88 C1500 5.7L white smoke in exhaust

[ericinga]

A friend of mine is basically giving me an 88 C1500 5.7L short bed standard cab. It has 143K miles and looks pretty good. The only problem is white smoke in the exhaust. As soon as the smoke started showing up 5 years ago he parked the truck and stopped driving it. Now, his wife wants it gone. His loss = my gain (I hope). He is willing to part with it if I fix and drive it. I'm looking for a daily driver and this looks good.

I had this problem in a '99 5.7L and solved it with an intake gasket change. Before tearing into the motor, I plan to check compression and leak down pressures. I don't want to do too much with the motor if it's not needed. IIABDFI.

My question: Would you skip the compression / leak down tests and simply pressure test the cooling system?

There are a bunch of other small age related repairs but the truck is generally in good shape. Worst case, my dad can get a long block from Autozone with his discount for a little over a grand. I can go that route if the engine is toast.

TIA.

Eric

 

[Lanny]

Yeah I would get one of those testers from the parts store where you can tell if combustion gasses are getting into the cooling system. White smoke usually is a decent indicator that coolant is being burned. Also, pull the plugs and check their condition. They can tell a story as well.

 

[ericinga]

Truck first fired up and did not smoke. Finally started smoking after about 1 mile of driving at 25 MPH or so.

Motor starts strong. runs smooth. no ticking or other noises. 6 spark plugs were hand tight. Did not take effort to loosen them. 2 plugs were very loose; literally did not need a ratchet.

Compression tests:
1 - 145
3 - 140
5 - 140
7 - 145
2 - 140
4 - 145
6 - 145
8 - 140

Looks like head gaskets are fine. Intake manifold?

 

[Oldblue98]

Did it have any history of being run hot ? What does oil look like ? If it has never had intake done that is almost a given ! Mine made it to 195 K before it needed it. But mine was not going in engine.
Can't beat the price ! Almost giving is a good price for a SWB regular cab !

 

[ericinga]

Did it have any history of being run hot ? What does oil look like ? If it has never had intake done that is almost a given ! Mine made it to 195 K before it needed it. But mine was not going in engine.
Can't beat the price ! Almost giving is a good price for a SWB regular cab !

Last owner drove it 5K miles in 10 years. He never ran it hot. Parked it as soon as the smoke started. The smoke does not smell sweet but is very moist. Tailpipe drips water. It starts to smoke after warming up. Probably after the thermostat opens up.

I cleaned at least a pound of sludge out of the passenger side valve cover. Some of it looked like vaseline. Drivers side had a little hard sludge but not as much as other side. It seems to smoke less after cleaning out the crud.

I may just yank the heads, get them refreshed and call it done. Then I know the top end is fresh.

Everything else looks fine. It runs strong after a tune up.

Eric

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[90halfton]

For a free truck I would say f### it and throw a new crate motor in it. Skip all the headache, troubleshooting, and parts throwing. Consider it getting a nice truck with a new motor for 1400ish dollars. That's just my approach, others will differ.

 

[Oldblue98]

For a free truck I would say f### it and throw a new crate motor in it. Skip all the headache, troubleshooting, and parts throwing. Consider it getting a nice truck with a new motor for 1400ish dollars. That's just my approach, others will differ.

Its all got to do with what a person wants, if you want it that is all that matters ! What others think is just opinion. In the last two years I have sunk around 8 K in mine does that make sense ? NO it don't, but it is what I wanted for my own reasons. Enjoy your truck and do what you want with it ! SWB 400's in nice shape or not getting any cheaper and I don't think they will be going down unless it is rolling scrap iron.

 

[ericinga]

Decided to replace the intake gaskets today. Plenty of sludge in the lifter valley. Need to finish dressing the engine tomorrow night and get it back on the road.

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[90halfton]

Nice looking truck man

 

[joep88cheyenne]

Nice exterior. Looks like a nice project/fixer.