Old 400.. Need advice
Senior User
Joined: Dec 2001
Posts: 207
Likes: 0
From: Brockport USA
Old 400.. Need advice
I have a 79 F250 Wrecker with a 400 4 speed, and 159,000 miles on it.
The 400 runs great but has some problems. After running about 10 min. it puts up a white cloud of smoke. I know It should have a rebuild,
but I have Kids in college (Now's not a good time). Could the white smoke be a head gasket problem...(The Oil looks good)?.Someone told me it could also be an intake manifold leak. Also, there is alot of flakey rust on the exhaust manifolds, and smoke seems to rise off them after its warmed up. Could the gaskets between the block and manifolds need replacing, or do I need to replace the manifolds? And Last... What is the minimum I could get away with doing for a rebuild? I plan on using the truck for an occasional plowing of the drivway, and about 4 Tows a year.
Thanks
Wrecker
1979 F250 Supercab 4x4 Towtruck 400CI 4 Speed
The 400 runs great but has some problems. After running about 10 min. it puts up a white cloud of smoke. I know It should have a rebuild,
but I have Kids in college (Now's not a good time). Could the white smoke be a head gasket problem...(The Oil looks good)?.Someone told me it could also be an intake manifold leak. Also, there is alot of flakey rust on the exhaust manifolds, and smoke seems to rise off them after its warmed up. Could the gaskets between the block and manifolds need replacing, or do I need to replace the manifolds? And Last... What is the minimum I could get away with doing for a rebuild? I plan on using the truck for an occasional plowing of the drivway, and about 4 Tows a year.
Thanks
Wrecker
1979 F250 Supercab 4x4 Towtruck 400CI 4 Speed
Senior User
Joined: Jan 2002
Posts: 107
Likes: 0
From: Dallas Ga
Old 400.. Need advice
White smoke generaly means coolant in the combution chamber and the intake can't do that on this motor because the 400 has a dry intake and coolant does not run through it. Yes it could be a head gasket but the best thing is watch your coolant if it is not leaking and your losing coolant then it is probaly going into the motor.
Junior User
Joined: Mar 2002
Posts: 93
Likes: 1
From: Montrose USA
Old 400.. Need advice
[updated:LAST EDITED ON 20-Sep-02 AT 10:03 AM (EST)]I may have read wrong but I think that the smoke is coming off of the manifolds not out of the tail pipe. Most times I've seen this is a valve cover gasket leak. does it look like it is leaking? when you stop at stop lights can you smell burning oil? This is a simple fix. Just a thought on what to check. Good luck.
Edit: yeah I did read wrong. I agree with 1979f150, it could be a head gasket. Check your coolant. But if you do rebuild you can reuse the exaust manifolds as long as they don't leak. take a steel bristle brush and scrape all those rust flakes off.
Edit: yeah I did read wrong. I agree with 1979f150, it could be a head gasket. Check your coolant. But if you do rebuild you can reuse the exaust manifolds as long as they don't leak. take a steel bristle brush and scrape all those rust flakes off.
Lead Driver
Joined: Nov 2000
Posts: 6,640
Likes: 349
From: Albuquerque
Old 400.. Need advice
[updated:LAST EDITED ON 20-Sep-02 AT 11:10 AM (EST)]If you aren't losing coolant check your tranny. If the modulator valve leaks it will suck tranny fluid up into the intake. Assuming you have an automatic.
...Ooops! I see you have a 4 speed.
...Ooops! I see you have a 4 speed.
Senior User
Joined: Dec 2001
Posts: 207
Likes: 0
From: Brockport USA
Old 400.. Need advice
All ready changed the valve cover gaskets. It almost looks like somthing on the manifolds (Cant see anything but flakes of rust) is burning off, Like it does if you spill a little oil on them when filling the crankcase. The difference is this dosen't seem to go away.
Thanks
Wrecker
1979 F250 Supercab 4x4 Towtruck 400CI 4 Speed
