Blown Head Gasket

[Rgpmalibu]

Hi Gang,

I've been relying on you guys to help me with my Malibu, but now I have a question for a different car. I just bought a 78 Nova to match my 78 Malibu. It's a beautiful, clean car, no rust, small block chevy, but the guy we bought it from said the engine was "blown". When I picked up the car, I asked him what he meant by "blown". He said he thought it was the head gasket. I thought, phew, I was thinking rod through the block. Ok, I want to go simplest things first. The oil is milkshake. I want to drain the oil, look for metal, check the cylinders, change the head gaskets, and try to get the thing running. I know the oil system will need to be flushed. Unless I find out otherwise, I'm going to assume bearings are ok, for now. My question: What order do you recommend I do things? Flush oil first, head gasket first, compression test first? Then what would you do? I've never had to diagnose and fix a problem this major before, so I need all the help I can get. Thanks in advance!

Rob

 

[64nailhead]

If you want to diagnose and repair what's broke without a complete teardown, then perform a leak down test with all of the plugs removed. If it's a head gasket, then it will painfully obvious. Perform the test with the radiator cap and oil fill cap removed. Also, pull the oil filter and cut it open and drain the oil into a clean pan. I wouldn't bother with a compression test if you already know it has an issue.

There is a possibility that you have an intake gasket leaking coolant into the base, if that's the case, then the leakdown test will be decent.

 

[Bonnewagon]

What a nice Nova! Congrats. When the oil is that contaminated, I usually flush the system with waste oil. Drain the coolant to stop the damage. Drain the milkshake. Fill the engine with the waste oil you save from oil changes. Run the engine just a few minutes to circulate and flush the bad oil. Do not let it get hot. It should only take a couple of flushes to get all the bad stuff out. Then I fill it with cheapest on-sale oil I can find and run that for a while to really get it clean. Then drain and fill with good oil. You can't do that with no coolant so probably just fill it with the cheap oil and stop there. Do you have an oil pressure gauge? If the pressure is great I would assume the bearings are OK. If not, then time to remove the engine and do what needs to be done. Good time to put a new oil pump in too. If OK the heads can be done in the car but of course it is way easier on a stand. Once the oil is flushed a compression test will let you know if the engine is tight. A car that nice maybe send the heads out for a cleaning and valve job while you are at it.

 

[Ribbedroof]

My two cents. If the oil pan is full of milkshake my question is how long did they keep adding coolant and driving it thereby killing the bearings? If it was in my possession I’d be yanking it out , blowing it apart, going through everything rather than trying to Band-Aid it in the car

 

[Rgpmalibu]

My two cents. If the oil pan is full of milkshake my question is how long did they keep adding coolant and driving it thereby killing the bearings? If it was in my possession I’d be yanking it out , blowing it apart, going through everything rather than trying to Band-Aid it in the car

I can appreciate that, but even if I get a summer out of it, I'd rather find out if it's going to live first. Either way I'll be rebuilding, but this way I might be able to get her on the road. I'm trying to avoid the full teardown until I'm certain it's necessary.

 

[spongbob]

First drain coolent into bucket ect.Take plugs out turn motor over with hot battery .several times clean any fouled plugs with carb spray .. then put the plugs back into motor with wires; leave old oil in crankcase unless it's shows over full you can drain some to see if waters on the bottom separated ..take fan belts off the water pump take the thermostat houseing off the intake and FILLthe engine untill the waters level with the face of thermostat houseing , take the breather lid off t he carb put a spoon full of gas in the motor and get car started at that point watch what happens in the thermostat houseing to see if you see small bubbles of if the water gushes out from the thermostat houseing..if you have no large bubbles or visible displace ment wait till the motor runs for say 3 or 4 minets keep it at a high idle say 800 rpm..to 1000.after the 3 to 4 minet of warming rase the motor to say 4000 rpm still no medium bubbles you may not even have a blown head gasket....if water gushes out the top of the thermostat houseing tear it down ...and buy both gaskets ,heads intake ect..the thing hear I want to stipulate you don't have to have water in the oil to have blown ( or rotton) head gasket ...never use the head gasket sealer in a can it will not work ...Hint" ? never done chevy head gaskets ?then leave the rockers alone untighten only the head bolts and there will be a couple rockers in the way of your 5/8 socket you can loosen them rockers for room but count how many turns out you turn them if it takes exactly 12 turns ( removing some rockers) then write that down on a drawn picture with the number 12 use the same number to tighten them back .count the threads at the top of the rockers and feel them with your index finger you do not want to over tighten these rockers if anything leave them a half a turn loose untill you finished the rest of the assembly ..(torqueing head bolts) there's a good writeup with pictures on a site called instructables if you search the instructables " valve grinding 4 engines it will have a lot of tips and homegrown techniques for you

 

[Rgpmalibu]

Here's what I know. The guy I bought it from told me he bought the car in California, which is totally believable because I can't find a spot of rust on the car - deals and bushings are shot though. He went on to say that the engine "blew" in Oklahoma. Something happened, and he said it was probably a blown head gasket. So something happened to put that water in the oil, something more significant than the intake leaking or something. I don't know if he lost oil pressure, but I'd like to find out if it has any. I'm going to try the leak down test because I just bought the gauges. See what that says. The rad also seems to be empty, at least what I can see.

 

[ELCAM]

Simplest thing to do is pull all the plugs and see what they look like. Then look into the spark plug holes and see what the tops of the pistons look like if they have carbon on them and they are dirty that is normal if the top of the piston is bright and shiny you know it has been steam cleaned by water.

 

[Rgpmalibu]

Does anyone feel like rust could be an issue? I'm not sure how long this engine has been sitting like this, and I don't know what this milkshake sludge is capable of. I just got the car last night so I won't be able to take a good look until the weekend.

 

[ELCAM]

If the engine turns i wouldn't worry about it to much. Water is heavier than oil so it goes to the bottom of the pan with oil on top.

If there is a lot of water in a bore and it has been sitting for a long time it will be rusted solid and will not turn.