Oil Squirters on the M104 – Do You Really Need Them?

So, you’re building an M104, and now you’re deep in the debate: do you need oil squirters, or did Mercedes know what they were doing when they got rid of them?

Some people swear they’re crucial for piston cooling, while others say they’re completely unnecessary—especially with modern forged internals. Then there are those who’ve gone all-in and drilled their blocks to add them, because why not?

And here’s the wildcard—some oil squirters have larger spray holes, which means better piston cooling than smaller variants. So, should you add them, ignore them, or just send it?

Let’s break it down.

Why Did Mercedes Remove Oil Squirters from Some M104 Engines?

Early M104s had oil squirters to spray oil onto the bottom of the pistons, helping with cooling and lubrication. Then, post-1994, Mercedes said, "Nah, we don’t need these anymore." But why?

✔ Updated conrods with internal oil passages – Instead of oil squirters, these rods directed oil to the wrist pins and piston bottoms.
✔ Improved conrod bearings – These helped with lubrication and heat dissipation without needing extra nozzles.

So, if you’re running OEM rods and bearings, your engine was already designed to work without oil squirters. But if you’re going fully forged, things get more interesting.

Do You Need Oil Squirters for Your M104 Build?

NO – If Your Setup is Already Optimized

• If your M104 conrods have built-in oiling, you’re already covered—Mercedes made sure of that.
• Most aftermarket forged pistons aren’t designed for oil squirters, so they may not even be effective.
• Plenty of high-horsepower engines block off oil squirters on purpose to help maintain oil pressure.

YES – If You Want Extra Cooling and Peace of Mind

• Oil squirters help reduce piston temperatures, which is never a bad thing—especially if you’re running hard for long periods.
• If your forged rods don’t have internal oiling, then you’re missing a cooling function that the OEM rods had. At that point, check with the manufacturer to see what they recommend.
• Some builders have successfully drilled their blocks and installed M104 oil squirters.

MAYBE – If You Like Fine-Tuning Every Detail

• Some oil squirters have larger spray holes, meaning they provide better cooling than squirters with smaller spray holes.
• Some pistons may have reinforcement ribs in the exact spot where the oil spray should land, meaning you might have to adjust the nozzle angle for proper cooling.

Final Verdict: To Squirt or Not To Squirt?

✔ If your engine has the updated internal oiling system, you don’t need them.
✔ If you’re running forged rods without internal oiling, they’re a good idea.
✔ If you have the means to add them, it’s extra insurance against heat.

At the end of the day, oil squirters aren’t a must-have, but they also won’t hurt. If your M104 was built without them, it’ll probably be fine. But if you’re fully rebuilding the engine, why not add an extra layer of cooling?

So—are you for squirting or against squirting? Let’s hear it in the comments.