[1998 Fiat TD100] How clear is suspiciously clear?

[Popsy]

Very clear oil, aka miracle in my motor?


A few days ago, it was time for an OC in my old 1998 Fiat Marea 1,9 Turbodiesel. I grabbed a new oil filter, some Rimula R6 M oil I just bought in bulk...

Except that was not Rimula R6 in the tin (my bad, got caught by a coolant sensor issue and grabbed the wrong tin), it was a "Frankenbrew" made of some various oil (~50% Shell HX7 10W40 diesel and Elf 10W40 diesel, ~50% Elf 5W30 "gasoline" and Helix Ultra 5W40 "gasoline").
Oil pan was already filled with Frankenbrew, and since all these oils are API CF, I figured I'd wait and see what happens. Motor was running fine and smooth, I drove ~900 miles without troubles.
Today I checked and the oil is still very clear, almost impossible to see on the oil stick!
With this old tech motor oil is usually pitch black as soon as you change it and turn the motor on, I've never seen oil this clear, even when it was new!
EGR is disabled and the sensor I fixed corrected some minor spark advance issue I had when hot, but I don't think this is the cause for clearer oil.

Is it a sign the oil can't handle the soot? Should I change it right away?

(I usually use this "Frankenbrew" in some lawn mower of very old motor like Peugeot J7 diesel, good enough for it)

 

[Pontual]

If the oil doesn't get to normal operation temperature, the detergents doesn't act pretty well. Cold oils don't clean engines. Your Frankenbrew shouldn't kill the detergent package from the oils involved, since they are much more compatible e complementary with each other than some FMs or AW, for instance. someone more knowgeable could shime in, in that regard, although.

 

[Taildragger]

Originally Posted By: Popsy
1998 Fiat Marea 1,9 Turbodiesel.
minor spark advance issue I had when hot


Hmmmm,

 

[chrisri]

All of these oils you mentioned are dual rated A3/B3 or B4, so they are mixable and you can use it for this OCI. I wouldn't mix it on purpose, but in situation like yours why not. Oil staying clear is a bit of oddity, but I wouldn't worry much. Maybe it's related to EGR delete.

 

[chrisri]

Originally Posted By: Taildragger
Originally Posted By: Popsy
1998 Fiat Marea 1,9 Turbodiesel.
minor spark advance issue I had when hot


Hmmmm,


He probably meant ignition advance...

 

[Popsy]

Sorry, meant ignition advance, controlled depending on temperature by calculator.

Oil does get to right temperature (at least water is), and egr disabling is far from new, but if you say it is ok to keep it, I will, till the next oil change.
Turbo is a bit more noisy at low rev, but this may be due to lower visc I guess.

I still wonder why the oil is so clean!

 

[Yah-Tah-Hey]

I'd like to comment but don't want to get banned again.

 

[HerrStig]

"Fix it agains" are very interesting automobiles.

 

[chrisri]

Popsy, if you feel uncomfortable change the oil. Diesels produce soot as a combustion process, this is why oil have detergents and dispensers. Detergent job is to clean soot and dispenser is to keep that soot soluble, so it can be draind with oil.
My guess would be that your mix doesn't have high enough detergent level or additives are not compatible with each other. Personally I would still use it, at least for shorter OCI.

 

[Popsy]

Actually this car is all I never wanted to have. First I bought the car without motor, than I bought a similar crushed car for its motor, and put them together. These were fun days when I was young!
And many years later I still have it. It handles like a barge, but it is comfortable, roomy, and has a correct mileage. All my friends are making fun of me though, and there's often some minor tweaks to do, but never has serious issues

Edit: thanks, I'll keep the oil for a few months then!

 

[chrisri]

Originally Posted By: Popsy
Actually this car is all I never wanted to have. First I bought the car without motor, than I bought a similar crushed car for its motor, and put them together. These were fun days when I was young!
And many years later I still have it. It handles like a barge, but it is comfortable, roomy, and has a correct mileage. All my friends are making fun of me though, and there's often some minor tweaks to do, but never has serious issues

Edit: thanks, I'll keep the oil for a few months then!


You could do worse, like driving a French car

If you wanna keep your hands dirty there's plenty of diesel Laguna's for cheap these days. Senic II diesel, also a good car LOL.

 

[Popsy]

Renault diesel don't have much of a reputation of reliability here, lol. Got a friend which is a Renault fan, keeps his hands even more dirty than mine!
What I want is a 1980 Mercedes break, I like rusty diesels

 

[Jetronic]

I wouldn't worry.

the oil in my new Giulietta stayed clear for the first 5000 miles.... if you had little old oil left in the engine, there won't be much discolouration. does this engine have an EGR system? these are big contributors to sootening of the oil.

 

[Popsy]

Hum, it is an old indirect injection mechanical pump diesel. It had egr, but I disabled the pneumatic command so it stays closed all the time.
Your engine is much more modern, nice car!

 

[chrisri]

Originally Posted By: Popsy
Renault diesel don't have much of a reputation of reliability here, lol. Got a friend which is a Renault fan, keeps his hands even more dirty than mine!
What I want is a 1980 Mercedes break, I like rusty diesels

Shop around Marseille, I'm sure you could pick up clean, rust free example. But be warned; they are DEAD slow.

 

[artificialist]

Originally Posted By: chrisri
Originally Posted By: Popsy
Renault diesel don't have much of a reputation of reliability here, lol. Got a friend which is a Renault fan, keeps his hands even more dirty than mine!
What I want is a 1980 Mercedes break, I like rusty diesels

Shop around Marseille, I'm sure you could pick up clean, rust free example. But be warned; they are DEAD slow.

Since some guys in this thread know about engine swaps, I'm sure someone knows how to swap a more modern diesel into an older Benz. Here is someone who did exactly that:
http://www.caranddriver.com/features/mercedes-engine-transplant-modern-diesel-in-a-1992-190e-26

 

[Popsy]

Wow!

I can't imagine the work involved to make it work!!!

I had a 190E too in the nineties, inherited from my Grandfather, it was a 1992 190E 1,8...tiny motor, but god I loved this car. Wish I hadn't sold it after it blew a head gasket at 200000Km+


Regarding my Fiat, I think I'm gonna change the oil this weekend, turbo is making more noise than I like. I'll keep the "used" oil to put in my lawn mower!

 

[friendly_jacek]

i've never ever seen clear oil in a diesel (regardless of EGR). they get dirty just after an oil change and the very first start. something is seriously wrong here. do we know oil pump is working at all?

 

[Popsy]

I guess it is working, oil has slightly darken since last time. I'm going to change it today.
Water temp is normal, but I don't have oil temp indicator.

 

[Jetronic]

Originally Posted By: friendly_jacek
i've never ever seen clear oil in a diesel (regardless of EGR). they get dirty just after an oil change and the very first start. something is seriously wrong here. do we know oil pump is working at all?


I have seen it, with my own car and others. It's the leftover soot loaded oil that colours the newoil black, but if tere's little old oil left and with little soot loading (no egr) the oil can stay light for a while.