White smoke at start up from exhaust

[JSpence]

I get white smoke as described in the title. My worst fear is with the bad radiator before I replaced it the heads were cracked. The curious part is it puts out the smoke for 1-3 minutes then it goes away. At the same time I smell antifreeze. Other then that it runs like a champ with the new radiator installed. You should know The Cat has holes in it and the catback is original from 91 with holes in the muffler as well. I am replacing the catback with the new Cat already purchased. Any help would be helpful.

 

[bisjoe]

If you hadn't mentioned the antifreeze smell, I'd say that white smoke at startup is most often worn valve stem seals or guides. The oil pools up when not running, and is burned on startup. Not enough is running through to make it smoke when running. This is normal on a high mileage engine. The only way to fix is a valve job on both heads. The smoke would smell like burnt oil.

If you are sure about the antifreeze smell, then yes, you could have a minor crack in the head that allows coolant to pool in a cylinder while off. Does the coolant need to be topped up?

 

[vroomzoomboom]

and can you see bubbles in the antifreeze with the rad cap off? if you can, either a head gasket, or cracked head is your problem

 

[JSpence]

The coolant did need to be topped off with the old bad radiator. As for the new one I installed on Sunday I'll have to watch the coolant level and let you know.

 

[73Elsinore]

Watch your coolant level. If you are slowly losing coolant, and you don't have any leaks, you have cracked cylinder heads. "slowly" means the level in the recovery bottle drops after a few days of normal driving.

You can verify this with a cylinder leakdown test.

VERY common. Ask me how I know The guy that did my heads says that all these heads will crack eventually. The replacement heads are A LOT heavier. Ask me how I know that one too

 

[djsk8r33]

how about much did it cost to get that fixed?

i have the same anti-freeze problem.

 

[little x]

The replacement heads are A LOT heavier. Ask me how I know that one too

I didn't know they made replacement heads that weren't OEM. Where did you find those? $?

 

[73Elsinore]

I did all the work myself except for the machine work. They bought the heads, did the machine work to cut the seats, and installed the old valves in the new heads with new seals and pressure-tested the heads.

To that add a top end gasket set (Victor Reinz) and two sets of head bolts. I bought two sets of bolts in case I screwed up one set becasue they are torque to yield so you can only use them once. The bill out the door from the machine shop was $890.

The replacement aftermarket heads came from the automotive machine shop. He bought the head blanks, cut the seats and installed the valves from my dead heads . I'm not sure where he got them or who the manufacturer is - I could find out if you want to know.

Not sure what this would cost you from a shop but figure their labor is almost $100/hr and this is a six hour job minimum. I'd guess $1400 minimum for this job.

 

[92exp4x4]

LMC truck has replacement heads for the 4.0 www.lmctruck.com These may be the same ones you have. I never called them on it. They are cast iron and about $300 a peice. They come without valve components.

 

[djsk8r33]

I did all the work myself except for the machine work. They bought the heads, did the machine work to cut the seats, and installed the old valves in the new heads with new seals and pressure-tested the heads.

To that add a top end gasket set (Victor Reinz) and two sets of head bolts. I bought two sets of bolts in case I screwed up one set becasue they are torque to yield so you can only use them once. The bill out the door from the machine shop was $890.

The replacement aftermarket heads came from the automotive machine shop. He bought the head blanks, cut the seats and installed the valves from my dead heads . I'm not sure where he got them or who the manufacturer is - I could find out if you want to know.

Not sure what this would cost you from a shop but figure their labor is almost $100/hr and this is a six hour job minimum. I'd guess $1400 minimum for this job.

that really sucks.
i have a jasper tranny/motor with about 50k on each.
but i have the exact problem with my coolant leaking.
i doubt the heads were fixed/redone/whatever in the re-build.