HI All, I have a 1985 International S1900 Truck with a DT 466 Engine, 5+2 tranny, and 173K miles. I have always been impressed by how leak free this truck has been....The undercarriage was basically dry of all leaks. In all fairness though, there was an old accumulation of oil on top of the valve cover towards the rear of the engine (where the blow by tube attaches to the top of the valve cover itself)....The oil there and towards the back of the engine was obviously old and baked dry....nothing wet or moist. However, just yesterday, the truck started having massive amounts of blow by out the blow by tube / exhaust and used / leaked as much as 3 gallons within about 40 miles (good thing the driver had to do a stop because had it been a long highway run I'm sure the truck would have run out of oil before he would have known anything was wrong). Anyways, the undercarriage of the truck was a mess so I thoroughly cleaned / degreased the engine area so I could see where the leak was.... Turns out the oil is leaking from the blow by tube (literally drip drip drip at a rate of approximately 2 drips per second so it is pretty fast....almost a small thin stream) and there was a fair amount blow by out the blow by tube and exhaust smoke to boot (not coal but oil burning). The engine runs pretty smooth but has a slight shake to it more than normal.... What could cause this ? What is the cure? It may have happened at one time before (as evidenced by the previous baked on oil) but I have driven it a lot with no issues until yesterday (Actually it was my helper driving it....I did notice as he drives sometimes he lugs the engine by up shifting too early or not splitting the shifts.... Could this be a cause of the issues ? Thanks in advance for any and all help. Andrew
Check your air filter and turbo. After that it is probably internal.
The air filter is grayish (dirty not clean white) but the filter minder says restriction is OK (unless it's defective and stuck in the good range). What to look for in the turbo? There were no external leaks around the turbo .... Thanks
I'm leaning towards a scuffed piston and liner.
If you disconnect the turbo drain and run it to a bucket with a hose, and plug off the engine side and then compare after you have disconnected the turbo drain, it should tell which it is coming from.
Would a coolant pressure test be of any troubleshooting value - this is suggested because I have been informed by the truck engine mechanics the typical diesel piston can tolerate no coolant, ergo my DT466 scalded a piston from a small coolant leak into that cylinder.
Is this the engine that overheated recently?
Is it "making oil"? {check the dip stick} The inj. pumps are notorious for getting fuel in the oil.. just a thought.
HI, To keep this from happening to other engines, what causes a scuffed piston and liner ?
HI, Oil level is fine, no diesel leaking into the oil.... More recently, I've had to add oil due to the extra blow by and oil dripping out the blow by tube... I've had to sideline the truck because of blow by and oil leakage
Way too many causes for me to list. One would be a dribbling injector, another would be a driver that likes to lug them down with full fuel with out downshifting. I did it once to my own service truck with a 7.8L Ford engine, a long coast down a steep hill with a steep upgrade at the bottom. cooled things down and then jumped on it hard, felt it right away. oops.
As far as I know this engine has never been overheated.... My 1999 truck from another thread is the one that overheated recently (sadly mobile mechanic said its probably a head gasket bit it could be a cylinder liner etc UGH....)...
sadly I do think he lugs the engine a bit.... Being used to tractor trailers he was keeping revs WAY too low (large Tractor trailer engines operate at revs way lower than a DT466 ) when I first started training him on the 5+2 ... I told him to try to keep revs up a bit relative to what he seemed to want to do and as a minimum try splitting the 3 to 4th gear shift (there is a large jump gearing wise between 3rd and 4th) so as not to lug the engine... Anyways, good to know.....this is our only stick shift truck so far and maybe our last because it's hard to find people who can drive them well.....
HI, I read this idea somewhere on the web BUT how would this actually cause blow by or oil coming out the blow by tube? I'm thinking this has happened before since the area above the valve cover where the blow by tube attaches to the valve cover was oil covered probably 3/16 of an inch of dried crusty oil....I used a putty knife to help remove the crust so the engine degreaser could work its magic easier... Being that the engine was fine for a long time while I owned it I wonder what the solution was before? Thanks
Sounds like a damaged cylinder to me. The accumulation of old oil in that area is normal on an engine that has been in service for a length of time. If you have the ability I would isolate the cylinders by cracking the injector lines one at a time to see if it reduces the blowby. If you find one that does that should eliminate the turbo as the problem.
