White smoke but not HG? (1 Viewer)

[Theidmet]

Hey everyone. I have a 76 Toyota Chinook with a 20R, Weber Carb. (Just a Hilux with a glorified camper on the back.)

It's had a habit of burning a little water. Occasionally threw a little white smoke, would get water droplets out of the rear, a bit more than I felt was normal but nothing excessive. Would usually clear up. It always ran like a top. Used very little coolant, almost never had to top it off.

However, I figured "oh great, head gasket, better take care of that."

Took it in to my mechanic about 6 months ago. He called me back, said that a compression test on all cylinders turned out just fine, and he couldn't see any signs of an HG failure. However I did have a corroded-to-poo radiator, so we spent my cash to replace that, instead. The white smoke stuck around for the next 6 months or so, but it didn't really seem to be causing any problems, so I just let it be.

Moving on; a few days ago it started blowing a lot more white smoke. It's still not horrendous, but it's at least 3-4 times as much as before, plus a good bit of liquid water. If I let it run on the street I'll have a nice little puddle in about a half hour. It's not ignorable.

However, after doing some research and thinking about what my mechanic said: The thing still runs just fine. If I wasn't looking at my rearview I couldn't tell there was a problem. It does seem to be eating up more coolant, now. Oil doesn't appear milky.

My first thought was "Head Gasket, now?" But apparently this thing should be running on broken legs if there was a big enough head gasket leak to put out this much smoke; and I would have coolant in my oil?

What gives? Water jacket? Any ideas?

 

[Mudder]

It could also be a hole in the timing chain. I know 20rs and 22rs aren't known for it. But the chain could have enough slop and wore put the guide and work a hole through the water passage through the timing cover. Your best best would be to pull the valve cover and look down it with a flashlight.

 

[KLF]

A hole in the water passage of the timing cover would milkshake the oil, but not cause white smoke.

Does the exhaust or the drooling water smell like coolant?

A leaking head gasket can present in many ways, and a simple compression test is not conclusive. Do a leakdown test. Pressure test the cooling system.

Disappearing coolant is not normal. It doesn't evaporate or get used by a normal engine, so it's leaking somewhere.

 

[pappy]

Water out the exhaust is normal, especially when the engine is warming up. It's a product of combustion and until the exhaust system warms up it will come out liquid, or as noticeable steam.

Timing chain cover is also a potential issue.

 

[Theidmet]

Water out the exhaust is normal, especially when the engine is warming up. It's a product of combustion and until the exhaust system warms up it will come out liquid, or as noticeable steam.

Timing chain cover is also a potential issue.

Thanks.

It's much more than normal, and it doesn't stop once the engine warms up.

 

[Theidmet]

Water out the exhaust is normal, especially when the engine is warming up. It's a product of combustion and until the exhaust system warms up it will come out liquid, or as noticeable steam.

Timing chain cover is also a potential issue.

I honestly don't know if it smells like coolant. I've heard it will smell slightly "sweet." I guess it does.

Just based on the need to top off my tank, I'm guessing it's burning or leaking the stuff.

 

[Theidmet]

It could also be a hole in the timing chain. I know 20rs and 22rs aren't known for it. But the chain could have enough slop and wore put the guide and work a hole through the water passage through the timing cover. Your best best would be to pull the valve cover and look down it with a flashlight.

Thanks. I'm going to take it in. Curious, though: If it's "the timing chain," do you mean just the cover or like the chain has bored a hole through the block?

 

[pappy]

Thanks. I'm going to take it in. Curious, though: If it's "the timing chain," do you mean just the cover or like the chain has bored a hole through the block?

No, the cover is a different part that bolts to the front of the block, made of aluminum. When the chain guides fail it allows the chain to slap the timing cover. There is a water jacket in the cover, and the chain will wear a groove into this water jacket. But, like has been said ... it mixes water with your oil making the characteristic milkshake.

 

[Mudder]

As KLF said it won't be the cause of the white smoke, my bad for not thinking last night. But but would cause coolant loss. Basically what happens is the chain looses tension and can wear out the guide on the drivers side of the motor and cause a hole to form in the timing chain cover, Which is replaceable.

 

[Theidmet]

No, the cover is a different part that bolts to the front of the block, made of aluminum. When the chain guides fail it allows the chain to slap the timing cover. There is a water jacket in the cover, and the chain will wear a groove into this water jacket. But, like has been said ... it mixes water with your oil making the characteristic milkshake.

Alright. Makes sense.

So I guess I am looking at HG as most likely?

Very unlikely: But I noticed it started this up after some heavy rain. The optimist in me thought maybe, somehow, there's a bunch of rainwater managing to pool somewhere in my exhaust line.

But I really can't imagine how it'd get there.

Obviously just wishful thinking; I'm losing coolant.

 

[KLF]

Wouldn't a 20R have metal guides? Dual row chain? I don't remember.

 

[Theidmet]

Wouldn't a 20R have metal guides? Dual row chain? I don't remember.

Yea, supposedly the timing chain is "indestructible," metal guides and dual row chain.

 

[KLF]

Well it's easy to check, just pop off the valve cover, shine a bright flashlight down by the timing gear.

 

[Theidmet]

Well it's easy to check, just pop off the valve cover, shine a bright flashlight down by the timing gear.

Gotcha. Thanks for the ideas.

 

[pappy]

I think we have come to the conclusion that it's not your chain. That said, should you ever have to replace the chain please, please, please use a Toyota chain. My second engine came with metal guides. They survived (sort of), but on a trip to Baja the chain broke. Your engine is only as strong as the weakest link ... and aftermarket chains are junk. Double or not.

 

[jgranthevagrant]

Yes, use a OEM chain, and replace the tensioner.

 

[bigredmachine]

No, the cover is a different part that bolts to the front of the block, made of aluminum. When the chain guides fail it allows the chain to slap the timing cover. There is a water jacket in the cover, and the chain will wear a groove into this water jacket. But, like has been said ... it mixes water with your oil making the characteristic milkshake.

as well as the milkshake oil you would also get excessive noise from the timing chain on start up.

Wouldn't a 20R have metal guides? Dual row chain? I don't remember.

20r and re were double roller, 22r and re were singe roller. I think that you can swap the timing set from the 20 to the 22

 

[Onebadlc]

I bet the head has a small crack between the valves on one cylinder!

 

[toy_tek]

I believe the 20r intake manifold water jackets are identical to the 22r: right next to the #1 & #2 intake runners. Since you mentioned corrosion I’d definitely take a close look at the ports at the head mating surface, I’ve seen the intake manifold corrode away right between the water jacket and intake runner. Just pop the intake off the head to inspect. If just the intake gasket is compromised it could be sucking water in Across it right there as well.