On my new to me '91 245 I had a bad heater control valve. I either had full A/C or full heat or a bypass position which allowed outside air. After fixing this I now have variable air or heat which is good however I don't have a vent only choice. With A/C off and the control level all the way left I get a little bit of heat blowing through or a fair amount of heat when loading the engine up-hill or accelerating. Is this normal or did the dealer overlook something?
thanx guys .... and ladies

Here's an update .... the valve was replaced but the shop didn't adjust it quite right. Re-adjusted cable by removing set cable clamp and using a wire tie to allow further extension of cable to close the valve all the way. Now no heat ciculates through the cabin with the lever all the way to the left.

What is normal is that the factory set up that slide valve to allow a little coolant to flow through the heater even when closed off. That way the coolant in the heater core will not just sit in there and possibly corrode the tubing.

However - you pay for that protectin with is hot air when you don't want any at all. So most valves can be adjusted to remove that factory setup. Once done, it may seem like a vast improvement in the a/c system! BUT - you must remember to open the heat about once a month. Do it when you start up in the morning, before the coolant heats up.

Remove the kick panel on the left side of the central control panel - a screw on the upper rear corner and a 1/4-turn plastic hold-down on the lower rear corner (note that "front" would be toward the firewall).

It helps to use a flashlight and look at the upper front corner of that panel to see how it is held to the firewall by a clip-in bracket. PITA to get back in correctly.

Watch the valve while you move the slide control. When it is in the fully closed position, loosen the cable clamp a little and move the slide control a little to the hot side. Tighten the clamp and push the control fully "Cold". the cable may even bulge to the side a bit, but the valve will be closed tightly.

If your heater control gets you air that is either 'way hot or 'way cold, never just warm, it's that valve that has failed. Repairing means replacing, and that's another story. Not today.

What do you mean by vent only choice...? Do you mean the recirculating push button?

If that doesn't work, it's a rather large job to fix - again another story on another day.

Good Luck,

Bob

:>)

What do you mean by vent only choice...? Do you mean the recirculating push button?

Previous to the dealer replacing the valve the lever would lock into a leftmost position where only outside air passed through. From your post I think the PO must have performed this cable adjustment .. with a bad heater control valve. I might get in there and adjust it again now that the valve is replaced.

Hi Jac -

(Don't use that greeting in an airport!)

The sliding cold-to-hot lever modifies temp by modifying the abount of hot engine coolant that flows through the heater core, not by modifying the amount of non-heated air. Now - that is all based on my experience with 240s up to the 1988 model. Your newer model may be different.

Slide in the leftmost position means the heater core should be getting NO engine coolant at all.

Inside the airbox, the air can come in through the grille in front of the windshield or, in recirculating mode, through intakes on either side of the central control panel. All 100% of the air goes first through the a/c evaporator and then through the heater core and thence to the varioius outlet vents.

Other cars, maybe even Volvo models, use the blended air method of varying the temp of the cabin air. The 240s use varying amounts of hot coolant.

I hope you can see how your expectation of getting only outside air should be an option is not understood by me. Whether or not the air is from outside or recirculated is controlled by the rightmost push button, or should be.


Good Luck with your project,

Bob

:>)