I’m getting some puffs of blue exhaust smoke under some conditions and I suspect my turbo oil seals are bad (225k miles). Has anyone rebuilt or replaced the turbo in a 4d34 and have any advice. I haven’t pulled the hoses yet to check for oil residue as we just got back from a trip.
99 FG turbo rebuild or replace
- Thread starter kerry
- Start date
yabanja
Explorer
These old diesels smoke periodically, I would be hesitant to say anything is wrong. IE if it isn't broken don't fix it. Valve guide seals would be just as likely a candidate. That having been said:
I suspect turbo technology has improved significantly since 1999. I have looked at the Kinugawa setup(https://store.kinugawaturbosystems....bishi-fuso-4d31t-4d34t-3-6-3-9l-diesel-canter), but am holding to my resolve to keep it stock for ultimate reliability and longevity. The factory exhaust manifold is very restrictive and coupled with additional fuel and a larger exhaust and exhaust brake I am sure you could get more ponies/ economy. Likely additional smoke as well so back to square one!
Allan
Took the hoses of the turbo. Some evidence of oil on the outlet. A fair amount of play in the shaft. About 1/8" side to side. No in and out play at all. I'm pretty sure the turbo is original but the engine isn't since the block is not painted. So it's more likely it's the turbo seals rather than valve stem seals.
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The conditions under which I am getting puffs of blue smoke is upon heavy acceleration after a downhill section in which I have my foot off the accelerator. I believe it happens when the exhaust brake is not activated although it's possible it might be happening when the exhaust brake is engaged on the downhill. I haven't had a chance to confirm the exhaust brake factor. It may also only be occurring when the engine is relatively cold. For instance, yesterday I started the truck and within a minute or so went down about a 3/4 mile section of downhill dirt road in 3rd gear, no exhaust brake. When the road started uphill i stepped on the accelerator and got a puff of blue for about one second, maybe 2. When the road started down again, I tried to get it to repeat by taking my foot off the accelerator for a while and then accelerating downhill. No blue smoke, but the load on the engine was considerably less than accelerating uphill. Typically, on a gasoline engine with bad valve seals I'd expect to see blue smoke coming down a long hill with foot off accelerator. It's not doing that. I'm thinking it's something like oil passing the turbo seals when it's not spinning that fast on a downhill and then getting blown into the intake when it spools up on hard acceleration.