YACT: Engine flushes, PCV valves and oil pressure, oh my.

[Eli]

'81 Chevy Custom Deluxe 1/2ton w/ HiPo 350.

Was out doing some routine maintenance on the truck over the last few days. Changed the plugs & air filter.

Also changed the PCV valves and the attached tubing. I had been meaning to do it for a while, the grommet on the left one had broken, so I just stuffed a rag in there.. It had been like that since last June.

Anyway, I had noticed before that there was a lot of gunk inside the rocker arm covers.. visable with a flashlight. I didn't really realize the extent of it until today when I was fiddling around. I reached in there with a flathead screwdriver and gave a gentle scrape, and it was quite frankly horrifying. The tip of the screwdriver was just loaded with nasty sludgey carbon-laden asphalt-like substance.. the likes of which have no business being in an engine. lol. :Q

So let this be a lesson, change your oil, nomatter what you use! He was running synthetic, and someone told him he could just change it every year. Big mistake, eh? He ran it like that for 3 years before I found out. 3 oil changes in 3 years.. Ugh. The thing is, he probably only drove 8 or 9k miles a year. But they were the worst kind of miles.. Frequent, short trips. And he always let the the engine warm up idling.. took abut 5 minutes. I'm sure his oil was toast about 8 months before he actually changed it......

Yeah. So I'm going to take the rocker arm covers off and give it a thorough cleaning in there, and also adjust the valves while I'm at it.

So here's one of my questions. What should I use to clean the engine out? I'm going to flush the engine until the inside of the filter and the oil are virtually clean after some pre-determined (short) milage. Flush, fill, drive, flush, fill drive........

I bought a bottle of Sea Foam, and am going to use that first to see how well it works.

The engine only has ~30,000 miles on it, so it should be worth saving.

OK, now onto my 2nd question..

Where the hell is the oil pressure sending unit?! The Hayne's manual says "near the distributor" :roll: But I can't find it. Is it like right in the middle next to the firewall or something? heh. Maybe I'd have better access from below?

Just recently(last time it was driven), the oil pressure gauge was noticed to be at.. 0. But I don't believe it, I think (hope) that the wire came loose or something.

The sending unit in the engine isn't right for the gauge, so it normally always reads ~60psi.. lol. It raises to ~70 when you start the engine, and ~85+ when you rev.. At least, it used to.

So that's what I want to fix next.

What are the chances that a chunk of carbon has lodged in a major oil passage and is blocking oil flow? That would... suck?

I don't want my engine to have a heart attack...

 

[Scouzer]

I haven't really got much advice for you, but I know you are mechanically adept. So I am quite curious what you find about Seafoam. I can't figure out if its real or totally overrated.

Please, follow up on Seafoam.

 

[DurocShark]

Don't flush. I've heard good things about seafoam. But the problem is that you don't NEED it!

Switch to synthetic. Do your oil changes at 3k miles even on synthetic. You'll discover you don't need a flush at all after 2-3 changes.

Flushing is snake oil. If your engine is so gunked up that it needs seafoam, you don't need seafoam, you need a rebuild. Some of the oil passages are TINY and any flush you use will run the risk of clogging them with suddenly loosened gunk.

 

[Oger]

Eli, you are going to open up a nasty can of worms if you try flushing that engine out, no matter how careful you are the "gunk" as you call it (actually broken down oil, acids and water otherwise known as sludge) will find it's way throughout the oiling system causing more damage.
Your best bet is to just change the oil and filter and leave it alone, also if the drain holes in the cylinder heads are not blocked with sludge do not clean under the valve covers, this will break loose the carbon and sludge thus flushing this crap once again throughout the engine.

The oil pressure sender on pre 1986 Chevy small blocks is directly behind the distributor, they are often times hard to see, on later small blocks they are mounted down below on the side of the block on the drivers side below the exhaust manifold.
Once the sender is found, remove the wire and ground it to the block, turn the key to "on", the gauge should peg to the top, if it does then either the sender is faulty or the oil passage leading to it is blocked, if it does not peg itself to the top then either the wiring to it is faulty, the gauge is faulty or there is a faulty voltage regulator in the dash cluster.

