oil belch
Moderator: Fatmobile
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fujiapple402
- Glow Plug
- Posts: 2
- Joined: Wed Jul 07, 2010 2:56 pm
oil belch
Well heres my dilema. 82 NA diesel rebuilt injection pump, valve cover gasket, glow plugs and recently its been building pressure and blowing the oil filler cap off causing oil to purge out of it. Any ideas what would cause this? to bandaide this situation i put a breather on the tube that runs from the valve cover to the intake and now it just slowly blows oil out the breather i put on every once in awhile. I'm wondering if this is a head gasket issue or what. I was told that it was recently rebuilt when i bought it. when it starts in the morning it blows lots of blue smoke (I'm assuming from the breather tube i put on) then kinda white but after its warmed up it runs completely fine except for the oil coming out of the breather. I also have to cycle the glow plugs 3 times for it to start well when its cold. I don't believe its rings cause it runs pretty well and my mechanic said when he had the oil pan off it looked really clean inside. also this problem just started happening after the new pump. I drove it 6 hours home from where i bought it and had no problems, this was only months ago Its now also starting to heat up but not over heat. I also tried spraying some brake clean into those valves that are on the intake where the hose from the valve cover runs. this seemed to help for a while but then would later belch oil again. Any help would be really really appreciated!
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rsxsr
You are describing excessive blow by. Excessive blow by can usually be traced to poor ring seal. Most likely the rings have lost their temper. Glowing the glowplugs a 2nd and 3rd time could be disguising low compression related to the rings as well.
That said, the crankcase pressure should be coming out the hose in the valve cover that is plumbed to the intake. For the cap to "blow" off, something has really failed including the cap. It should be a twist and positive lock similar to a conventional gas cap or radiator cap on an american car. The oil cap seals will harden and maybe with vibration allow the cap to "untwist", but I have never seen that. Also with that much blow by, if you try and stop it, it will blow the oil seals out. I would recommend removing the valve cover and really clean the breather part of it. Next, I would run the breather hose from the valve cover into a used oil bottle with some holes in the top of it. See how much oil you collect. If enough oil is getting into the intake because of excessive blowby the engine could "run away" which is indeed very scary.
Bottom line, you need to do a compression test and then a leak down test. That should give you a decent indication of the ring seal. Also, you should check the draw on your glow plugs. It is possible some are burnt out and that is the reason for the extra glow cycle.
That said, the crankcase pressure should be coming out the hose in the valve cover that is plumbed to the intake. For the cap to "blow" off, something has really failed including the cap. It should be a twist and positive lock similar to a conventional gas cap or radiator cap on an american car. The oil cap seals will harden and maybe with vibration allow the cap to "untwist", but I have never seen that. Also with that much blow by, if you try and stop it, it will blow the oil seals out. I would recommend removing the valve cover and really clean the breather part of it. Next, I would run the breather hose from the valve cover into a used oil bottle with some holes in the top of it. See how much oil you collect. If enough oil is getting into the intake because of excessive blowby the engine could "run away" which is indeed very scary.
Bottom line, you need to do a compression test and then a leak down test. That should give you a decent indication of the ring seal. Also, you should check the draw on your glow plugs. It is possible some are burnt out and that is the reason for the extra glow cycle.
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Fatmobile
- Global Moderator
- Posts: 7564
- Joined: Wed Oct 30, 2002 10:28 pm
- Location: north central Iowa
Re: oil belch
What valves on the intake?fujiapple402 wrote: I also tried spraying some brake clean into those valves that are on the intake where the hose from the valve cover runs. this seemed to help for a while but then would later belch oil again. Any help would be really really appreciated!
Does a vanagon have the restrictors on the intake like the MK2?
Also make sure the vacuum pump is connected,
any vacuum leaks will be pumped into the crank case.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
oil eater
My '83 diesel vanagon does the same thing. I am suspecting blowby as well. I believe the "valves" being described on the intake are the small holes where the valve cover breather hose attaches to. My question is, is a re-ring fairly straight forward? Seems to me that timing the thing is the biggest challenge.
'83 diesel vanagon
'85 diesel Jetta
'86 diesel Golf
'85 diesel Jetta
'86 diesel Golf
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rsxsr
Re-ringing is considered a "field" fix. It can be successful, but may not. For the rings to seal, the cylinder walls need to be as straight as possible. Using a stone hone to straighten the cylinder walls and restore the cross hatch, neccessary for the rings to seat and to control oil. The down side of the stone hone, is you may end up honing too much to straighten the walls opening the bore beyond spec.
The other option is to use a dingle berry hone. These will not straighten a worn cylinder wall, but if the wear is minimal, you can put a nice cross hatch in for the new rings. In both cases, the proper way to do this would be with the engine completely disassembled. That said, if you are extremely clean, you can do this with the engine installed and the pan and cylinder head removed. Wrap the rod journals with masking tape to keep the pumous from honing out of the oil holes. Once you have the walls honed, you need to wash the cylinders and the inside of the block with soap and water. You need to have all the pumous gone. You should be able to run a clean rag against the cylinder bore and have "no" residue.
Since you have the rods and pistons out, you could also replace the rod bearings. So this is quite a big job requiring some special tools including reseting the pump and cam timing.
The other option is to use a dingle berry hone. These will not straighten a worn cylinder wall, but if the wear is minimal, you can put a nice cross hatch in for the new rings. In both cases, the proper way to do this would be with the engine completely disassembled. That said, if you are extremely clean, you can do this with the engine installed and the pan and cylinder head removed. Wrap the rod journals with masking tape to keep the pumous from honing out of the oil holes. Once you have the walls honed, you need to wash the cylinders and the inside of the block with soap and water. You need to have all the pumous gone. You should be able to run a clean rag against the cylinder bore and have "no" residue.
Since you have the rods and pistons out, you could also replace the rod bearings. So this is quite a big job requiring some special tools including reseting the pump and cam timing.