Engine/Transmission (1994 - 1998) getting lots of blow by??????

[JBrookshire]

for about a moth I have been getting lots of blow by out of the crank case vent on my 1996CTD, it gets all over the tail gate and is making a mess and it is loosing oil quit a bit on the dip stick. I have checked the turbo and it moves alittle bit and it looks like it may be hitting the side. Is there any other way to tell before I go buy a 40/35 turbo??? it has 235,xxx miles on it the head gasket was replaced around 15-20,000 miles ago. What u fellas thing??? Just help me so my truck will stay clean. Thanks Justin

 

[matches]

search the forum for something about the breather on the valve covers, your truck I think, has a crankcase breather up top also that gets plugged or something, not an expert just trying to help.

 

[Andy Redmond]

You might also find a Cummins shop with a manometer and proper orifice for the blowby tube, the readings will inform you of blowby from piston rings etc.



Sometimes switching brands of oil can cause this (burning and using oil).



Good luck and let us know what you find out.

Andy

 

[Vaughn MacKenzie]

JBrookshire I was reading on this subject quite a bit last night. There were a few other guys with a similar problem, one it was a bad turbo seal, another a head gasket leaking to an oil gallery, and another guy it was a broken compression ring.



On the turbo situation I think the seal was letting boost pressures blow back into the crankcase via the oil return hose. So, you might try removing it and getting a long piece to route to a jug then start it and let it idle a minute or so (not too long so it won't empty the crankcase). I don't know if this would be concluse though without having boost but if you free-rev to at least 2500 it may give you enough boost to see if it's blowing past the seal (and you see vapors coming from the drain hose).



Another thing to do . . . with a warm engine crawl underneath while it's idling and take a close look at your draft tube. If there's a pulsation to the vapors, you probably have a head gasket or broken ring problem (more likely head gasket, I doubt broken rings happen very often). Another check if the gasket is suspect is a compression test, but getting a hold of the gauge and adapters for Cummins isn't cheap, and not easy to find/borrow. This test may not be that conclusive anyway.



I am having a similar problem with mine. I did the head gasket 15000 miles ago and am blowing oil out the draft tube. There is noticeably more vapor out the blowby tube. 10k miles ago it was a slow, gentle vapor, now it's coming out at a steady velocity. I'm using at least 1 qt of oil every 1000 miles, not long ago it was more like 2500+ miles per quart.



I have 366,000 miles on mine now so it's likely a new set of rings are in its future. It just bothers me how quickly this became a problem. Before I only had a drop or two out the blowby hose at night, now in the morning there's a small puddle about 2" across on the ground. I'm going to check my turbo, it's the original, and I drove it hard towing 9000 miles across the US last month.



Vaughn

 

[JBrookshire]

Thanks for the replys, I have not got to do much work on it yeat, I am going to try to check the vent tube for pulsing, I am pretty sure it is the turbo I have some in and out play and I am betting a roar sound out of it like when I let off the go pettle u can hear it. It just stinks my truck is white and by tail gat is gray from the blow by and it leaves a puddle every where I go I am going to get on it this week I have been calling around on turbos and sounds lik a b1 turbo is the best chouse then I can do more mods heheheheheh well we will keep u posted thanks for the help. Justin

 

[PKemp]

Justin: Pull the air inlet tube off the compressor side of the turbo (air cleaner to turbo hose). Look at the compressor wheel with a good bright flashlight. The fins on the "fan" wheel should all be clean and in one piece. The surface area of the housing may have a slight oil coating on it but thats normal. Press the nose of the compressor wheel in lightly. It should not touch the housing anywhere but may have a "slight" in and out feel. Grab the nose of the wheel and turn it around and "feel" how it turns in the bearing housing. Again a very "slight" amount of side-to-side/up and down play is okay but it should turn smoothly with no "ticks" or "bumps" as you turn it, and not touch the housing anywhere. Take the intercooler boot off the bottom side of the turbo compressor housing. Examine the inside of the boot and feel the inside of the compressor outlet. It should be clean. Look for excessive oil. A lot of oil here is a real problem. Are there any oil leaks anywhere on the turbo side of the engine? Check the rubber line to the wastegate on the turbo, it could be dry rotted and cracked. I am guessing that you change your air filter, oil filter and oil often and use good oil and filters. Why was the head gasket changed awhile back? How high do your EGT's run? Is your crankcase vent clean and open, not restricted at all?



