Reddish Varnish Inside Valve Covers and FrontCover

[BaReinhard]

couldn't tell you, it was a random picture taken off this site. I used it primarily for an example. However, to me it looks like a japanese dohc engine to me. I would have guessed ka24de, but its been a while since I've seen the inside of one of those.

 

[OVERKILL]

Originally Posted By: BaReinhard
Just so I can clear up the theory portion of your post am I reading this correctly?

As the engine partially combusts fuel, liquid nitrated and oxygenated monomers will form in the oil. With the monomers present in the oil and exposed to heat they will turn to varnish then eventually sludge if left untreated. In addition, if the monomers are exposed to carbon/water/solids they will turn to sludge without needing to turn to varnish.


Basically. You have combustion byproducts that are picked up by the oil as well as the oil breaking down itself due to exposure to areas like the ring lands, where heat is intense. There is only so much room in the oil for these contaminants before they start to fall out of suspension and plate surfaces where oil flow is low, such as the lifter valley, rockers, tops of the heads....etc. Once you hit this tipping point, cleaning this back up, after the deposits have formed, is difficult, as per what Shannow noted, this stuff is polar and it wants to stick. On top of that, it wants to stick to itself, so you do this a number of times and you get built-up layers of this garbage, which in turn changes its colour. The more that has plated, the darker it gets. When it gets REALLY thick it will look black, but it hits a deep red hue first, which is what your equipment exhibits. Also, keep in mind carbon will tint it. If you have an engine with a lot of blowby, it can tint the varnish darker than an engine that doesn't, even at the same thickness. So your earlier observations about black deposits, if that was an older 80's mill with poor crankcase ventilation control and a fair bit of blowby, it is quite possible that the varnish levels you are seeing here are just as bad, they simply lack the carbon tinting to make them appear black. Food for thought.

Regarding sludge, the way I read the diagram is that varnish + carbon/moisture/solids creates sludge. You need that resin to bring it all together to create the sludge, but you also need the other three components. I think this is most clearly articulated in the bottom part of the diagram, whereas the upper triangle part might be a bit more confusing.

 

[OVERKILL]

Originally Posted By: Bottom_Feeder
Originally Posted By: OVERKILL
I think you and I have different opinions on what constitutes "filthy"

Regarding varnish, barring sludge, I would say this engine meets the definition of filthy.

Indeed we do but I respect what you're saying.

 

[Garak]

Or, you just get an Audi from the 1990s with a turbocharger and poor oil choices, and you simply wind up with coking all over the bloody place.

 

[OVERKILL]

Originally Posted By: Garak
Or, you just get an Audi from the 1990s with a turbocharger and poor oil choices, and you simply wind up with coking all over the bloody place.


Yeah, that's another way to get there too, LOL!

 

[SonofJoe]

I have to confess I had to look up on Wikipedia what AFM (Active Fuel Management) and DOD (Displacement On Demand) were. Sorry, we don't have many of these big V8's here in England.

However once I realised what they were, I started to wonder if such systems might have specific problems with engine oil. I did wonder whether trapped pockets of what is essentially exhaust gas, being constantly compressed and expanded might gradually overheat (a fired cylinder will be tempoarily hotter but is constantly chilled by every new influx of cold air and fuel). I also wondered whether the piston rings in a deactivated cylinder might not behave as they should. Top rings especially need the pressure generated by combustion to splay the ring and create a tight seal. No bang and maybe there's a gap for oil to leak into the trapped gas?

So I Googled around and I stumbled on this...

http://parts.olathetoyota.com/blog/4920/gmc-chevy-afm-oil-consumption

I am now thinking that what we're seeing in this engine isn't tradition varnish but burnt engine oil that has been 'captured' by the engine oil but has progressively dropped out of solution as the oil's solvency reserve has been depleted.

It's partly the red colour of the deposits and it's uniformity of deposition that makes me think this might be right. Generally tradional varnish is yellow to brown and tradition sludge very dark brown to black. This stuff definitely has a reddish quality to it. It sort of reminded me of this YouTube video of some bloke fixing a Toyota engine that had been burning oil.

https://youtu.be/7Ef2hYmcZzA

The piston skirt deposits also have a reddish tinge.

I might be way off but I'd put my money on burnt engine oil as the root cause...

 

[OVERKILL]

FWIW, I've had the red colour before, this was the BMW we had for a while. High mileage, probably run on a non-LL-01 lube at OLM intervals:

 

[SonofJoe]

Didn't BMWs have a bad reputation for consuming oil at one time (along with Subarus and Audis)?

