Head Gasket Replacement - 3VZ-FE

[johnlandice]

Does anyone have any advice?
I blew the head gasket in my 1993 ES300, as evidenced by overheating, bubbling coolant and thick white smoke. Is there any straight forward/reliable way to be sure which cylinder bank (V6) blew?

I've finished replacing the head gasket on the front cylinder bank and have begun re-assembly. I got to the timing belt (replaced 5,000 miles ago, so I didn't remove it for this repair) and was reading on some of the timing belt installation threads about the ratio of crankshaft rotation to camshaft rotation, something about 720 degrees between the two. Anyway, during the timing belt installation i got to the point were i needed to rotate the crank(harmonizer) in order to be sure of TDC and I discovered the crank would not rotate more than 360 degrees in either direction.

Can anyone offer any advice on why i cant rotate the crank more than 360 degrees, Ive broken a 3/8" socket at this point (tried to force it)? I thought maybe the compression or transmission was the issue, so i pulled all spark plugs and put the trans in neutral...what am i missing? Shouldn't i be able to rotate the crank continuosly into infinity?

The engine is a non-interference engine so, even if the timing is out of sync that shouldn't be the issue...?

Please help!

[JohnGD]

Remove all spark plugs. See which one(s) have coolant on it/them. Sounds like hydrolock. Can't compress coolant in the cylinder(s).

[johnlandice]

If I removed all the spark plugs there shouldn't be any compression and therefore i wouldn't think its hydro lock, what else would prevent me from rotating the crank more than 360 degrees (I dont think i mentioned it earlier, and im not sure if it makes a difference, but im using a breaker bar on the crank pulley to achieve my rotation).

The crankshaft seems to turn smoothly in either direction until I get close to a full revolution and then its like i hit a brick wall. I cant figure out what force is stopping me.

When i pulled all the plugs though i did notice dried and crusty coolant on one of the plugs in the rear cylinder bank (like John mentioned, thanks) so now i'm going to commit to replacing that rear head gasket as well...working on the rear bank is a much greater pain in the ass.

[JohnGD]

The Lexus 3VZ isn't listed as interference engine. Without the spark plugs in place what I'd do again is to remove the timing belt, see if you can turn only the front cam a couple of revs. A breaker bar/socket on the cam bolt can help smooth out the spring action.

And without the timing belt and no spark plugs (easier to turn), you should be able to turn the crank very easily and endlessly with 2 fingers on a standard 1/2" drive ratchet. Maybe squirt some oil in all the cylinders and try again?

If you remove the rear bank it's also a good time to change out all the valve stem seals too (the front bank too while at it). The down side is you'll need special spring compressors suitable for recessed springs (c-clamp for off-car and lever type for on-car) and stem seal pullers (they get baked on there tight). (Plus the rope trick or compressor for the front bank.) Or an engine shop can help. You have new head bolts right?

Originally Posted by johnlandice

If I removed all the spark plugs there shouldn't be any compression and therefore i wouldn't think its hydro lock, what else would prevent me from rotating the crank more than 360 degrees (I dont think i mentioned it earlier, and im not sure if it makes a difference, but im using a breaker bar on the crank pulley to achieve my rotation).