Hi guys

My mechanic tells me that my secondary air pump could be on the way out and I have a hissing sound coming from around the area of the coolant tank. I am wondering if it is just a ruptured vac line or if it is the pump.

If it is the pump how easy is it to change? and where is the pump located? and is their a DIY out there?
Thanks
James

 

I think it may be a vacuum line. On my 2.8 there is a vacuum diagram sticker on the underside of the hood. Check to see if you have one. If you have a hissing noise coming from underside of the coolant reservoir, it maybe that you have a leak from a line that is going into the bank 2 combi valve. I had one just like that.

As for the secondary air pump, it should be located below the air box. (At least that is where mine is on 2.8) Removal is pretty straigt forward. No special knowledge required. There is a plastic pipe coming from the front of bank 1. It goes into the secondary air pump. Then there is another line going from the pump to the air box. Just disconnect the piping and one additional electrical connector. Then that is it.

 

I don't know how common it is for the actual pump needing to be replaced, you might as well just change all the vac lines, clear any cel and see if it goes away. Also check out the crank breather hoses

 

The pump will sound like a vacuum cleaner or have a very high pitches whine if the bearings in the pump are going bad. If you just hear air escaping when the pump is on then its most likely an SAP line or a vacuum line to the combi valves on the back of the cylinder heads. The SAP pump is commonly on the driver's side under the car, directly under the airbox. Take the belly pan off and you can see the pump, its really big. One of the lines will come off the pump and go directly to the airbox, there is where it draws its air from, it then supplies air to the exhaust VIA the combi valves in order to heat up the cat converters upon cold start. Thats all it really does, so if you really do need the $300 SAP pump it isn't a necessity until your next SMOG check is due, because it will cause a check engine light.

 

Sorry to bring this back from the dead but do you think its easier to access the pump from the top or bottom. I am going to replace mine tomorrow, I havent looked at it yet but I am just wondering if I should invest in a set of ramps or it would be unnecessary.

 

You can only get at it from the bottom, just take off the belly pan (skid plate) and its right there on the passenger's side under the airbox.

 

Excellent, thank you for the reply.

 

I had a mechanic tell me that my SAP was making a hissing noise, wehn I got home I found the vac check valve was actually making the sound, the mechanic tried to silicone it back together, I have also had a failed SAP, Vacuum cleaner is the best way to describe that sound, not a hiss.