Philes’ Forum – Spring 2019


By Vic Lucariello, Sr.

Hello Bimmerphiles! This time out I have a couple follow-ups to recent Philes’ Forums, the That Ain’t What It’s For [Spring 2018] column and the Coolant Schmoolant [Summer 2018] column. Archived files of these newsletters can be found at our website

In That Ain’t What It’s For, I wrote about the under-dash OBD II diagnostic connector [See Photo #1] and how I, along with some respected, experienced BMW techs, do not recommend using the OBD II connector to supply auxiliary battery power to your Bimmer while changing batteries.

Photo #1 – OBD-II Diagnostic Connector

Well, a recent thread on iATN [The International Automobile Technicians Forum] presented an example of why. On some BMW models, use of the OBD II port for auxiliary battery power can result in a blown fuse, one that supplies the instrument cluster.

In Coolant Schmoolant, I wrote about the different types of automotive coolant available today, and that it is very important not to mix coolant types. I also offered to write a follow-up on cooling-system flushing.

Well, to the hundreds of you who emailed to ask for said follow-up and who have been waiting with breath abated, here it is.

Photo #2 – The Sneaky One

This description applies specifically to the E30 M3, but is applicable to Bimmers with engine-block-drain plugs and without electric coolant pumps. BMW has seen fit to eliminate block drains on some later models. On electric-coolant-pump models, a special procedure is required to bleed the air out of the cooling system after it has been drained and refilled. I’ll save that for a future column [A follow-up to a follow-up?].

The S14 Motorsport engine in the E30 M3 has a plethora of small coolant hoses in addition to the normal radiator and heater hoses. Given an OE coolant-hose life of about 15 years, or according to the Roundel’s Mike Miller’s Lifetime Maintenance Schedule, 120,000 to 150,000 miles, your M3 either has new coolant hoses or it needs them.

Since the S14 radiator, thermostat and heater hoses are straightforward, I will focus on the hoses more likely to be overlooked, particularly one sneaky bugger.

BMW provided a self-bleeding cooling system on the S14. [On some other E30s, along with E36s, E46s, et al, there are coolant bleed valves that need to be opened to expel trapped air.] On the left side of the S14 cylinder head near the front is a little hose [the sneaky one, see Photo #2] that connects to a tube that runs to the rear of the cylinder head. This tube connects to another hose [Photo #3] which attaches to the coolant-expansion tank. A second bleed hose [Photo #4] connects to the top radiator tank. This hose connects to yet another tube that runs along the right side of the engine compartment, leading to yet another hose [Photo #5]. The sneaky hose connected to the cylinder head and its cousin connected to the radiator are subject to full engine operating temperature, the same as is the upper radiator hose. The hoses connected to the coolant- expansion tank are subject to almost this same temperature. So, changing the radiator hoses, a common maintenance procedure, without changing the coolant-bleed hoses is, to me, rather foolish.

Photo #3 – Sneaky’s Connection at Expansion Tank

Mike Miller recommends a two-year coolant-maintenance cycle and the use of BMW OE coolant and distilled water. While my experience suggests that two years may be on the conservative side depending upon how much you use your Bimmer, I recommend the use of BMW coolant and distilled or deionized water, and said so in Coolant Schmoolant.

The following is the flush procedure I have developed over the years and use on my personal Bimmers. You may think that this procedure is on the lunatic fringe, and you may be right. If so, you can skip the flushing part and simply drain the radiator AND ENGINE BLOCK and refill the system with a 50-50 mixture of BMW coolant and distilled or deionized water. This alone will be much better than what is done at some professional car-repair facilities.

Photo #4 – Radiator-Bleed Hose

I start with a cool engine and by setting the heater-temperature control to full hot and removing the radiator and engine-block drain plugs. On the S14 and many other Bimmers, the block drain is a 19-mm hex located behind the exhaust manifold. I use a flex socket and long extension to remove the block-drain plug, and a magnetic socket insert works even better. Coincidentally, as I was composing this today I received an email from our Webmaster and recent Champ Series winner Colin Vozeh stating that he, too, uses a long extension and flex socket on the drain plug.

Photo #5 – Radiator-Bleed Connection To Expansion Tank

When you remove the block drain, be sure to capture the drain- plug sealing ring. Sometimes it remains on the drain plug, sometimes it falls to the floor, and sometimes it remains stuck to the engine block. You do not want to re-use this sealing ring, but you definitely want to ensure that it has not remained stuck to the block.

