98 V70 secondary air pump On and Off shortly after startup..

mr_chase · Post by **mr_chase** » 15 Feb 2008, 11:35

It's early morning, still dark, cold out: I start my 98 V70R (122K) and I can see the headlights get dimmer, then come on strong, then dimmer again, until I drive off. I also hear the rad. fan come on and off. This seems to be in tandem with the radiator fan comes on shortly after startup almost every time even when the car is cold... is this normal? I understand that the lights are dimming in reaction to the generator, but why the on and off of the rad fan?

Is this a thermostat issue, etc.? Coolant level is almost always to -MAX-, but seems to have less since topping it off after the heater core change.

Post by **MadeInJapan** » 15 Feb 2008, 14:32

I think it's a temperature issue but not in the way that you might think. How is your temperature sensor (for your coolant)? If it is bad it will kick the fan on. Is the gauge on your dash at 3:00 after your car warms up?

mr_chase · Post by **mr_chase** » 15 Feb 2008, 14:35

The temp gauge climbs as it warms up and rests at the 3 o'clock position.

Post by **MadeInJapan** » 15 Feb 2008, 14:58

Since you're in Canada, I assume that it's really cold. If not your temp. sensor, then maybe your thermostat. The only reason it's staying at 3:00 is because your fan is coming on so much. Just a hunch but I'd bet that if you have a warm day or two you'd see your temp gauge clime beyond 3.

mr_chase · Post by **mr_chase** » 15 Feb 2008, 15:07

Thanks, I will check the thermostat, and get back to the forum.

But where is the coolant temp. sensor located? -- I can't seem to find it listed in FCP or my VADIS, et al.?

Post by **MadeInJapan** » 15 Feb 2008, 15:11

Right under the thermostat...comes out the bottom of the thermostat housing, is brass colored, has threads and 2 wires coming out of it.

mr_chase · Post by **mr_chase** » 16 Feb 2008, 07:26

Grrrr...I got in the car this morning, and nothing -- no power anywhere: no power locks, no digital clock... Alternator? Might explain the fading lights and rad fan, and drain on the battery?

Had to borrow my brother's S60 to get to work!

I will diagnose and get back to the forum...

mr_chase · Post by **mr_chase** » 17 Feb 2008, 12:55

I charged the battery, and started the car to do an alternator test, with and without load. The Voltmeter indicated the correct increase (according to Chilton's) of Volts of approx. 0.75 - 1 Volts with and without load. When I started the car, a fan or motor started up -- not the radiator fan -- this is the fan that I heard before the car's battery went dead, and what was causing the headlights to dim. It sounds like it's coming from underneath or near the air filter box...

What is this fan? Is it the intercooler fan? And why would it be coming on at start-up?

Help!

Post by **MadeInJapan** » 17 Feb 2008, 13:12

I believe you're talking about the secondary air pump....it is under the battery. It helps pull exhaust out of the system- an emissions control device on some late model 850's and early 70 series Volvo's. It's suppose to come on when you first start your car and I've read from some that it comes on when you stop at stop lights too, especially if the air/gas mixture needs to be leaned out.

The secondary air pump can be a weak spot in the electrical system and many have had to replace this as well as what's called the SAS valve (up near the fire wall- it looks like a brass mushroom with a small hose attached to it) that feeds the air pump and the cause of the air pump wearing out. If it is excessively loud, its bearings could be going bad, pulling extra amps when it comes on and dimming your lights. It would be worth investigating. There is a write-up about it in the repair database.

Good luck.

mr_chase · Post by **mr_chase** » 17 Feb 2008, 13:17

You know, I think that sounds right, considering that I have had poor gas mileage, and I had an emission fault code indicated on the OBDII after the check engine light came on.

I will check the air pump, etc. and get back to the forum.

Thanks!