If the sender has more than one wire runing to it do not ground it to the block, this type of sender (late models) require a high impedance ohmeter to test it correctly.

 

[Technonut]

Originally posted by: DurocShark
Don't flush. I've heard good things about seafoam. But the problem is that you don't NEED it!

Switch to synthetic. Do your oil changes at 3k miles even on synthetic. You'll discover you don't need a flush at all after 2-3 changes.

Flushing is snake oil. If your engine is so gunked up that it needs seafoam, you don't need seafoam, you need a rebuild. Some of the oil passages are TINY and any flush you use will run the risk of clogging them with suddenly loosened gunk.

There is a product out there that is not snake oil, and not harmful to the engine like the harsh quick flushes. I have personally used it in a few mid to high mileage engines of my own, and know it works well.

Auto-RX

Also be sure to check out the Additive Forum at bobistheoilguy.com. Lots of great info...

EDIT: Fixed Link

 

[Oger]

Auto-Rx® will work as you drive, liquefying the dirty deposits of sludge, carbon and other debris in your engine, and preventing clogs in the flow of your engine?s oil.

Believe what you will but you are still pumping this crap throughout the engine, even if this "miracle" substance liquifies the sludge, it will dilute the oil and there are still acids in the sludge that no product can disperse, these acids will find thier way into the bearings, cam lobes etc. causing wear and damage.

 

[Toastedlightly]

I'd just take the engine apart and give 'er a rebuild. Might be a pain, but it seems it is the best way to clean the engine out..

 

[Red]

Another vote for Auto-RX. I've seen some nice before and after pictures... thorough instructions on how to get the gunk out of your system asap.

 

[Technonut]

Originally posted by: Oger

Auto-Rx® will work as you drive, liquefying the dirty deposits of sludge, carbon and other debris in your engine, and preventing clogs in the flow of your engine?s oil.

Believe what you will but you are still pumping this crap throughout the engine, even if this "miracle" substance liquifies the sludge, it will dilute the oil and there are still acids in the sludge that no product can disperse, these acids will find thier way into the bearings, cam lobes etc. causing wear and damage.

All I can say is I believe what I see.... As long as the instructions are followed, there will be no damage.

The folks over at the forum I linked above are as serious about their oil as we are about computers here..

The people that have run oil analysis on their own engines while using AutoRX have not seen any harmful wear #s while using it.

Anyhow, Just look into it... I was just pointing out some helpful info. I have nothing to gain if you use the product or not..

 

[Eli]

Originally posted by: Oger
Eli, you are going to open up a nasty can of worms if you try flushing that engine out, no matter how careful you are the "gunk" as you call it (actually broken down oil, acids and water otherwise known as sludge) will find it's way throughout the oiling system causing more damage.
Your best bet is to just change the oil and filter and leave it alone, also if the drain holes in the cylinder heads are not blocked with sludge do not clean under the valve covers, this will break loose the carbon and sludge thus flushing this crap once again throughout the engine.

The oil pressure sender on pre 1986 Chevy small blocks is directly behind the distributor, they are often times hard to see, on later small blocks they are mounted down below on the side of the block on the drivers side below the exhaust manifold.
Once the sender is found, remove the wire and ground it to the block, turn the key to "on", the gauge should peg to the top, if it does then either the sender is faulty or the oil passage leading to it is blocked, if it does not peg itself to the top then either the wiring to it is faulty, the gauge is faulty or there is a faulty voltage regulator in the dash cluster.

If the sender has more than one wire runing to it do not ground it to the block, this type of sender (late models) require a high impedance ohmeter to test it correctly.

Thanks.

I was kinda afraid of that.... But the engine is so new really... There has to be a way to save it, or at least halt the rapid reduction in life expectancy...



I'd be willing to try the synthetic thing, but it's really pretty bad... at least under the covers. I can't imagine the synthetic cleaning it out any better than something designed to do that. Either way, particles are going to be traveling through the engine, hopefully to the oil filter.

