Recalcitrant Volvo

starting
engines
batteries

#1

We have a 97 Volvo 960-170,000 mi.-it keeps not starting when left to sit for more than a day (or if it is raining) We put in a new battery, and when it doesnt start, if we jump it, it starts immediately and runs with no problem. It is an air cooled engine, and the fan runs for a long time after the car has been turned off, in fact, it comes on and runs arbitrarily at various times when the car has not been driven. My theory is that there is something wrong with the fan, or the thermostat that controls the fan, that causes it to run even when the engine is not running, and runs the battery down. Or something is getting wet, and that causes the batttery to die. The mechanic is not buying either theory…do you have other ideas?


#2

This could be a symptom of corrosion at the body ground point of the battery negative cable. A jumpstart would effectively bypass such a problem because the helper battery is grounded directly to the engine and not through the battery negative cable.

The fan is thermostatically controlled and will run for a time after the car is turned off, and may restart if needed. If this is all that is happening, it is normal.


#3

What makes you think your engine is air cooled? Unless I missed this one your engine is water cooled,uses a radiator and electric fans.It is normal for the fans to run for a period after engine shut off,notice I said “a period” they should not run for ever.Excuse me if your vehicle truly fits the description of “air cooled”.

Has you mechanic performed a charging system test,complete with battery load test and parasitic draw test?


#4

Would the corrosion cause the battery to actually run down, or is it just not starting because it is not completing the circuit? If that is the case, the battery should have a charge if it is checked? it did, when we checked it. Is the body ground point of the battery neg cable something I can check? Could it get wet or damp and more likely to happen?
Also curious to know-what would make the fan need to restart if it cooled the engine to a certain temp? would it do so even in very cold weather?
Thanks for your response-surely makes sense since the battery was charged.


#5

Volvo has never marketed a car with an air-cooled engine. Can you imagine trying to get the interior of the car heated in the winter–in Sweden–with a car that has an air-cooled engine?

That being said, it does sound as if there is a problem with the temperature sensor that activates the fan that cools the radiator. There could be other problems as well that cause a parasitic drain on the battery, but replacing the temperature sensor should be the first course of action.


#6

Ah, you are correct, that the engine is water cooled with a radiator. The fan does not run all the time, but it seems to run more than it should-is it thermostatically controlled? The mechanic has performed a charging system test, but I am not sure about the load test and draw test. Thanks for your input.


#7

As you might guess…I am sort of mechanically challenged, but still willing to learn! didnt think about the heat issue-just the fan, air…well, you get the gist…Thanks for the reply.


#8

A bad connection would not cause the battery to run down but it would inhibit starting. The ground point should not be difficult to find. Likely either the negative cable goes to the battery tray and then to a ground point on the body, or the cable goes directly to the body. If there is high resistance in the ground connection, water, by creating additional ground paths (to distant points unknown), would reduce voltage even further.

The fan is thermostatically controlled:

http://www.jcwhitney.com/ENGINE-COOLING-THERMOSTAT-SWITCHES/GP_2000903_N_111+1997+200729327+600001645_10101.jcw