Advice: Caterpillar 3126TA Diesel Engines in 2001 Sea Ray 420AC Aft Cabin

[ccargnino]

I am thinking of purchasing a 2001 Sea Ray 420AC Aft Cabin with twin 3126TA diesel engines. Both engines have less than 100 hours. These are original engines that have only been used a few times each season. I took the boat on a sea trial and they seem to run great. Before I sink the money into a mechanical inspection, I wanted to get opinions on this engine. I have only owned gas engines in the past and this is a big step for me, primarily because I know nothing about diesels....other than they are costly to buy and costly to work on or replace.


Any suggestions or input is appreciated. Please let me know if you have this engine / boat set up.


My concerns are:


1) Are diesels better?


2) is the 3126TA a good engine?


3) Anything else I should know?

 

[Turtlesboat]

Yes, diesels are better. They are cheaper to run, easier to maintain, and last like 3 times longer. Yes, the 3126 is a great engine if it's maintained, like any other engine. You can do a search in the forum, lots of discussions about these engines.

 

[fwebster]

In a heavy boat like the AC, diesels are better....far better.

The 3126 is a great engine; however, there were 2 different manufacturing problems with early ones. One is a soft block (French block) problem (excessive blow-by and oil consumption) and the other was improper hardness on the valve stems (keepers falling off and valves dropping into the engine under power). Caterpillar repaired or replaced all engines reported to them....unfortunately not all the blocks or all the valves were bad so running down affected engines by serial number wasn't possible. Both problems occurred for owners at 125 to 150 hours. And, there in lies your problem......these engines are so low time that they may be affected, and Caterpillar stopped warrantying both issues in about 2005. The engines might be fine, but they might not. I would get a full Caterpillar engine survey done by a Cat dealer who is equipped for a blow-by test (a proprietary test for Cat engines) and who has enough knowledge and experience to run down the serial numbers to see if they were in the group of engines that could possible contain the bad valves.

These engines also have some deferred maintenance issues that need to be caught up as well.

Good luck with it..........

 

[peterkvs]

+1 for what everyone has said. Diesels use half the fuel and will run a long time if maintained by the book. No cutting corners, use only Caterpillar parts and fluids. I too had a lot of consternation about diesels vs gas in my purchase of my 400 DA. I am very happy I went with the diesels. They are amazing engines. Good Luck. Pete

 

[HUMPH]

They run great for me! Same engines, just a couple of years newer in my boat. Change the fluids and filters annually, keep your fuel filters fresh and have the top end reset by a certified mechanic if you buy it. These are the only way to go with a boat that heavy.

 

[ktcanuck]

Just a supplement to Frank's comment. I called a Cat dealer in Florida armed with my serial numbers and he was able to confirm that both were corrected on my engines. There was no charge for this. Perhaps this would be a cheap step to take that might, or might not, give you more confidence in those particular engines?

In a heavy boat like the AC, diesels are better....far better.

The 3126 is a great engine; however, there were 2 different manufacturing problems with early ones. One is a soft block (French block) problem (excessive blow-by and oil consumption) and the other was improper hardness on the valve stems (keepers falling off and valves dropping into the engine under power). Caterpillar repaired or replaced all engines reported to them....unfortunately not all the blocks or all the valves were bad so running down affected engines by serial number wasn't possible. Both problems occurred for owners at 125 to 150 hours. And, there in lies your problem......these engines are so low time that they may be affected, and Caterpillar stopped warrantying both issues in about 2005. The engines might be fine, but they might not. I would get a full Caterpillar engine survey done by a Cat dealer who is equipped for a blow-by test (a proprietary test for Cat engines) and who has enough knowledge and experience to run down the serial numbers to see if they were in the group of engines that could possible contain the bad valves.

These engines also have some deferred maintenance issues that need to be caught up as well.

Good luck with it..........

 

[ccargnino]

Thank all of you for your replies. I am relieved to hear that there are positive stories out there! When I did a search online, it is mostly complaints, and I knew that had to be positive comments as well. I will let you know what I decide!

 

[ImpulseIII]

There is a thread on here somewhere that list the problematic engines serial number starting 3 letters/numbers. It was posted several years ago so searching may present some challenges. That said, my boat is also 2001 and the starting sequence of the engines is 1ZJ If you have this sequence, according to Caterpillar, you are fine. Good luck.

 

[ccargnino]

I checked the serial numbers of the engines. Port engine is 1ZJ01783 AND Starboard is 1ZJ01779. I guess that is good thing!?!?!?!?!

 

[tc410]

As suggested above, call your local CAT franchise Monday and have them run the serial numbers in their system. This is always my first bit of due diligence when lookinag at a new boat. CAT will tell you about any historical warranty repairs that they made to those engines specifically, as well as any outstanding service bulletins. If the PO(s) had them serviced by CAT, the service history will come up as well. They will usually print these reports off and fax/email them to you for free.

 

[Gimme Time]

I have to say I have a 2001 420 AC with 3127TAs with just under 800 hours on them and can't say a bad thing about mine. As everyone said before have CAT do a full enginer survey and negouciated any recommended repairs with the seller including all new filters, fluids, belts, impellars adjustments recommended by Cat as well as your hull survey and you should be very happy if the boat as been maintained and taken care of. Best of luck and safe travels.