1995 Volvo 940 Heater blows cold.

PPP

MEMBER
1995 VOLVO 940
4 CYL
2WD
AUTOMATIC
200,000 MILES

Replaced the water pump summer of 2007. Every few months since, the coolant needs to be topped up.

Don't seem to be leaking coolant, or anything other than the trademark turbo Volvo oil leak.

End of this summer (a couple months ago) the auxiliary fan died. Haven't fixed it yet since the weather immediately got really cold.

So on to the current problem. Yesterday the heater blew hot. Today it blows cold. What could this be? It's a cold day - but so was yesterday. Engine temp seemed to climb as well, not high but definitely well above dead-center.

Ideas? I bring up the coolant situation because. Could it be an air bubble in the heater core? I haven't checked the coolant in a couple months.

3 Replies

JAMES W.

MECHANIC
2,395 POSTS

Usually, the first thing to cause a no heat condition is low coolant. If coolant is full, look for an air bleeder screw in the area of the thermostat housing or anywhere along the heater core return line. Sometimes there are two in different places.

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Saturday, November 22nd, 2008 AT 4:30 PM

PPP

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2 POSTS

Thanks. The heat worked today, which leads me to think it's TOTALLY this problem. This is supposed to be a self-bleeding system, but clearly it isn't working 100% at that. Also it's entirely possible I have a minor seal crack that is causing coolant to get where it shouldn't in very small quantities. The car is definitely due for new seals!

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Sunday, November 23rd, 2008 AT 8:25 PM

JAMES W.