What I do next is install a special drain fitting to the block-drain port. [See Photo #6.] I made this fitting by drilling and tapping a spare drain plug with 1/8 NPT threads and installing a 45-degree street elbow and a drain cock with a hose connection. I connect a clear hose to the closed drain cock. The 45-degree street elbow is not mandatory, but it makes life a lot easier.

Photo #6 – Custom Flush Fitting

Next I pour in distilled water until the water draining from the still-open radiator drain runs clear, then I close the radiator drain and continue filling the system completely.

Next I start the engine and quickly open the drain cock on the block drain. I let the engine idle and continuously pour in distilled water, keeping the expansion tank full, until the fluid escaping the block drain runs clear, then I shut the engine off. Note that you do not want to let the engine warm up, and by continuously pouring in distilled water, it won’t.

Then I open the radiator drain and let everything drain out, after which I reinstall the block-drain plug [the exhaust manifold will be hot, so you may want to let it cool a bit] with a new sealing ring and close the radiator drain.

I installed a gallon of BMW coolant [you can use 4 ½ – 5 quarts on the S14 if you prefer] and finished filling with distilled water and 8 ounces of Redline Water Wetter. After warming up the engine, driving the M3 and letting things cool to ambient, I checked the coolant concentration with my refractometer and it came out to 48%, pretty close to the desired 50% if ya ask me. I had to add a few more ounces of coolant to get the level in the expansion tank to the Cold-Fill level.

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at I’m interested in comments, tech tips, repair /maintenance questions, repair horror stories, emissionsinspection sagas, product evaluations, etc.

© 2019; V.M. Lucariello, P.E.

Philes’ Forum – Spring 2018


By Vic Lucariello, Sr.

Hello bimmerphiles! This time out I would like to talk a bit about that diagnostic connector under the left side of your dashboard on your 1996-and-newer Bimmer. Actually, it is found on almost any 1996-and-newer passenger car.

Diagnostic connectors on cars were nothing new, even in 1996. Indeed, my 2002 has one under the hood, as shown in Photo #1.

Photo #1 2002 “Diagnostic” Connector

On 2002-era cars, before the advent of computer-controlled everything and serial-bus communication, the diagnostic connector merely provided a convenient test point for a few critical electrical parameters, such as whether or not the starter was being commanded to operate. The parameters available on the diagnostic connector could in most cases be easily accessed at their sources with a voltmeter, but the connector brought the parameters together so that a factory diagnostic tool could be easily and quickly connected.

In the E30s [1984-1991 3-series], earlier model years had a different- style connector [See Photo #2] that essentially provided the same information. Later model years had a 20-pin underhood connector [See Photo #3]. BMW used this connector until about the 2002 model year. [Most 1996 – 2001 Bimmers had both the 20-pin underhood connector and the OBD II connector described below.] Diagnostic devices that plug into car-manufacturer-provided connectors, or ports, came to be known generically as “scanners”, because in the computer-control era these devices can scan and display multiple process parameters, or PIDs, such as coolant temperature, etc.

Photo #2 Early E30 Diagnostic Connector
Photo #3 Later E30 Diagnostic Connector

You will note that on the three BMW models above, there are three very different diagnostic connectors, all located in different areas of the engine compartment. And that is just for Bimmers. Add the other car manufacturers into the mix and one is faced with a veritable cornucopia of different connectors and locations. Indeed, for my old Snap-on scanner, the number of required diagnostic adapters pretty much doubled the size of the carrying case! And of course, I still had to buy the BMW 20-pin adapter separately.

Our federal government and the Society of Automotive Engineers noticed that all these different diagnostic connectors posed a huge problem for non-dealer technicians and for technicians who worked on several different makes of cars. And thus was born the idea of a standardized diagnostic connector and OBD II [On-Board Diagnostics – Level II] regulations. OBD II – compliant vehicles [Pretty much every passenger car sold in the US starting with the 1996 model year.] must all use a standardized connector in a pretty much standardized location inside the vehicle under the dashboard [See Photo #4]. So, one should be able to take any so-called Global-OBD II – capable scanner and plug it into any OBD II – compliant vehicle via the standardized connector and view diagnostic trouble codes [DTCs] and emissions-related engine and transmission parameters.

