M117 Intake manifold gaskets

May 9, 2026

After a long drive, my 560SEL would leave a puddle of coolant under the car. The puddle wasn’t from the front, it was from the rear of the engine. The most obvious thing here was heater hoses, but I let the car get nice and hot put the heater on and there was no leakage.

The next step was to run a coolant pressure test, so I bought a cheap kit from Temu and ran it. It was pretty easy to get coolant to leak, from that same location. Looking from under the car, it looked it was running down the side of the engine block. I wasn’t sure the exact location – perhaps a core plug or something like that?

I took the car into my mechanic for him to look further and he came back that the leak was from the intake manifold. The coolant would leak out in the valley of the V8 and then pool in there, and then slowly run down the side of the engine block.

I didn’t want to drive the car much like that. Overheating an alloy engine is a good way of destroying it. While the leak wasn’t huge, it could get worse. So late last year, I parked the car up and started to order the parts.

While the leak was coming from the main gaskets between the intake manifold and the heads, there are a lot of other parts that should be replaced at the same time. Consulting the EPC, I came up with the following list:

117 141 2480 – Left Side Intake Gasket – Genuine NLA, Victor Reinz
117 141 2580 – Right Side Intake Gasket – as above
117 140 0265 x8 – Rubber sealing rings, Genuine
126 430 2029 – Rubber vacuum line – I couldn’t find this in the end
116 090 0882 – Idle Air hose – Genuine
116 997 1286 x4 – Plug for air distribution hose, MTC
102 094 0212 – Cap for air hose – Genuine
117 990 1278 – Air line
116 094 2582 x2 – Air distribution hose – Genuine
000 000 001448 x2 – Bolt
000 912 008066 x3 – Bolt
000 912 008063 x10 – Bolt
000 912 008060 x4 – Bolt – couldn’t locate this one
117 094 0982 – Hose
116 140 0618 – Air flow boot, genuine

Not that is is my list, I would not take this as the definitive guide.

My mechanic suggested that it was better to get new bolts, if I could. I was able to get most of them. I wasn’t sure if he would need the air flow boot, but I got one because they are still available new. It seemed like a good thing to have on hand even if he didn’t need it.

It was a while before we could get the car scheduled, so I hardly drove it while I waited to the job, just the odd short trip to keep things going.

I bought the car from the original owner, and he didn’t think the heads had ever been off. This seemed to be the case looking at how the intake manifold came off. Not bad after almost 350,000km. In my case, the reason we did the job was coolant, but this job is commonly also done due to vacuum leaks due to the rubber sealing rings.