How many ounces of dishwasher to clean oil in cooling system?

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How many ounces of dishwasher to clean oil in cooling system?

Post by Turbo_Boss »

Hello Guys

I have a 2008 Volvo XC90 3.2 and the coolant reservoir was full of oil sludge.

A couple of weeks ago I replace the Water to Oil cooler because it was cracked and it was allowing oil to pass to the cooling system.

We flush with water all the cooling system until clear water come out from the radiator.

A week later there is still a little oil floating in the water and grease stuck to the walls of the coolant reservoir. Check my pic.

I have flush again with water, but there is still oil floating and also is sticking to the walls of the coolant reservoir
I want to clean the entire system very well, before adding the coolant.

I have read that many people use liquid dishwasher to clean up the remaining oil residue.

How many ounces of liquid dishwasher should I add to the coolant reservoir to completely clean the residual oil that remains in the cooling system?

Thx for your time and help


Oil grease stuck to the walls of the coolant reservoir

Cleaned after the water flush


This thing was very dirty wil oil
IMG_20200118_142346.jpg (140.45 KiB) Viewed 120 times
Last edited by Turbo_Boss on Sun Jan 26, 2020 4:21 pm, edited 2 times in total.
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Post by RickHaleParker »

You want to use a Detergent.

Simple Green® Pro HD Heavy-Duty Cleaner is popular. It is biodegradable and non-corrosive, safe for cleaning aluminum, stainless steel and other metals. The professional-grade, engine-safe formula breaks down tough grease, oil, grime and other automotive fluids.

One part Simple Green to three parts water (25% solution volume/volume). Run engine for 15 - 30 minutes, Drain, Rinse and Refill with Straight distilled water or Antifreeze if you know you got all the crud out.

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Post by SuperHerman »

I had the same issue on my XC70 and Subaru. I just kept cleaning it every few weeks - after 2-3 times the issue went away. I never thought of doing a flush, but I did clean everything I could before reinstall.

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