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Do the tops of these pistons tell you anything?

I recently posted about a problem with my '89 Cressida, with water loss presumably through the head gasket. I pulled the head today but the metal portions of the gasket aren't broken per-se.

Here's a pic of the tops of the pistons. I notice the front 2 and back

1 seem to be cleaner around the outer perimter of the piston tops than the middle 3. Possibly caused by steam cleaning?

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I can't see a crack in the piston walls with an eyeball check with the pistons at bottom. A car I had that had a cracked block hd a very obvious crack in the cylinder wall, should it be visible by visual inspection if it were an issue?

If the gasket isn't broken and the block isn't cracked, and assuming the head checks out, what else could it be? Do these pistons make you suspect something in particular?

Thanks for all input.

Reply to
Doc
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Unless you notice the presence of water in the crankcase oil, it's probably just leaking through the top end. How did the plugs look? I think that it would be very unusual for a cracked cylinder wall, especially if they are sleeved, but cracks can usually be seen.

Reply to
user

I'm certainly no expert, but piston #1 looks exceptionally clean to me...

Reply to
Hachiroku $B%O%A%m%/(B

The "water injection" looks like it de-carbonized the top of the piston a bit. I bet if you saw a pic of the head that combustion chamber would look similar.

Reply to
user

Yup! That's what I was thinking!

Reply to
Hachiroku $B%O%A%m%/(B

Yes. A gasket can leak without a break in the gasket. If you look carefully at the gasket, head, and block, you may be able to see where the coolant was seeping past.

Cracks are generally visible, but not 100% of the time. I doubt if the block is cracked.

Head was not torqued sufficiently. When you replace the head, get new head bolts.

Reply to
Ray O

How did the head bolts feel when you loosened them?

Reply to
Steve Austin

May not help but here are some photo's of mine. I never found anything that I could even remotely see as a cause. Or damaged for that matter.

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Even the head bolts had the correct tension so for lack of a better answer

58lbs must just be wrong. But why out of the clear blue sky after 15+ years and one hundred and some odd miles it would give out I sure dont know.

Lucky for me it had just passed it CA smog test and I happend to notice the exaust while waxing the car so it never really was driven like that and the head was still ok.

Dan

Reply to
Danny G.

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grrr...

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snipped-for-privacy@pacbell.net there in the Junk Drawerfolder.

Reply to
Danny G.

The pictures are not in high enough detail for me to determine whether it is coolant washing or oil consumption past the rings that is causing the appearance on pistons #1 and #6. Since you mentioned that you are losing coolant, I would assume that it is coolant that has "steam cleaned" the pistons, but the pattern is more reminiscent of oil consumption IMO. There's no law that says you can't have two problems at once. The headgasket failing at cyl #6 is extremely common. If I saw it in person I could likely point out the failure spot(s). I would say that a crack in the head or block is highly unlikely.

I would hand scraper the old gasket material off carefully, check deck and head with a straight edge, and machine the head if necessary before reassembling. Also, now is the time to think about new rings. This engine can be re-ringed in the car, but it is a big job.

Google alternate aftermarket head gasket technologies and torque specs. I have had good success with the factory parts/procedure, but I have no choice when working at the dealer. Better stuff is out there.

Toyota MDT in MO

Reply to
Comboverfish

I have seen some head bolts before that you could almost twist them out with your bare fingers.I bet you almost 100 percent of the vehicles running around today have a few head bolts that have lossened up. cuhulin

Reply to
cuhulin

An old ''trick'' used to be to slowly dribble some water (not to much that would cause the engine to stop running) into the carburetor.That is suppose to ''steam clean'' the carbon off of the pistons and cylinder head(s) I have never tried it out before though.Another one is to soak the cylinder head(s) over night in water,suppose to loosen up the carbon so it will be easier to scrape off the carbon.I did once try that one out, I couldn't see that it made much difference though.Back in the old days, people used to do a carbon job on their vehicles every few weeks.Motor oil is much, much better nowadays. cuhulin

Reply to
cuhulin

You forgot the rice.

Reply to
Steve Austin

HAY! Where you been?!?!?!

Reply to
Hachiroku $B%O%A%m%/(B

What up, 86? Oh, I've been around, 'spoze... jest chillin'.... How are things?

Toyota MDT in MO

Reply to
Comboverfish

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