Could try this stuff that purports to dissolve everything. I suppose that's what they all do though, hmm?

It's hard to imagine doing any more harm than is already being done.. but I will proceed with caution.

 

[Eli]

Still don't really know what to do, but just leaving it the way it is and changing the oil regularly just doesen't sit well with me.. but that's what I'll do if it's the best course of action.

 

[Eli]

Ok, so I think I've found the oil pressure sending unit, and it does appear to be the type that has multiple wires.

Something curious I've noticed.. when the key is at the first notch(ACC?), the oil pressure gauge reads something like 8PSI. When I switch it to the 2nd notch(ON?), it goes to 0.

edit: Or maybe it is the single wire unit... Right next to the distritubor there is something screwed into the engine block with multiple wires going into it.. It has something else attached to it, with a tan wire hooked up to that. Keep in mind that the sending unit on the engine is NOT correct for the gauge... the original engine in the truck was a 6cyl.

According to the book, the wire going into the sending unit is supposed to be tan. But grounding the wire to the block doesen't do anything. So I guess that means it's in the gauge cluster?

How can I hook up a gauge manually to test the oil pressure? I don't like starting and having the needle stay at 0... lol.

 

[rezinn]

Synthetic oil will clean it out. But it will turn black/brown within ten minutes of use from how you describe it, and you'll want to be changing the oil filter frequently (in a few hundred miles) if you do change over. You might also, as someone else said, dislodge some gunk and get it stuck in an oil passage.

Really, three years of bad maintainance is not all that bad, comparatively speaking. I had a mechanic friend who used to say that running one quart of transmission fluid in place of one quart of oil was a good way to clean the engine out, since it apparently has some sort of detergent properties. He used to do this just before an oil change - drain a quart of oil out and replace it with trans fluid.

Just change your oil pressure sending unit and stick the correct wire on there. If the guage moves at all when you start it, but sits at 0 otherwise, the sender is probably bad.

If you've got any oil leaks right now, they will likely get twice as bad if you use engine cleaner or change to synthetic oil. Just something to think about - you're going to end up fixing them then.

 

[Eli]

Originally posted by: rezinn
Synthetic oil will clean it out. But it will turn black/brown within ten minutes of use from how you describe it, and you'll want to be changing the oil filter frequently (in a few hundred miles) if you do change over. You might also, as someone else said, dislodge some gunk and get it stuck in an oil passage.

Really, three years of bad maintainance is not all that bad, comparatively speaking. I had a mechanic friend who used to say that running one quart of transmission fluid in place of one quart of oil was a good way to clean the engine out, since it apparently has some sort of detergent properties. He used to do this just before an oil change - drain a quart of oil out and replace it with trans fluid.

Just change your oil pressure sending unit and stick the correct wire on there. If the guage moves at all when you start it, but sits at 0 otherwise, the sender is probably bad.

If you've got any oil leaks right now, they will likely get twice as bad if you use engine cleaner or change to synthetic oil. Just something to think about - you're going to end up fixing them then.

No oil leaks. The engine is only 3-4 years old... well, 3-4 years since complete overhaul. So even with crappy maintenanace, it should have a lot of life left.

I don't think the sending unit is at fault, assuming I've got the right wire... touching it to the engine block results in.. nothing. So that means it's either the wiring or something in the gauge cluster. Which is a good thing, as far as I'm concerned..the sending unit would be a PITA to change, and if the engine is so bad inside that the oil passage to the sending unit is clogged, welll........ lol

But now I need to put in my own oil pressure gauge I guess.

Haven't researched that at all. Is there such thing as a universal gauge, or something? Maybe that has dip-switches to set the right ohm range? That'd be pretty cool.

Otherwise, I guess the easiest thing to do would be to buy a gauge/sending unit combo. Bah.. lol

 

[Eli]

After I get the new oil pressure gauge installed, I'm going to do a "quick flush" with the Sea Foam at the recommended dosage. Actually, maybe I won't.. I just feel that I need to justify the 6 bucks I spent on the bottle.