Photo #4 OBD II Diagnostic Connector

What are DTCs? Glad you asked. DTCs are set, and usually the dreaded “Check Engine” light [AKA: MIL – Malfunction Indicator Light] is turned on, when the engine or transmission computer detects an abnormal condition that can adversely affect vehicle emissions. Another advantage of OBD II is that generic-type DTCs [in the form of P0xxx] are supposed to be the SAME among the different vehicle makes. So, if either a 1996 328i or a 2004 VW Jetta or a 2008 Subaru or a 2010 Corvette or a 2018 M4 records a P0300 DTC, that means the engine computer is detecting random cylinder misfires. Similarly, a P0420 indicates that the catalytic converter is not performing properly in cleaning up exhaust gases.

Another function of the OBD II port is to allow downloading of computer-software updates, from the vehicle manufacturer or from aftermarket-software providers [tuners]. But if you have not fallen asleep by now I would like to talk about an available “function” of the OBD II port that I think you should avoid.

Of the pins on the OBD II connector, one is from the battery bus [always “hot” regardless of whether the ignition is on or off] and one is a vehicle ground. The purpose of this is to power a scanner. To repeat: The purpose of this is to power a scanner or simple DTC reader. The purpose is NOT to connect a battery charger, battery maintainer, or so-called “memory saver”.

Memory savers are used to supply auxiliary power and maintain computer memories when the vehicle battery is disconnected, say to install a new battery. I am a proponent of connecting auxiliary power during battery work, but on a BMW, I use the underhood B+ and ground studs thoughtfully provided by BMW.

I talked to three expert, professional technicians about this: Matt Kimple, Sal Puleio and Chris Roberson. Matt and Sal need no introduction to Philes’ readers. Fellow [as is Sal] iATN member Chris Roberson is a BMW-trained technician from the Left Coast whom I came to know via his many valuable BMW-related iATN contributions. iATN is the International Automobile Technicians’ Network, with something like 70,000 English-speaking techs worldwide.

Both Chris and Matt maintain that there is no need to connect auxiliary power to a recent Bimmer when disconnecting the vehicle battery. Earlier cars could lose radio codes, reset DTCs and monitors, and possibly lose seat and sunroof settings. In rare cases, especially if the battery were left disconnected for a couple of days, the “alignment” of the anti-theft system [EWS or CAS] could be lost, resulting in a no-start situation when the battery got reconnected. “Honey, to save some money I installed a new battery in your X5, but now it won’t start.”

Sal and I tend to connect auxiliary power whether we need to or not; one reason being that it is difficult to know for sure whether a particular Bimmer [Also, Sal and I work on other cars in addition to Bimmers] should have auxiliary power during battery work. Sal says, “It certainly does not hurt anything to connect auxiliary power, so provided it is done correctly, why not?”. One thing that Chris, Matt, Sal and I agree on completely is that, if you are going to use auxiliary power during battery work, PLEASE don’t connect a memory-saver device to the OBD II port! That ain’t what it’s for!

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at I’m interested in tech tips, repair / maintenance questions, repair horror stories, emissions-inspection sagas, product evaluations, etc.

© 2018; V.M. Lucariello, P.E.

Philes Forum – Fall 2016


By Vic Lucariello, Sr.

Hello, bimmerphiles! I am closing the 30th year of Philes’ Forum publication with a few unrelated tech tips.

Most of us know about or have patronized Harbor Freight Tools. While some tool snobs out there might pooh-pooh HF stuff, my opinion is that some of their hand tools provide good value, especially for occasional or DIY use. Hey, a set of inexpensive combination wrenches in the trunk of your Bimmer beats the heck out of no wrenches. However, according to reports on iATN [International Automobile Technicians Network], you should be wary of HF automotive fuses. These fuses, which come in an assortment, look pretty much like fuses from traditional manufacturers such as Bussman and Littelfuse.

In a recent thread, an iATN member reports testing the fuses from one HF 5-30 amp fuse assortment. He reports that they ALL held about 75 [that’s seventy-five, folks, you read it correctly] amps before blowing! Fuses have a temperature-time curve, meaning that the time to failure depends not only on the amount of current flowing through the fuse, but the amount of time the current flows. For example, a 10-amp fuse might endure 13 amps or so for a few minutes before blowing, while the same fuse should blow much more quickly at 20 amps. Regardless, a 5-amp fuse holding 75 amps for any amount of time is pretty scary.