 

[OVERKILL]

Originally Posted By: SonofJoe
Didn't BMWs have a bad reputation for consuming oil at one time (along with Subarus and Audis)?


This one had no discernible consumption (surprisingly). Some of the M-cars did, but this was a 328i.

 

[dave1251]

Originally Posted By: SonofJoe
I have to confess I had to look up on Wikipedia what AFM (Active Fuel Management) and DOD (Displacement On Demand) were. Sorry, we don't have many of these big V8's here in England.

However once I realised what they were, I started to wonder if such systems might have specific problems with engine oil. I did wonder whether trapped pockets of what is essentially exhaust gas, being constantly compressed and expanded might gradually overheat (a fired cylinder will be tempoarily hotter but is constantly chilled by every new influx of cold air and fuel). I also wondered whether the piston rings in a deactivated cylinder might not behave as they should. Top rings especially need the pressure generated by combustion to splay the ring and create a tight seal. No bang and maybe there's a gap for oil to leak into the trapped gas?

So I Googled around and I stumbled on this...

http://parts.olathetoyota.com/blog/4920/gmc-chevy-afm-oil-consumption

I am now thinking that what we're seeing in this engine isn't tradition varnish but burnt engine oil that has been 'captured' by the engine oil but has progressively dropped out of solution as the oil's solvency reserve has been depleted.

It's partly the red colour of the deposits and it's uniformity of deposition that makes me think this might be right. Generally tradional varnish is yellow to brown and tradition sludge very dark brown to black. This stuff definitely has a reddish quality to it. It sort of reminded me of this YouTube video of some bloke fixing a Toyota engine that had been burning oil.

https://youtu.be/7Ef2hYmcZzA

The piston skirt deposits also have a reddish tinge.

I might be way off but I'd put my money on burnt engine oil as the root cause...


Chrysler developed this technology with GM and it was introduced in the HEMI over a decade ago. There are far less reported issues with Chrysler's MDS compared to GM's AFM.

 

[SonofJoe]

I was thinking a bit more on this red deposit thing and I found this 'red oil' BITOG post from 2004.

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=99409

There were a couple of points in this thread that reminded me of something I'd long forgotten about.

Now engine oils and engine oil additives tend not to be red in colour. Base oils are straw coloured or nowerdays more usually water white. ZDDPs & phenolic AOs are yellow. Detergents & Ashless dispersants are dark brown. Molys are usually black. Di-Phenyl Amines AOs can be very pale pinkish but definitely not red.

However back in probably 1997, when I was first getting into engine oil formulation, someone gave me a sample of an Oronite (Chevron's oil additive arm) DI pack. I can't remember the exact product code but it was something like OLA 4616. It was a deep red wine colour and if you made engine oils from it, the oil itself was a pinkish-red colour. If you read the old BITOG thread, it seems Chevron have form for making red oils (one of their employees rang up Chevron's head office to check if the oil was contaminated).

Being a bit thick back then, I didn't have the first clue as to why it was red but as I recall the cause was judged by my peers to be due to a combination of Moly and Phenate. Again there's a post in the 2004 thread that blamed Moly so maybe this is significant. I'm no chemist but if you're looking into issues of colour, generally you look for two things; the presence of nitogen and aromaticity (azo-dyestuffs are well known for their optical activity). Well Moly-Dithio Carbamates contain nitrogen (it's the 'am' in carbAMate) and Calcium Phenate contain aromatic rings (that the 'phen' bit). I'm wondering if you get Moly & Phenates complexing in the oil, maybe this imparts colour?

The OLA DI sample was a one-off thing. It was the only time I ever saw a red DI pack. However these are very common additives so such things could still be happening out there. It could possibly be that the fresh oils aren't red but if you chew the oil up a bit, maybe then you have suitable conditions for a Moly/Phenate interaction?

This is all speculation on my part. If there are any old Oronite formulators reading this, maybe you would care to comment?

 

[Shannow]

turbine oils have nearly nothing in them, and the varnish through the machine ranges from a nearly un-noticeable yellow, through to red/mahogany, and it's not long after that you start to get black deposits and sludge.

It's an eery sort of light when you have got your head inside a box with a torch, and there's sort of a candy coated effect on the walls and components, regardless of colour.

 

[SonofJoe]

It's funny but I'm come across strange 'red' problems in the past.

