Engine Oil

[davidtch]

Bro, above boiling point is too hot. You'll need to be on 70/30 coolant to water mix and above, or the pressure will be too high and you'll pop something in your cooling system. Not fun when on the road. Happened to me before: parked the car and FWOOOM! It was like a pregnant car breaking it's water bag No choice but to call a tow truck.

Perhaps your thermo or temp sensor needs changing? Those things are regular replacement items.

It is normal for the pressure to be this high. I had double check with another mechanic working in PML. The water pressure is about 1 bar.

 

[t2ribena]

Why do you guys say that BMW engines run hotter? Do you know this for a fact? I thought all auto engines run at the same temp of 93C determined by the thermostat in the cooling system. Does BMW use a hotter thermo than the industry standard?

bro...all engine does not run at the same temp...depending how it is tuned (lean or rich) which effect how hot the engine runs and the coefficient of the cooling system...

for example...if the engine at its combustion chamber temp is about 260C, if the cooling system is design to cools at a factor of 2.8 then we could say the resultant temp around 93C and other car which has the chamber temp about 200C with a cooling factor of 2.15 then the resultant temp is also 93C...this is just an example of heat source and cooling factor relation...

engine does not run at same temp but it also depends on the cooling system designed for the engines...too low temp, the fuel is not combusted perfectly, too high then u run a risk of overheating and also condition where the fuel burns just as it enters the combustion chamber...so the temp must be high enuf but then u have headache of cooling and engine oil spec/consumption etc...:top:

 

[turbology]

Cooling system run under pressure.
When release(open) the coolant cap while engine is hot and running, will drop the pressure inside the system thus drop the boiling point . Therefore the water boil spotaneously and turns into bubble and steam for few seconds. Just like Geyser.

 

[t2ribena]

Bro, without a thermostat, how would your on-demand water pump know when it's in demand?

I believe all current engines run at 93C. I may be wrong, so why don't you use your Google/Bing to prove me wrong for once?

the electric water pump does not operate based on the mechanical thermostat condition but from the output of the temp sensor located on the inlet and outlet of the coolant hoses...:top:

 

[turbology]

bro...all engine does not run at the same temp...depending how it is tuned (lean or rich) which effect how hot the engine runs and the coefficient of the cooling system...

for example...if the engine at its combustion chamber temp is about 260C, if the cooling system is design to cools at a factor of 2.8 then we could say the resultant temp around 93C and other car which has the chamber temp about 200C with a cooling factor of 2.15 then the resultant temp is also 93C...this is just an example of heat source and cooling factor relation...

engine does not run at same temp but it also depends on the cooling system designed for the engines...too low temp, the fuel is not combusted perfectly, too high then u run a risk of overheating and also condition where the fuel burns just as it enters the combustion chamber...so the temp must be high enuf but then u have headache of cooling and engine oil spec/consumption etc...:top:

May I add:
1. Almost all gasoline engine run at about the same temp. The different Is the cooling speed (energy draw away from combustion).
2. In order for spark plugs to work correctly, it need to be at 500c to 950c, with most running around 800c to 850c during lean cruising speed. Higher temp reduce carbon deposit.
3. The temperature of Spark plug's insulator tip is usually the actual temperature within the combustion chamber.
4. 90% of the combustion heat is transfer to engine block through spark plugs. Thus, you have heat range for spark plugs. With cooler type transfer more heat to engine block faster.
5.. You can cool the running temperature down with richer mixture, alcohol/NOs/etc. Is also one of the reason higher RPM or high boost require richer AFR to prevent spark plugs fouling/pre-ignition.

What I know:
1. Gasonline are heated/warm through heat from engine block before it enter the combustion through injectors. Warmer gasoline "vapourize" better, provide better Volumetric Efficiency and MPG.
2. Fuel won't burn when it enters the combustion chamber regardless how hot it get.(Unless is glowing hot). You still need spark. We use gasonline, not diesel

 

[Schwepps]

Hahaha! A lesson on thermodynamics in an oil thread. Sorry for influencing this going OT!