So, while carrying an HF wrench set in your Bimmer may be a good idea, carrying their fuse assortment might not be.

After writing the foregoing I happened to see the following HF ad for a ½- inch pneumatic impact gun:

The ad claims that the HF is more powerful, lighter and quieter than a Snap-on model, at less than 1/3 the price!

Many of you change your own brake pads, and hopefully you don’t use pads from HF [kidding of course]. I’m sure you use OE [Original Equipment – from your BMW dealer] or OE-quality pads from a reputable aftermarket source, but what about that new pad-wear sensor?

I have previously written about the evolution of BMW brake-padwear sensors, so I won’t repeat my tome other than to say that recent Bimmers use sensors that actually predict how many miles remain until the pads need replacing. Older sensors simply illuminated a dash lamp when he pads wore to the replacement point. The old-style sensors could be reused if they hadn’t yet turned the lamp on, but I always replace them. On cars with the newer-style sensor and the Condition Based Service [CBS] feature, it is important that you use an OE or OE-quality new wear sensor when you replace brake pads. I have experienced difficulty, and read others’ reports to this effect, in getting the CBS brake-pad monitor to reset after the new pads and sensor have been installed, and the problem turned out to be an aftermarket pad-wear sensor that the CBS electronics didn’t “like”. An OE sensor fixed things. So, if you are buying brake parts from an aftermarket source, be sure to confirm with them beforehand that the pad-wear sensors they supply will not cause CBS-reset problems. If you inform them of problems afterwards, be prepared to be told that you don’t know how to reset the CBS. [Heck, you will probably be told this anyway.] Personally, I always use OE sensors, regardless of what brake pad I am installing.

Although the following applies to many Bimmer models, some as much as twenty or more years old, this specific account applies to an E46 325i with over 150,000 miles. A fellow had a valvecover- gasket oil leak [Imagine that!] and after replacing the valve-cover gasket he had no more oil leak but he had an illuminated “Check Engine” lamp. OBD II diagnostic trouble codes P0171 and P0174 were stored in the engine control computer [DME in BMW-speak]. WTF!?

These codes set when the DME detects a lean-running condition; the 171 code is for Engine-Cylinder Bank 1 and the 174 code is for Bank 2. Banks on an in-line six? Yes: Bank 1 is cylinders 1-3 and Bank 2 is cylinders 4-6. So the codes suggest that the whole engine is running lean. But how can a valve-cover-gasket replacement cause the engine to run lean?

First of all, whenever you remove a “plastic” valve cover from any BMW engine, especially a six, it is not unlikely that the cover will be warped. Removing the cover and replacing the gasket will NOT correct the warp situation; Indeed, it will probably make the problem worse. Don’t ask me why this is, but it is so. [Remember that on the subject E46, there were no lean-running codes stored prior to the valve-cover-gasket replacement.]

Second, BMW’s engine-crankcase-ventilation [PCV] system tries to maintain a prescribed vacuum on the engine internals. The actual vacuum spec varies from engine-to-engine, but the vacuum one should measure on a warm-idling E46 325i is about 4 inches of water column. If there is an air leak on the valve cover, either due to a bad gasket or that warped valve cover, the PCV will, in trying to maintain the engine internals at the prescribed vacuum, suck a lot of unwanted air into the intake manifold and…..BINGO…..the DME will set lean-running codes.

On the subject E46, the owner lucked out with the valve cover itself insofar as warpage, but when he checked his work, he found a piece of the original gasket had been left on the cylinder head when the valve cover was removed the first time. So the piece of old gasket created the air leak that caused the lean running codes.

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at

I’m interested in tech tips, repair / maintenance questions, repair horror stories, emissionsinspection sagas, product evaluations, etc.

© 2016; V.M. Lucariello, P.E.

Philes’ Forum – Summer 2016


By Vic Lucariello, Sr.

Hello, bimmerphiles! I hope you are enjoying the hot NJ Summer. I write this at our new place in Colorado. This time out I talk about a problem that I have seen on many OBD II [1996 and newer] Bimmers. The problem presents itself as a misfire, on one or more cylinders, shortly after a cold start. The “Check Engine” indication [Official OBD II Name: Malfunction Indicator Lamp, or MIL] comes on and sometimes flashes. If the engine is shut off and restarted, the misfire is gone and the engine runs seemingly perfectly until the next cold start, or maybe the following cold start. The MIL goes off. Sound familiar?

