somewhat urgent: valve/tappet/rocker cover pressurization + oil consumption

[Krazyistkarl]

Okay...I'm getting oil into my intercooler as well as some oil blowing out through my oil filler cap (has anyone on here personally vented their caps or valve covers? When I instal my oil catch can I'm thinking I will also route a line from the cap into the catch can) I've searched around online on various other forums and they say this screen is usually the cause, and this is the first and cheapest thing to check.
I believe the root of my issue to be caused by running a few different additives to clean the engine as well as some Engine Restore, all of which has now caused the valve cover screen/ filter to be plugged.

What I could not find on the other forums is If I will need to replace the valve cover gasket with a proper gasket, or can I use RTV gasket maker? (I think I can see a little bit squeezing out in a few spots) Should I do my valve stem seals while in there? Its not showing any symptoms of them leaking, but I figure if I'm under there anyway, might as well do them?

It looks as though the engine consumed about 500ml of oil in 500km or so, I always had some oil in the intercooler, but the oil level never really dropped a noticeable amount. The van doesn't exhibit any noticeable smoke.

[Big-Bird]

The valve cover of the 4M40 (aka 2.8TD) has a hose near the back that is supposed to be connected to the air filter box intake hose. The oil caps are not vented and if you have oils leaking past the gasket the metal tabs on the cap can be bent slightly to get a tighter fit. The gasket in the oil cap can become hard with heat/age so it won't seal properly. Thankfully this gasket can be found on lots of wrecker cars that have the MItsubishi 2.6 gas engine which is found in lots of Chrylser cars/vans from the late 80's and early 90's. The gasket can be purchased from your dodge dealer as well if you tell them you need a oil cap from a late 80's 2.6L gas powered Plymouth Voyager.

The valve cover gasket is only secured with 2 bolts and requires a good quality sealant that can handle diesel oil and high heat. Usually black RTV is best but you need to read the temp/resistance to chemicals data. The stock gasket can sometimes be reused but if its brittle, cracked, or spongy(swollen from exposure to a solvent) then you need to replace it and the 'half moon' chunk that sits at the back of the head.

Search this forum or even youtube on how to change the valve cover gasket on a 4M40. You might get something being done to a Pajero but the principals are identical.

I would not recommend venting your oil cap....use the stock valve cover breather hose when you install your oil catch can. Oddly enough I am getting ready to so the same install but can't decide on what brand from ebay to buy or if I should make my own out of white PCV.

A small amount if blow-by is normal given the age of these vehicles but if you are thinking of changing the valve seals you will need some way to keep the valves closed while you do this. Usually air pressure is the most effective but that means injecting air through the glow-plug holes.

500mls in 5000km is not that unusual and its probably being burned in the combustion cycle. Do you have any leaks at the valve cover or the turbo? hope this helps with your search/fixes.

[Krazyistkarl]

Thanks big Bird, very detailed!
I actually ended up finding that tid bit about being able to use older Plymouth (Mitsubishi) 2.6l oil caps. Brings me back to my Caravan days...
But back to the Delica.. I'll give bending the tabs a try for a tighter fit.
I assume the gasket has been changed when the timing chain was done, so I'm going to hope for the best and try and talked the job without ordering one *knocks on wood* one of the rubber bushings on top is cracked, could I use RTV for that? I'll give YouTube a search on the procedure. Since the only reason I was going to tackle the valve seals was really to justify having the gasket shipped halfway across Canada and opening up the VC anyway, but really, if it ain't broke don't fix it might be a more sensible option.
The van consumed 500ml in only 500km, not 5000! Yikes, it didn't seem to consume any before.
As far as catch cans go, we've got ProVent ones on some of the equipment at work, I'm trying to see if I can absorb one that's been damaged lightly that I can fix, other wise I may go the PVC route as well, or for a bit fancier look, a stainless steel flask and some copper pipes and 90's soldered on

I think I've seen you mention on here about having tech nights in Calgary? Maybe I'll have to make a trip out from Saskatoon one of these days and learn a thing or two from you.

[Big-Bird]

I thought I read 5000km......500ml in 500km is a problem.

If it was my ride any leaks would be checked, fixed if needed.
Leaky VC gaskets are common and if the leak is bad enough you could lose enough oil to add up to your estimate. Is the back of the motor/tranny bell housing wet?

As for the top grommets, these do get small cracks, generally very little oil will ever exit here, i have never had to seal these personally. Valve seals are a plausible concern as are the piston rings.

Used to own a 1981 Dodge challenger with the Mitsu 2.6L power plant and its surprising how similar the 2.5TD, 2.8TD and 2.6Gas engine are alike.

[Krazyistkarl]

No other leaks other then oil from the filler cap, the gromets don't leak at all, im just worried they might break apart when I pull the VC is all.
No smoke at start up, or anytime.
The intake side of the turbo has oil in it from my breather tube, I've taken it out of the airbox and wraped it in a sponge for now, see if this makes a difference. The intercooler and piping also coated in oil inside.
I put a bottle of engine restore through, and seemed to notice a bit of a power increase, but maybe it was more of a placebo affect then anything. It claims to help piston rings seal better. I have yet to do a compression test or leak down test as I dont have a diesel compression tester

[Krazyistkarl]

So a little update, I opened the valve cover and cleaned it as best I could without drilling out the rivets, cleaned it with brakeclean, solvent, hot water and compressed air until it was coming out clean. Put it back all back together and I'm still getting a lot of oil vapor coming out the breather. I'll try again, next time I'll drill out the rivets so I can actually see the screens, then I figure I'll JB weld it back together.

And also to answer a few questions I'd asked, the gasket can be reused (this wont always be the case, but I knew it has been changed when it came into Canada), black gasket maker should be used on either end on the crankshaft half moon, and the valve cover bolts are torqued to 3ft/lb

[Big-Bird]

Been thinking out your excessive oil usage and poked around the valve seal in the schematics. They can get hard/crack/break off and that would allow pressure from.the cylinder to blow into the head and mist up oil. It would also allow oil to leak into the cylinder...if its bad enough the oil can act like fuel and create a run-away condition....very bad!

If you have bad valve seals then you're gonna need a valve spring compressor that works with an in position head. Then you need an air adaptor to put air pressure into the cylnder to keep the valves up/closed. Then you can change the seals and reinstall everything.

My Montero buddy just did it with 3.5L and it was striaght forward.

[Krazyistkarl]

I've been researching it more as well. I've found some generalized TDI info (not necessarily specific to the 4M40) saying that because of the lack of intake vacuum on a diesel, worn valve stem seals don't play a very large part in oil consumption.

Take this info with a grain of salt, I pulled it from a random source online
"Here is the thing that most people seem to misunderstand about a turbo'd engine. There is no oil sucked into the engine from valves. There is constant pressure that goes through the intake and exhaust valves into the crankcase. That means BLOW-BY. That can cause a lot of oil consumption by pushing oil into the intake manifold by way of the crankcase vent (CCV)"

On other forums it's well documented these engines suffer from a lot of crankcase pressure.

When I pull the valve cover off again I'll pour some seal softener around each valve, hopefully some will make it to the valve steam seals, might help a bit?