W113/W111 water pump leaking? Gasket set 1215860020
Short answer: If, after parking a Mercedes W113 230 SL or W111 220 SEb, there is a coolant puddle at the front under the engine and the sealing surfaces around the water pump are damp, the cause is usually the gaskets between the pump housing, pump cover and engine block that have hardened over the decades. The clean solution is the complete water pump gasket set with part number 1215860020 (NOS, unused) for 79,00 €. If, on the other hand, it drips from the relief hole or the pulley has play, the pump itself is worn – then no gasket set will help.
Anyone who drives a six-cylinder from the sixties knows the picture: the car sat overnight, and in the morning there's a palm-sized, sweet-smelling stain on the ground – at the front, roughly in the middle. Before you order a complete water pump: often the pump is still mechanically fine, and only the gaskets between the pump, cover and engine block are leaking. This guide shows how to tell the two apart without special tools.
Symptoms
| Symptom | Likely cause |
|---|---|
| Coolant puddle after parking, front center under the engine | Leaking gasket at the joint between water pump/engine block or at the pump cover |
| Whitish or rust-brown crust around the pump housing, area sticky | Gasket seeping for some time: water evaporates, antifreeze salts remain |
| Coolant level drops slowly, hoses and radiator are dry | Gradual loss at the pump sealing surface – typical for settled old gaskets |
| Drip comes from the small relief hole on the underside of the pump | Not the flat gasket: the internal mechanical seal is worn, the pump needs to be repaired or replaced |
| Rumbling or squeaking at the front, pulley has noticeable play | Water pump bearing damage – a gasket set won't solve the problem |
| Not to be confused with: Pump area dry, but the heater doesn't get warm or the interior smells of coolant | Then it's not the water pump. On later model series with a duo valve, the heater valve is almost always responsible – see Heater not getting warm? Check the duo valve |
Causes
The gaskets on the water pump housing are paper and fiber gaskets, some with a cork content. They're meant to be compressed once and then last for decades – but not forever. Working against them are the constant heat cycles, the glycol in the antifreeze, which makes the sealing material brittle over time, and the settling behavior of the fasteners: a gasket that was already compressed decades ago during the last removal has hardly any resilience left. Then there's the sealing surface itself – where coolant has seeped for years, corrosion sits, and roughly scraped surfaces carry scoring. Both cause a new gasket to start weeping again immediately. Vehicles that sit idle a lot also dry out further: leaks therefore show up more often after long periods of standing than in engines driven regularly and brought up to temperature.
Checking it yourself
- Clean and observe (costs nothing). With the engine cold, clean the area around the water pump, pulley and thermostat housing dry with brake cleaner, drive until warm, park, and check with a light and mirror after a few hours. Only a clean surface shows where the moisture is really coming from – airflow while driving spreads coolant toward the rear.
- Rule out the cheap suspects. Tighten hose clamps, check the cap along with its seal, feel along the radiator and heater hoses. An old cap that no longer holds system pressure pushes coolant out at the weakest point and makes it look like a defective pump gasket.
- Check the relief hole. There's a small hole on the underside of the pump housing. If it's damp or dripping, water is getting past the mechanical seal from inside – then you need a different pump, not a gasket set.
- Check the bearing. Remove the belt, turn the pulley by hand while holding it at the top and bottom. Rough running, grinding or radial play indicate bearing damage – in that case the gasket set alone won't help either.
- Pressure test. If it's still unclear, pressurize the cold cooling system with a pressure tester to the value specified on the cap. The leak point shows up within minutes, without having to touch hot parts.
Solution
If, after these steps, the joint remains the source of the leak, the case is clear: remove the pump, recondition the sealing surfaces, and fit new gaskets. To go with that, we have the complete water pump gasket set with part number 1215860020 for the W113 230 SL and the W111 220 SEb in stock – an NOS part, meaning a new, never-installed stock part, complete and unused, at a price of 79,00 €. A 5-year warranty is stated for the part. Please refer to the product image for which individual gaskets the set contains.
Installation success depends on the prep work: remove old gasket residue with a plastic scraper and gasket remover, not with an angle grinder or a coarse wire brush. Check the sealing surfaces for flatness and degrease them. The new gaskets go on dry onto the clean surface; sealant is neither necessary nor helpful on intact surfaces. Tighten the bolts evenly in a crosswise pattern, fill with fresh coolant, bleed carefully, and check again once cold after the first warm-up drive.
Gasket set water pump complete – W113 230 SL / W111 220 SEb
Part number: 1215860020 · NOS, unused
79,00 €
View gasket set 1215860020Looking for a different part for your classic? Take a look at our other spare parts and in all spare parts is worth it – tested used and stock parts are added there continuously. Anyone already working on the cooling circuit will find in our guide Heater cold when idling? Check the auxiliary water pump the typical follow-on faults on the heater side of the circuit.
Compatible vehicles
| Model series | Model | Part number |
|---|---|---|
| W113 | 230 SL | 1215860020 |
| W111 | 220 SEb | 1215860020 |
| W111 | 220 SEb Coupe | 1215860020 |
No other model series are documented for this gasket set. If you're unsure whether the set fits your vehicle: send us the chassis number and model year, and we'll check the part number.
FAQ
How can I tell whether only the gasket or the entire water pump is defective?
The leak location is decisive: coolant at the joint between the pump housing and engine block or at the pump cover points to aged gaskets. If it comes out of the relief hole or the pulley has play, the mechanical seal or bearing is worn – then a gasket set alone is not enough.
Does the gasket set 1215860020 also fit other Mercedes model series?
The set is documented for the W113 230 SL and the W111 220 SEb including Coupe. No other model series are documented for this part. If in doubt, send us the chassis number and model year – we'll check the number.
What does NOS mean for this gasket set?
NOS stands for a new, never-installed part from old stock. The set is listed as complete and unused; the product photo shows which individual gaskets are included.
Do I also need sealant?
Generally not. The gaskets are designed for dry installation on clean, flat surfaces. It's more important to remove old gasket residue completely without scratching the surfaces, and to tighten the bolts evenly in a crosswise pattern.
What does the gasket set cost and is it available for immediate delivery?
The complete water pump gasket set with part number 1215860020 costs 79,00 € and is in stock in multiple units, so it's ready to ship immediately.
KFZTeile-Thot is a specialist for tested and refurbished Mercedes parts with our own test benches. What leaves our warehouse has been inspected beforehand – over 1,000 positive eBay reviews speak for that. You can reach us at 0179 8991069 (Mon–Fri 8 am–6 pm) or anytime via our contact form. Best to give us the chassis number and model year right away, and we'll tell you definitively whether the part fits.