97 W/ milky oil and smoke bomb

97 4.0 AW4 2wd
Just picked it up two days ago from a guy in the Navy, practically giving it away cause base housing was hounding him. Paid 300 for it, he said it had a blown head gasket and it ran a little rough(I guessed sensors). I brought a fresh battery and started it up, what I witnessed was in line with what he said, so i bought it. Its only 300, why not.

Got it home, pulled the head, gasket, got all gasket material cleaned off the matting surfaces, and put it all back together. This isn't my first head gasket job so it was done right.

I started it up and she's still puffing a little bit of smoke (minimal) at idle but open up the throttle and there is still a massive smoke bomb. Opened the oil cap on the valve cover and it's back to milkshake... So I'm thinking this guy must have overheated it like a champ and warped the the head. Oooooor maybe a crack in the head, I only ran it for about 30 seconds so I wouldnt think there would'nt be that much fluid transfer in that short amount of time. And it's a 0630 head, and I dont hear about them cracking really.

So I need opinions, what do we think. Warped, Craked or if you've got anything else throw it out there. I think I'll go to the junk yard and grab a head there and try to throw that on to see if theres a difference.

And I'm at work now so in the a.m. I'm gonna run a comp test...leak down test if autozone has a tester available as a loaner. I'll post up results.

Thanks all

Remove the rad cap and watch for bubbles in the coolant. You could also remove the fuel pump relay, remove the plugs, reinstall one plug at a time and crank the engine over and look for bubbles. You can also pressure test the cooling system and look for leaks. You may need to pull the valve cover and oil pan for this.

If it was ran long enough with oil like that your bearings are toast. Still $300 is a good price even for that. Basically salvage price. Worse case you get a good used 4.0L or a rebuild and run it.

I would lean towards a warped or cracked head. whatever you do don't keep running it like that, every bit of water infused oil that goes through there is drastically shortening the life of every bearing in the motor.

I would pull the head and take it to a machine shop to have it magnafluxed and checked for cracks, then decked to make sure the bottom is flat when you bolt it back on.

GrimmJeeper said:

I would lean towards a warped or cracked head. whatever you do don't keep running it like that, every bit of water infused oil that goes through there is drastically shortening the life of every bearing in the motor.

I would pull the head and take it to a machine shop to have it magnafluxed and checked for cracks, then decked to make sure the bottom is flat when you bolt it back on.

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I agree. Don't drive it. That head is going to have to come off. And I wouldn't put another one on (salvage yard) unless it was checked for straightness and cracks at a machine shop. Money WELL spent.

When you changed the head gasket did you change the oil at that time also? If not that would explain the milky oil.

Is it possible that there was just a good amount of coolant still laying in the exhaust system that was burning out?

After you get it sorted out I would change the O2 sensor(s) since its mosty certainly contaminated now.

wheeling365 said:

When you changed the head gasket did you change the oil at that time also? If not that would explain the milky oil.

Is it possible that there was just a good amount of coolant still laying in the exhaust system that was burning out?

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This is what I was thinking too...

wheeling365 said:

When you changed the head gasket did you change the oil at that time also? If not that would explain the milky oil.

Is it possible that there was just a good amount of coolant still laying in the exhaust system that was burning out?

After you get it sorted out I would change the O2 sensor(s) since its mosty certainly contaminated now.

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Oil was changed and distilled water and that flush shit was put in place of coolant. I didnt even bother running a leak down test or comp test, I'm just gonna take the head off and im gonna run it over to the shop on Monday and have them test it. Guy there said he would pressure test for cracks and see if it's flat, if not he'll deck it for me. He'll do all that for 100 bucks.

I thought that about the coolant in the exhaust but I doubt that cause its seeping smoke at idle then dumping at wot the exact same way it was before. And once I get it runing without smoke im gonna go through and test all sensors.

Thanks for the help gents, I'll post up monday night weather were running smoke free or if I light the damn thing on fire. Either way ill take a pic...

I'd think the head is warped from the same event that blew the head gasket.
To verify, either pull the head and buy a machinist's straight edge to check it for warpage or pull the head and bring it to a machine shop for them to verify its condition.
Could be cracked, too, though I'd bet warp before crack.
Like others have said - don't run the engine as-is.

I forgot I made this thread but just as an update, I took the head of again and cleaned it all up. Took a really close look this time and I dont know how I missed it the first time but there was a crack at the water jacket in between the #2 and #3 cylinders. So I got a new (junkyard head)thats been tested and milled down thats about to go on. Going out of town for a few days so I'll get it buttoned up after that and in goes the For Sale sign.

At least change the oil and filter

So I got the head back on, should I put the rockers that were on the original head on it or the rockers that I got with the jy head. I have both sets laid out in order, but a little confused when everyone says keep all the matching parts together (like make sure the connecting rod is used with the same rocker it was with originally).... does that include the lifters or valves our both..

thanks for input

At this point I'd be happy if it ran at all! That being said, I'd use the new head's rockers (if they're OK) and the engine's pushrods (once again it they're good). This way the only place old meets new would be the smallest interface at the tops of the pushrods.

My understanding is that the only valvetrain parts that are absolutely critical to match up are the lifters to the camshaft lobes. I have heard various opinions about using new lifters on an old cam, but everyone seems to agree that once a lifter has been run for any amount of time on a cam lobe, it can never be used on another lobe. Apparently it destroys the cam pretty quickly.

The other parts like rocker arms and pushrods, it is recommended to match them up, but I don't think it's impending doom if they aren't. I think I would try to match them up unless some of the parts are badly worn or bent, then I would swap in those parts from the other motor and not worry too much about it.

Yeah the lifters are the only thing that you absolutely need to keep matched.

awesome, thanks for the fast responses gents.:thumbup:

First off, lets get back to basics. What color is the smoke? If it is white, then it is antifreeze. If it is black, it is oil. If it is blue, it is fuel. Another test is to smell the tailpipe. Sweet means antifreeze. You can normally tell if it is running rich vs. burning oil.

Smoking at an idle means the valve guides are shot. Smoking under accelleration means the rings are shot.

A cracked head/leaky head gasket can be diagnosed better by taking it to a shop and having them use their hydrocarbon sniffer in the radiator.

Oily smoke is rarely caused by a head gasket or warped head. The combustion chamber is under a lot more pressure than any oil passage so it does not tend to infiltrate into the combustion cylinder.

He already said he found a crack

He didn't say it was back together yet and not smoking from what I read.

I also posted as a reference for future readers. People tear in to a motor many times when the best troubleshooting is when it is together. I hate to see people waste time or money.

old_man said:

He didn't say it was back together yet and not smoking from what I read.

I also posted as a reference for future readers. People tear in to a motor many times when the best troubleshooting is when it is together. I hate to see people waste time or money.

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You are right it's not back together yet... Oh, and it's definatly coolant, knew that before purchasing. I just didn't take as close of a look at the head itself before putting it back together the first time:twak: .I've dropped the pan and caps, bearings look perfect. The only reason I did this is cause I didn't know how long the PO ran it in the shape it was.

Thanks for the other info old man, knew it already, but still good info none the less.

I started it up and she's still puffing a little bit of smoke (minimal) at idle but open up the throttle and there is still a massive smoke bomb

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I guess it is a matter semantics. To me Smoke=Oil, Coolant=Steam.

Just hope everything works out.