Agree with the others as to the old accumulation, to find the bad hole with the engine idling crack loose each injector line to stop fuel delivery to that cylinder then retighten, the one with the bad bucket will be obvious when you get there. Either little to no change or hammer like hell when fuel stops. Blowby only occurs when either turbo boost or engine compression gets into the crankcase. One really wide swing could be if has air brakes where a air compressor going to hell and back CAN discharge into the crankcase.
DMiller is usually correct! We are all giving advise on a problem we have not seen first hand. All the holes could be worn out or have broken rings on several holes. That makes it more difficult. Start with the easiest first. Check turbo.
HI All, Thanks for the suggestions to date ....Here is an update.... I checked the turbo for end play etc....I didn't notice any real play up or down or in or out so I assume (?) that means the turbo is OK ?....well at least the bearings.. I suppose there could be a bad oil seal in the turbo l BUT I don't see any oil leaking outside BUT I suppose a bad oil seal could also be internal and that may put oil into the air stream giving the appearance of burning oil (of course that doesn't explain the more recent "miss" I feel). Anyways, I just thought, maybe I could or should check the turbo tubes for signs of oil in them to see if the turbo is blowing oil fumes into the air intake making for an oil burning of sorts. Further research online also seems to indicate a failed gasket can cause turbo boost to enter the crankcase.....Supposedly the valve cover gasket and the intake gasket are such that a break in the wrong place can have turbo boost going into the crankcase! Anybody here able to confirm that or is that just a rumor? As another test, I run the truck today and cracked each of the injectors to help determine the problem cylinder(s). The theory being, If I crack an injector, and the engine runs "rougher" then I know THAT cylinder was probably OK. I did this for each of the 6 cylinders and the only cylinder to NOT make a difference in running when the injector was cracked was the one furthest in the back of the engine (when viewed from the front). I suppose THAT isolates the cylinder to that one as far a the miss is concerned... Given the new findings, what should I do next ? I have thought of maybe buying an injector to see if that solves my problem (kinda costly with no guarantees of fixing the problem) BUT I suppose another test would be to swap injectors between 2 cylinders and see in my problem "moves" to another cylinder. While I can understand an injector making a miss and possibly extra smoke out the tailpipe if not injecting correctly, It still doesn't explain the oil out of the blow by tube....maybe I'm double whammied with a blown gasket (turbo boost into crank case) and bad injector (miss and smoke out exhaust) ?? Thanks in advance for any other suggestions.... Andrew
It aint the turbo or an injector if you have a dead hole and blow by. It's the piston or liner in the dead hole. ETA... I would have that injector checked to be sure its not a dribbler while you are rebuilding that engine.
Will be time to pull either the oil pan(easiest to reinstall) or the head and have a internal look. Number six dead hole, most likely scored and rings destroyed where not building compression just sending it to the crankcase. Pan off roll the engine to 1&6 at tdc will be able to see cylinder wall damage/scores, is there is severe enough damage to the piston that will be really evident from the bottom, may be pieces in the pan.
The theory with the valve cover allowing boost into the crankcase is only on the electronic engines. Those were a combination unit of intake manifold and valve cover gasket the Boost pipe went straight into the top of the valve cover. The fact that you were able to loosen injector lines and create a miss for troubleshooting says that you have a pump line and nozzle engine so this is not one of your concerns. Extracting nozzle injectors from an old conventional head can sometimes be very difficult you may need a special puller for that. Having having said that I would start spraying them up with penetrating oil and letting them soak. Regarding chasing the injector around see if it follows the injector or stays at the same hole is very valid and a common one that we all use from time to time. But again the downside is when removing the injectors if it is stuck to the cup you will run the risk of removing a cup with the injector. Reading your posts it's nice to see that you are trying to troubleshoot it in a logical and methodical way rather than just throwing Parts at it Keep up the good work
Was it a dead cylinder w/ absolutly no change?? I'd swap it w/ the furthest hole AWAY FROM the suspect cyl. I'm just typing out loud here> IF it was a cracked piston & the inj. was good, it would have to be "making oil".. the fuel would be running right past the piston into the cr.case. Either way, the engine cant be running "fine" other than oil out the dipstick.. there HAS TO BE a skip if breaking an inj. doesn't make a dif..
