I thought I'd change the oil while the blower was out to replace the return heater hose on a 2001 XJR. From other posts it looks like the unit holds approximately 7 ounces while mine held exactly 4 ounces. I noticed a lot of carbon buildup on the lobes when pulling the outlet plenum and wondered where it came from - thinking it was the gear oil leaking past a seal? Can anyone tell me if this amount of oil use is a problem on a 70k mile engine? I'm assuming a sealed-for-life unit should not be losing oil. If so are these units rebuild-able? Thanks for any feedback.

I also noticed a lot of debate about setting oil levels, so here's a side view of the unit sitting on a level table. The bottom of the case is parallel to the top - what appears to be an angled bottom is reinforcing bosses cast into the case.

 

I believe you have an Eaton M112 Gen lV SC in your XJR model.

Those lobes are supposed to have an ablative type coating usually black in color.

It is somewhat unlikely that you have oil from the SC bearings at the front, or rear, leaking into the chamber.

Oily carbon on the lobes or the outside exposed SC is more than likely caused by venting from the sump. This can be considerable with SC cars which is why I have an oil catch can.

There is often almost total blockage of the charge cooler matrixes as a result of this carbon so it is well worth cleaning them while you have access to them by soaking in appropriate chemicals.

I often smile when I see people doing all sorts of mods to decrease air intake temps for XJRs and totally neglect cleaning of the SC charge coolers.

Lots of argument about how much the EGR contributes.

Do you get any "play" when you rotate the pulley?

Did you get any "rattling" when you were running the SC?

Bottom line is there are several companies that rebuild these units.

I had mine done by PSE Superchargers, OK.

They added a 10% pulley and did some porting. Mine being a GEN V gains little from porting unlike yours.

The rear bearings they used did not hold up! So I had to take the SC off and ship it back to them where they redid the rear bearings under warranty.

I have since replaced those same bearings myself, because of my screwup, and they are easy to do with a press.

 

Thanks for the info. The unit was running fine and everything's quiet and tight with little or no play - the only concern is the depleted oil level. If that's not a major problem I'll plan to refill the unit and just check the level occasionally. Question regarding the intercoolers - can they be cleaned in place or do they need to be removed? Also any recommendation as to the best cleaner would be appreciated.

 

If the oil level is truly depleted then that is of concern. How did you drain the oil?

Do the lobes rotate without any hint of clashing?

It is possible for oil to leak out from the nose to SC main body seal if that is not good. That would leak to the outside under the SC body.

The charge coolers really need to be taken off as you need to soak them for at least 24 hours.

I used two tubs of something I found at Walmart and I forget the name. It was very dark brown in color.

After the soaking I used carb cleaner liberally to rinse the cooler out.

My throttle body was heavily carboned up as well at 103,000 miles.

The carbon is softer than what you get inside combustion chamber.

 

The blowers that comes stock on the x308's do not have a teflon coating, that only came on the later 4.2 engines. My guess is the part load breather is clogged causing excess oil buildup in the intake and respectively the blower.

It can be tricky to get all the old blower oil out, they generally don't lose oil as the oiled part is sealed. The blowers are rebuildable, pretty much everything can be done on your own, except for the rotor pack bearings. If there's no play in the rotors and they're not colliding you're probably OK. If the blower itself is leaking oil, I'd guess it'd be the snout leaking, and you can open that up and reseal it if there's a suspect leak there (as well as to be sure you got all the old oil out, and inspect the gears, and so on).

 

That looks like EGR deposits, I've used brake cleaner on the intercoolers, but any quality engine cleaner will lift off the gunk. Did you use the syringe and fine tube technique to empty the old oil as this can be fiddly to get all out.
Of course these can be reconditioned but shouldn't be require it at 70K, you can do most of the stuff on the bench. If there's little to no backlash on the pulley a cleanup should be all that's needed. Look up EGR delete to keep it cleaner inside the induction tract.

