Best Way To Clean Hydraulic Lifters

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JSP
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Best Way To Clean Hydraulic Lifters

Post by JSP »

I have a 1993 Legacy, 2WD non-turbo EJ22. I have issues with my car running roughly (as if it's dropped a cylinder), while climbing a hill. When I get to the top of the hill, I just need to slip the car into neutral, and give a few revs, and the engine comes good again. The car also lacks power under strong acceleration. A Subaru specialist told me it could be a problem with lash adjustment in the hydraulic lifters, from the lifters being clogged. The car has done 140,000 miles, and has never had any major work. I have recently replaced the MAF and also new plugs, leads, fuel filter and coil and cleaned the throttle body. The specialist believes the easiest way to clean the lifters is to run the car on a very light oil - he recommended 0W-20 viscosity. Is this oil too thin to run in an old, worn engine, especially in a warm climate area? I tried adding a bottle of Hydraulic Lifter Noise Additive, and it seems to have fixed the issue while climbing a hill, but now the engine runs a bit rough at idle and also under acceleration. Any suggestions?
arse_sidewards
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Re: Best Way To Clean Hydraulic Lifters

Post by arse_sidewards »

It's really hard to diagnose stuff like "running rough" over the internet.

You probably do have somewhat of a sludge problem. 140k over ~30yr means few highway miles. Synthetic oils didn't become cheap enough for everyone to justify until recently. I would be weary of diluting the oil in pursuit of fixing it. That is a great way to kill piston rings and connecting rod bearings.

These engines prefer 10w30 or 10w40. If you want to try and remove sludge toss in a quart of something very high in detergents, like ATF. When mixed with the other ~4qt in there the overall viscosity will still be in an acceptable range. The reverse flow cooling system also means the oil runs warmer than in other engines. I would not run ~20 weight oil for any appreciable length of time.

The bearing clearances are not spec'd with it in mind and inadequate oil viscosity is just asking for trouble in an engine with a broad rpm range like these (force required to make a part reciprocate goes up with the square of frequency, do the trig if you don't believe me).

Those anti-sludge oil additives are generally somewhere in the realm of diesel fuel or kerosene. You're gaining nothing by using them instead of just dumping a quart of diesel in 30min before your next oil change and letting it idle. I would advise against letting an engine with any sort of fuel oil like that in it do anything other than idle.

When these cars drop a cylinder it's really, really noticeable. You could just have a misfire problem. The lifter doesn't care about throttle position (i.e. climbing a hill). I would check your plugs but you said you already replaced them. I assume the ignition stuff was replaced after this problem started.
'93, '93 and '94 Legacy L, wagons, FWD and AWD, all are NA 2.2 w/ 4EAT.
jefferson
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Re: Best Way To Clean Hydraulic Lifters

Post by jefferson »

I kind of second the misfire climbing a hill being something other than lifters. Under load the engine is torqued over and a plug wire may be rubbing on something. Might check your engine mounts as they could be allowing the engine to move around more than it should under load.
91 Black SS 5spd. Edm lights, wrx gauges in dash, 45 degree airbox, cryoed drilled and slotted brakes. Invidia divorced downpipe with custom stainless exhaust. To be installed, aluminum a-arms, manual belts, awic.
JSP
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Re: Best Way To Clean Hydraulic Lifters

Post by JSP »

I replaced the plugs recently. They had only done 7000 miles. Every time I put new plugs in, the old plugs look great, with no signs of being rich or lean. The misfiring problem was definitely only occurring while under load, climbing a hill. The problem still has not returned since I added the lifter additive, so I guess that's cleaned up the lifters quite well. I have run 15W-40 oil in the car for 20 years, but I'll switch to the recommended 10W-30 at the next oil change. I might try a can of upper engine cleaner as well, although that's never made much improvement in the past, and I'm not really a fan of additives. Thanks for the feedback and suggestions!
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