Engine Cleaner(s)

Keadeen

Well-known member
Fozzy asked about Upper Engine Cleaner in another thread, which made me think of jotting down a few things about different engine cleaners (what/why/my experience).

Upper engine cleaner (internal manifold):
- Is recommended by Subaru at major service intervals (SA 459). Other makes also recommend it for their direct port injection engines to "decarbonise" inlet ports and valves. With direct injection engines the injector injects directly in the cylinder instead of within the inlet manifold. This means the fuel doesn't "wash" the inlet port and valves and carbon builds up which eventually will lead to a compromised seal and hence loss of compression (as well as extra wear on the valves and valve train over time if heavily built up). Normally injected engines (like our EJ series) will suffer less carbon build up as the injection happens just before the valves in the manifold and hence a certain amount of carbon is washed off as the fuel makes it way into the cylinder. However, some will build up anyway. In turbo charged engines, especially those with high(er) boost, more oil will make its way back around to the intake system (CVS / PCV info Link) This will in turn increase the carbon build up too. So, although the EJ has normal pre valve injection, we do get more oil contaminants that cause carbon build up due to "blow-by" - and hence Subaru recommends using upper engine cleaner. All that said, I have never used it on my Subarus... although I have used it on MINIs, 1.8T VAG and Mitsubishi GDI engines (last one also notorious for carbon build up). Knowing why it should be used and how well it works on other engines I will use it on my next Subaru service (just never thought of using it on my EJ). BTW, note that it is recommended to use just before you change the oil as some might get past the rings into the oil, so better to use it just before you put new oil in.
Link to Youtube to see how to apply SA 459 Subaru upper engine cleaner.
Link to other forum with info on Subaru upper engine cleaner

Internal engine flush:
- is good to do maybe every 50k as a preventative measure on a well serviced engine. If relatively clean (well serviced engine) then just add flush to oil and drive for 20-50kms in a single journey from adding it (varying revs but don't cane the car) and do the normal filter and oil change. If service history unknown, or intervals (too) long, then it is a good thing to flush it out so the built up "crud" is dissolved and frees up oil galleys and bearing surfaces (and hydraulic tappets on for example VAG engines) etc. In such a case, for best results, first service the car with a new filter and oil. Add the flush and drive the car for 50-100kms in a single journey from adding it (again varying revs but don't drive the nuts off it). Then service again with a fresh filter and oil. That can stay in there for longer, but not the full length of the normal service interval as more crud will still dissolve if it was a "dirty" engine and sit in the oil, so maybe do the next service at half interval - after that normal servicing interval again. It will make a world of difference to the longevity of your engine.
Note: on high mileage engines this is again good to clear crud - BUT note that crud will also seal leaks around failing / old seals. So, if you use flush then you may well see oil seepage around seals and rocker cover gaskets before long. All it means is that they need to be replaced (and were long overdue to be changed). It is a bit of a headache to do, but not flushing to "prevent" having to change seals/gaskets is a false economy as the cost of engine damage related to crud build up is much higher than replacing a few seals and gaskets.

External engine cleaner:
- Only to be used if engine heavily soiled (maybe due to a failed seal / oil leak) to clean that off. In general it is a bad idea to use external engine cleaner on a relatively clean engine (whether it is a chemical based clean or steam clean). It strips surface finishes. So it will look great and clean after doing it, but not long after all the surfaces will start to oxidize and in time the engine will look a lot worse than if you'd left it alone in the first place. Obviously there are also the concerns of getting it into electrical components and damaging them, or at a minimum causing a water / bad electrical connection related running problem. So if a clean does need to be done make sure to cover/protect any plug connections, fuse box, alternator, etc. There are products for sale that allow you to apply a new protective finish to a cleaned engine to help mitigate some of the corrosion issues. I recommend to apply something like that. Typically you will not be able to get it as well protected as it is from the factory, short of taking out the engine and stripping it before applying. So, whereas it is better than leaving it totally unprotected it isn't worth doing a clean and a partial protection on an engine that is not soiled and relatively clean (IMO).


Injector Cleaner:

- Highly recommended (in case anyone wasn't already aware). Especially vital on diesels (and even more so on bio diesel powered cars as way more contaminants and fewer cleaning agents). Marine diesels which constantly run can get up to double to triple the run hours on injectors if injector cleaner is used every 100 run hours. Also recommended for petrol engines, although on average not as vital as on diesels. Subaru recommends a bottle of injector cleaner with every service on all their engines. It will keep the pump and injectors free off gum build up and helps lubricate them too. In the case of the injectors it will help prevent sticking injectors, and/or compromised spray patterns (which will affect atomisation of fuel into the air-stream and leads to loss of power, unburned fuel => poor fuel economy). Make sure your fuel filter is, or has been, replaced within the service interval before using fuel additive like injector cleaner. If filter is dirty (and/or tank) then the cleaner will wash/dissolve/suspend dirt into the fuel and can actually cause injector issues as that dirt then is moved from the tank/filter to the injector nozzle where it clogs stuff. If injector cleaner has been used throughout the life as mandated in the service schedule, and the filters are kept serviced too, then use it with every service. If it hasn't been used and/or filter and/or tank is dirty then this needs to be addressed BEFORE you add fuel injector cleaner. So in case of a dirty tank it needs to be drained and washed and the fuel filter then needs to be replaced. After that use the injector cleaner.

That's all I can think of now.
Feel free to add / comment.
 
Excellent information there - thanks very much man. Have you any idea where you can buy the upper engine cleaner - Subaru dealer maybe?
 
Get the auto glym engine cleaner just spray it on a cold engine and it with dissolve all grim oil sh*t with a hard blast of water I have it. It’s non abrasive cleaner then use rubber plastics cleaner to give it that shine job done till it rains
 
Get the auto glym engine cleaner just spray it on a cold engine and it with dissolve all grim oil sh*t with a hard blast of water I have it. It’s non abrasive cleaner then use rubber plastics cleaner to give it that shine job done till it rains

So Im not the only one who though this was for cosmetics, hes on about internal :)
 
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