Vaughn: Does the word "overhaul" ring a bell? Rings, at least are in your immediate future.

Do you have any loss of power?

 

[Vaughn MacKenzie]

Vaughn: Does the word "overhaul" ring a bell? Rings, at least are in your immediate future.

Do you have any loss of power?

What? Overhaul? Why do you say that PKemp? :-laf



Just a thought, it may be possible for a turbo to have good bearings, but leaky seals (?)



Actually power is good, runs great except for slight miss, and fires instantly on cold mornings (low 20s) without being plugged in. Getting 16+ mpg in town and 19 at 70 on the highway.

 

[PKemp]

Vaughn: Okay, its very true that you could have a leaking seal but still have serviceable bearings, but not enough to put that much oil on the ground without either a mechanical failure due to oil starved or oil foamed bearings because of pressure by-pass into the oil return line, or even a runaway. But looking at your stats: 350k+, big injectors, at least a 215hp pump, big exhaust, and a manual transmission. No doubt the timming has been "moved". The urge to dust a rice burner in town or a f*rd on the highway has had to come up from time to time (sustained high egt's). What say about 50k a year since 1996? A working, daily driver with muscle! Power still good. But heat over time in a working trucks life will wear down the oil rings and bores and you did say that there appears to be a lot more constant "vapor" blow-by. Pressure in the oil gallery from a leaking head gasket could also be the cause true, which brings up a question... . Was replacing the headgasket awhile back just because of the desire for the ported head idea? Or because of too much boost? or was there another mechanical problem reason? Things can add up over time..... Is there any metal in the pan, on the drain plug magnet? Next time you change your oil filter, keep the old one, drain it and cut it in half with a band saw and closely examine the insides for gray metal or tiny "sparkly" flakes. All indications of excessive wear. Don't let this sit. Examine the turbo connections as well for excessive oil. Have you done an oil analysis lately? P. S. I hear new crate motors aren't that expensive anymore... .....

 

[JBrookshire]

I do not know???

I pulled the lower inercooler hose of the bottom tonight and it is pretty clean I checked the inlet of the turbo is is pretty clean to. I checkrd the fin for play and it dont have in or out every thing looks good I just put a BHAf filter 10,000 miles ago But there is no way to tell if the seals are bad????or is there??? I just wish I could defently know what is wrong with it before I start to throw parts at it. The head gasket was replaced because of some seapage, It was don bevore I owned the truck. So I am at a x road as what to do???? It would suck to tare the head off and it is the turbo and vise versa??Justin

 

[Vaughn MacKenzie]

PKemp the gasket was leaking coolant externally near cyl #1. I did mild porting sort of as "what the heck, I have the head off. " Thicker headgasket as suggested by PDR because head was decked . 010" and incase I decide to run a cam (ensure piston/valve clearance). Wish I woulda stayed stock.



There was a miniscule amount of metallic residue on the drain plug magnet after 6000 miles of towing on one drain, about the same as the previous changes. Will try separating the filter, and sending in a sample. I have a AFE cone filter, going to jerk that off as soon as I get a stock airbox. Bought the truck used at 350k. Mostly hiway miles but tire wear and clutch pedal wear seemed to say a lot of city miles too.



Just before the headgasket job I did a blowby flow-rate test at 2200 and 2800 RPM unloaded. Numbers were right on for a "new" engine, around 65 LPM. That was at 352k. I'll bet it's a lot higher now. All indications then were this thing had another 100k easy, now it's not looking like it.



Vaughn