I'm looking for an engine flush/cleaner

[Big_Ed]

I have a 1998 GMC Sierra with 5.7 V8. I was checking my oil last night and decided to look down the oil fill tube. I noticed it looks kind of sludgy inside the valve cover. I've only had the truck for 5 months. It has about 145,000 miles on it. I gave it an oil change right when I got it, because I really had no idea how long the oil was in there. I'm about 500 miles or so away from my next oil change, and I am looking for some type of flush or cleaner I could run for a while to clean up the engine before I change the oil again.

Any recommendations?

 

[DieselTech]

I'd so go with some MMO for the rest of this oil nchange then fill with MMO and PYB at the OCI

 

[ahoier]

You'll get a lot of naysayers in this thread I'm sure, so throw on your flame retardant suit

As far as flushes, the only thing I've ever used and can vouch for is seafoam. 1.5 fl. oz. of seafoam per quart of oil crankcase capacity. Dump it into a cold engine (doesn't sound smart to dump a room temperature liquid into a 100+ degrees crankcase, right?) and run the vehicle as normal for a couple days; depending on how brave your are.

Some people say there's a risk riding around with the Seafoam in your crankcase - BUT, right on the bottle and their website it says Seafoam can be used as a POST-oil change treatment (dump it into fresh oil directly after an oil change, and change the oil at 3,000 miles), or as a PRE-oil change treatment (dump it in before your next oil change, but monitor oil color; if the oil gets too dark [black] then change the oil, don't go more than 3k with the Seafoam in the crankcase).

You'd be following the PRE-oil change treatment. Sure, I wouldn't advise WOT runs at cold-start or anything of the sort

But other than that, I got compliements from the KIA tech who serviced my vehicle after a Seafoam treatment. No, I didn't tell him I used Seafoam; lol that's my secret. All he could say, "oh must be that Bulk Pennzoil we got here!" pfft...lol.

 

[DieselTech]

With the age of that engine I would not use anything harsh as a 15 minute miracle bottle. Looking at this long term is going to be much better for you. You dont know whats in the pan and I wouldn't want to risk restricting flow through the pickup by harsh cleaners.

MMO and a good detergent conventional will take a little longer to cleanup, but it is much safer route to go.

 

[Hemi426]

You could use the new GF-5 rated Pennzoil 10w-30. It's supposed to clean 40% of the sludge in your engine with just one use. $12.50 for a five-quart jug at Wal Mart.

 

[qship1996]

Redline oil will clean the sludge and even scrub the metal!

 

[buster]

Try the new Amsoil Engine flush. It's detergent based. (About time).

Or, switch to Mobil 1 High Mileage. That oil will certainly clean up any existing sludge/deposits.

 

[Big_Ed]

I currently have Seafoam and MMO. If I decide to go with MMO, how much should I add, and how long should it be left in?

 

[DieselTech]

run a qt of MMO

 

[HTSS_TR]

One quart MMO in about 1k miles. Or you can try Lubegard Engine Flush 95030.

 

[55Test]

I used a bottle of Gunk engine flush (a whole quart bottle) on my old Corolla wagon one time. I left it in 5 minutes longer than recommended (10 minutes rec'd, I left it in for 15) then proceeded to drive the car up onto my wheel ramps to change the oil. The oil pressure light flickered at me a few times. I suppose I should have put the car up on the ramps first.

 

[mechtech2]

I'd use the MMO [full qt], but also use a thicker oil to compensate - esp. in summer.

 

[Big_Ed]

Originally Posted By: HTSS_TR
One quart MMO in about 1k miles. Or you can try Lubegard Engine Flush 95030.


Well, I put a quart of MMO in and will change the oil in about 500 miles or so. I think when I get to within 500 miles of the next oil change, I'll do the same thing with the can of Sea Foam I have. Sound like a reasonable plan?

 

[addyguy]

Sounds like a good plan.

 

[demarpaint]

Originally Posted By: Big_Ed
Originally Posted By: HTSS_TR
One quart MMO in about 1k miles. Or you can try Lubegard Engine Flush 95030.


Well, I put a quart of MMO in and will change the oil in about 500 miles or so. I think when I get to within 500 miles of the next oil change, I'll do the same thing with the can of Sea Foam I have. Sound like a reasonable plan?


I've never used seafoam in the oil. I would use a qt of MMO and run it for the full OCI next run. If you are concerned with thinning your oil too much, then step up a grade as already mentioned. Or you could try this, lets say your engine calls for 5W30 and holds 5 qts, use 2qts 5W30, 2 qts 10W40 and 1 qt MMO. MMO will clean the engine safely, just keep an eye on the oil level.

As a side note, here is another option and something I do from time to time. Add a pint of MMO for the last 1000 miles of your OCI's, then run the full qt during the winter, no need to go up a grade. HTH