Parts for your 2020 Holden Colorado-Sump plug washers

2020 Holden Colorado sump-plug-washers

Based on Holden/GM technical literature, a sump-plug-washer is used on the 2020 Holden Colorado (RG series). The Holden RG Colorado Service Manual (MY20), under Engine – Lubrication – Oil Pan – Drain Plug, specifies fitting a sealing washer to the drain plug during refit. GM’s Electronic Parts Catalogue for RG Colorado also lists a separate drain-plug gasket/sealing washer for the 2.8 Duramax diesel. ACDelco’s Australian/NZ catalogues mirror this by offering replacement sealing washers for the Colorado’s drain plug. So yes—this model is designed to run a sump-plug-washer.

What does that mean in the real world? The sump-plug-washer is the little hero that stops engine oil weeping past the drain plug. It crushes slightly as the plug is tightened, creating a reliable seal between the plug head and the sump. Without it, even a correctly torqued plug can mist, drip, or slowly sweat oil—messy driveway, oil smell, and a low level between services.

• Seals the drain plug under heat and vibration
• Protects the sump face from galling by spreading clamp load
• Helps achieve correct torque without over-tightening

For servicing your 2020 Colorado, treat the sump-plug-washer as a consumable. Most OE-style aluminium or copper washers are single-use: once crushed, they don’t spring back the same. If your plug uses a bonded rubber (captive) seal, inspect the O-ring for nicks, flattening, or hardening and replace the seal or the plug if it’s past it. Replacing the washer at each oil change costs peanuts and helps keep the sump bone-dry.

A few practical tips the workshop pros follow:

• Confirm the correct washer style/size by VIN or OE spec before you start.
• Clean the sump face and plug head so the new washer seats perfectly.
• Tighten the plug to the workshop torque spec—don’t “send it” with a breaker bar.
• After the first heat cycle, have a quick look for any weep around the plug.

Choosing washers? OE or a quality aftermarket brand is the go. Avoid reusing old, visibly grooved, or hardened washers. If the plug shows burred threads or a chewed sealing face, replace it too—cheap insurance for the Colorado’s Duramax.

Technical sources referenced: Holden RG Colorado (MY2020) Service Manual – Engine Lubrication (drain plug/washer fitment note), GM Electronic Parts Catalogue (RG Colorado, 2.8L LWN) listing a separate drain plug gasket, ACDelco Australia/NZ catalogue entries for Colorado drain plug sealing washers.

Does a 2020 Holden Colorado actually need a sump-plug-washer?

Yes. The RG Colorado is designed to use a sealing washer on the drain plug. It’s part of the factory procedure because it ensures a proper oil-tight seal after every service.

How often should the sump-plug-washer be replaced?

Best practice is every oil change. Aluminium/copper crush types are single-use. If your plug has a bonded rubber seal, inspect it each service and replace at the first sign of flattening, cracking, or leaks.

What are the signs the washer needs changing?

Fresh oil mist or drips around the plug, a damp patch on the sump, or a plug that needed extra muscle to seal last time. If you see any of that, fit a new washer and torque it correctly.