I've read around on the Bobistheoilguy additive forum a bit, and it seems people there swear by LC20 and Auto-RX.

I've read nothing but good about LC20, from very knowledgeable people, so I'm going to give it a try.

It's due for an oil change, so I'm going to change the oil & filter.. making sure to note the visual condition of the oil. I'm also going to cut into the oil filter and see what kind of stuff it's holding, to use as a base reference. It's been about 6 months since it was changed. But only about 2,500 miles.

I'll run the new oil for about ~500 miles(Or ~8 hours with the throttle stuck at ~2500rpm..) to let the fresh detergents do their job. I will check the dipstick several times on a clean paper towel to note the visual condition. I haven't decided which oil I will use for the cleaning, whatever I find that is cheapest. My goal is under 1$/quart.

Then I'll add the SeaFoam. I haven't decided how long I will run the engine with the SeaFoam, but not very long. After that period of time, I will drain the oil and once again note the condition of the oil. I'll also cut into the oil filter and see whats in there.

The point of this will really be to see how wells the SeaFoam acts.

I've got the LC20 on order. After the quick flush with the Sea Foam, I will change the oil again and add the LC20. It takes time to work it's magic, so it will be in there for a while. I'm going to use this thread to update the whole process, hopefully with before and after pictures.. if I decide to take the valve covers off each time... which would be a PITA, but it's in the name of automotive research, eh?

Should be fun.

I've gotta get a job doing R&D for some sort of engine-related company.. I love this stuff.

 

[Insane3D]

Let us know how it works out.


FREAK!

 

[Analog]

Originally posted by: Oger
Eli, you are going to open up a nasty can of worms if you try flushing that engine out, no matter how careful you are the "gunk" as you call it (actually broken down oil, acids and water otherwise known as sludge) will find it's way throughout the oiling system causing more damage.
Your best bet is to just change the oil and filter and leave it alone, also if the drain holes in the cylinder heads are not blocked with sludge do not clean under the valve covers, this will break loose the carbon and sludge thus flushing this crap once again throughout the engine.

The oil pressure sender on pre 1986 Chevy small blocks is directly behind the distributor, they are often times hard to see, on later small blocks they are mounted down below on the side of the block on the drivers side below the exhaust manifold.
Once the sender is found, remove the wire and ground it to the block, turn the key to "on", the gauge should peg to the top, if it does then either the sender is faulty or the oil passage leading to it is blocked, if it does not peg itself to the top then either the wiring to it is faulty, the gauge is faulty or there is a faulty voltage regulator in the dash cluster.

If the sender has more than one wire runing to it do not ground it to the block, this type of sender (late models) require a high impedance ohmeter to test it correctly.

Good advice from Roger. I would not flush this engine either - letting loose all that gunk will surely amount to trouble later. So what if it looks clean from the inside!

 

[thedarkwolf]

I'd be leary of running an engine flush in a engine like that too. Maybe I'd run some marvel mystery oil or plain old ATF through it every oil change for awhile. Something a little milder to hopefully keep any big chunks of goo from breaking loose and clogging it up.

After market oil gauges usually come with their own senders or will atleast say which one you need to buy.

 

[radioouman]

I would just drive it. Change oil often and get that sucker hot. Drive it on some long trips. Clean oil will clean that engine up eventually.

 

[OrganizedChaos]

it may not be as bad as you think its is, on the inside of the valve covers is where most of it sticks from being blasted with oil. make sure you have a putty knive, and maybbe access to a parts washer. changing the filter every few hundred miles for awhile might be a good idea

 

[Eli]

Originally posted by: OrganizedChaos
it may not be as bad as you think its is, on the inside of the valve covers is where most of it sticks from being blasted with oil. make sure you have a putty knive, and maybbe access to a parts washer. changing the filter every few hundred miles for awhile might be a good idea

I guess we'll know when I pull the valve covers off. I figure a valve adjustment is in order anyway.