iXchange Issue #20

September 1998

A newsletter for BMW 325 iX Enthusiasts.


Air Conditioning Tuneup 1
The Ultimate AWD Road Car 2
Transfer Case Chain Sources 3
Ferodo Pads 3
Tips & Tidbits 4


Air Conditioning Tuneup

by Gordon

This is one of those stories with a happy ending, but without an absolute conclusion and an identification of the guilty party. The air conditioning in Bev's '89 iX was functioning and providing cool air, but it had lost some of its punch. On those really hot days this summer we never had an overheating problem with the engine temperature, but It seemed like the AC was marginal. The system would start up OK and initially provide plenty of cool air, but after it ran for a while, the amount of cooling seemed to decrease. We had a trip to Utah planned for early August with Bev's parents and we wanted to be sure that the AC was functioning properly--particularly before setting off for cloudless skies and 100 degree temperatures with 4 adults and a dog in the old faithful iX! We needed a 4-door car for this trip and really did not want to squeeze into the 2-door M3 or rent a car.

I ran some driveway tests and found that after the car got warmed up, the AC compressor would not stay on for a sufficient length of time to create enough cold. In addition, there were some bubbles visible in the sight glass of the receiver/drier (located in the engine compartment behind the right headlight cluster) which is an indication of a loss of Freon. When I cleaned the sight glass with a bit of water and a Q-tip I also noticed an occasional small bubble forming around the edge of the sight glass between the sight glass and the body of the receiver/dryer, indicating a very slow Freon leak. I tightened the sight glass with an Allen wrench and added about half a can of Freon R12, using a can from the supply I had bought several years ago when it was still available from the local auto parts house.

The bubbles in the Freon in the sight glass were gone and there was no evidence of the Freon leak around the sight glass. At times the system seemed to function just fine and the temperature of the air coming from the vents would be in the low 40-44 degree Fahrenheit range which is normal for a R12 system. But occasionally the compressor would not stay on for more than a few seconds until it cut off. When this occurred, the system performance was marginal and the vent air temperature would not drop below 50 degrees. The system was improved, but still not right.

The BMW Electrical Troubleshooting Manual (ETM) provides a good description of how the AC system works. There is a high and low pressure sensor on the receiver/dryer; if the pressure in the system exceeds 385psi, voltage to the compressor clutch is removed. Then every 10 seconds or so, the clutch is engaged and the pressure is tested again. This cycling continues until the pressure falls to safe levels. It appeared like the pressure in the system was too high--perhaps I had added too much Freon.

I decided to get some professional help so I turned to Cal Parker at BimmerWerks (303.460.9900) in Broomfield, Colorado. Cal was somewhat familiar with this behavior and actually had 2 other E30s in the shop with similar symptoms. (I later found that some other BMW models from the late '80's and early '90's have developed similar problems.) Cal agreed to troubleshoot our '89 iX and try to figure out what was really happening.

Cal checked the pressure and it appeared to be within spec. This indicated that the compressor was fully capable of doing its job and that the amount of Freon in the system was OK. Nonetheless, the compressor was still cycling excessively after the system had operated for a while. Then Cal found that the 6 ohm resistor (called the "Auxiliary Fan Normal Speed Blower Resistor" in the ETM) had failed as an open circuit. This caused the electric auxiliary cooling fan in front of the radiator to NOT run at low speed when the air conditioning switch is depressed. Cal tried to simply bypass the resistor, reasoning that the extra air flowing through the air conditioning condenser (radiator) would provide added capacity. But the noise from the fan running at high speed was excessive and he simply replaced the resistor which is located behind the grill, on the aux. fan housing. Replacing this resistor so that the aux. fan ran when the AC was on made a big improvement, but the compressor still would not stay on for any length of time.

Cal dug a little deeper and reasoned that there may be excessive pressure in the system at times, perhaps due to contamination and blockage in the lines. So he replaced the receiver/drier and the expansion valve in the passenger compartment. This made a slight improvement, but in retrospect, replacement of these two items was probably not necessary (but I believe that it helped somewhat and it solved the Freon leak problem.)

