Thread: High Silicon in engine oil

There is no silicone source within an engine. It is dirt from outside. Check carefully that the air filter is sealing fully inside the air box. Make sure you have a good quality filter. Carefully check over the crankcase ventilation system for leaks (bad connections, cracked hoses and so on). What engine?

Originally Posted by Red90

There is no silicone source within an engine. It is dirt from outside. Check carefully that the air filter is sealing fully inside the air box. Make sure you have a good quality filter. Carefully check over the crankcase ventilation system for leaks (bad connections, cracked hoses and so on). What engine?

Actually there is silicon sources within most oils themselves as silicon is used as an anti-foamant and silicon levels can be raised after gasket changes, eg when something akin to RTV or Hylomar is used, but elevated silicon levels really need to be addressed as per Red90's suggestions.

Look at the silicon levels in concert with potassium, have they increased at the same time?
How are the wear metals looking?

Hi guys, thanks for the suggestions.

To answer your questions, it's the Ford/PSE 2.2 diesel used in the Freelander and early Disco Sport, which mine is.

Rick is correct that there is silicon in new oil as an anti-foaming additive, and I've had new oil tested as a benchmark and it starts with 4ppm, so as it's now at 37ppm it's not just that.

Wear metals are at 'normal' levels and the lab doesn't test for potassium, and in fact it's probably easier I just post the test result here so you can see exactly what's going on...

Oil Analysis.jpg

I'm on the mobile atm so scrolling backwards and forwards but yep, I'd be really looking at the sealing of the element and out of curiosity, is it a genuine element or aftermarket you are using?

E.g. In TD5's I'll only use Mann or Genuine. I've found that even the old mechanics standby of Ryco are undersized and don't seal properly.

Also, is each column a new oil or a progression of an existing sample?
Really interesting the different additive levels in the last column, the last looks like a mid-SAPs oil with the reduced calcium/phosphorous levels.

Originally Posted by rick130

I'm on the mobile atm so scrolling backwards and forwards but yep, I'd be really looking at the sealing of the element and out of curiosity, is it a genuine element or aftermarket you are using?

E.g. In TD5's I'll only use Mann or Genuine. I've found that even the old mechanics standby of Ryco are undersized and don't seal properly.

Also, is each column a new oil or a progression of an existing sample?
Really interesting the different additive levels in the last column, the last looks like a mid-SAPs oil with the reduced calcium/phosphorous levels.

Hi Rick,
The car has been main dealer serviced so it'll be a genuine air filter element, at least it'd better be at the price they charge!
I replace my oil religiously every six months (again a throwback to my history with marine diesels), and take an oil sample for analysis just before that so I can report any problems to the dealer. So, to answer your question, each column is a different batch of oil and has about 10,000 kms on it. The oil is Castrol Edge Professional 5W30, which is ACEA A3 so yes is a mid-SAPS oil, so as to why the additives are so different in the latest sample, I cannot answer that as it's supposed to be the same oil each time!

Anyway, back to the silicon - I've read that another potential internal source is gaskets and seals. Has anyone heard of high silicon content in oil being a precursor to seal failure - which is my main worry!

Anyway, I'll definitely take a look at the air filter, and raise the issue with the dealer when it goes in for it's service at the end of the month.

Originally Posted by Mamil

Hi Rick,
The car has been main dealer serviced so it'll be a genuine air filter element, at least it'd better be at the price they charge!
I replace my oil religiously every six months (again a throwback to my history with marine diesels), and take an oil sample for analysis just before that so I can report any problems to the dealer. So, to answer your question, each column is a different batch of oil and has about 10,000 kms on it. The oil is Castrol Edge Professional 5W30, which is ACEA A3 so yes is a mid-SAPS oil, so as to why the additives are so different in the latest sample, I cannot answer that as it's supposed to be the same oil each time!

Anyway, back to the silicon - I've read that another potential internal source is gaskets and seals. Has anyone heard of high silicon content in oil being a precursor to seal failure - which is my main worry!

Anyway, I'll definitely take a look at the air filter, and raise the issue with the dealer when it goes in for it's service at the end of the month.

As I mentioned above gaskets/seals/silicon can show when a component has been changed and the gasket is new or fresh RTV/Hylomar/etc has been used as the gasket or as a dressing.

I'd still look at the air cleaner sealing, panel filters have a bit of a reputation for not sealing well.
I've got into the habit of using a rubber safe grease on the seals (even though they are probably polyurethane) and checking to make sure it seals.

[edit] Also, on top of what John suggested above, and I'm not trying to teach you to suck eggs but things like the dipstick is seating properly, the O rings ok where it seats into the tube, the O ring into the block is ok and the tube itself isn't cracked (had that on a 300tdi)

Originally Posted by rick130

As I mentioned above gaskets/seals/silicon can show when a component has been changed and the gasket is new or fresh RTV/Hylomar/etc has been used as the gasket or as a dressing.

I'd still look at the air cleaner sealing, panel filters have a bit of a reputation for not sealing well.
I've got into the habit of using a rubber safe grease on the seals (even though they are probably polyurethane) and checking to make sure it seals.

[edit] Also, on top of what John suggested above, and I'm not trying to teach you to suck eggs but things like the dipstick is seating properly, the O rings ok where it seats into the tube, the O ring into the block is ok and the tube itself isn't cracked (had that on a 300tdi)

Hi Rick,
Thanks for your advice, and don't worry you're not teching me to such eggs. I don't have much experience with car engines so welcome advice from those who have! Most of my experience is with large marine diesels, and the beauty of the marine environment is that the air is so clean that you can get away with a simple foam filter element.
There haven't been any repairs since new that would introduce fresh gasket or sealant (and I do scour the service reports to see exactly what the dealer has done) so don't think it would have come from there. Would gradual (or rapid) deterioration of existing oil seals and the like lead to silicon contamination I wonder?
Anyway, I'll check all the places you mention for air/dirt ingress, and I like the idea of a bit of grease around the air filter, and will do that as soon as I get it back from the service with the new element.
Cheers, Andy.

So I just had a look at the air filter, and it's definitely a genuine LR part, the seal looks pretty effective, and the engine side spotless!. Also had a look at the dipstick and air intake manifold and couldn't see any cracks or obvious places where air would be getting in, but not an exhaustive look by any means.

Air filter.jpg