1990-1996 Infiniti Q45 (VH45DE) oil catch can

[Infinitiguy19]

I see that many F50 Q45 (VK45DE) owners have oil catch cans on there cars. I was wondering if a oil catch can would yield any benefits on the 1990-1996 Q45 (VH45DE)?

I was hoping it would keep oil out of the plenum....

Mounting the catch can may also present another problem.

[elwesso]

i never really understood what the point of a catch-can was..

seems like taking the plenum off every 60-100k miles is easier than messing with that.

[Infinitiguy19]

Well the point of cleaning is to get back to as new performance. So by installing a device that routes the oil into a can where it can be emptied or back into the oil pan some time is saved.

I sure as hell do know Infiniti is not perfect from the mistakes I see in the service manual. TCS is spelled TSC on certain pages for one.

[Q45tech]

Depends on the oil consumption level. Obviously the VH design had tighter and longer lasting rings .

The PCV valve design is MATCHED to the oem system. Increasing backpressure via a catch can probably means a valve design change will be required [or not]............maybe just larger inside diameter in hoses feeding can and plenum?

All these thing can be measured with a high sensitivity manometer [< 30" water column should resolve 1.0" water column =~ 1/27.7 of a single psi.

The problem is the plenum [vacuum or lower than atmospheric pressure] can go from 8.8 psi [idle and cruise] to 14.0 psi {WOT}...............getting an accurate reading can suck the diaphram out of an accurate mechanical manometer.

The easiest thing to do is stop [lower] the oil vaporization in the first place with high quality oils of full synthetics.Make sure the oil never exceeds 210F in sump.

An intersting test is to drill a tiny hole in a spare oil filler cap install a tiny metal tube and measure the positive pressure inside the valve cover under all engine [driving] conditions. Again accurate test equipment is required.

Where does the pressure come from = the ring blowby during power stroke and backpressure from pcv system.

[subtle_driver]

if you have un-perfect piston rings/ less than ideal compression, or a forced induction system, its not a bad idea to have a catch can. But if the engine is in near perfect shape, the oil that makes it up there, in my mind, helps upper cylinder lubrication. too much blowby is bad, and too much crankcase pressure is bad too; can cause seals to blow out.

My engine isn't perfect. So I'm planning on installing one in the future. I also have one on my other turbo project cars, it keeps the oil out of the intercooler.

[qship96]

If owners would check to see that the factory installed brush is still inserted in the pcv hose, much oily plenum problems could be avoided.Many unknowing owners{and mechanics} have removed the brush, thinking someone left it there by "accident", or replaced the hose with generic hose that does not include the brush.

In 246,000 miles, I have never needed to clean the plenum, and seriously doubt it was cleaned while at T3 for its first plenum job at 203K a couple years ago, but the car has only seen full {real} synthetic oil since brand new.

[qsiguy]

I installed a homemade catch can but after testing and installing it I realize that that particular tube will almost always be pulling air from the intake tube, not feeding it. Non forced induction the only time you might have vapors entering the intake from this tube would be at WOT. I had to disconnect that line from the intake because under boost I was pressurizing my crankcase and once popped out the dipstick followed by an oil geyser. Here's a couple photos but it's never had even a drop of oil enter it.

I have used catch cans on other vehicles and the oil accumulated you would NOT want to dump back into the crankcase. It's typically nasty stuff.

[Infinitiguy19]

If owners would check to see that the factory installed brush is still inserted in the pcv hose, much oily plenum problems could be avoided.Many unknowing owners{and mechanics} have removed the brush, thinking someone left it there by "accident", or replaced the hose with generic hose that does not include the brush.

In 246,000 miles, I have never needed to clean the plenum, and seriously doubt it was cleaned while at T3 for its first plenum job at 203K a couple years ago, but the car has only seen full {real} synthetic oil since brand new.

So your plenum is pretty much spotless with a gold tint like the one shown by Unknown007?

If so then this topic was a failed idea.

How does Mobil one 0W-30 look as a synthetic?

[qship96]

0w-40 is Mobils absolute BEST oil, unlike many of the other grades they offer, 0w-40 is a true group 4 pao based oil.....the others are group 3 "fake" synthetic....they do not need to disclose this in the USA ONLY.....check their msds sheets for every other country where they must disclose it and it becomes very obvious.

I have nott looked inside my plenum in a few years, but last time I looked it was ok- I dont see the need to look for problems, car idles perfect and no drivability issues whatsoever.......probably helps that car has seen frequent oil changes since brand new with real, full synthetic oils that have very low evaporation{boil off} rates-{ 6% with Redline 5w-30 or 10w-30}

[Infinitiguy19]

Well my next oil change will cost me then. I was thinking about doing 2 BG Quick cleans with cheap oil and filters, then I will use the Mobil one 0W-40. and prey my parents don't find out.

So Mobil one 0W-30 is a mixed synthetic?

I think I still have a spare hose with that brush or I might have sold it to Unknown007, Which SUCK!!!

[qship96]

Skip the BG crap and go straight to a quality filter{ mobil 1 or Pure One #24457} and 6 qt of 0w-40. Nothing wrong with M1 in 0w-30/5w-30/10w-30, but for the same coin, the 0w-40 is a superior oil.

[Infinitiguy19]

The reason for the BG Quick Clean is to cure the HLA tick at startup. Would Mobil on 0W-40 cure it alone?