awfulwaffle

Doing a headgasket change on an old chevy g20 van that i got for free. It was suckin coolant pretty bad, so the previous owner dumped "a whole **** ton of radiator stop leak" in there, in his own words. I didn't know that sludge could be this bad man, it's solid. I tried poking through it with a screwdriver, and it barely made a scratch on it. Any suggestions on how i could possibly get that oil valley clean? I do have access to an industrial steam cleaner. Anyways, here are some pics from before I pulled the heads.

SABL

I will tell you what I would do.

You ID'd the van as a G20.... that is an older model. I'm going to guess that the body is much lighter now due to rust. The suspension clunks and rattles. The mileage is high or moderately high.

How much service you expect and intended use or frequency of use along with overall condition of your van will dictate what you need to do.

The bearings are probably not is great shape and oil pressure will be low. The camshaft will also be in question..... the lift is .258 (1/4"+ .003)... very easy to have worn lobes.

You can remove much of the sludge with some scraping and wire brushing while vacuuming away the debris. I made an "inteceptor" out of a 5gal bucket by cutting holes in the opposite sides of the lid and using 2 hoses ..... 1 connected to my shop vac and the other as the "pick-up" for the suction to remove the gunk. I used a 3/4" heater hose for the pick-up hose and inserted it well below the vac hose level (very top of lid).

I don't know if I would use the power-washer or steam cleaner and NO harsh solvents. With the use of solvents you will open Pandora's Box and bring about all kinds of problems. The biggest problem will be oils leaks. You will lose the gunk that may well be keeping you seals from leaking..... front and rear main seals along with valve stem oil seals. The valve stem seal might not be an issue because they are more of a shield and not a true seal.... they are more like a rubber umbrella that keeps a direct oil flow away from the valve stem. A true seal does exist but I don't think the OEM uses them ($$$). The solvent will remove the gunk that has built up around the valve stem and masking stem wear. Once the oil is allowed to drip down the valve stem the spark plugs will foul and misfire.

Make sure all oil return passages are clean and clear..... a 22cal gun brush might be handy for that task.

I'll leave it at that for the time being. If your van is in better shape than I think it is there are better options. But, like I said, I suspect bearing and camshaft wear are involved.

Post back and let us know mileage and condition of van.
SABL

awfulwaffle

Hey man, thanks a lot for the prompt reply. The van's a 93 w/ 160xxx on her, so the motor should still have some life in her. Oil pressure was way high, but that may have to do with the fact that the original owner filled her up with 20w50 when the headgaskets blew, to try and get a bit more mileage out of her (I'm assuming the idea was to try and prevent ports from clogging). The suspension (struts and springs + one of the ball joints) was replaced at around 100k (original owner had receipts for me to prove it), and the frame is actually fairly clear of rust. According to the owner, it also got a fully rebuilt Allison OD tranny at around 150k (can't verify this, no receipts). As for the valve seals, we're in the process of rebuilding the heads right now. We sent em off to a machine shop to have them boiled and checked for straightness, and we're replacing the guides and seals ourselves right now.

I was considering using the steam cleaner simply because the sludge is so thick and so hard. Like I said, I tried stabbing into it, with considerable force, with a screwdriver and it barely made a mark on it. I was thinking of using the steam cleaner to try and heat and soften it up a little before I got to work trying to remove it.

I understand that there's a significant risk of screwing some seals or the rod bearings once the gunk is removed, but apparently the van was running very well before the gaskets blew. After they were blown, it was driven for several hundred miles by the original owner, but no more. My best idea was to do a few pan drops w/ seafoam or some other solvent once I've got it running again (after getting off as much of the visible gunk as I could). Given the conditions I've described, do you think this is a good idea?
From what I can see, all the return channels are pretty clear, and only one of the ports on the block had a significant amount of gunk built up in it when I pulled the intake manifold off.
That shop vac rig definitely sounds like a good idea, I'll have to find a spare bucket somewhere and go out and buy me some hose. Thanks a lot for the idea.

So yeah, there it is. If there's a better way to go about it, I'd definitely love to hear it. I'm waiting a few days to start, so that I can get all the opinions that I can first.


