Hello, I am new to trucking and recently bought a 1986 Peterbilt 359 with 531,000 original miles. The truck has been great and I have only had to put minimal money in to it. It has a 400hp Cat 3406b in it. There is a breather on the valve cover with a hose down to the ground. After working the truck moderately hard it smokes quite a bit out of the hose and smells like coolant ( looks like the truck is over heating even though it isn't). I had the coolant tested and it checked OK. My mechanic says its just an old truck and I should learn to live with the smoke. Has anyone else seen this problem? Is there a solution? Thanks in advance!
I ran an 89 with a 3406 for years, did the same thing. More than once I would park the truck, leave it idling and walk across the yard, look back and there looked like there was more smoke coming out of the bottom hose than out of the exhaust stacks. Never did cause a problem. If there is coolant in the oil it will turn into a creamy looking gloppy mess. I ran mine for over 12 years and it never caused a problem, or ever got worse. Seemed to only show up if I wasn't running the truck hard too. George
Send in an oil sample of the engine oil. My guess is that you have some coolant in the oil if you are getting steam and coolant smell out of the draft tube.
smokee
Does it do this after you ran it hard and it is idling? It could be a blowby issue. I used to have a 3406B 425 in a '87 LTL 9000 that did it, but it was nothing too serious. Keep an eye on your oil, coolant, and temp. and monitor it for any changes. If your oil level rises and smells like diesel fuel then it more than likely will be ring issues and/or injectors leaking. You might need to have the overhead ran on it. You can always Google for info. about it too. There are plenty of websites that address issues on diesel engines and/or Cat specific problems. Good luck!
It's blow by. Its that compression from the cylinders that is getting into the crankcase. It will cause the engine to pour smoke out of the breather. The coolant smell is blow by from the sir compressor which is water cooled on the 3406. The only way to fix it is to re ring the engine, and the compresssor. In the trucking industry "if it works, run it." As long as it ain't pouring oil out of that tube, and the engine starts good, I'd let her smoke, she old enough to (lol)! When she gets hard to start, then you might think about rebuilding her! It's your equipment, and only you know if its bad enough to justify the cost of a major overhaul! Thats what it'll take to stop her from smoking!
If you aren't looseing much coolant and the oil looks like oil you are prolly OK , you can loosten the oil pan drain plug when the engine is cold , if there is coolant in the bottom it will run out first, Air compressor head is cooled and is a possible source,as is water pump as willis stated watch for oilly residue in the top of rad, usually oil cooler or head gasket , you could also try running a lower pressure rad cap. 3406 mechs are known to be durable engines an head gasket problems are not common, Do you know if that engine has had bottom end bearings?? If not it's prolly time:cool2
Heck I'd pullin to the zone woth a load of hot rock on and have been on the interstate, running hard. Once I hit the zone, and sat there ideling, my truck looked like it was on fire. After about 5 to 10 minutes of ideling, it stop smoking so bad!
Thanks for all the quick responses! I've checked all the quick things to check that everyone suggested. The oil is not milky or gloppy, doesn't appear to have diesel in the oil, coolant level isn't changing, and no oil in the coolant. For now I guess I'll just go with Rino's advice "In the trucking industry: if it works - run it."