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Cause of White smoke from exhaust?
Engine was rebuilt last year has been and still running great.
I am on the highway for at least 30 min, doing 70-75.
If I stomp on it to bring it to 80-85 I get white smoke out the exhaust. If I let up on the gas back down to 70, the smoke only lasts for about 10 seconds.

Under normal acceleration, I can go to 90, with no probs.

I had my mechanic check it out but he said everything looked fine, including compression, plugs looked fine too.

This just started to happened right after I had my trans fluid changed/ serviced.

Anyone have any ideas?
Well about the only tie to the transmission is the vacuum modulator. I have seen them fail and allow engine vacuum to pull trans fluid into the combustion chamber and produce smoke. It seems unlikely on a fresh rebuild. But I thought it isworth consideration. Plus I would think there be some color to the smoke. Usually white smoke is from steam.
Maybe a bad vacuum modulator allowing transmission fluid to get sucked in to the intake and being burned in the combustion process is causing the white smoke you are seeing.

351w - Ford racing GT40X 178 cc aluminum heads - Ford racing(crane) 1.7 roller rockers - Comp Cams 280H magnum cam .544" / .544" lift - ARP fasteners - hedman longtubes - magnaflow exhaust with X pipe -  MSD digital 6al box - MSD coil - optima red top battery - tuff stuff 140 amp alternator - ported weiand stealth intake  - edelbrock 1406 600 carb  - march pullies and brackets - Be cool fan controller - derale electric fan - FMX trans - motive 4.11 gears - traction lok - competition engineering subframe connectors - lakewood traction bars.                                            

The obvious suspect is a head gasket leak. Do another compression test, inspect the spark plugs and check the coolant condition.
Kit Sullivan;197251 Wrote:The obvious suspect is a head gasket leak. Do another compression test, inspect the spark plugs and check the coolant condition.

How do you check for a head gasket leak?
Compression test, inspect the spark plugs, check the condition of the coolant.
On a fresh rebuild all the bolt fasteners should be retorqued after 500 miles the most important being the head bolts. then checked again after another 1000.. Did you do that ? A common problem is the felpro head gaskets they are known to "weep" or leak after time ESPECIALLY if you didn't do the retorque procedure..Start with checking torquing every bolt to spec..Your going to have to pull the valve covers to get to some of the head bolts. You need to do it anyway if you didn't so start with the simple stuff first

If the modulator checks good using a a hand operated vacuum pump (Mighty-Vac), use a cooling system pressure tester to check for leaks at the head gaskets. You can also use a leak down tester to narrow it down to specific cylinders. With the engine cool, remove the radiator cap and pressurize one cylinder at a time and watch for air bubbles at the radiator reservoir. Be patient. It can take several minutes for a small leak to show up at the radiator. Let us know what you find.

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