Thanks a lot,

Alex

SABL

Hi Alex

OK, this is sounding a little better!! With the indication of more than just a head gasket fix means you are serious. The heads are at a machine shop and are being refurbished..... focus will now go to the bottom end and getting ready for reinstall of the top end.

With the effort you are willing to spend and reconditioning the heads, it will be wise to do a decent cleaning of the rest of the engine. Time to be a little more thorough.... 5.7's are a nice engine. I have a 4bolt on an engine stand at this very time.

I made my "interceptor" many years ago when clearing the return passages in a 260ci Olds Cutlass. I did a mild solvent clean using kerosene as the solvent.

With what you describe, you seem to be serious and cleaning the engine can and will add some extra life. I'm mulling over the idea of a steam cleaner.... it can work, the only time I did that was with a total teardown and after a soak in a "hot tank". If you can get the pan drained without a great amount of time-lapse you may be in great shape..... at my speed I would end up with a pile of iron oxide (rust).

The biggest thing to look for is displacing any lubricant and replacing with water. The lifters should be removed.... they MUST be marked to make sure they are installed back in the right location. The lifters may hold water that will contaminate the oil after the initial fire-up.

I am not trying to scare you.... you seem to be attentive and wish to do a proper job. Just think through the job at hand and use caution... think about cause and effect.

bruiser

If you don't want to tear it all the way down, and want a sludge remover, look for AutoRX. Also check out bobistheoilguy. Lots of info on sludge and sludge removal on bobistheoilguy.

wrench97

The biggest problem I see, is that your going to end up getting debris in the bottom end which will plug the oil pump screen and wear the pump if not lock it up and break the drive shaft or distributor drive gear.

bruiser

AutoRX is a slow working sludge remover. It doesn't cause it to break up in chunks. Lot of people saved their Toyota engines when Toyota had the sludge problem a few years ago by using AutoRx. No, I have nothing to do with the company.

What? You never knew Toyota had a sludge problem?

bruiser

After looking at the pics some more, and reading that a screw driver doesn't do anything, I doubt the Auto RX would do anything, especially if any oil passages are clogged. You could send the pics to Auto RX and see if they have anything to say about it.

I've used Seafoam for carbon busting and fuel system cleaning, and have read it will clean an engine, but you need to follow the instructions as precisely as possible.

awfulwaffle

SABL, I see what you're saying there about the rust. I'm not sure if I've got the hustle to get everything reassembled after cleaning before the metal starts to oxidize, but it's the best option I've thought of so far. If I were going to attempt it, I'd get a few helpers. I was thinking of dropping the pan before starting, and steaming the oil valley first. If it goes the way I am hoping it will, I'll at least soften up the gunk up top to the point where I can start getting it off. Any run off should drip out the crank through the drain channels. After that, I'd get to putting steam through the ports, to try and flush them as best as I can and get rid of any clogs that may have formed inside them. I see what you're saying about the water being a problem, but some residual moisture left in the crankcase after steaming shouldn't be too big an issue, considering that we're planning to do several oil fill ups w/ solvent and flushes, and any residual water would be carried out by all the flushes (correct me if I'm wrong in this assumption). Hopefully though, that should be enough to dislodge most of the gunk I fear may be lurking in the block. I am also a little concerned that some of the drip channels may have been blocked, starving the cam of oil. I'm debating pulling the cam for inspection.

Wrench, I got what you're saying too, but that's why we're going to be doing so many pan drops, to get as much of the large chunks out of the crankcase as possible.

Bruiser, I'vdefinitely look into it.e actually never heard of AutoRX, but I'll As for the seafoam, I've used it quite a bit before, and it definitely does the trick as well as any other kerosene based solvent that I've seen. Then again, I've never encountered a sludge buildup quite this bad. What I'll probably end up doing is, after the first pan drop and drain, fill up the motor with oil, dump half a can of seafoam in the crankcase, and run the rest through a vaccuum line to do a bit of top end cleaning as well. A few repetitions of this, and I hope that I'll be able to get the engine clean enough to run reliably (and hopefully sludge free haha) for a good while longer. I'll definitely try to get in contact with AutoRX and see what they've got to say about this whole deal.

Thanks a lot for the input everyone

Alex