The temperature is getting to be around 70 degree regularly in Dallas, TX!

Engine Heat is causing me to turn the AC on/ let down the window for some air.

My engine is not overheating/temp. normal. I know a V8 can put out some heat w/ the Fan Clutch blowing, but what??

I appreciate the Schooling!

840way to C

I recently replaced both batteries, Duralast - new, a few weeks ago!

I never saw a "Tran Fail-Safe Prog" OBC message!

Should I perform the E31Faq.com - Coast Down Procedure!

I am not for sure how long my driver's side battery was not charged/holding a charge!

Again, more Schooling is most appreciated!

840ways to C

The temperature is getting to be around 70 degree regularly in Dallas, TX!

Engine Heat is causing me to turn the AC on/ let down the window for some air.

My engine is not overheating/temp. normal. I know a V8 can put out some heat w/ the Fan Clutch blowing, but what??

I appreciate the Schooling!

840way to C

This is a common problem for E31 and E32 cars caused by the failed heater solinoids. Read on:

Symptoms:

* Uncontrolled high heat out of the driver side (particularly the side window vent and floor); and
* A periodic gurgling sound emanating from the heater core area behind the console.
* Able to shut down the heat by having the climate control system operate in recirculate mode.

Tools needed:

An easy job for 1/4" tool set and a long extension to access the two 10 mm bolts that hold the fresh air intake hood to the firewall.

* 13 mm socket
* 10 mm socket
* 8 mm socket
* 6 mm socket
* #2 Philips screw driver
* An old large flat bladed brake adjuster to remove the plastic cap over the valve assembly.

Procedure:

Turn the windshield wipers on and turn off the key while the wipers are in the vertical position.

Remove the fresh air intake duct to extricate the valve assembly.
Remove the rubber engine hood sealing gasket
Remove the three 10mm and one plastic 9mm bolts that secure the intake cover. While at it you may want to replace the two microfilters that are now visible (careful how you install them as they are directional).
Remove two 8 mm bolts on either side of the intake duct using a 6" extension and lift out the duct. It has a tab in the middle for positioning and additional stability. Very simple to do.

Disconnect the two electrical connectors (one on the firewall with 2 wires for the auxiliary pump and one on the back of the solenoid body with three pins for the valves). Also detach the clip on the firewall that holds the auxiliary pump electrical connector. It is fragile and easily broken so be careful (as far as I know, no one has identified the part number for this one). Now you can access and remove the valve assembly.

If you have not already done so, remove the plastic cap over the valve assembly held in place by 3 metal clips. Careful, it breaks easily but is not costly. Spray some WD-40 underneath and then pry it up carefully with a brake adjuster. That exposes the three 13 mm round head nuts that the plastic cap clips onto.
Remove the three 13mm nuts and the three hoses that lead from the car to the valve/pump assembly. The unit is now free. One additional hose leads from the pump to the valve assembly. You needn't remove that one now.
At your bench remove the remaining hose (noting its orientation) and remove the strap that holds the pump to the solenoid assembly.
You can now see the impeller inside the pump housing. Turn it with a pencil and test it with a 12 volt DC power supply. If it has seized up remove the four screws and carefully separate the motor from the pump housing (there is a large O-ring to keep the unit from leaking). There is also a small stainless steel washer between the impeller and the black plastic part of the housing. This is a magnetic driven impeller, a nice little design and easy to clean out but prone to fail if there are metallic impurities in the circulating coolant water.
Remove the six screws that hold the solenoid valve assembly together. Past posts have described the 4 parts of this assembly: i) plastic cage, ii) solenoid assembly, iii) plate, and iv) valve assembly.
Using a sharp knife, separate the valve body with the 3 hose connections from the plate sandwiched against it and inspect the interior of the two valves. Apparently there are several designs of the valve assembly itself. Most of the time the diaphragm on the driver side will be mostly missing, allowing hot water to pass through the heater core at all times. Replace the valve (Part Number 64 11 8 391 417) and reassembled the valve/pump assembly. If you need to wait a few days for the part(s) you can plug the three hoses with wine corks (a nice Montrachet fits well) and clamps. Very little coolant is lost in the repair process and you can top it off while cold to the proper level. Then Park the car on an Incline nose up.

Cost:

About $140 for the solenoid valve assembly and a couple of $$ for each of the vibration dampers that the solenoid is mounted. Total bill should be under $150.

Since you are doing this it is a good idea to replace the plastic hose connections. They can be brittle due to time and engine heat but it would be an easy fix for an additional $120 (Part Number 64 11 8 390 090).

Hope this help.

If you are not willing to do this on your own you can take it to your local mechanic and get it done. Should not be more than an Hour's labor.