A/C putting strain on engine (2003 Outback)

[Theophilus]

When I inherited a 2003 Outback a few years ago, the A/C system had a leak and wasn't working.  (I don't know how long it hadn't been working before that.  Maybe it had been years.)  Last month, with the summer heat, I finally got around to replacing the high pressure line, the receiver-dryer, the O-rings, and the valves.  Then I pumped out the system and refilled it with coolant.

 

That was more than two weeks ago.  The A/C is still working great and blowing cold, but...

• there's a noticeable strain on the engine when the A/C is on,
• my gas mileage has plunged dramatically, and
• there's often a noticeable smell of gasoline outside the car after it's been running and even if it's been sitting for awhile.

Any thoughts?  Is this normal for a Subaru in hot weather?

 

I'm wondering if I need to adjust the timing or fuel mixture for the engine now that it has the additional strain of turning the compressor.  I'm also wondering if maybe the compressor is faulty in some way and isn't turning as smoothly as it should.  Is there a way to test the compressor and/or check the compressor oil level?

 

Any input welcome! 

[Fairtax4me]

A 2-3 mpg drop is normal with the AC running. An AC compressor can take as much as 20 horsepower to run, so you will notice a difference in power, and fuel mileage.

 

You should not have any smell of fuel with the compressor running. A fuel smell means there is a leak of some sort. It could be a vapor leak from some part of the evaporative emission system. Or it could be a liquid leak from the fuel supply or return hoses that run from the fuel pump to the engine.

After you've had the car running a while and notice the smell, see if you can track down where the smell is coming from on the car (front, back, left, right,). Look for any wet patches under the car. A fuel leak doesn't always leak enough to leave a puddle so you may not find anything wet on the ground.

Its common for the filler tubes to rust out at the bottom and cause a fuel smell. Theres a plastic cover on the tube that catches dirt and water and salt and traps it against the filler tube and causes it to rust. A small pin-hole is all it takes to produce a very strong fuel smell. Remove the cover from the filler tube and check that first.

[Cougar]

You might also check the engine operation using a reader and looking at fuel trim levels and the make sure the coolant temperature sensor for the ECU is operating like it should be. I assume the CEL light isn't on but it does work during the TEST function of the warning lights.

[Theophilus]

Okay, I'm still getting the gasoline smell, so I need to investigate.

 

Remove the cover from the filler tube and check that first.

 

 

Can you elaborate on that?  Do I remove the cover from above, using those screws around the gas cap, or do I need to get under the car and remove it from there?

[Rooster2]

Okay, I'm still getting the gasoline smell, so I need to investigate.

 

 

 

Can you elaborate on that?  Do I remove the cover from above, using those screws around the gas cap, or do I need to get under the car and remove it from there?

Replaced both covers on fuel fill pipe on my Outbacks. You need to get under the car to remove the cover. Also, need to remover the road wheel to get it out of your way.

 

Replacement fill pipes available on line at various auto parts stores. After replacing the fill pipes, I left cover off, didn't see any real need for it.

[Fairtax4me]

Its in the wheel well behind the wheel. Removing the wheel isn't necessary, but helps a bunch to get it out of your way so you have more room to work.

Remember to put the car on jack stands, don't just use a jack to support the car while you are working under it.

Edited July 30, 2016 by Fairtax4me

[Theophilus]

A fuel smell means there is a leak of some sort. It could be a vapor leak from some part of the evaporative emission system. Or it could be a liquid leak from the fuel supply or return hoses that run from the fuel pump to the engine.

After you've had the car running a while and notice the smell, see if you can track down where the smell is coming from on the car (front, back, left, right,). Look for any wet patches under the car. A fuel leak doesn't always leak enough to leave a puddle so you may not find anything wet on the ground.

 

Okay, I've found the leak.  It's on top of the gas tank at the fuel sending unit.  When I lifted up the rear seat and took off the cover on the passenger side, I found a shallow pool of gasoline around the three hose fittings there.  Below the car you can see that the gas has been flowing down the side of the tank and wetting all the bars and hoses underneath.

 

So what now?  I don't see any obvious holes or cracks in the fuel lines or the top of the sending unit.  Is there a good (safe) way to narrow down the leak?

[1 Lucky Texan]

the plasic can crack, the fittings could fail to seal - hard to know.

 

'maybe' one approach would be to dry/clean everything thoroughly. Then, watch the top of the pump carefully while someone cycles the key from OFF to ON, stopping for 4-5 seconds in between. Don't start the car, just key cycle - the ECU should run the pump for a few seconds each time so, you'd get max flow from the pump while watching the suspect area.

[Theophilus]

Okay, getting closer.  I did what Texan recommended and watched for awhile.  The gasoline is leaking from the connection to the fuel supply hose.  The Haynes manual says that if the connector or O-ring is damaged I need to replace the whole fuel line.  But (as far as I can tell) it doesn't explain how to replace that fuel line.

 

Any guidance?  Is the replacement self-explanatory once I start following the existing line?  I have no idea what route the line takes or how much of a hassle this is going to be.

[Fairtax4me]

Do the hoses not have metal clamps on the ends? Usually tightening the clamp will seal up a small leak like that.

 

If it has the plastic hoses, you can often disconnect the hose and make sure the nipple is clean and free of any dirt or rough edges, remove the o-ring from inside the hose with a small pick tool and clean that off as well as you can, then apply some heavy grease to the nipple and pop the hose back on see if that makes it stop leaking.

 

Those o-rings can be replaced as long as you replace them with the same type of material.

[Theophilus]

They aren't the usual sort of metal hose clamps.  These are plastic and they are described in the Haynes manual as "two-tab type quick-connect fittings."

 

I'm not having much luck finding the right replacement parts.

[Fairtax4me]

To replace the entire hose I'm pretty sure you have to remove the tank from the car, which is a major pain on a Subaru.

 

That's going to be a dealer only item, or get a used one from a u-pull-it yard, or maybe find someone parting out a car from that year range. Not really worth the hassle IMO.

 

If cleaning it up and putting the grease on it doesn't fix it, get the o-ring out of the hose and see if you can find/order one online somewhere.

I would go so far as to RTV it before attempting to replace the whole hose.

[1 Lucky Texan]

maybe there'd be a way to 'bypass' the original style connection? cutting the connector off and using some short hardline, short hose and 3 screw clamps? Camp the hardline in where the old connector was cut off, thene new hose, then the new hose to the pumps nipple?

 

I don't remember what that all looked like, I had our 03 OBW's pump out once for inspection - might not be a way to clamp onto the pump's plastic fitting.