Finally, Cal actually removed some of the Freon, so that the system was filled with the specified minimum amount. This resulted in some bubbles showing up in the sight glass, but the compressor no longer cycled on and off excessively. Cal thought the system was performing pretty well so I took the car back and we drove it for a few days to check it out.

Great news! The vent air was solidly in the low 40 degree F. range and there was plenty of cooling capacity at all times. We took our 2000 mile trip to Utah and never wanted for more cool air, even in 107 degree temps in the desert areas. In fact, the iX never missed a beat and ran beautifully--even through the 7 miles of mud in the cone zone on the entry road to the north rim of the Grand Canyon.

As I mentioned in the introduction to this article, we have a happy ending, but I really cannot identify one particular item that actually "fixed" the problem. If you have similar symptoms and the compressor seems to be OK, I'd first check the aux. fan resistor, then make sure that the system is not overcharged, then replace the receiver/drier, then the evaporator. If these do not fix the problem, then I'd consider a replacement of the compressor. Or, of course you could always just park the iX during the hot summer, keep the snow tires on and anxiously await the first sign of snow. Weather or not!


The Ultimate AWD Road Car --

A Start

Malcolm Morgan of Sausalito, CA provides an update on the buildup of the "ultimate AWD road car"... After months of carefully studying every catalog, brochure, and magazine I could get my hands on, I was just beginning to put the suspension package together, when I suffered a most unpleasant setback. I had just installed a new set of Brembo cross-drilled rotors, new stainless steel lines, pads, and super blue fluid; prior to attending the Golden Gate Chapter safety school, which was a great experience... more on that later... I took the car out one evening, and left it parked in the parking lot of a Grand Auto store while I shopped downtown. Unfortunately, while I was away, someone or some group decided to vent their feelings about foreign cars in the USA.

The car was badly scratched with logos from the big three US auto makers, and the BMW logo was scratched out, along with some derogatory remarks about BMW owners. They got every side, even the roof. The damage was strictly cosmetic, but went way below the skin in terms of personal pride and faith in humankind... Anyway, the car is now in the process of a complete repaint; I swallowed hard and agreed to pay the extra to repaint the (few) areas that were not covered by the insurance claim.

I finally settled on a color change and a new design that I worked out with the experts at Eurocal auto body in Santa Rosa, CA. The are trying to get the car finished in time to make the BMW corral at the Montery Historic Races at Laguna Seca Raceway in August. This was an unfortunate setback in the project, as some of the money I had set aside for the performance upgrade is now going to the new color scheme. Oh well, there is always next year...

When we finally get the car back, I will be going ahead with the suspension kit that I have put together from Korman, Ireland Engineering, and BMP. I will keep you all appraised as I go along, and look forward to meeting any of you at the Historics. Happy Motoring from Malcolm and Julie Morgan.


Transfer Case Chain Source --

NOTE NEW UPDATE: Xfer Case Chain Source

From: "Jack Colburn"

I have ended my search for a transfer case chain -- a company out of Norfolk VA called ATC Distribution Group (1-800-622-6997) were the only people willing to help for a price of $138.13 plus s/h. The vendor Tanstar (see below) only sells to company's not to individuals. So I have the chain in hand and am feeling a little better.

Ron Rinehart of West Hollywood, CA writes:

My iX is at BMW Performance Specialists in Thousand Oaks now, and the mechanic has removed the transfer case and sent it to his transmission shop. It will apparently need a new chain (part no. 1-2724 1226 319 OR 1-2724 1227 036) and perhaps pulley, so could somebody help with prices on these items that might be better than the $339 that the dealership charges for the chain at the shop rate? Also, the gasket kit (1-2711 1224 677) will be needed, and the seals (1-2721 1224 636; 1-2620 1226 104; 2-2711 1226 814).

Please let me know where I might get these inexpensively as the transmission shop is going to charge $295 to rebuild the transfer case and I need to keep cost down as much as possible on parts. So far I am looking at $390 to BMW Performance to remove the transfer case and reinstall it.

