W126 V8 intake manifold R1161416501: buying guide 420 & 500 SE
Anyone taking apart the intake side of the V8 on a W126 420 SE, 500 SEL or a 500 SEC – for example to renew the intake manifold gaskets, eliminate vacuum leaks or completely overhaul an engine – will find the lower intake manifold section under the air plenum. After more than three decades, this casting not infrequently shows corrosion on the sealing surfaces, damaged threads or traces of improper disassembly. Then the question arises which replacement part fits – because the Mercedes V8s come in several versions. This guide shows how to recognize damage and what to look out for when buying.
How do you recognize wear or damage?
The lower intake manifold section sits in the V of the engine between the cylinder banks and is bolted to both cylinder heads. It distributes the intake air from the air plenum through eight intake runners to the cylinders of both banks and carries the injectors. The casting has no wear parts in the strict sense – damage results from age, corrosion and assembly.
| Finding | Meaning |
|---|---|
| Crack in the casting, on a flange or mounting lug | Replace the lower section – a crack on sealing surfaces cannot be repaired permanently and reliably |
| Deep corrosion pits on one of the two cylinder head flange surfaces | The new gasket can no longer seal properly; vacuum leaks are the result |
| Stripped or overtightened threads | Depending on location, repairable with a thread insert, otherwise replace |
| Damaged seats for the injectors or the vacuum port | Leaks at valves or vacuum lines possible; check the condition carefully before assembly |
| Idle fluctuates with a warm engine | Not automatically the intake manifold – often a vacuum leak at hoses or the idle speed actuator, see Idle control valve defective: idle fluctuates |
| V8 cranks for a long time on a warm start | Not intake manifold damage – often the fuel accumulator, see W126 V8 cranks long when warm? Fuel accumulator 0438170055 |
Causes
After decades, three things mainly affect the cast aluminum. First, moisture and coolant or oil residue: they attack the aluminum, especially on sealing surfaces that lay under an old gasket for a long time. Second, assembly: seized bolts that are loosened by force and uneven tightening can damage mounting lugs and threads – on the V8 with two cylinder head flanges, tightening evenly is especially important. Third, storage: lower sections from parts engines that stood open for a long time often have dirt and water in the runners.
What to look for when buying
- Compare the casting number: The number R 116 141 65 01 is cast into the component and is not a Mercedes order number. Compare it with the casting number on your own lower intake manifold section.
- Clarify the engine version: The 450 SL, 450 SLC, 450 SE and 450 SEL models with the M117 4.5 l have their own intake manifold. V8 engines with D-Jetronic are likewise a different version – this lower section does not fit there. If in doubt, the VIN will help.
- Look at the condition of the flange surfaces: Both cylinder head flanges and the eight runner openings on top for the upper air plenum section should be flat, without deep corrosion and without cracks. On our example the sealing surfaces are bare; a few casting burrs and grinding marks can be seen on one runner, and no cracks are visible.
- Check the scope of delivery: Our offer is the lower section only – without throttle body, air plenum and injection parts. You transfer these parts from the existing engine. Plan on new intake manifold gaskets right away.
- Refurbished instead of unchecked used: A cleaned and newly coated part saves you from cleaning the runners and shows damage openly instead of hiding it under dirt.
Solution
If the existing lower section is damaged, a refurbished genuine part is the economical solution. Our lower intake manifold section with the casting number R 116 141 65 01 (1161416501) has been cleaned and newly coated in silver, and the sealing surfaces are bare. The price is 189 €, and we give a 5-year warranty on the refurbished part. It is a one-off piece. Before installation, carefully remove gasket residue on the cylinder heads, use new gaskets and tighten the fasteners evenly.
Lower intake manifold section V8 – casting number R 116 141 65 01
W126 420/500 SE/SEL · C126 420/500 SEC · refurbished, lower section only · 189 €
View lower intake manifold section
The lower intake manifold section is a one-off piece. You will find more parts for your car in our categories W126 and Fuel system & injection. There is a separate guide for the inline six-cylinder M110: M110 intake manifold R1101412401: Buying guide W123 280E & R107 280SL.
Compatible vehicles
| Model series | Models |
|---|---|
| W126 sedan | 420 SE, 420 SEL, 500 SE, 500 SEL |
| C126 Coupe | 420 SEC, 500 SEC |
Assignment according to the dealer's information on casting number R 116 141 65 01. Does not fit 450 SE/SEL/SL/SLC (M117 4.5 l) and V8 with D-Jetronic. Please compare the casting number on your own intake manifold; if you have questions, we will check against your VIN free of charge.
FAQ
Is R 116 141 65 01 the Mercedes order number?
No. R 116 141 65 01 is the casting number cast into the component. It serves to identify the version. Compare this number with the casting number on your own intake manifold.
Are the throttle body and air plenum included with the lower intake manifold section?
No. Only the lower intake manifold section is offered, without throttle body, air plenum and injection parts. You transfer these parts from your existing engine.
Does the lower section also fit a 450 SE, 450 SEL or 450 SL?
No. The 450 SL, 450 SLC, 450 SE and 450 SEL models with the M117 4.5 l have their own intake bridge.
Does the intake manifold fit a V8 with D-Jetronic?
No. V8 engines with D-Jetronic are a different version; the lower intake manifold section does not fit there.
How much does the refurbished lower intake manifold section R1161416501 cost?
The refurbished lower intake manifold section with the casting number R 116 141 65 01 costs 189 €. It is a one-off piece with a 5-year warranty on the refurbished part.
KFZTeile-Thot is a specialist business for tested and refurbished Mercedes parts with its own test benches and has over 1,000 positive eBay reviews. Not sure whether the lower intake manifold section fits your V8? Call us at +49 179 8991069 (Mon–Fri 8 am–6 pm) or write to us via the contact form – ideally with your VIN or a photo of the casting number.