No doubt, you can raise the boiling point of your cooling system by using more ethylene glycol coolant than water as the medium, but that has to go with an upgraded cooling system, among other mods, because the system will be running hotter and under pressure. But a stock system temp is set by the engine designers by having rated thermostats and temp sensors trigger the valves and pumps. What is the temp rating of the stock cars we are driving? Most thermostats these days are rated at 93C or thereabouts. What are BMW thermostats for the N46/N52 rated at? Does anyone know?

 

[astroboy]

... What is the temp rating of the stock cars we are driving? Most thermostats these days are rated at 93C or thereabouts. What are BMW thermostats for the N46/N52 rated at? Does anyone know?

No matter what combustion temperature the engine designer wish to run, they are always limited to the boiling point of the pressurized ethylene glycol-water mix coolant.

As we all know H2O boiling point is 100C and with combustion chamber temperature running at above 500C, H2O can't cope with those temperature and will start to boil pretty fast and once they boil, they will vaporise and vanish themselves from the cooling system, which is not a good thing to the engine.

Apart from serving as a lubricant, anti freeze and anti rust, the ethylene glycol raise the coolant boiling point, the same with the pressurized cooling system, so that our coolant will not boil and vaporise at above 100C but by how many degree more?

Standard water temperature gauge available in the market max out at 120C, so your thermostat better open way before that and I would think that for performance engine, thermostat better open quicker.

Here's another one which tells u what is the blue zone and red zone..

A friend's Lotus Elise has overheating problem because wrong thermostat was used. The rear engine Elise radiator is actually mounted to the front section of the car, if thermostat opens at 93C, by the time the water reach the radiator, cool down and return to the engine, the engine temperature has already blown over the roof! Took them very long to trouble shoot..

 

[Schwepps]

So far no one can say for sure that our Bimmers operate at a higher temp based on the setpoint of a relevant part then.

 

[turbology]

I see no reason to run at "higher temp"
I won't surprise if BMW does run "hotter" because learner mixture create more heat, but help reduce emission and improve FC

 

[ebby37]

wow... lots of confusing threads for a non car 'mechanic' like me !!! I salute you guys for your knowledge !
BSoosay it seems terribly long that your idrive takes 7-8 mins to get a reading for your oil, mine is done in a few seconds. Maybe yours is actually working and schwepps and mine are actually not functioning and giving out erroneous readings ?

 

[BMWs]

wow... lots of confusing threads for a non car 'mechanic' like me !!! I salute you guys for your knowledge !
BSoosay it seems terribly long that your idrive takes 7-8 mins to get a reading for your oil, mine is done in a few seconds. Maybe yours is actually working and schwepps and mine are actually not functioning and giving out erroneous readings ?

Exactly what i was thinking. Since everyone's car seems to be drinking oil. Mine, yours and Schwepps aren't.
Does that mean everyone else is normal and ours is abnormal?

Now i'm worried.

 

[Schwepps]

Why do you assume that my reading comes up in seconds? From a dead start, it takes a few minutes to get a reading and mine is the same.

 

[astroboy]

I just drove my kid home from school, push the car a bit, with DS mode, DSC off.. When reach home, my radiator fan keep blowing despite engine shut off and key fob removed. It didn't stop. After few minutes, I worry it might drain my battery. I popped the hood, stick my hand in to feel the air blowing out from radiator, its not that hot. So I got worried that it might never stop. Jump into the car, start up the engine and let it run for about 10 sec, to at least charge back the battery a bit, then stop engine again, this time the fan stop..

Pheeww... this is the 3rd time I experience this.. any similar experience out there?

btw, my OBC oil gauge doesn't come up immediately from a dead start as well. Best check the level after a short drive and car must be stationary. I usually do it at a traffic light stop. No need to wait, the gauge immediate gives u the reading.

I am at 27k km now, 2 more months till warranty expire.. trying very hard to find fault with the car..

 

[Schwepps]

The delay is because fluid level monitoring is continuous, but not something that needs to be in realtime. So to keep OBC resources free, it samples the sensors in set intervals, eg every few minutes. From a dead start, there is no data stored yet, so you have to wait for the first sample. Once that's in, it's stored and if you call it up, the last stored sample pops up immediately. Because of this, there's really no need to wait until you're stationary to check.