Ed note: I suggested Ron contact Bekkers 800.624.5410 or Eurasion Parts Select at 800.824.8814. All in all, the prices that Ron quotes seem pretty reasonable to me.


Ferodo Pads --

by Gordon

I've been using Ferodo brake pads on my '88 and '89 iXes for several years and have been very pleased with their performance, particularly for on-track use while instructing at our Rocky Mountain Chapter driving schools. Occasionally when stopping at a stop light or stop sign on the street there is a slight metal-to-metal squeal from the pads, but I've never had any problem with fade on the track under very severe conditions. I have been disappointed with factory pads and with Metalmasters on the track. (However the stock factory pads on the M3 are fantastic.) You can order Ferodo pads from Performance Automotive in Connecticutt.

Front Pads: FDB303A
Rear Pads: FDB296.
Also, see my brake info page for some helpful comparisons.



Jack E Kleiner of Morrisville, PA advises:

Here is a tip: Add some baking soda to your regular car washing water and you will find that dried bugs come off easily!  I found the tip in my owners manual and tried it.


Ken Warnock of Essex, Massachusetts
After reading the latest issue (#19), Ken Warnock of Essex, Massachusetts had a few comments that might save people some time-

1. Concerning the article on drivetrain rebuilding - I think that the extra, "unused" female spline length in the transfer case front output shaft is intentional. Based on what I remember, it appears that this extra length lets the front driveshaft be pulled back into the transfer case, allowing the front guibo to be disconnected and removed. This allows differential work and tasks such as re-sealing the Xfer case front output shaft seal to be completed without removing the transfer case, rear drive shaft, etc. as would have been the case during a complete driveline rebuild. Maybe more area for torque is possible, but keeping the joint clean and properly lubed should give plenty of longevity with a stock engine.

Editor's note:
Front driveshaft spline failure due to lack of lubrication is very uncommon, but several owners of '88 iXes have reported this problem (I checked my '88 and the shaft lubrication was just fine.) If you are concerned about this, I'd recommend that you check that the front shaft is liberally lubricated. If it has become somewhat dry, add some name-brand molybdenum wheel bearing grease. If the splines are worn, it appears that there is sufficient clearance to allow the shaft to be extended by a half inch or so. If you would like to try to extend the driveshaft rather than replace it, measure the clearance and then have a good machine shop weld in an extension which allows more contact between the splines and the teeth on the gear, but which still allows the shaft to be installed and removed.

2. Regarding re-sealing the oil cooler thermostat housing - I carried this out easily a while back without removing the front oil cooler lines from the thermostat housing (I hesitate to disconnect more than necessary, especially pipe fittings on light aluminum tubing). If I remember right, there was enough flex in the rubber hoses between the thermostat housing and the cooler to allow the center bolt in the housing to be removed, and then the whole thermostat housing swung upward into the engine compartment to be re-sealed. Also, because the hose connections aren't disturbed relative to the block, re-assembly of the tstat housing to the engine block is simplified, as the hoses tend to "hold" the housing in its original position. Saves time, money, and the chance to wreck your oil cooler fittings.

3. A handy item for those looking to add trouble lights or engine compartment lights , especially on our aging fleet of iXes- GM makes a great little trouble light assembly that mounts under the hood of their large pickups. This consists of a 2"X2" 12V lamp with magnetic base, on a reel with 18-20' of retractable cord. I've mounted one in my wife's 1994 iC under the hood, and it's very handy. One drawback- we can't use it in the iC to play Starsky and Hutch, since the magnet base keeps falling off the "roof" whenever I accelerate. Time for one on the iX, I think.

The GM part number for this is 12341801, listing for $20.60. This includes the lamp and reel assembly (about 2"X4"X6") with an on/off switch, a 2-wire wiring harness with fuse, and 3 sheet metal screws to attach it where you please.



Don't forget the following:

Change brake fluid every 2 years.

Add some Anti-Rust/Water Pump lube to your coolant every season unless you change the coolant.

Check that transfer case fluid (ATF)

iX in the Snow Thanks to Richard Poole of Caledon East, Ontario, Canada who whets our appetite for iXperiences to come. Anticipation!