phenob

Noticed some coolant corrosion around that tucked away water bypass no. 4 hose where it connects to the intake on my 93 3VZ-E. Pulled off the hose and found that both the hose and the flange (or whatever it's called) to the intake are completely clogged with, what looks like, chunks of metallic copper-reddish rust colored material. Clogged solid. Took off the hose and cut it open to reveal what really looks like a torn up piece of gasket or something like that completely clogging the hose, right up at the intake end of the hose. The "gasket chunk" was black with little red, hair-like, pieces of red metallic substance. Dont know if this really is a chunk of something that came loose or if sludge+rust+time = a chunk like that. No idea about the red metallic thread pieces. Looks like the kind of thing you might find inside a hose, but cutting this one open shows nothing of the sort. The reinforcement on this hose is simple whitish cord, didn't see any metal at all.

The pics I took aren't clear enough to really show any of the good detail. Will try to take more and post if necessary, but thought I'd throw this out there and see if anyone has an idea. I don't see any problem at the throttle body end of that hose, and the no.5 water bypass looks clean and fine. What in the world could have gotten in there? My only idea so far is a rusted water pump spewing bits of material into the stream. Pulled it off and sure enough the blades are very rusted. Don't know which way the stream goes through that water bypass though. Hell I didn't even realize it was there until I pulled the throttle, which looks all good far as I can tell. The end of this bypass hose that fits on the throttle looks nice and clean, no signs of trouble until you look at the end that goes to the intake.

Wondering if I should flush the system real good or let it be? I'm replacing the no.4 water bypass hose for $8, and i've cleaned that flange out the best i can by scraping stuff up and out with a tiny flathead. I'm betting something else needs attention but no idea what. Unless someone has a better idea, I will bolt her all back up and see what happens.

1993 4Runner 2WD V6 SR5 3VZ-E @188k. All stock. Headgasket blown 3 times in the last 10 years. Probably blown again, hence why im tearing her up myself now.

mt_goat

Have you owned it long? Maybe the previous owner used some radiator stop leak crap in it. Since that hose is one of the highest points in the cooling system its a likely place for air pockets to form and those stop leak products react with air form clumps.

BTW, I have totally bypassed my throttle body, the coolant hose goes around it now, because I didn't see the need to dump extra heat into the intake.

mt_goat

This drawing should help with that:
http://personal.utulsa.edu/~nathan-b...05descript.pdf

Sure go ahead and flush it real good, can't hurt.

phenob

Thanks for the clue. That's a good idea about the high point collecting some additive junk. With the flow going toward the throttle, this acumulation of crap at the slightly higher manifold side of the hose could support that idea.

I've owned the truck since 95 @ 50k, but the engine has had serious work re: headgaskets 3 times, all with what turns out (now that im a little wiser) to be shoddy work. Can't really trust anything in there now, and I'm sure glad yotatech has gotten my back for the last few years of maintaining it myself.

I'll give it a good flush and see what comes out. Thanks for the advice!

SEAIRESCUE

Go with ARP head studs and junk the head bolts. That will likely be the last time you do a head gasket.

runethechamp

If you do things right there is no reason why this should be true. Lots of other more likely reasons for a headgasket repair to go wrong.

phenob

next time you are tempted to dump some snake oil into your truck, think of this..



also pulled this high-performance water pump. make me an offer!

nate V

haha looks like you found the cause of your discoloration. Which is good to now because i have the same discoloration seeping past some of my hose clamps. on and if its still for sale Ill give ya 5$ for it hahaha

runethechamp

Wow, I changed out my waterpump during my rebuild, and my guess is that the old one had all of the 4runner's 150,00 miles on it. But there was NO discoloration of any kind in there. Looked clean as a whistle, but I changed it for my peace of mind anyway, hoping to avoid opening up the front end again ni a few hundred or thousand miles.

GSGALLANT

There should be very little rust in the cooling system of an engine that's had its coolant changed regularly (if a proper coolant to water ratio is used.)

phenob

note that, before finding that clogged water bypass, the clue for this was tiny rusty metal shavings sticking to the sides of the coolant reservoir. the coolant itself was nice and clean, as even with a few leaks, the level was staying pretty constant.