In some cases, the problem begins with an occasional misfire or rough running after a cold start, with or without the MIL. As the engine warms up, things smooth out. The problem becomes more frequent and severe over time, finally getting to the point where you need to stop and restart the engine in order to clear the misfire and get the MIL to go off.

What the heck is OBD II, you may ask? Well, OBD II stands for On Board Diagnostics, Level II, and it has been federally mandated for about twenty years now. OBD II vehicles have sophisticated software that monitors a large number of parameters that can affect exhaust and/or evaporative emissions. Examples of things that are monitored are:

  • The vapor integrity of the fuel tank, lines and gas cap
  • The signal quality of sensors such as the crankshaft-position sensor
  • How efficient the catalytic converter[s] is
  • The response of the oxygen and/or fuel/air-ratio sensors
  • Whether the engine is running rich or lean
  • Whether the VANOS is properly positioning the camshafts
  • How smoothly the engine is running

In monitoring how smoothly the engine is running [This is called the Misfire Monitor, and BMW calls it the “Smooth Running” monitor.] the engine-control computer [DME in BMW-Speak] looks at minute changes in crankshaft rotational speed and acceleration every time a cylinder fires. The DME can detect if a cylinder is not contributing as much as it should, and if the contribution is below a threshold, the MIL comes on. If the contribution is below another threshold, the fuel injector for that cylinder is deactivated in order to protect the catalytic converter from being damaged by unburned fuel. The cylinder will remain deactivated until the engine is stopped and restarted. If the cylinder is still misfiring, its injector is again deactivated and the MIL stays on. If the cylinder contribution is acceptable, the MIL goes off and the cylinder remains in service.

If you have read this far, you are seeing how OBD II monitoring can be involved in the problem we are discussing. But what can cause a cold-start-only misfire on an otherwise perfectly running Bavarian Work of Engine Art?

A lot of things can, but most if not all of them will also affect the warm running of the engine. You may not perceive a problem with the warm running, but examination of the running data [another OBD II feature] in the DME will usually contain a clue. But that is a topic for a future Philes’ Forum.

A common cause of a cold-start misfire, cylinder deactivation and MIL illumination is a sticking valve or sticking hydraulic lifter. What happens is that an intake or exhaust valve fails to close fully, thereby reducing the compression pressure in that cylinder below what is necessary for ignition. Believe me, a lot of parts have been thrown at this problem, both by individuals and shops. Moreover, the problem is difficult to diagnose because the symptom is sometimes so fleeting.

Depending on the severity of the problem, engine disassembly may be required. However, in many cases, the following procedure has been proven to reduce or eliminate the problem, especially if the symptom has recently presented itself:

  • Put some Marvel Mystery Oil, CRC Valvekleen, or the snake oil of your choice in your crankcase. Some techs use ATF, but I like the CRC stuff. While you are at it, check your oil level. On Bimmers without a dipstick, this is done via the instrument panel. See your owner manual.
  • Warm the engine up by driving slowly and at low RPM.
  • Get on the highway where you can maintain a steady speed for, say, a half-hour. This may be difficult and you may have to do this at night or on a Sunday morning.
  • Select your transmission gear such that the engine is running at about 4000 RPM or so and you are not exceeding the speed limit.
  • After running like this for a half-hour, change the oil and filter while everything is still hot. The idea is not to let the oil cool off.

How to prevent the problem in the first place? I’m glad you asked. Use a high-quality “synthetic” oil of the correct viscosity and change it more frequently than suggested by your on-board maintenance reminder. In selecting your oil, consider using oil right from your BMW dealer. Use an OE-quality oil filter. While used-oil analyses are the only real way to determine the optimal oil-change interval for your particular oil and driving, sometimes it is better simply to put the oil-analysis cost towards an oil change. For some time now, I have been recommending an oil-change interval of, at most, about half of what your maintenance reminder suggests. If you do a lot of short-trip driving, a third of the maintenance-reminder interval may be better.

I hesitate to recommend a particular oil, because seemingly everyone has one that they just know to be the best. But I can tell you that I have had great success for many years with BMW oil, Mobil 1, Lubro-Moly [now Liqui-Moly], and Redline.

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at I’m interested in tech tips, repair / maintenance questions, repair horror stories, emissions-inspection sagas, product evaluations, etc.

© 2016; V.M. Lucariello, P.E.

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