help? cracked block? head?

[duppyconqueror]

Hi everyone,

my gutlass cutlass 3.8 had been overheating, losing coolant (no visible leaks), and having water and steam come out the exhaust. I'm pulling the heads now, got one off and the head gasket looks new. I can tell it had been replaced before I bought the car 3 years ago... So should I just get the heads machined and put them back on with a new gasket, or is it likely that the block itself is the problem and I should just buy a hoist and pull that sucker on out....

thanks for the advice guys

 

[Fox80]

I myself would pull it out, that said you could clean the top of the block very good to check for cracks, you should also run each piston to full down and carefully check each cylinder, you should also check to deck for flatness with a known straight piece of metal. You should also take the heads and have them checked and resurfaced, now if you got it hot at all I would pull it out and have the block pressure tested. More than likely a crack would go from the cylinder to a water jacket hole or cylinder to cylinder, and more than likely will show up when cleaned up. You are taking a chance tho, if this were my car I would pull it, have the block checked, zero decked, line bore the màins, bore&hone the cylinders, resize the rods, polish the crank, install new cam bearings, soft plugs. Then have the heads resurfaced, a valve job, new guides, seals. This is the correct way to do it but will be pretty expensive, its a fifty fifty shot the block is fine, it's kind of up to you, you won't have much money invested but your time will add up if it fails again, I did this everyday in a production garage, and never pulled a motor out just cleaned everything and carefully checked everything and never had a failure, what scares me about your car someone already did it once. It could have been a bad job is why it failed again

 

[pontiacgp]

Water and steam out of an exhaust isn't coolant being burnt. There were some things to check before tearing the engine apart. What colour were the plugs, they would tell you if coolant was leaking into the cylinder. The loss of coolant could have been a number of things other than the engine. As for the overheating what condition is the rad in and was the cooling fan working properly.

 

[Fox80]

Water and steam out of an exhaust isn't coolant being burnt. There were some things to check before tearing the engine apart. What colour were the plugs, they would tell you if coolant was leaking into the cylinder. The loss of coolant could have been a number of things other than the engine. As for the overheating what condition is the rad in and was the cooling fan working properly.

I was also going to point out it very well could have nothing to do with the motor internally, but he stated he already had one head off, so I assume he determined the motor was to blame

 

[pontiacgp]

well at least now he can look at the valves and pistons and their colour will tell if it was burning coolant

 

[duppyconqueror]

Thanks for the input guys here's some more background info

I had changed the radiator hoses and the fan clutch and flushed the radiator. The radiator might not be cooling as good as it should because the air blowing off the fan wasn't super hot. It was pretty warm though so I know the radiator was working to some extent. I thought coolant was leaking into the block because of the coolant was still going low but with no visible leak. That plus the overheating, lack of power, white smoke, water droplets, occasional knocking and sludgy oil led me to believe it was the a problem with the motor itself and not the cooling system. Maybe I should have replaced the thermostat and radiator before tearing into the motor, but I was pretty sure it needed a rebuild. It looks like the last guy didn't do the best job of cleaning the mating surfaces before putting it back together.

Fox80 I would be interested in hearing more about how you rebuilt engines and cleaned them up without pulling them, though I may just get a hoist and pull it. I don't think I want to spend the money to have this 3.8 machined, If I'm gonna do it might as well do a 350...

 

[pontiacgp]

what do the spark plugs look like and what color are the valves.....here's a picture of a nice clean valve with a white film that's been cleaned by burning coolant

here's a picture of a plug that was burning coolant

 

[duppyconqueror]

Thanks for those pics that is very helpful. I will pull my plugs and compare and get back to you. Unfortunately I am out of town right now so I won't be able to work on my car again for a few days. When I do get back to it I will compare to the pics and decide weather or not to pull the motor

 

[Fox80]

Haha, I didn't mean it to sound like I rebuilt the motor in the car, my bad, I meant on newer cars/trucks that will go into "limp home mode" long before they get hot enough to hurt anything all we did was pull the heads clean the top of the block visual everything good, resurface the heads ( cams installed if a OHC motor) then reinstall the heads, that is standard service procedure by all factory manuals, however if it were my own 30+ year old car I would use the opportunity to go ahead and freshen the motor. Sorry for the confusion,

 

[duppyconqueror]

ah ok I see what you are saying. Thats pretty much what I was planning on doing when I tore down my motor, but now I can see that I'm gonna have to do it right and pull the whole thing. Is it best to pull the 3.8 with or without the transmission attached? Also I was wondering how hot the motor has to get to crack? Mine got up to like 230 a couple times but then I shut it off and limped home. It would only be up to 230 when idling at a light or something then I'd shut it off, though it is possible it got hotter before I installed the mechanical temp gauge.