03-07-2012 10:59 AM
Last time I face same problem in marine engine. In my case engine throw oil and dip stick.
I found piston compression was leaking in to sump due to bad piston rings.
02-16-2012 02:17 AM
as you mentioned that due to crankcase presssure, there is possibility of oil seal damaged.
actually i detected this oil seal failure in an industrial engine 2000KVA.
during seal rubing unusual vibration detected and lube oil consumption also increased.
what are the reason for this crankcase pressure in industrial engines?
other reasons for seal damage?
03-04-2011 04:08 PM
Engines have natural crankcase pressure possibilities due to compression leakage through the compression ring gaps on each piston. Turbo-charged engines have increased crankcase pressure possibilities due to the additional boost pressure the turbo creates in the combustion chamber. Proper venting of crankcase pressure is essential and is usually done by a crankcase breather tube usually found in the valve cover or the side of the engine block. Excessive crankcase pressure is usually caused by 1 of 2 things
1. Crankcase breather restriction (kinked vent hose, build-up of contaminants inside hose, hose end being trapped in mud or dirt, etc.)
2. Leakage of compression during the compression stroke of one or more of the cylinders in the engine. I usually find severely worn piston rings and liners on engines that wont start easily or dont have power sufficient to run a heavily rated load. I also have found one or more broken fire rings on engines that will start and run good, but have severe crankcase pressure and sometimes they pick up engine oil and leak copious amounts of it out of the breather tube. This is usually caused by excessive use of starting fluid. Leakge through worn valve seats can also cause excessive pressure.
I've never seen a turbo charger cause this problem. Failed turbos usually cause oil consumption or loss of power. Seal failure in the compressor side of the turbo will allow oil under pressure to be distributed into the compressor housing and transfered to the combustion chamber causing the blue smoke you see when the engine is combusting that oil. Failure of the seal on the exhaust side of the turbo causes the pressurized oil to leak into the exhaust side, usually burning it but excessive oil will actually blow out of the stack and also show oil at the exhaust connections.
I hope this helps.
02-26-2011 10:26 PM
Nice info, I'm not from a trucking background, so this is great info for the OP.
That being said, how can CAT, their dealers and sub-dealers allow ANY engine to operate in a condition that blowing off the oil fill cap is considered "normal"? Maybe living in California skews my outlook a bit, but can't quite come to agree this could be ok somehow, guess I'm showing my age.
A Kudo for you!
02-24-2011 06:09 PM
The Acert Engine created more crankcase pressure than previous engines. The oil fill cap blowing off was a common problem. If the oil fill tube is smooth on the inside, the cap would slide out. The fix was to run a tap down inside to cut threads in the tube so the cap had something to grip. Oil out the breather was also another problem with the Acert Engine. The previous design could not handle the extra vapor. A oil mist separator was available for the C15 to reduce oil out the breather but was never used on the C13. Check the breather to make sure it has not come apart, some did. Also make sure the dipstick is calibrated properly. The oil level on the C13 was reduced by 2 quarts, deep sump was originally 42 qts, now 40 qts. Shallow sump was originally 36 qts, now 34 qts. Be careful if oil level is lowered, some chassis manufactures monitor oil level. Other area's that can cause excess crankcase pressure is the air compressor or stuck rings on the pistons, would need to isolate air compressor and measure blowby with a meter. Your local Cat dealer should be able to put in a service request.
02-20-2011 11:16 PM
About the only way I can figure a turbo can cause excessive crankcase pressure is if the compressor seal is damaged and boost pressure is somehow getting down the oil drain back to the sump. I'd think if the compressor seal was that bad there would other issues like high oil consumption and low power, black smoke, etc.
02-20-2011 04:36 PM
Its not dumping oil on the ground other than a drop every now and again. From what I know, both times its been down to the CAT facility, they have replaced one of the turbos, but for some reason left that clamp on the oil fill, which I thought was weird. I will take your suggestion and present it to our shop. Thank you for the information.
02-20-2011 04:15 PM
I'm not a C13 expert, but have been around CAT engines over 30 years. First, you have serious engine problem that is not properly resolved may result ina catastrophic engine failure. Not a great possibility for a piece of emergency service equipment.
Putting a clamp on the oil filler cap to prevent it blowing off is nearly one of the most ignorant things I have heard, the oil fill location is at least venting the excess pressure. If you're launching the dipstick then you've also likely blown the rear and front oil seals, how big of a mess does this truck leave in your garage and/or on a site? Just from an environmental liability issue this is dumb, not to mention what if critical piece of equipment dies on the way to a call because someone jury rigged a repair?
Are you using a CAT dealer or a truck engine dealer? Time to ask whoever it is to get the CAT Factory Rep involved. If where ever it's getting worked on has a CAT sign out front and says they are an authorized dealer, then they access to a rep, or you can call 1-800-CALLCAT or go to the website and let them know you have a safety concern about a CAT engine powered piece of safety equipment.
Good luck, Mike L.
02-16-2011 11:10 PM
Trying to find some info on this forum. I'm an apparatus operator for a local government fire department in California. My apparatus is a 2006 Tractor drawn tiller ladder truck with the Cat C13 motor. For some time, it has been having issues with what I've been told is the crankcase being pressurized. It started with the oil fill cap blowing off while driving. Our shop put a clamp over the oil fill cap so it wouldn't keep blowing off, and now whenever the truck is run, the oil dipstick is ejected.
It has been in for service twice in the past 2 months for this issue, and both times the local Cat repair facility has said it was one of the turbos, and did something to fix them (our shop hasn't been clear to me what the repair facility did). But after twice in the shop concentrating on the turbos, the dipstick is still blowing out.
I'm not a mechanic, but is there any other ideas that any of you Cat experts can come up with so I can maybe lead our fleet maintenance facility in another direction?
Thank you very much for the information.