 

Since the blower's off the engine I drained the oil by tipping the unit. It did take repeated attempts to empty - reminded me of trying to empty a torque converter with no drain plug. I'll continue to attempt to drain - it's hard to know how to orient the unit without knowing how the internals are configured. Hopefully we'll manage a few more ounces and my disappearing oil problem will be solved. There's no external evidence of leakage.

My throttle body was fairly clean but I did notice a lot of carbon buildup in the EGR valve and replaced that. Once I figure out where the part load breather is I'll check that for buildup as well. Everything else feels and sounds happy -
no backlash or noises - so hopefully some fresh oil and new gaskets and we'll be all set. All of this for a new heater hose! Many thanks for the input.

 

your carbon build-up looks the same as mine did. I doubt you have a oil leak and would not recommend you rebuild any part of it at 70K miles. Just add new oil until full and re-install. Be carful of the bi-pass hoses on re-install as it is easy to end up with an air leak that is not visible.
There is excellent advice on the forum to slot the rear the bolt hole at the rear of the supercharger and install the bolt before re-installing the supercharger. I learned the hard way and recommend you do this

 

Also, highly recommend that you change both knock sensors while you have the supercharger off. I had to pull mine off again 2 years after changing the hoses to change the sensors.

 

Appreciate the tip on the knock sensors - I have a new one from an earlier code that ended up being a broken wire in the harness - will pick up another and install them now. I'm assuming the slotted rear hole is to prevent losing the bolt in the intake on reassembly? I'm fortunate to have the motor out on a table doing this work so access to everything - including those bypass hoses - is a breeze.

 

Slotting for the bolt is to ease installation of the SC with the bolt in place, not tightened down.

Then you can "slide" the SC back into place without having to fiddle to insert the bolt.

I had no trouble with that bolt on my X350.
I use paper towels to cover orifices when doing work to prevent accidental bolt/nuts being dropped where you do not want them.

However. The screw up I mentioned earlier is because I did not see a rolled up paper towel in the elbow below the throttle body. It was pushed in to far.

After reassembly on starting the engine there was a dull thudding noise as that paper towel was sucked into the SC and it jammed it solid.

It actually ruined my new back bearings.

It did not damage the impellers/lobes at all.

I had to take the SC off for a 3rd time to press in new rear bearings.

At least I was becoming an expert on SC removal and installation.

 

Oil catch can.

I was asked a about my oil catch can so am posting pics.

2 pics of the "corvette" style oil catch can on my X350 low load breather and one on the high load breather RHS of engine.

Also a pic of the elbow under my throttle body when I first took off my SC at about 103,000 miles. This along with the charge coolers being really clogged up is why I installed the oil catch cans.

The low load side hardly collects any oil. Not so on the high load side which starts at the mushroom and leads around the side of the SC into the elbow under the throttle body.

I am not familiar with the X308 setup. Looking on Ebay it seems as if you do not have a high load breather?

I am sure someone will chime in who knows more than me.

The silver insulation you see is wrapped around my stage 1 intake and it keeps that whole duct much cooler. Dose not look "pretty" but highly functional.

 

Hi jackra_1,

thank you very much for your detailed info on the oil catch cans.

The setup for the x308 is similar to the x350s. There's a part load breather, which is routed from the left cam cover to the intake elbow and ends up in the Evap canister purge valve. It does not only return the crankcase vapors into the intake air manifold, but (if EVAP valve opened) fuel vapors too.

Finally there's a full load breather hose from the right cam cover directly into the intake air tube.

So I'll have a deeper look into where to get an appropriate oil catch can here in Germany, since I have a better idea on how you did the installation.

Cheers, Alexander

 

When looking at oil catch cans go for one with internal baffles apparently they are more effective.

Mine has internal baffles and it also had an optional "filter" on top to the open air of all things. That I threw away and have a brass screw on cap in its place.

Finding room for the CC was a bit of a challenge.

Now I am seriously considering water/meth injection and finding room for the kit is the challenge. This mostly to keep things clean as opposed to performance.