Cat 3126 engine

[Scarlett]

I can’t remember if the 3126 was the Cat engine that had the problems or if it is a good engine. I would like to hear from the experts on those engines and their pros and cons. Thanks in advance, John

 

[jim rosenthal]

They were among the problem engines for Caterpillar. That group included the 3116 (I had a set), the 3126s, which suffered from casting problems that would make some blocks leak, the 3176, and 3196. I believe some of these engine designs survived into the modern era as various C series engines, and I think they are now much better, but back then, having those engines made your boat virtually un-re-sellable. I would certainly not buy any boat with any of them, although I suppose you COULD argue that any of those engines which are still around have proven themselves as reliable. But I don't know if I'd believe that. And with so many other engines to choose from, why would anyone want to mess with any of those Cats?

The funny thing is that they also built some really good engines in that era- 3208s, 3406, 3406E, etc. Not to mention 3408 and 3412 and its relatives. It just seemed like for a while they had really lost their way on smaller marine diesels. Smaller being a relative term, here.

 

[Pascal]

I forgot which is engine was affected but the issue was with a specific series of block that were cast in france. Other production runs were fine. I also believe that engine numbers allowed any cat specialist to tell where the block came from

 

[Timeless72]

My experience in shopping boats for just about ever and talking with mechanics... These engines definitely had their issues but these should be past tense. Any trouble would have exposed and been addressed by now. Wouldn't bother me unless the engines had under 500 hours. Then again, any older boat with that few hours would bother me.

 

[mike.s]

I wouldn't be scared of a boat with 3126's, in fact I've had 3. They did have the French block problem but according to Cat every single one of them was replaced. I have always been told they are good motors as long as you don't overload them. They do have a lot of zincs to change, I think its 12 per motor. Cat also recommends replacing the after coolers on a time basis due to dissimilar metals, I think that may be 10 years but not sure.

 

[Pascal]

Cat has dropped the ball on their newer aftercoolers (about 2005 and up). While there were never aftercooler issues on the 3412s, the later engines incl the C32s have had problems. Initially cat said it was a faulty design but then started recommending aftercooler replacement every 6 years... not cheap

 

[jim rosenthal]

And I don't think ALL the French block engines were bad.. but a lot of them were, and those engines had to be rebuilt with new blocks by Cat.

 

[cww]

I walked from a Huckins with 3176's I had under contract over this. The engine surveyor found the aftercoolers were leaking into the engines. Replacing the aftercoolers on both engines was $15k+. Engine surveyor used to be a CAT tech, was very knowledgeable. Said there were multiple recalls but they never really fixed the problem and eventually just said screw it, ya'll are on your own. They're considered a 4-5 year wear item in warm salt water. When the engine surveyor told me that, I was out. What kind of engine do you have to replace $15k in coolers every few years because they're designed improperly. The boat is Ellie Mae, if anybody is interested. On the 3116/3126, my dad had a SeaRay with 3116's and they replaced one engine, the entire long block, multiple times under warranty. He sold the boat because of it. Oddly the other engine was fine.

P.S. super happy I didn't get that Huckins because I found a better Hatt.

 

[Sea Horse]

The Cat 3126 had two engines both called 3126. The 3126A Cat was a good engine IMO had two of them in a repowered 41 Hatt. They never gave me one drop of trouble and were very fuel stingy.
The 3126B was a huge problem and I would stay away from them. Different injection pump and aftercooler plus lots of other changes that had issues. Cats repower program chose the 420HP 3126A as the engine they were using to compete with the reman Cummins B&C engines. Was told by a Cat rep that their reman engine was 90% new parts and if I was going to repower would really consider one of them.

 

[rmatt]

The French cast blocks were FAPS blocks.Some of the castings were soft(not all). Failures were 300 hours or less.
Cat did replace the blocks and or engines. Any of the engines still out there would not have a block issue.