About Van Expertise I have been maintaining a fleet of approximately 55 light, medium and heavy vehicles for over 20 years. Most are 4X4 pickups and off road fire fighting trucks. Some medium duty trucks. Some military light trucks.
I can answer most questions concerning 4X4 engine, drive line, suspension, electrical, and fuel, both diesel and gasoline. Ford, GM, and Dodge, old and new, but prefferably not newer than 99.
Question I have a 1988 Chevy K2500 pickup with a 5.0L TBI and 3 speed automatic transmission that I bought about a year ago. The motor has burned a little oil on startup since I've had it, but recently it's smoking much more, and not just on startup. Sometimes it's not that bad, but at other times it's an extreme amount of white smoke mixed in with the bluish white smoke. At the same time this started, I noticed that I'm losing transmission fluid, almost a quart a week, yet there are NO drip puddles under the truck when parked, even for an extended period of time. I've also noted that even though the truck is presumably burning oil, there seems to be slightly MORE oil on the dipstick than when it was last changed a few weeks ago.
Could these two things be related, is there some way that transmission fluid could be getting into the motor to cause the occasional smoking? Or is it just coincidence that these two problems surfaced at the same time?
Answer Hi Bob,
Chevy V8's have for years had a problem with valve guide seals getting hard and cracking, and allowing oil to be drawn in past the intake valve stems, and burned.
I was thinking they should have cured that problem by the 88's, but you may still be getting some of that.
In addition, check the PCV valve to see if it is dirty and sticking.
That is all for the little oil that is what I would expect your cold start smoking to be.
Now, for the transmission...
Older Chevy transmissions had a vacuum modulator valve in the right side of the tranny, that if the diaphragm is ruptured, could suck transmission fluid into the intake manifold and burn it.
I am about positive the 88 does not have that, but check to see. It is easy to check. Just get a vacuum tester, or just a small piece of vacuum hose, and connect it to the modulator valve, and suck on it. It should hold vacuum.
There is no connection for the transmission fluid to the engine, but there is a transmission fluid cooler inside the radiator, and if it leaks, tranny fluid can be mixed into the coolant.
If that is occurring, check it, and repair it soon, before coolant begins to migrate into the transmission, since antifreeze will ruin the tranny quite quickly.
There should be a vent from the top of the transmission housing, to the atmosphere. If someone has connected a hose from that vent to the intake manifold, it could suck fluid, but even that shouldn't cause you to loose that much.
But check inside the radiator, and see if there is tranny fluid in there.
Also, check the condition of the tranny fluid, and make sure it isn't getting milky.