What are you talkin about FWF?? spending hundreds of $ BEFORE you find a problem makes you appreciate the "small things" in life.!!! LOL.!!! Just pullin your leg, Andy..
Another less invasive test is to pull the injector and put the bad cylinder on TDC with the valves closed and pressurize the cylinder with air. I use a big rubber tip on a pipe extension on a blow gun valve. I've found many a bad valve that way, if the piston is chunked you should hear air in the crankcase filler hole.
Maybe put in gear and set the brake so the engine does not turn much.
Excellent Idea.. RZUCKER..
Yep, forgot to add that you may want to lock the crank, some engines will turn pretty freely. I usually regulate the air down between 45-60 psi.
If you don't lock the crank and decide to do the TDC thing, make sure your fingers are clear of any parts that may suddenly rotate if it gets to one side or the other!
Thanks for the compressed air and drop the oil pan idea....I was really dreading the head removal if not needed (unfortunately may still be needed tho) As potentially something easier, Is there some way to use a diesel compression gauge to figure out things without removing an oil pan etc ? Thanks
Sure, use the compression test adapter to charge the cylinder with air. You still want to lock the crankshaft somehow. Top gear, wheels chocked and park brake set. Get your valve cover off , roll engine over til number 1 valves are on overlap, check number 6, pushrods should spin freely and rockers should be loose. Pump air in the cylinder, 30-40psi or about 2 bar. Listen carefully for air entering exhaust, intake or bottom end. A little is ok, blowing straight through is not. The odds of having a tight mechanical engine are pretty slim. Use judgement. I described testing for 6 as you said that was the hole with the least contribution.
On second thought, run your overhead. Adjust all intakes and exhaust. Document any that are tight or have zero lash. This simple maintenance practice can tell you a lot.
Admittedly, I have not messed with valve adjustments on any of the trucks since I got them. Most likely, they should have been looked at early on BUT sadly we did not. Could a poorly adjusted valve make for blow by ? Could a broken / really worn valve guide cause the issues? (there is no rattling noise so I assume nothing loose?). Thanks
Yes, valves tend to beat the seats into the head. That actually reduces clearance. If you dropped a valve you'll know because you won't be able to establish any clearance. And since the valve cover is off. Time to do the bypass test
I looked up "bypass test" but didn't see anything helpful.....what is the bypass test? Thanks
The test RZucker suggested and we all elaborated on.
Bypassing compression by the rings into the crankcase.
Today I figured we'd try one last thing before admitting defeat and actually looking inside the engine (hopefully...fingers crossed...THIS would be the cure !). Anyways, we took the injector out of the rearmost cylinder and swapped it with an injector from a cylinder that was working well hoping all along that the problem would follow the "bad" injector to the new hole..... Drum Roll... No such luck....the rearmost cylinder still did not make any difference when the injector line was cracked on a known good injector.... On a positive note, the injector from the bad cylinder was shown to work when put into a different cylinder... A small victory of sorts.... Oh well I guess we'll start with the valve cover next hoping for something "simple" (maybe a valve guide or something?).
Your time, money and effort but I would have already had the pan down.
If you had the injector out why didn't you try the air test? Massive blowby and a dead hole is not an injector. It's a piston/liner issue and you wont find anything under the valve cover either. It's under the head.
I guess I was SOOOO hoping it was an injector, It didn't dawn on me to do the air test.... Had I had less hopes of an "easy" fix, I probably could have thought more logically.... I guess I will have to admit defeat and face reality shortly...soon the engine is coming apart....Sigh Thanks to all who have helped me in this.... I'll keep you posted as I progress on this BUT I will probably have to fix the head gasket (at least I am hoping it's just a head gasket and not a liner seal also) on the truck that overheated first since that truck is more universally usable by my helpers (automatic trans) .
When you have the head off should you need to roll the engine over for cleaning use bolts and washers in a few head bolt holes to hold the liners down otherwise could lift one and disrupt the sleeve lower o-ring seal. That also makes certian the sleeves fully seated to check liner protrusion to make sure the head gasket will seal.