that there's a leak with the engine static, you should check the level with the engine stone cold, and then re-check it after some days without ever turning the engine on in between.
If upon this second check you see a lower level, then you definitely have a problem and you'd better involve an MTU engineer as CJ suggested.

From the MTU site there are 3 marine dealers within 30 miles of Los Angelas. Pacific Power Group, Harbor Diesel and Equipment, Brown engine inc.

I wouldn't screw around with anyone to work on 183's that isn't factory trained on them. If you can't find an independent that's factory trained, then go to a dealer and spend the money. Mistakes are extremely costly on these engines. Also crutial that the engine belts are changed in pairs and in good condition, if they break at cruise, the motor overheats and grenades by the time the alarm goes off and you back the engine down to idle.

https://www.mtu-solutions.com/eu/en/contact/sales-and-service-locator.html

I paid $12k to do that job on a 58' Azimut about 5 years ago. To pull exhaust manifolds and install new gaskets, we were only leaking exhaust so nothing done to the heads. I believe it's an age thing with the 8v183s and gaskets drying out, becoming brittle, failing. Access was good on inbound side and very poor on outbound side.

Don't forget what I said in post #3.
Unless already done, those engines by now are supposed to be fully overhauled.
So, manifolds are just one (arguably small) part of the work to be done, I'm afraid.

That aside, just a couple of days ago while reorganizing my archives I came across an old review of your boat, which you might be interested to check out. I am attaching one page of it, but can't upload the complete article because it exceeds the forum size limits.
I can email it to you if you're interested.

Email sent.

WHat was the reason the entire short block was replaced on the other engine? Was it water intrusion that caused the motor to hydrolock and split the block?

The more I think about your situation and given the age and hours. Rather than spend the money to pull the exhaust manifolds and re-install them, I would bite the bullet, with 4200 hours and do a major overhaul and inspect all of those parts very very carefully. I think if you just do the manifolds, you're just spending good money after bad.