Yet another AC cold driver/warm middle/hot right thread

[Rockmelon]

Originally Posted by tdgard

I have not looked at the E53 setup-but on my old E34 I cobbled those hoses together with fittings before they went into the regulator. This kept the coolant flowing but bypassed the heater core (which had blown out). You also need to disconnect any wires running to the valves.

thanks. this is what i was thinking about. in a place where there is not enough cool air, why bother to replace the heater core.

[m5james]

Originally Posted by Rockmelon

James, can this heater valve be bypassed to always get cold air? my winter here has higher temperatures than summer elsewhere.

I don't see why not, you'd just have to know the directions of flow for the T connectors to make sure you dont have any issues. I'm in Seattle now and don't have access to any of my stuff, but I'm sure Weasel or Killcrap have documents showing flow pattern/direction somewhere.

[Weasel]

Hell, why even deal with the hoses at the valves? Just disconnect both from the heater core and hook them together with a 90 degree elbow or something.

[Rockmelon]

good good

[haigha]

As an update to the thread I put on 1,500 miles on my trip and my AC worked great after the re-charge. So if you experience the problem in the thread title, having the refrigerant level checked should be your first course of action since it is the least expensive potential fix.

I stated that my mechanic checked the level in April but it was not hot enough to tell there was a problem then.

[Rockmelon]

same here. still enjoying good cold air after topping it up a few weeks back despite temp exceeding 104 almost daily. lets hope it stays this way.

[tdgard]

Originally Posted by Weasel

Hell, why even deal with the hoses at the valves? Just disconnect both from the heater core and hook them together with a 90 degree elbow or something.

That's the line of thinking I was refering to--just that on the 5 series it was accomplished easiest where the hoses went into the heater control valves at the firewall. The only reason I brought them up is if you stop the coolant from flowing through them, it would be wise to disconnect their power so they dont keep actuating without lubricant.

[Weasel]

That's all fair and good, but that still isn't likely the issue with these AC concerns... 90% of the time I get this cold/warm/hot vents complaint it is due to low refrigerant charge. If it were the heater valves sticking etc. causing the heater to be stuck on the AC would still blow cold first thing in the morning before the heater warms up. I'd suggest to try that before even dealing with your heater hoses.

[Rockmelon]

this will depend on whether the compressor can cool faster or the heater can warm up faster on cold start but i suspect the heater will take a longer time to heat up based on the engine warm up time of a few minutes. of course, that's assuming the cultprit is the heater valve.

[Weasel]

I know it only takes half a block before my ac blows cold, but over half a mile before the heater warms up. Easy to check in the morning when you first start it. Either way, reading running pressures will indicate the problem.