Ok, I have a few questions and anyone feel free to come up with answers. I've had my brother's 92' Lexus ES300 forever it seems, I made a trade out of pity to him (77' F-150 4x4 4inch lift 35's blah blah ). I'm not sure if it has a blown head gasket or a cracked head, but I'm looking into it as a "what the hell" kind of project. I'm kind of wanting to increase my car and truck knowledge through first hand experience. I took me forever to get all the vaccum hoses, gazillion of those, and tubes and whatnot out of the way and it has the entire intake off. I'm trying to see if I can guess exactly what is wrong before I pull the heads. But first off I wanted to ask a couple questions and then explain the symptoms.

1. What exactly causes a head gasket to blow out? Extreme pressure? High Heat?

2. Are there any telltale signs as to which side (v6) is blown, or both?

3. Is there a way to tell if it's a cracked head rather than a blown gasket?

4. How does coolant get into the oil? Is it through a blown head gasket or is that a cracked head?

Ok, here are some of the symptoms and my observations.

1. The engine never creates pressure on the cooling system, meaning you can take the cap off when it's hot and it doesn't spray everywhere.

2. There's a pulse of steam coming out of the radiator when you take off the cap.

3. The oil has coolant in it.

4. Coolant drips from the tailpipe and it steams out as well.

5. When I took out the spark plugs all of them smelled slightly of gas, but the rear 3 were dry like normal used spark plugs are, just looked a light grey. The front three however were a bit wet and almost looked as if they had been cleaned off, possibly from coolant being burnt?

That's about all I can think of right now. Right now I'm leaning towards it being the front head gasket, but still I'm not sure. I guess I'll find out for sure tomorrow, as soon as I figure out how to get the cams out (DOHC) I took off all the caps and I figured they'd come out together kind of like when you take off the main caps of a crankshaft and it just lifts right out... or drops But they don't move at all. Wait.. I just had a thought. Ugh, feeling dumb. I haven't worked on an overhead cam engine before, but I remember seeing some guys when I worked at a bodyshop and they took apart a v6 in an '06 camry. Looks like I'll be removing the Timing chain. I love it when I think long enough and I figure out things without asking. GRRRReat. So.. yeah. Just a whole lot of food for thought. I'm learning.

ps. I dunno if I WANT to fix it. That stupid L on the car makes the price of gaskets go ... wow.

 

From my experience (I am not a master mechanic by any means) if you pull the radiator cap off and that coolant is forthing and bubbling in there then you definitely have a blown head gasket. I have experienced this one.

Oil in the coolant - blown head gasket - I have experienced this one too.

I think to tell where the gasket is bown you can do a compression check on the cylinders. That should narrow it right down to where it is.

Maybe someone else will chime in with some better advice or info.

 

Ok I got the front head off and the gasket on that one was blown on the driver's side. This was the head that had the three wet plugs while the other side had dry crispy looking plugs. It blew RIGHT next to a water jacket, I mean it's not even a 1/4 inch from the cylinder. So it must have been pumping a lot of water into it because if you topped off the coolant it would overheat in like 10 minutes of idling or 2-3 minutes of driving, take your pick. I'm still wondering how it gets INTO the oil. I understand the coolant out the tailpipe because it's getting burnt (or not) and sent out the exhaust. Does it escape past the piston rings and into the pan? or would it have to blow by an oil return or something like that? the oil return holes are raised on this block. I'm just trying to get some answers that probably don't matter right now. BTW never let a car sit for a year if a headgasket blows, rust at the top of that cylinder. I've hated this car since my brother bought it. I'm sort of tempted to take it all out and add some "go" parts to it. I dunno.. a 3.0liter v6 24 valve DOHC... with a turbo would be cool. In my dreams unfortunately. Only wish it had the straight six instead of the V. Straight six is in the supra among other toyotas and lexus.

I'm gonna see if I can lure my brother into paying to have me fix it since he misses the car and only swapped with me because it blew on the way here from idaho. Of course he'd have to fix the truck I gave to him. *******. The front right wheel nearly fell off. I went up there for a visit and the hub was...gone, wheel was tilted, who knows what else. the 4 wheel shifter is broken so now you can't shift at all unless you wanna crawl underneath and do it manually and he said the engine sounds funny now. that's what happens when you drive it for a couple weeks when it's "stuck" in 4 low, ya moron. Hell, I'll make him pay to fix this car and call it even. I like 25mpg on the freeway better than I did 12mpg in that truck.. if that.

blah blah blah blah......

 

I would recommend doing the other head gasket while your into it that far, it was subjected to the same troubles the other one was. Manufacturers view head gaskets kind of like a relief valve, they should give out before other parts get damaged. Seems like they let go too easy sometimes. Some even go out like clockwork, so many miles and they're gone.

 

I agree. Once you've gone that far you are better off doing it all. Better now than two months from now having to tear all of that down again. That would suck big time.

 

I don't mind if it blows two months later. I plan on getting rid of it as soon as I fix it with as little as I need to fix. I'll sell it for $2,000 just to get rid of it if it's running good and if my efforts fail due to any reason that might be then it's a parts car for $800. Parts for these cars aren't cheap, someone will want it. Like I said, I just wanna learn a bit with this one. It was going to be a parts car before I tore into it.

 

The heads may be warped and need to be machined at a machime shop.
If one is warped it will blow the new gasket.
I am not sure about it but I think .006 is warped out of limits.