S40 - 2001 Heater Issue

scubajimatl · Post by **scubajimatl** » 22 Nov 2010, 18:06

I've read over as many of the forums and postings as I can, and it seems my problem is falling between the cracks...

The a/c unit blows cold no matter what. I've checked for the ECC and I don't think that is an option on mine (no blinking on light), I've checked the blower, it works great; I've checked the damper motor/actuator and it moves back and forth as I raise and lower the temp control. So I think I'm left with the heater unit itself not working for some reason.

I'm a bit lost as to how to check the two pipes through the fire wall - a few links are broken, perhaps very old. I think this is what I need to do next, but any pointers out there?

Is the coolant/antifreeze the same for the entire system - car radiator as well as the heater unit under the dash?

Thanks all!

Jim

scubajimatl · Post by **scubajimatl** » 22 Nov 2010, 19:05

Well I pondered over this for 24 hours before my first post - so either I've just gotten amazingly lucky, or I now have an intermittent problem.

Continuing to read over the forums and look at my system, I found that the coolant/antifreeze level was just a tad low... It took about two or three cups. Even though the system ran find yesterday with no hot signals (engine temp indicator right around 3:00), that appear could have been the issue. I've gotten heat out of the system for the first time in 36 hours (perhaps since last winter however).

Does this make sense - can an antifreeze level being a little low effect the antifreeze getting to the interior heating block?

Thanks all!

Jim

Post by **billofdurham** » 23 Nov 2010, 12:09

Welcome to Matthew's Volvo Site.

It's great when members sort out their own problems, it means we can sit back and relax.

To answer your questions:
1. The coolant in the radiator/engine does circulate to the heater.
2. There may have been an air pocket in the heater core or a heater hose interfering with the flow of coolant through the heater core. If this were the case the air pocket may have moved on and the coolant level would drop. Keep an eye on the level as there may still be a little air in the system.

One way to tell if the coolant is circulating through the heater core is to feel both heater hoses. Both the inlet and outlet hoses should feel hot when the engine is at normal operating temperature and the heater is on. The outlet hose may feel slightly cooler as some of the heat will have been drawn off. You would probably need a thermometer to tell the difference.

Bill.