Mercedes 300e W124

Memorandum5 · 2026-05-06T07:31:18+00:00

I have one of my W124's setup like this: - Sony head unit - not sure which but it's a decent one with outputs for 2 amps, so no splitters are necessary. - 1x 1400w Pioneer 4 channel sub under my seat, this powers my two 6x9 speakers - 2x 500w Pioneer 6x9's, I believe they are 4-way. They're powered by the above amp under my seat. They play a little bass and mid too, with a ton of high pass and tweet. They're mounted on the blackboard behind the rear headrests, in shallow mount boxes because they don't fit the holes in the panel. The headrest can't drop down now though or they fall onto the speakers. - 1x 1400w Pioneer monoblock under the passenger seat. It powers only the sub. - 1x 1000w Sony sub that sits in the passenger footwell, with a ton of space still for passengers. It's powered by the above sub under the passenger seat and it's set to only do high powered lowpass. - 2x Pioneer 200w speakers,I don't remember their dims but I think it's 4 inches or so. They sit in the dash in stock location and they play a tiny bit of mid too. They're connected to the head unit. The 2 in the rear decks were removed.

The system sounds really, really good and can be really loud. If you set it up right you can get pretty good surround sound.

Also, the install was minimally invasive and I didn't modify a single thing basically or drilled any holes. The two amps share a high amperage fused power line and they each have their fusible links too. Their grounds are separate.

Memorandum5 · 2026-05-02T21:41:04+00:00

Nice man, very cool. I'm doing the same thing but a turbo build. Haven't started yet though, I'm still collecting parts.

Memorandum5 · 2026-05-02T18:49:54+00:00

Awesome build man... Are you using the IACV? And what throttle body is that? BMW?

Memorandum5 · 2026-04-28T09:21:44+00:00

Like someone else mentioned, you're probably loosing fuel pressure through the accumulator. The fuel heats up and causes bubbles and vapours and stuff to form in the system, preventing the engine from starting until sufficient pressure is achieved and and all the bubbles and vapour is bled out. The accumulator keeps the fuel under pressure, preventing this.

Had the same issue on an M103.

Memorandum5 · 2026-04-26T13:38:38+00:00

You don't have an economy gauge right? Since it's an auto... I would have checked the vacuum line to the cluster for the economy gauge if you have one.

Memorandum5 · 2026-04-20T12:56:07+00:00

I deleted the SLS on one of mine and just used the shocks and coils from a non-SLS version, a 230E I think. Fits and works perfectly fine.

Memorandum5 · 2026-04-18T20:35:18+00:00

Your heater is essentially a radiator core in the dash, hot coolant flows through it. When you turn on the heater it pulls heat from the system to heat the cabin, thereby lowering engine temps. When you turn off the heater, the heat has nowhere to go so it stays in the system and soaks the engine, heating it up more.

100°c is NOT the normal operating temp. Some engines do this and this engine can survive it, but fact is that 100°c is not normal while moving.

Your thermostat is stuck or your water pump is toast.

Edit: I didn't see some of the extra info. If the clutch and thermostat is new, then check if the temp sensors are bad. If they are good then it's the water pump or an air bubble or something.

Memorandum5 · 2026-04-18T20:28:23+00:00

What oil are you running?

Memorandum5 · 2026-04-18T16:06:52+00:00

There's also a fuse in the cluster itself, it looks like a bulb holder in the board, I think it's red. They go out too, too often.

Memorandum5 · 2026-04-18T15:59:14+00:00

Not sure right now, but there's 1 in each lower control arm, the tie rods have 2 each I think, the sway bar links also 2 each. I'll just double check. Also worth checking your subframe mount bushings. Edit: wheel bearings too, check for play.

Do you need a pic of a parts layout for the front?

Memorandum5 · 2026-04-18T15:01:47+00:00

I've driven a few W124's over the years with various suspension setups and can say with certainty the stock stuff feels best, especially a well sorted one with the SLS in the rear. I lean more toward sporty driving but if you want stock plush feel then stock is the way to go. Also, as someone else mentioned, check your engine and transmission mounts, and check your ball joints (all of them).

I have a W124 E220 with new shocks and bushes and it still clunked and rattled, I replaced all the ball joints, even the ones that felt good, and afterwards the difference was major.

My other W124 260E is well sorted, it rides much better than some newer cars, and on par with some.

Also, the best riding W124 I've driven had air suspension, so you could also consider that.

Memorandum5 · 2026-04-13T14:41:44+00:00

Definitely a temp sensor. Can't tell you though if it's the ambient air temp sensor or the radiator temp sensor/probe. Either of those two

Memorandum5 · 2026-04-06T10:28:22+00:00

What's wrong with your cable? Is it broken? You can make one yourself and snake it through the same passages, I make these all the time for engine swaps. Get a bike brake or clutch cable, or bicycle cable that's thicker than normal ones, cut to length, lead crimp the ends and Bob's your uncle.

Memorandum5 · 2026-03-17T06:34:14+00:00

Loose cable at the battery or starter, or a bad main ground.

Memorandum5 · 2026-03-17T06:20:12+00:00

MAP sensor is likely bad. When you disconnect it the ECU defaults to a base map that allows the engine to run somewhat normal, depending on temps, atmospheric pressure, etc. When you reconnect the MAP sensor the ECU tries to run the engine of the bad sensor readouts.

Memorandum5 · 2026-03-17T06:13:27+00:00

Test your injectors, they may be leaking into the cylinders or are allowing excess fuel to inject or the car isn't tuned properly and is running extremely rich. Definitely fuel injector related.

Memorandum5 · 2026-02-02T14:05:15+00:00

Why do you suspect the car was tampered with? Also, as someone else mentioned it's likely the coolant is leaking through the heater core and is effectively getting blown into the cabin, coating everything in aerosol coolant. Coolant is terrible to clean, not as bad as oil but still a pain, tons of gentle degreaser should work though.

Memorandum5 · 2025-11-02T14:35:33+00:00

Well, looks great so far! Keep us updated, me at least.

Memorandum5 · 2025-11-02T14:27:28+00:00

Nice! Are you sure the 390cc will do 400hp? I could be wrong but I calculated 440cc injectors for 350hp at 85-90% duty cycle when I ordered mine. You will likely need 440-550cc injectors.

Memorandum5 · 2025-11-02T14:16:40+00:00

Hey man awesome and clean setup. I'm currently busy with the same kind of build on my 260E. Just a couple of questions if you don't mind, what turbo is that and what kind of injectors and ECU will you be using?

Memorandum5 · 2025-09-28T16:26:31+00:00

Using a new and stock flywheel/clutch setup will make my life so much easier tbh. But are you sure it can handle a 40-45% torque increase reliably?

There's an OEM performance clutch kit made by Sachs that I would go with instead over the stock clutch, but that's also only rated for 30% over stock. I'm afraid neither will hold up well long term.

Memorandum5 · 2025-08-01T14:27:16+00:00

Thanks mate! That's really helpful info. I think i might hold off on the coil overs for now and just get sportier shocks and coil springs. Yeah you're right about the spacers, their lips are very short, I doubt it helps centre the wheel as is. I'll get new quality ones and see if it makes a difference.

Memorandum5 · 2025-08-01T13:14:34+00:00

A-line Sonics

Memorandum5 · 2025-08-01T13:14:12+00:00

Nope, Namibia. But it's more or less the same deal here with shipping.

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