Serious engine troubles

[hypophthalmus]

So I was embarking on a 250ish mile trip. About 100 miles in, I loose power. I look down at the dashboard, and the engine was all the way hot (it was normal the entire trip). The radiator didn't feel very hot.

I let it cool down a bit, and start it again. The needle quickly goes back to the middle. I drive a few more miles, and lose power again. (Don't remember what the needle said this time).

Now it won't start. The starter motor turns, but it doesn't sound like it's cranking normally.

My best guess for what might have happened is I had a coolant hose loose (has a screwed clamp) for a few seconds by accident after I checked my valve clearances. Maybe it sucked in some air?

Thankfully the engine failed 3 miles away from a uhaul (expensive bringing it home though). It could as easily have been 20+ miles to the nearest town.

The engine oil looks pretty normal, but then this happened *very* suddenly, so I don't think it would have gotten much time to mix with coolant.

How should I proceed? Start disassembling and see what the head looks like?

[hypophthalmus]

If I did introduce air to the coolant that way, it went at least 600 miles of high speed riding before actually being an issue.

[Stig / Major Tom]

Describe sound when you try to start.
Miles, age?
Has the engine seized?
If not, shouldn't it start after cool down?
Can you burp air from coolant tank?
Compression still good?
Valve lash still normal specs?
Don't  understand concern of oil in coolant, or vice versa. ...unless serious damage.
Keep talking to us.
Stig

[hypophthalmus]

18,000 km, 10 years old.

Now that it's cool, the starter is still running strong but the engine isn't making the turning sounds I'm used too. It basically just sounds like the starter.

I haven't tried turning the engine by hand yet. It'll be a bit before I get a chance to, since I'm going back out to where I was trying to in the first place... sadly in a minivan this time.

I'll try turning the engine and checking the valves once I get back. I'm not sure how to check compression, but if I figure it out I'll check that too.

Seeing the temperature needle on H right as the engine died has me worried the head gasket is blown, or worse.

Oh, and something that I forgot to mention is that the engine was making a very bad sort noise the second time it stopped.

[hypophthalmus]

Okay, I'm back now.

I had a chance to try turning the engine. It turns freely... too freely. It doesn't feel like it's compressing or expelling anything.

[Stig / Major Tom]

Okay, I'm back now.

I had a chance to try turning the engine. It turns freely... too freely. It doesn't feel like it's compressing or expelling anything.

Is there a spark plug in it's proper hole? In other words, did the spark plug come unscrewed?
Stig

[hypophthalmus]

The spark plug is still there. I can't turn it with my fingers, so it seems tight.

[hypophthalmus]

Some more thoughts/questions:

When the trouble started, it was shortly after filling up on gas. My first thought was that maybe the gas was bad. But then as it started to seem more serious, I decided that bad gas won't cause this sort of problem.... right?

The first time the engine stopped, the oil light on the dash board came on. What does this light actually mean? What triggers it?

The engine temperature is taken from the engine block, right?

[hypophthalmus]

I attempted to check the valve clearances. However, with the flywheel's T mark lined up with the line, there's a *huge* amount of play in the valves.

I'm also noticing now that when I turn it slowly, once in a while it seems to catch a bit. But not consistently, and not in the same place twice.

[hypophthalmus]

So that sounds like somehow the camshaft position became different from the crankshaft rotation. Although I don't understand why or how.

[ole two wheels]

I hope I'm wrong, but you described perfectly a broken rod.. here's how to find out. Take the spark plug out. Get you a new or long pensil and insert it ,ereser end into the combustion chamber. Then turn the engine, by hand, slowly clockwise. If the rod is still intact you will feel it when it comes up to the pencil. STOP and remove the pencil NOW. If you continue to turn after contact you will break the end of the pencil off in the cylinder. Let us know what you find out.

[CROSSBOLT]

Engineering seems to be similar on several types of machines so I will ASSUME it is similar to the DT and GTi. The oil light has two purposes: oil pressure and oil change. The pressure sensed in these machines is very low because of all the ball and roller bearings. When the engine stops with the key on the oil light lights. The oil light also lights up when the maintenance odometer reaches its limit. The engine temp sensor is on the block. Engines can stop and/or falter due to bad gas but not lose compression.

The valve clearances are the alarming part. When you see the "T" in the window you should also see the cam sprocket two small holes lined up parallel with the top of the head. To show confirmation of timing there should be a third hole visible in the cam sprocket above center. Make one more crank turn if this is anything but described. Then the clearances should be whatever but not enormous! Timing has slipped if all these indicators are not met. Loose cam chains can cause this. The tip-off was the overly large clearances when the T was showing. Even if the cam was not in position, like on the exhaust stroke, the clearances should not be large. Another posibility is the clearances have not been set and they really got big but all of a sudden? Nah! Find why the valve clearances are big and that is probably the cause.

Karl

[hypophthalmus]

Sometimes the holes are mostly as described (but the small holes) aren't quite parallel. Sometimes it's about 180 degrees from that. It doesn't seem to be consistent (although I'm second guessing my memory of whether it was or not).

Actually, there doesn't seem to be *any* position where both of the rocker arms are close enough to the valves to be reasonable, though they do get there one at a time.

I used a thin, square offcut of pine since I had that on hand instead of a pencil. I was paranoid about not feeling anything and it breaking it off, so I kept taking it out. I never did feel anything, but eventually the engine stopped turning. I turned it backwards, and it stopped that way too. Eventually it started turning again, so I tried to feel something again The same thing happened, and it appears to be stuck that way.

I'm *pretty* sure nothing broke off. I guess an advantage to using a pencil is it'd be easier to tell... but the end of the offcut still looked cleanly cut.

[hypophthalmus]

I can't decide what to think of all this.

It's sort of shocking that the engine failed so badly, so suddenly, and without warning.

Was this all a result of accidentally allowing some air into the cooling system? Or was the sudden surge of heat a symptom of something else that happened? Is it just a matter of these engines not being able to withstand these sorts of long, high speed trips? Or something else?

Maybe this requires too much speculation at this point still.

[CROSSBOLT]

Are the adjusters still on the rocker arms?

Karl