My old oil refinery started up it's Visbreaker unit (a very simple residual oil thermal cracker) in 1979. From the get-go, the Visbroken diesel stream, instead of being a nice straw colour was deep ruby red. Nothing like this had ever shown up in the R&D development work and it caught everyone by surprise.

It wasn't that funny either. Here in the UK, highly taxed road diesel is clear while low tax agricultural diesel is purposely dyed red. If the taxman caught you with red diesel in your tank on the road, even if it was all properly taxed, his first assumption was that you were a tax cheat!

The problem was traced to some strange aromatic nitrogen species that was bring formed in relatively tiny amounts which was 'dyeing' the entire diesel production stream. We quickly made the problem go away by cranking up the hydrotreater temperature way beyond what it needed to be.

It's interesting how in three very different oil applications; diesel fuel, turbine oils and engine oil deposits, when colour is a factor, it invariably comes in 'red'...

 

[Shannow]

When we started having our varnish problems (industry switched from GrI to GrII and didn't tell us), I had a really bright undergrad in my team.

We sponsored his thesis on membrane patch colorimetry for testing varnish actual (rather than the potential that RBOT and RULER were supposed to measure, and were hopeless at...oxidation life remaining wasn't an indicator of varnish).

and Yep, red is the change looked for...was RGB, but red was where the action was.

https://wearcheck.com/virtual_directories/Literature/WearCheck/WC-MPC.pdf

BTW, it wasn't an ASTM test at that stage, it was still being standardised...we proved that a mid range flat bed scanner, with a high end calibration sheet would allow you to trend well with varnish production.

 

[Silk]

Originally Posted By: SonofJoe
reminded me of something I'd long forgotten about.

However back in probably 1997, when I was first getting into engine oil formulation, someone gave me a sample of an Oronite (Chevron's oil additive arm) DI pack. I can't remember the exact product code but it was something like OLA 4616. It was a deep red wine colour and if you made engine oils from it, the oil itself was a pinkish-red colour. If you read the old BITOG thread, it seems Chevron have form for making red oils (one of their employees rang up Chevron's head office to check if the oil was contaminated).


Back in the early '70's we used Caltex (Chevron) oils where I worked - the multigrades were red. Engines were clean on this oil, but of course nearly every engine was sludged up back then in pre PCV days. I remember on early oil changes it came out pink.

 

[BaReinhard]

GM's AFM or DOD definitely has had its problems. Especially on the G8 platform it is one of the most common problems aside from their problematic LCA's. That being said, it's easy enough to remove the system in its entirety with new lifters, lifter trays, cam, and oil pressure relief valve. Of course while you are in there you may as well do a few other things but I digress.


Anyway, I just got the car back last night and took a quick video of the car with the new cam and engine oil in it. So far no check engine lights (I am not expecting any to be on, but its worth noting)

Without further adieu,
G8 Startup and Idle

 

[BaReinhard]

I like where your head is at! I never even considered that. However, if that were the case I would expect far more threads on the G8 forums about red oil or varnish inside the engine as cam swap's are commonplace with these cars, even if performance isn't the goal.

Then again, it is entirely possible that its more common for AFM cars to have the varnish than say... non AFM cars.

 

[BrocLuno]

I suspect that many folks are seeing this color change, but just assuming it's normal in "modern" oils.

As long as it's not actual sludge, they are not concerned, so don't say anything about it ...

I'd still Kreen it and see what happens

 

[SonofJoe]

Hi Silk,

Thanks for sharing the old Caltex (50:50 Chevron:Texaco for those that don't know) red engine oil story.

It's interesting. I've always regarded Oronite (Chevron's additive subsidiary) as being primarily a Phenate based company; something that feeds into their their strong positions in marine lubricants and HDDO. I've played around with a couple of their products (OLOA 216 & 219?) and they're both good quality Calcium Phenates.

Going back to your story about the 70's reminded me of something. Most Calcium Phenates that you find today are what's called 'sulphur-bridged'. However back in the day, I read that they could also be 'nitrogen-bridged'. I assume that nitrogen-bridged Phenates gradually died out because of the bad effect of the nitogen on seal elastomers. I'm now wondering if your red oils might have been the result of these old Phenates which put nitrogen and aromatic rings together in the same molecule?

 

[BrocLuno]

Maybe ... Back in the day, all Chevron motor oil products were pretty bright red (dye). Maybe they knew about the possible red deposits and just decided to pre-empt the customer by having red oil ... That way everyone would think it was just the oil color and cruise on