Fan doesn't want to stop: maybe your thermostat gets stuck astro? Try your luck, report it to SC.

 

[etquah]

I just drove my kid home from school, push the car a bit, with DS mode, DSC off.. When reach home, my radiator fan keep blowing despite engine shut off and key fob removed. It didn't stop. After few minutes, I worry it might drain my battery. I popped the hood, stick my hand in to feel the air blowing out from radiator, its not that hot. So I got worried that it might never stop. Jump into the car, start up the engine and let it run for about 10 sec, to at least charge back the battery a bit, then stop engine again, this time the fan stop..

Pheeww... this is the 3rd time I experience this.. any similar experience out there?

btw, my OBC oil gauge doesn't come up immediately from a dead start as well. Best check the level after a short drive and car must be stationary. I usually do it at a traffic light stop. No need to wait, the gauge immediate gives u the reading.

I am at 27k km now, 2 more months till warranty expire.. trying very hard to find fault with the car..

Better get it check and change before warranty expire. Whatever the problem is, change it is the safest before waranty expire. Have you change your brake pad or wiper already ?

 

[astroboy]

My base line model OBC will not have oil check option if the car is not stationary..

The next time if I catch my fan running after I off the engine, I will spray some water from the grille into the radiator to help the cooling process to see if it still run for so long.. if really radiator cool down yet fan refuse to stop, I will make a complaint to SC.. unless the fan is running on a timer like turbo timer the moment it detected some high temperature, and run for a fixed timed duration, then my little experiment won't prove anything..

Front pad still had 10k km, wiper still okay wor.. but those are BSRI covered items. My BSRI still got 1 year and 2 months to go.. so its alright. Only worry about the non BSRI items which is only covered by warranty for 24 months from date of purchase. Rachel just claim her side mirror motor, again! and her head light controller suspected to be faulty because high beam is "now u see it now u don't" and is waiting for parts now. Those are warrantied items and after 24 month, BSRI does not cover those, need to break wallet lio!

My side mirror is non motorised, use hand lipat wan, less one worry. (base line model )

Ok.. back to oil topic.. who want to try this..

Btw, they have 5w-30 too, but that's under another trade mark ~ "Ultraman".. hasn't reach yet, so I can't inspect the label.. obviously Astroboy fly a little faster with the jet boosted after burner under his feet..

 

[Schwepps]

I dunno Astro, I've never had the fan continuing after I switch off my E90 after a fast run, although it does on the Merc and some previous cars. Eg, the Volvo T-5 had a timer and would run for ~3 mins. Battery never lasted more than a year. Hopefully others will chime in whether the fan continues in theirs or not, but I think you should get it checked anyways since you're looking for things that have gone wrong

 

[RIKI]

brought my car for an oil check at AB since I see it drop 1 bar from max.I just wanted to top up and check the oil quality.

The service person at AB Glenmarie insisted that I should wait until the warning for oil change come up before coming for the free oil change, which the computer says would only be coming in the next 10k km.

I made noise a bit so they said if the oil quality is still good then I have to pay for the oil top up or change

I was shock to know that the oil quality had dropped to 35% and they sheepishly acknowledge this and changed the oil and filter for me ( with Shell Ultra I noticed)

just imagine if I had followed the computer advice and wait for another 10k km?? What utter rubbish is this!!!! Imagine the possible damage if BMW insisted on their schedule change


From now on I will be insisting that they check the oil quality every 10 to 15k or so and not 20k km.

 

[racheltoh]

Riki, so did u pay or free under Bsri? how do we check for oil quality?
I just went for the brake oil change or check. I doubt in this service, they change the black oil, filter. now after reading this very very long post, i wanna do black oil change...

 

[glock_8]

Exactly what i was thinking. Since everyone's car seems to be drinking oil. Mine, yours and Schwepps aren't.
Does that mean everyone else is normal and ours is abnormal?

Now i'm worried.

my car doesn't drink oil too.am i not normal?